Related
Hi there!
Does anyone know of a way to operate the Universal solely on A/C power when there is no battery inserted?
I often use my universal as a WLAN media player in the kitchen. It just sits there for hours playing music and I would like to remove the battery from it during this time to extend overall battery life.
Unfortunately the device does not turn on when there is no battery inserted.
This should be fairly easy, if I understood well, you don't want to let the battery in the universal (even if normally the battery chargers apply a tickle current charge when the batteries are already charged to mantain it fully charged), so you just need to connect your power supply directly to the uni's battery contacts -BEWARE the power supply MUST be 3.7V REGULATED / 1A minimum current-.
Personally, I do not like to change the way the objects are, so I would try to keep it like this in this case, this means, no extra holes in my PDA, no extra connectors, etc. so you need a pair of mini alligators clips or miniclips to connect your unit to the power supply, be sure to verify the correct polarity, it's clearly written in the battery's contacts.
Alternatively, there should be a way of doing this by using the uni's own battery charger through it's own mini USB connector, it's necessary to cheat the PDA and let him "think" he's got the battery inserted, this should be fairly easy to do also, but I'm out of my work, so I could provide a complete solution like this until late april.
bye
downloadtest82 said:
Unfortunately the device does not turn on when there is no battery inserted.
Click to expand...
Click to collapse
Why don't you use an old battery?
I use this way in this particolar circumstances!
Why don't you use an old battery?
Click to expand...
Click to collapse
That's what I used to do, unfortunately the old battery I have is so worn down by now it won't even support the boot process any more, and the A/C power regulator kicks in only after basic I/O drivers are loaded on the device.
Since the old battery dies before this process completes I can't use that any more.
I don't believe the Universal's "battery detection circuits" are all that complex, in most modern electronic devices they can be fooled by simply bridging some of the connectors in the battery bay.
I don't know if this is true for this device also, however. So I was wondering if anyone else ever tried before I toast my PDA...
downloadtest82 said:
Since the old battery dies before this process completes I can't use that any more.
Click to expand...
Click to collapse
Oh.. I understand.. Sorry..
Well: be careful if you try to solve in other way..
Ok guys, so nuclear war stroke the planet, your brand new tv and pc got busted in the initial attack and you're left with your precious HD2 running some custom rom and about 16-32gb of storage. Hope you don't get borred, there won't be many apps on marketplace, or even a marketplace (servers got busted by the nuke )
Now to get more seriously i can't figure out why i would need a phone able to be powered on 24/24. But i guess at least it could be useful on camping trips or stuff like this.
This is the start of a project, are goals are something like this:
1. reverse engineer the charge algorithm used by HD2 (in involves at least 2 charging modes each with 2 stages, as i know so far)
2. assemble or buy a 5-10W solar panel (only the panel and a Schottky type fast diode)
3. get myself some old laptop batteries and strip them down for cells and controllers.
4. design and assemble a cell pack as a buffer between the solar panel and phone
5. design a switching mode voltage stabilizer and make a custom usb hub in order to also have usb host functionality if i feel geeky and need linux
6. design a charge controller for the cell pack when using solar power.
7. put all things together and test
The goal is simple. Although there are solar batteries that provide some extra juice to laptops or pda's they function somewhat like 2-3 hours discharge, about one day in full sun to recharge.
I want a system that can power a full load working hd2 (worst scenario) non stop (day and night) including cloudy days, nuclear winter or whatever. The system must also be able to power about 3-4 usb devices and sustain a full 500mA drain on each port while still being able to power the hd2 non stop. Aaah, yes, the thing must be portable, plug&play, reliable and maintenance free. At most, it should have the size of a regular 15 inch laptop and about 2kg weight (all things included).
Stage 1 completed
So i figured out how hd2 charges it's battery. It's pretty simple actually.
Charging is made in the same way for either wall charger or usb charging. Same pins are used. However, when the wall charger is used, charging current can be as high as 800-900mA. This will decrease to some 20-30mA when the battery will be almost 100% charged.
If you however connect the usb data pins to hd2 and to something (computer, hub etc) hd2 will change the charging mode to usb. This feature ensures that when connected to a pc, the phone will never try to get 8-900mA from a 500mA usb port pretty neat. Instead, maximum charge current is limited to about 400mA.
If you get access to the usb wires inside the cable you can trigger either mode by simply disconnecting or reconnecting the data pins (green+white on standard usb cables). This is useful because i can devise some means of redirecting the charge current to either external battery (let's say after a night of use for the hd2) or to the hd2 if .. for some reason it's internal battery is discharged.
A usb enabled pic microcontroller (say 18f2550) can be used to control the charging process of either internal or external battery by simulating a pc connection, thus enabling hd2 to switch to low current charge. However if i'm guessing right, a simple usb hub could also do the job as it also contains a microcontoller that "knows" the usb protocol. So because i will use an external powered hub for linux, I'll try to use it also for switching between charging modes. Besides is more easier this way and i (or others) will be spared the time needed to program a microcontroller, or fabricate a pcb for it and it's corresponding components. And.. in case of nuclear attack there won't be any radio shack or electronics store where you could buy microcontrollers
Stage 2 completed:
Well i got myself some time ago a cheap 10watt polycrystaline solar panel for use with a robot i'm building. It was about $50 here in Romania. I guess i'll be using this one, even if it's quite big (something like a 16 inch laptop). Anyway i could also power other things with it. Will do some tests, and if it's suited for the job, it will be used. It arrived completely assembled so it also spares me the trouble and time of connecting individual cells into to form a solar panel.
Update : completed, will use the spare 10watt panel, until a new one arrives.
Stage 3 completed:
Got some 5-6 old laptop batteries. Stripped them down and got some ~30 cells. I'll test them out and sort about 4-6 of them.
Stage 4 completed: I'm currently sorting out some cells. As far as design goes, the capacity of the "extended battery" will be 14400mAh (single charge, using no solar power). That could easily power a full 15 inch laptop for about 4 hours, so i guess hd2 will have no problems staying alive for one night until next day and the sunrise to kick in for the solar charging to take place
Stage 5+6 completed:
There won't be any linear voltage stabilizer design for the buffer between the battery and hd2. They are quite inefficient with 30-40% power lost in the form of heat. Switching mode stabilizers+converters will be the way for this design. Found a ready made voltage stabilizer (converter) that's suited for the job , Saved some good hours that would otherwise have been spent on designing one from available parts.
Stage 7: yep, i'm now building the damn thing. I've simplified the design as much as i could, while keeping it safe for the phone, i guess the project will be possible to make by anyone with basic soldering skills.
apr. 13 - update: construction delayed due to one cell failure (the difference in internal resistance between the cells was greater then i expected). Will now search for a replacement, recalibrate the battery pack and recharge. However I expect that the battery module should be ready by the end of this day or tomorrow.
ok then.. it was built, it was tested and i'm already using it or at least.. trying to figure out a use for it
Anyway, if you're the camping type, if you feel geeky or wanna make a eco-friendly charger for the hd2 (or other usb charging enabled things) here's how to build one
You'll need the following materials:
- patience, this is a long post, try not to get bored while reading it
- some basic electronics skills, basic understanding of components, measurements and circuit troubleshooting (this is not a beginner project i guess, as hard as i tried to make it, if done improperly... well of course, you risk killing the poor phone in the process).
- some second hand laptop batteries, 3-4 would be ideal, they can be kind of old, but must be functional to some degree.
- a cheap usb charger used for cars, the one that plugs into the cigarette jack OR some good electronics skills to design a switching power supply. Guess most of people will go with the first option, in order to be more helpful i also designed this circuit using this option. You should buy the cheapest adapter, the cheaper the better. That's because the expensive ones have a feature that enables them to stop working if the voltage of the car battery drops to a certain point. That's supposed to be some sort of protection not to allow the car battery to discharge and thus preventing you to start your car. We don't want this protection, we want to be cheap asses, we want dirt cheap. However the adapter you want to buy must deliver 5V at around 1-1.5Amps minimum. 5Volts at 500mA is to little, it will simply kill itself when you start the thing once it's completed.
- a standard usb hub, any will do. This is if you want usb host functionality or use linux.
- a 5-10W solar panel. The bigger the better - it will allow to recharge the buffer battery (the one you'll be building) at a faster rate. This is the single most expensive part of this build. If you simply want an external battery for the hd2 you can skip the panel, if you want solar charging.. this is .. of course, a must.
- one fast rectifier diode or a schottky diode, you should buy it if you use a solar panel, the supplier of solar panel could also recommend one to use with that specific panel. We have to use one, this will make sure the current goes from the panel to the battery, not the other way around.
- bunch of wires, a multimeter and a soldering tool witch you're not afraid to use.
- a variable power supply, either it be a wall charger with variable output voltage, a laboratory power supply, or some charger that can output anywhere from 3.6 to 4.5 volts at anywhere from 300mA to 1A. Any combination will do. This is required only once in order to precharge the cells to a specific voltage.
- one switch or something similar in order to ... switch the thing on and off.
- spare time/understanding wife/coffee etc
1. Ok, first of all you need to get those laptop batteries open. Use some sharp tool, your karate skills or whatever necessary to crack those batteries open and expose the individual cells inside. Be careful not to damage the cells in the process, at least if you use some sharp tools. Once exposed, the cells will be linked to each other, you need to separate them by cutting the wires or metal bands that links them. Once done sort them out, if you have multiple batteries, sort the cells from each battery in a different case or basket or whatever you want, the idea is not to mix them.
Here's mine:
2. You now need to measure up individual cells with a multimeter. You're looking for the voltage rating of each cell. If you find cells with 0 volts, they're dead. If you place the multimeter in continuity testing mode and the 0 volts cells are showing continuity across their leads, yep.. they're really dead. Never use these. Good cells have anywhere from 1volt to 3-4volts.
Once you selected your good cells start forming a pack. The idea is simple. The more cells you put, the longer the thing will last. Standard laptop cells are rated to a minimum of 3.7Volts and 2400mAh. Each of them is almost double the capacity of the standard battery that comes with the HD2. However since you're going to use second-hand ones, they will have sign of usage, a smaller capacity then that of a new one. Still they will perform at least the same as hd2 battery in terms of battery life. Minimum configuration starts with 2 cells, i recommend 4 cells as a decent start but you can go and add more cells if you like. The more cells the longer battery life but at the expense of added weight. My choice was 6 cells. If you had 2 laptop batteries and each of them had 6 cells, you can make your pack on anywhere from 2 to 12 cells.
Let's say you choose 6 cells (always an even number). If 6 is you choice, you will need to divide that number by 2. So you get 3. You need 3 working cells from the same laptop battery to form a pair. Go back to the place you kept the cells and select 3 cells, NEVER mix cells from different batteries. These 3 cells you have (first pair) will need to be linked in parallel connection. The negative ( - ) of each cell is linked to the negative of the other and the positive to the other 2 cell's positive. We'll get there, but at a future step. Now we need the second pair of 3 cells. Again look in your cell basket and try to find 3 more cells from the same battery. This battery may be different then that first one you selected cells for the first pair. Yet again, the 3 cells must come from a single battery, no mixes. And.... again, these 3 cells must be placed in parallel. So if we already imagine them connected, we would have 2 pairs, each of them with 3 cells linked in parallel. The 2 pairs must be linked in series, so the minus of one pair will go to the plus (positive pins) of the other. The unconnected pins of each pairs (one minus one plus) will be used for voltage supply - you'll get the combined voltage of the cell pack here. If i were to draw this things for you to better understand.. it would look something like this.
green is one cell pair, orange the other. The black things are wires. This are the connections for a 6 cell pack. If you have 8 cells, you will make pairs from 4 cells (2 pairs). If you have 4 cells - the pairs will have 2 cells. A charged cell will have something like 4 volts. A pair made up of several cells in parallel will still have 4 volts across it's leads, but the overall current capacity of the pair is increased by the number of cells it contains. So if you have 3 cells each with 4v and 2200mAh, the pair will have 4 volts but with 6600mAh. If you place 2 pairs in series like on that drawing, you increase the voltage of the group by the number of pairs you add while still having the same current capacity. So if you get 2 pairs of 4 volts and 6600mAh, you will have 1 group, 8 volts and still 6600mAh. That's the total output of your pack. Because hd2 needs 5V (not 8 !!) we need something to decrease the voltage from 8 to 5 volts. That's why we need that car usb charger. It normally uses the 12V available at the cigarette jack to output 5v your phone can use. Cheaper ones, can use 8 volts, or 7 volts (lower voltages) because they don't have a circuit to prevent deep discharging the car battery like expensive one have. We need one without this circuit, because our battery pack only outputs 8V. So the car usb charger will take the 8 volts at it's input and give us 5volts at output.
3. before linking cells to each other, you need to charge them to the same voltage. Use a charger/power supply etc. I used a lab. variable power supply, if i had none, my weapon of choice would be a nokia standard wall charger (or another brand), older ones, i would cut off it's jack, expose the wires and connect them to my cells, it outputs 3.7 volts, enough to charge each cell. So charge each cell to about 3.7 volts. You will need to connect the multimeter in parallel to the cell and monitor the charging process. When a cell reaches 3.7 V disconnect it and charge another one, until all of them have 3.7 V. After this, leave the cells for one day. Next day you will be measuring each cell again. If one of them drops charge by it's own and you find.. let's say 3 V, you got a defective one, back to step 1&2 and select other cell pairs. If all cells still have the same aprox. level (somewhere around 3.5 to 3.7 volts) you're good to go.
Here's one cell linked to my voltage supply.
4. start thinking of either a case of something to contain your build. I used copper plated pcb (from electronics stores, radio shack etc). I will be connecting my cells to this thing, kind of like a pcb assembly. You may use some plastic housing and connect the cells with wires and secure them with some glue. If you have experience working with pcb, etching the copper layer and such things, feel free to try using pcb.
Here's my blank pcb for this job - i've already cut it to required dimensions. It's the orange metallic thing in the center. Beside it you can see my hub and the usb car adapter i will use.
5. disassemble (i repeat disassemble.. no more karate skills) your hub (if you're going to use one) and your car usb adapter. My usb adapter looks something like this.
The hub interior will look different, we'll get on that on a later step. Anyway, speaking of the usb car adapter, i'll be needing that small pcb with the components, so i'll remove it from there. The board contains the switching mode voltage converter, yummy yummy, i want that. It basically has 1 chip that generates a pulse signal that is feed to the input of a power transistor which pulses the input voltage across a coil. By autoinduction the coil produces another current, other components rectify and filter it so the second smaller current, produced by the coil, it's basically what powers on the devices connected at the output. In simple terms .. that's how it works. Again.. we need this, don't break it
Mine has a funny oval shaped form, so i'll be cutting my pcb in order to insert it inside.
There are 2 wires coming out of the small board inside. That's were the cigarette jack was connected. We will connect our cell pack to that, so you might wanna remember their position. The red one will be the positive one, black being negative. In a cigarette jack, the center pin is always positive, so if your wires have other colors, the one that's linked to the center pin will be the positive one.
6. Look for a way to place the cells inside your casing or on your pcb. Since i will do a pcb with them, i'm trying to find a possible placement for them.
this was one way, but i figured it was easier for me to simply place each pair on a line and form 2 single lines of cells instead of 3. Once done, i begun drawing the pcb with some paint marker. I will then etch the pcb, so only the paint covered areas will remain.
here's the pcb after etching, i'm connecting various wires to complete the cell pack circuit before connecting the cell themselves.
If you're using some sort of case, it's time to begin assembling your cells together. Use the solder gun or whatever you have for soldering to attach some wires to the each cell leads. Li-ion and heat aren't good friends, be as quick as possible when soldering, you don't want to heat up the cell too much. If it starts to make any strange noise, hiss or is venting anything from it... run away, don't touch it, don't throw it.. simply leave it and run away. Of course, this is a very rare scenario.. but take your safety when working with high reactivity materials like li-ion cells.
You want to arrange the cells in that paint draw up in the post. 2 pairs, linked in series. First solder wires to make one pair, then the other, then connect the pairs to each other. If you use a case, use some insulator to cover the solder points and to avoid some accidental short circuits in the future.
Back to my pcb solution, here's my assembly.
7. If you want to use an usb hub, you can try to salvage some usb port from an old pc or laptop's motherboard. This way you could avoid using a permanently attached wire to the device you're building in order to have the hub connected to the phone. I found an old laptop motherboard with an intact usb jack.
i remove the usb port from it and soldered on my board.
8. Next you need to connect the car usb charger's pcb to the battery pack you assembled. Basically the 2 wires from the charger must be linked with the 2 wires from the battery pack. Insert a switch on the cable in order to be able to turn on and off the whole thing. In my case, i'll now connect the car charger's pcb to my pcb, in the portion i've cut.
9. now you need to modify your hub to be able to power on hd2 during usb hosting mode. There's a link in the linux section (ubuntu for hd2) about this, you may want to read that also. I basically soldered a wire across each hub's usb port positive pin (the 4 usb jacks) and the input usb jack. The ground connection is the same for all jacks. So all jacks including the one used for connecting to a usb host device (pc) have the power pins linked together. Those 2 power pins must also be linked to the output of the usb car charger so that when you power up the thing using the switch, the charger also powers up the usb hub. After you solder all the wires, also insulate the soldering points and secure the hub in your casing along with the battery pack and usb car charger's pcb.
Here's mine, it was soldered on my pcb.
as you can see, there are some couple of wires coming out from it. Those need to be connected to the phone for me to have usb host functionality. So i'll connect these wires to the usb port i've mounted at step 7 so i can use a standard usb - microusb cable to link this thing to the phone. If you want to make it simpler, cut out a usb - microusb cable and directly solder the wires onto the hub's pcb as shown in the guide on the ubuntu linux thread for hd2.
In my case, i use that port i salvaged, as i said before.
10. assemble the whole thing and carefull inspect the connections. The order of this will be - battery pack - linked to the car usb charger - that's linked to the hub power pins (for each usb port). You'll then have one usb port for use when requiring usb host functionality, 4 usb ports for connecting all sort of usb slave devices, and one usb port (the one that it's soldered to the car usb charger) for use when you want to simply charge your device normally.
Here's my build. I've also placed a fuse between the battery and the usb charger, so that in case of malfunction it breaks the circuit. The fuse holding pin is the black thing at the opposite side of the usb hub. Near the pcb, you can see the fuse and it's cap.
11. Check again all connections. when ready, press the switch and bring the thing to life. Use the multimeter and check all usb ports voltage. You shoudn't have more then 5.5Volts and no less then 4.5Volts. If you do, then you did something wrong, turn off, disassemble and recheck. If you did it right, you'll get a voltage inside the above interval. Inspect the device once again and make sure all things are safely placed and secured inside. Try plugging some cheap usb devices you may have, a mouse, usb flashlight, another hub etc. If they receive power and all it's ok you may try to connect the phone.
Voila.. usb charging from the ghetto style external battery.
And here's a small video of preliminary testing (i haven't yet tested the usb hosting capability but i have no reason to think it will not work). At this time i didn't placed any switch on the board so i switch on and off the thing by placing the fuse inside the holder or removing it
http://www.youtube.com/watch?v=yf6kRpNNqkw
Next step... maybe some of you may think.. well how does this thing recharge when the batteries are depleted. At this stage the battery pack is recharged by connecting a 8.4 voltage supply across the battery pack leads (wires) but the next logical step will be adding the solar panel to the build and securing this pcb to the back of the panel. Then.. further testing. I'll be keeping the panel and that rectifier diode handy. This is still work in progress.
When are we getting it?
i guess it will take about 1-2 weeks to do the job.
i'm also involved in 2 more projects, it could be done as soon as i finish my automatic dog feeder with video-streaming over internet, food sensors and audio feedback. )
facdemol said:
i guess it will take about 1-2 weeks to do the job.
i'm also involved in 2 more projects, it could be done as soon as i finish my automatic dog feeder with video-streaming over internet, food sensors and audio feedback. )
Click to expand...
Click to collapse
Hey facdemol I am not as versed in electronics as you are my friend. So my question to you is this is something that someone with a fair level of intelligents can attempt also? Secound is this, is the list you give in your first post all some one needs to try this? I would really like try this myself and maybe correspond my findings with you. Also thank you totally of you ammazing knowledge filled posts here on XDA.
lol.... Im not sure how to respond to this
Cant wait to see how it turns out, best of luck
sounds interesting!
Good man, keep us updated however things turn out... you sound like someone who isn't afraid of experimenting with electronics for the thrill!
Sent from my Nexus One
Wow! Pretty interesting
Hey facdemol I thought you might like to check this article in the Portal out if you have not already. Looking forward to hearing back from you here on your project.
good article, was inspiring
stage 2 and 3 are completed. Now working to design a high performance dc-dc (switching mode) converter that would take 8.4V input and give me some 5V @ 2.5A output for hd2's charging and the usb hub. Some work needs to be done here and some careful testing, if for whatever reason this converter fails, hd2 motherboard could get fried Working on a way to implement some safeties, also i'm studying the way older pda's and pna's used switching mode power supply's and converters. I'm thinking i could either salvage one of these modules or build one specifically for hd2.
Update : found a way to make this pretty DIY for anyone with basic electronics skill (so that you can avoid designing switching mode converters, making PCB's, winding coils etc).
I found some dirt cheap car adapters that output 5v (pc usb jack) and can be used for various usb charging enabled devices. I'm testing to see their performance with my custom battery pack and the solar panel. Results are pretty good so far, i managed to run them stable at arout 5.5-6Volts input voltage. 2 of these will be required for this project (2 amp max current) or one if the output transistor inside is changed or a heatsink is mounted on it. I will come back with results and in the end, a guide with the required modifications.
The second post contains the updated progress on this project.
Third post will contain some sort of guide for a DIY assembly of such device.
These are updated daily.
If everything goes smooth, i guess i will posting some pictures and guides to build such things, by the end of this day or tomorrow.
Current features of this design :
- 10watt solar panel module
- 14400mAh battery module - cell pack designed as 3p2s
- 2 charge modes (slow - similar to a pc's usb port and fast - similar to hd's wall charger)
- 4 powered usb ports (usb host capable)
- 1 high-power usb port (it can charge any device requiring 5V at around 500mA - 1500mA)
- uses standard usb-microusb cables, no need for other hacks or special cables
- feels geeky
facdemol said:
The second post contains the updated progress on this project.
Third post will contain some sort of guide for a DIY assembly of such device.
These are updated daily.
If everything goes smooth, i guess i will posting some pictures and guides to build such things, by the end of this day or tomorrow.
Click to expand...
Click to collapse
Sounds greet I will bee waiting to see what you have come up with man, this could be something that can change how we can use our HD2s on the go. n
Keep up the good work facdemol, I am also waiting to see if you post any more power consumption results in your other thread.
I would like to ask anyone reading this to help vote this to be published in the XDA portal by clicking the vote bottom at the top right of the first post by facdemol, he deserves recognition for his great work with this project and his others.
Very Interesting ! Good luck with the project! will be following to see what develops!
I love this. Great concept.
it took a while to charge the independent cells to the same level and to form a pack. The charge alignment is a must, otherwise, the battery back will discharge at an uneven rate among each cell. One done properly it should allow the maximum battery life and no future maintenance.
I've done some testing on it, already hooked up the hd2 to this thing, it's working properly, both charging modes, usb host etc. I guess i'll come back today with the guide and pictures to make this, it took the better part of yesterday to manually charge/discharge each of the 6 cells in the pack.
updated post 3, half of the buid is already done and operational. The battery and hub+charger module needs to be linked up to the solar panel and some of case to be built.
There are some pics and one video with the thing working. Just basic testing for now, i just finished it.
Very interesting...great job mate...
Hello,
this is a bit of a custom job. I want to take my Droidx and make it a dedicated display in my car. My issues are the battery is shot and buying another is more investment than I prefer. also the battery is not going to work for what i'm doing because it will not be on charge as frequently as it need to get a full charge.
so here is what i want to do. I want to hard wire the battery terminals to a 3.7 vdc source and use that as the primary power to the phone. and use the usb power to wake it on entry and while the ignition is on. right now i've got the usb cord without the battery and it works fine. but I wanted to maybe use the battery/usb to wake it. Anyone able to power the phone on the terminals for the battery?
Thanks
-xpbr2000
xpbr2000 said:
Hello,
this is a bit of a custom job. I want to take my Droidx and make it a dedicated display in my car. My issues are the battery is shot and buying another is more investment than I prefer. also the battery is not going to work for what i'm doing because it will not be on charge as frequently as it need to get a full charge.
so here is what i want to do. I want to hard wire the battery terminals to a 3.7 vdc source and use that as the primary power to the phone. and use the usb power to wake it on entry and while the ignition is on. right now i've got the usb cord without the battery and it works fine. but I wanted to maybe use the battery/usb to wake it. Anyone able to power the phone on the terminals for the battery?
Thanks
-xpbr2000
Click to expand...
Click to collapse
The phone works without a battery. Maybe bypass it and connect to USB?
Sent from my SCH-I605 using xda premium
You'll need to have a battery or something to keep it from just turning off when you turn off the car, won't you? I looked into doing something like that with the RasPi, and I you're not supposed to just remove the power supply.
Or can you wire it to wear it has power when the car isn't running?
sghsmorgan said:
You'll need to have a battery or something to keep it from just turning off when you turn off the car, won't you? I looked into doing something like that with the RasPi, and I you're not supposed to just remove the power supply.
Or can you wire it to wear it has power when the car isn't running?
Click to expand...
Click to collapse
if i could figure out what the battery supplies the phone then i could wire a 3.7v source to the battery terminals on the phone.
I've had this system wired up for a couple months and it works great. the only issue i've had is the age of this battery makes it not take a charge. so in the heat of the day i get in the car and the battery temp is 100+ the phone is dead because the battery doesn't operate. and the charger can't charge the hot battery and keep the phone powered. I never liked the idea of a battery inside the car. heat + battery = boom (maybe not but it could cause a big mess and damage the phone.
the question i need answered is what is required for the phone to run? what do each of the battery terminals do? obviously one is ground (marked) and one is positive (also marked) the middle terminal has to do with a temp or charge signal. it doesn't power on just the positive and negative to the best i can test it. maybe i'm doing it wrong.
and i have looked at a rasPI. we have one. but i can find a capacitive touch screen that is small enough to fit in my dash (4th gen camaro) without deleting my radio which isn't going to happen. plus they are expensive. idk y tablets and such are cheaper with the same type screen plus the hardware of the tablet.
Almost! Cept with a Hero!
OP: If you still have the battery, you should be able to find the Amperage listed in mHa near the voltage on the batteries sticker. After you have these 2 values you should be able to construct a small circuit to drop your cars internal voltage down to the appropriate level. Hook it up to the 12v from your car at Ignition/Accessory if you want it on whenever you can use the radio, or to the Constant 12v, after the fusebox, to have it usable whenever your car doesn't need a jump! Best of Luck!
So, I'm actually trying something similar right now except with a HTC Hero with a bloated battery that refuses to hold a charge. I've tried several times to boot the phone with just the USB cable, but all I get is a red battery icon : / I'm looking to just hardwire this stupid thing to a plug or even a 9v alternative. This is gonna be used around my house for various things
As of my posting this, I've found 3 threads on slightly similar topics, none with very good/any info tho. Thank you in advance for any help!
Can someone verify that the Nexus 7 can operates perfectly fine with the battery removed and only powered by the USB cable? I've read some threads eluding to this, but no one has confirmed. Mine is in the dash of my car so i cant verify this myself. If someone can. that would be amazing! Thank you.
look at the thread right below yours.
Old Guy said:
look at the thread right below yours.
Click to expand...
Click to collapse
I saw that thread, i was still a bit confused as they were talking about USB DAC and other devices hooked up to me.
I want to make sure data can still be transferred from the same USB cable and such.
Yes, it's possible, but has some side-effects
Yes, it's possible to power the Nexus 7 without battery from a USB-cable, but it involves sending power directly to the battery connection inside the Nexus 7, and it seems to have some side-effects.
The battery is a one-cell lithium polymer, which has a max charge of 4.23 V. I hoped the Nexus wouldn't fry when connecting 5 V, and it has worked fine the few minutes I've tested it. No smell of burnt electronics
Here is what I did:
Tear off the tape around the battery cable. You'll see it's soldered to a pcb-board, and the two black and two red wires are soldered together. The two wires in the middle is probably some kind of data-connection to the battery. Will investigate this further later.
Then I soldered loose the cables, so I could use the battery-connector, and soldered both red and black wires to red and black wires in a USB-cable. Drilled a hole in the back-cover right below the NFC-antenna. The back-cover is filled with all sorts of antennas, so scratch carefully with a knife before drilling. Attached some pictures of the process.
Side-effects I've noticed so far:
- It thinks the battery is at 0% and not charging.
- The clock is reset when you turn off the power. But if you have internet it will update from NTP within a minute or so.
- My computer (OS X) can't detect it anymore. So I suspect it doesn't work in USB device-mode anymore, but I'm able to connect a USB-keyboard with an OTG-cable, so it seems to work in host-mode.
Does anyone else have any experience with this, or any ideas why it doesn't work in device-mode? I'm considering adding a small connector so I can use the two extra wires from the battery to the data-wires of the USB-cable (and disconnect when not in use), and then solder a USB female cable to the original battery. That way I can (hopefully) connect the Nexus 7 to my computer when needed, and possibly analyze what the two extra wires is actually used for.
I have CM for Android 4.2, and Timur's USB-rom, but it's probably not needed for this hack, and I will probably install a stock rom if I get this working properly.
Be careful, and don't blame me if you fry your Nexus (or anything else). Be sure to turn off any fast-charge hacks when the battery is disconnected.
Old Guy - look at the thread right below yours
Click to expand...
Click to collapse
Threads are sorted by last post in each thread, so it's impossible to find which one you are referring to. Do you have an url?
Theory worked
I managed to connect the Nexus 7 to my computer again
I'm considering adding a small connector so I can use the two extra wires from the battery to the data-wires of the USB-cable (and disconnect when not in use), and then solder a USB female cable to the original battery. That way I can (hopefully) connect the Nexus 7 to my computer when needed, and possibly analyze what the two extra wires is actually used for.
Click to expand...
Click to collapse
Can confirm that this works. I didn't have any small connectors, so I hot-glued one header-pin and a female connector for a header pin on the data-wires in the USB-cable. Doesn't look good, but it works
When I have it in the car, I disconnect the header-pins on the USB-cable, and connect it to an USB power-source. When I need to connect it to the computer, I connect the header-pins and connect the battery (with the female USB-cable), and a regular USB-cable to the computer.
Sorry to bring up an older thread, but it sounds like the White and Yellow wires of the battery are for data?
if so, if I applied 3.7-4.2 volts on the battery connection and then still had a 5v connection on the USB would this work?
I would like to use Timur's ROM, and have power applied when my car is off (fixed install) for deep sleep and then apply the 5v when the car is on to bring it from the deep sleep. the issues would be faking it to not charge which I am guessing would mean to set the battery input to 4.23 volts to show as being fully charged. then when key on, the 5v would take over and you would still have the 4.23 applied at the battery connection ( probably have a diode on the + side to keep from injecting voltage to that supply
Has any one completed something like this?
The problematic usb port finally gave up on my Nexus 7 (2012). I've opened up it up, connected the black and red wires from a cut usb cable to the 1st and 4th pogo pins without removing the battery. Now charging's fast and stable..
Added: Tried 5v2a charging, it doesn't melt anything.. Fully charged in just slightly over1 hour.
This thread has been great help and a motivator for wiring my Nexus 7 to do a (permanent) dash install.
I've just removed the battery and wired it to a Pico-Box X5-ATX-180 carputer PSU with an adjustable voltage converter in-between to get around 3.9 volts to the tablet. Works great, but I found another drawback.
Like mentioned in a post before me, the battery status will show 0% which I thought wouldn't be too big of a problem. However, at the moment there is an Android update (4.4.3) available and when I try to update it first tells that the battery is too low and that I should connect a charger. So I did, but then it tells me too "wait for the battery to charge sufficiently".
So for anyone reading this wanting to do the same, know that you won't be able to update Android without a battery connected.
I have attached a photo of the tablet running without a battery for those interested.
Rutjes said:
This thread has been great help and a motivator for wiring my Nexus 7 to do a (permanent) dash install.
I've just removed the battery and wired it to a Pico-Box X5-ATX-180 carputer PSU with an adjustable voltage converter in-between to get around 3.9 volts to the tablet. Works great, but I found another drawback.
Like mentioned in a post before me, the battery status will show 0% which I thought wouldn't be too big of a problem. However, at the moment there is an Android update (4.4.3) available and when I try to update it first tells that the battery is too low and that I should connect a charger. So I did, but then it tells me too "wait for the battery to charge sufficiently".
So for anyone reading this wanting to do the same, know that you won't be able to update Android without a battery connected.
I have attached a photo of the tablet running without a battery for those interested.
Click to expand...
Click to collapse
You could use the factory image to update your nexus 7. It's just a bit more work.
Rutjes said:
This thread has been great help and a motivator for wiring my Nexus 7 to do a (permanent) dash install.
I've just removed the battery and wired it to a Pico-Box X5-ATX-180 carputer PSU with an adjustable voltage converter in-between to get around 3.9 volts to the tablet. Works great, but I found another drawback.
Like mentioned in a post before me, the battery status will show 0% which I thought wouldn't be too big of a problem. However, at the moment there is an Android update (4.4.3) available and when I try to update it first tells that the battery is too low and that I should connect a charger. So I did, but then it tells me too "wait for the battery to charge sufficiently".
So for anyone reading this wanting to do the same, know that you won't be able to update Android without a battery connected.
I have attached a photo of the tablet running without a battery for those interested.
Click to expand...
Click to collapse
What did you use to get the voltage down to 3.9 volts?
the exact thread I've been searching for.
Just completed by initial installation and now troubleshooting various problems.
The biggest being this battery scenario. So from what I've read in this thread is to use a DC-DC power switcher PICO for carputers and run that to the battery leads. How is the boot time though?
I've read that with a low battery, the kernal during bootup takes longer for checks to occur?
I have an idea.....:
If we can switch 12VDC to 5VDC during switched (Key On Accesory) with a regulator.....
we should be able to do the same with a sepearate regulator to switch 12VDC to5VDC during constant (Key off) when the switch voltage is lost.
This would retain the time you mentioned gets lost. Also, how much mAh (current) do you get out of that PICO regulator to the battery leads? The TIMUR kernal for FI-mode wants 1800mAh at least. Currently I'm using a cigarette lighter DC-DC adapter that has 2 ports. (2.1A, and 1A). The Nexus 7 is currently connected to the 2.1A and my HUB is connected to the 1A.
any advice?
Thanks
rezmax said:
Just completed by initial installation and now troubleshooting various problems.
The biggest being this battery scenario. So from what I've read in this thread is to use a DC-DC power switcher PICO for carputers and run that to the battery leads. How is the boot time though?
I've read that with a low battery, the kernal during bootup takes longer for checks to occur?
I have an idea.....:
If we can switch 12VDC to 5VDC during switched (Key On Accesory) with a regulator.....
we should be able to do the same with a sepearate regulator to switch 12VDC to5VDC during constant (Key off) when the switch voltage is lost.
This would retain the time you mentioned gets lost. Also, how much mAh (current) do you get out of that PICO regulator to the battery leads? The TIMUR kernal for FI-mode wants 1800mAh at least. Currently I'm using a cigarette lighter DC-DC adapter that has 2 ports. (2.1A, and 1A). The Nexus 7 is currently connected to the 2.1A and my HUB is connected to the 1A.
any advice?
Thanks
Click to expand...
Click to collapse
Why go through all the trouble? Just snip off any USB cable and connect to the pogo pins.. This way, you can charge at pogo's speed with any wall charger and still bring your tablet anywhere.
Hi guys just wanted to report i used your trick on my nexus 7 and it worked perfectly!
I used this method to check if the problem was the battery or if the screen was dead and it turned out to be the battery!
Now i have another battery on the way from Ebay.
Thanks again good job!
Hi guys me again,
I want to update the software but it wont let me because battery is on 1% for ever.
BUT i was wondering, what would happend if i simultaneously plug in the mini usb to another usb charger?
would that create some sort of an insane weird circut and burn my tablet?
any thoughts?
thanks!
Im thinking to use the Nexus 7 in car without the original battery. Constant 4.2V from car battery via converter to nexus battery pins and using the usb with ignition to switch the tablet between sleep and normal state. One thing i would want to reuse is the temperature sensor in the Li-ion pack. Has anyone some idea if the two extra wires are directly connected to temp sensor or there is a circuit for it on the battery controller? If so how it could be reproduced so i could use this to monitor the temp in car for example or if anyone knows any usb dongles that i could use for monitoring external temp with android.
So now i hav tryed the nexus without the battery aswell. At first i applyed 5v directly to the little black battery connector. tablet worked but showed 0%. Then tryed desoldering the batteryback from the little circuit and applyed 5v to the actual battery connectors on the circuit. It shows 100% battery and works and also the temperature sensor is working. One issue is that i need to plug in the charger before connecting the circuit to the motherboard, maybe the charger im using is just too weak that cant get the voltage up or something. And another thing is that i left it plugged in for the night and now the percentage goes down slowly as it would be discharging. havent figured out why that is. Maybe someone has tackled this before also?
freakadell said:
So now i hav tryed the nexus without the battery aswell. At first i applyed 5v directly to the little black battery connector. tablet worked but showed 0%. Then tryed desoldering the batteryback from the little circuit and applyed 5v to the actual battery connectors on the circuit. It shows 100% battery and works and also the temperature sensor is working. One issue is that i need to plug in the charger before connecting the circuit to the motherboard, maybe the charger im using is just too weak that cant get the voltage up or something. And another thing is that i left it plugged in for the night and now the percentage goes down slowly as it would be discharging. havent figured out why that is. Maybe someone has tackled this before also?
Click to expand...
Click to collapse
You supplied power to the protection circuit? I'm surprised that worked.
The battery is probably going down because the protection circuit is designed to prevent over and under voltage. Since you're feeding it 5V and a lithium battery is supposed to max out at about 4.2V it must be trying to lower the voltage somehow. The percentage going down is probably nothing to worry about, but I'd strongly recommend connecting to the battery connector instead, and only connecting it like this when you need to have a certain percentage to do a system update etc. Also be careful with the bare battery, if the two pins short it could catch fire.
Hi i tried that works ,however it doesn't boot when powered i have to turn it on pressing power button,any idea why?
As a car dash its pretty useless now
Just a quick message that I have managed to power my nexus 7 2012 from a USB cable connected to the circuit board that was attached to my dead battery. Battery level indicator is permanently at 100%.
Sort of like the above it involves using the battery circuit board but it is disconnected from the battery.
Step 1: Strip back battery wrapping revealing the board attached to the connector cables (that connects to Nexus 7)
Step 2: Cut the metal strips going from the circuit board to the actual battery part
Step 3: Solder USB cable Positive wire to board pad labelled VP and Negative to pad VG(? not 100% on last one, but it's the other pad)
Step 4: Solder short wire from VP pad to other side of the board onto the ++ pad (that goes to the red wires then connector)
Step 5: Wrap board up with elec/other tape to avoid shorts
Step 6: Connect up and power on
Not sure why the last wire is needed but it didn't work for me without it.
Next step for me is to wire it to the onboard micro-usb
Where is the ++ pad ??
dribbleboy said:
Step 4: Solder short wire from VP pad to other side of the board onto the ++ pad (that goes to the red wires then connector)
Not sure why the last wire is needed but it didn't work for me without it.
Next step for me is to wire it to the onboard micro-usb
Click to expand...
Click to collapse
Where is the ++ pad mentioned in step 4 ? Can you post some pictures ?
Does it damage the Board or not?
I accidentally did connect 5v for a second or so,
it did power on, i disconnected immediately, and after that it didnt power on for several hours,
but not sure if it was because of the interruption during boot, or overvoltage.
Can somebody confirm?
(i cant use a diode for voltage reduction, its a bit complicated, i use a load sharing capable solar charger board etc)
its a nook simple touch
Yow, don't do that!
Ok, it should be able to take it, but still.
I've often fed 4V to devices which had their battery blow up.
In worst cases I've used a diode for drop, but the voltage can be pretty variable over load.
The uboot on most things will not continue if there is zero voltage on the battery.
Also, the peak current of a device can go up to 600 mA or more at times.
That kind of current often can't come in through the USB connector.
Finally, battery packs have ID connections and thermistor.
Entirely disconnecting a battery pack will often prevent booting even when voltage is present.
If you have a dead battery pack always keep the the connector, cable and tiny PCB inside.
Attach a power supply to where the naked cells used to connect to the PCB.
For wiring of the battery pack see: https://forum.xda-developers.com/showpost.php?p=42552349&postcount=5
thanks, 2 weeks ago i prepared to measure possible resistors but did a google search before, found your description...
i use the protection board with a 18650 3000mAh lithium manganese (to prevent blow (up)) etc cell and charge it externally,
which requires switching between charging the batt + powering the nook over the batt terminals,
and using the batt for powering the nook , all that while the usb keyboard is connected and in use,
this is done via relay and a really big capacitor, which works great but is a bit ghettostyle.
i tried to use another charger board with load sharing circuitry instead,
but the only easy available module requires 5v minimum input, passes this 5v to load if the ac adapter is plugged in,
if not, it passes the battery voltage to load,
so a diode(+ parallel resistor to maintain voltage drop) or LDO doesnt work because it would at least steal around 0,5 v,
which is to much reduction for the battery voltage, because the nst powers off at ~ 3,7v,
easiest would be to just let the 5v to the nook but seems no good idea.
anyways, it works with the relay