yashsingh1/xdaforums huggingface dataset:
[Touch Pro2, Tilt 2 Accessories] Telek:
Grab yourself a cheap-o battery charger off eBay

http://cgi.ebay.com/o597-Desktop-Ch...wItemQQptZPDA_Accessories?hash=item439ae37701

and rip it apart - this will give you a clean mount for your battery. Less than $5 including shipping so you can't go wrong.

You won't be able to use that to wire it up to your phone without some modification (as it only has 2 battery contacts). However the total amount of power that a battery can output does depend on several factors including the load and ambient temperature - so for comparison sake you'll need to have a constant load and temp across all your tests. This means the resistor is going to give you more accurate results.

Honestly I'd run the battery until it dies and note the point at which it passes certain battery voltages (3.6V, 3.2V, 3.1V and finally 3.0V at which point you should stop the test).

Not all li-ion batteries are designed the same, and they each have different discharge curves and cut-off points to reach their maximum capacity. Similar to other rechargable battery types the discharge voltage is fairly constant over the capacity of the battery. You'll notice a fairly quick dip over the first 5% from > 4V per cell to around 3.6V, then it should only drop to about 3.2V over the next 80% of the way at which point it starts to drop off more rapidly.

Here's a pretty good article that isn't very long that'll give you some good information on this:

http://www.mpoweruk.com/performance.htm

So I'd grab the flowmeter 1, resistor, and a cheap battery charger to gut and you're good to go!
[Touch Pro2, Tilt 2 Accessories] Telek:
Oh and you can test for yourself wether or not a battery's usable capacity improves from a fresh battery after a few charge/discharge cycles! Just monitor the time to get to certain voltages over the discharge period of a fresh battery and then on the same battery after it's gone through a few discharge cycles to compare.
[Touch Pro2, Tilt 2 Accessories] d0ugie:
hmm

Thanks for that charger link, I could use that. Do the inner two contacts on the battery do anything pertinent to tests?

That sounds about right, a resistor noting various voltage milestones (in particular whatever I can determine to be the cutoff point for this phone) instead of the phone. But when I was running my phone this morning on empty, I noticed that the voltage fluctuated in the 3.65-3.66 range, not always descending, long enough for the mAh to rise at least a hundred more points. Well I'll read that article. How would you recommend I determine the cutoff point? Google it or just stare at some application that shows the voltage until it dies and do that several times?

You know, now that I'm thinking about turning this from a thing about aggregating feedback from other people who may or may not know what they're doing in order to help people who are willing and want to put their trust in me and my little science lab, and since I may be putting up results somewhere around xda and my sites (in addition to solicitations for money and/or batteries from xda folk and/or the battery companies) that may not go the way various manufacturers want it to, ways with some kind of holes for them to potentially use against me (for instance), I don't want it to look like I'm cutting any kind of corners here with a duct-taped job. Would you say there is any reason to splurge on the CBA II for that sake or is that just excessively unnecessary and I should lock in orders for the flowmeter 1, the 10 ohm resistor and the charger? Would going all out dropping triple digits only add to the appearance of how the results were produced and therefore how reliably they should be interpreted or would it also add something pragmatic like accuracy and simplicity? Charts from the cba thing may come in handy for comparing different batteries with different kinds of acceleration over a handful of cycles. But appearances too. You know what I'm saying? Also I may be doing this not just for TP2 batteries depending on the interest this generates.
[Touch Pro2, Tilt 2 Accessories] Telek:
Well the reliability of either the flowmeter or CBA2 can easily be called into question. Without going for a profressional battery conditioner (which is quite expensive) then people will always be able to point and dispute your claim (and even sometimes with the expensive equipment). However reproducability is the key here - if you can show that any given testing method gives you anticipated results for control cases and is repeatable then it's likely going to be above reproach.

Honestly I'd try the flowmeter 1 + 10 ohm + battery charger for contacts first. Make sure that you use your phone to charge the battery again (since we cannot guarantee that any cheap charger off eBay will do a good job) and make sure that you give the battery at least an hour (but the same for all tests) to cool off from the time it was charged to the time you start the discharge cycle so that the temperature is consistent. If that setup gives you results that you expect and is consistent then I'd say that it's a good setup to use.

The two inner contacts are used for communicating with the internal microcontroller that helps the phone to know the battery's current state and capacity.

For an added measure you could grab an infrared thermometer (http://cgi.ebay.com/Non-Contact-IR-...emQQptZLH_DefaultDomain_0?hash=item56362fa343) ($15 incl shipping) which would allow you to check to see the battery surface temperature during both charging, discharging, plus the temp of the resistor.

You could also grab a few different resistors as well to more thoroughly test the mAh ratings at different loads. Since they're pretty cheap as well this isn't an expensive proposition that gives you more data.

Whoops - I made a mistake on my original post - the battery is 3.7V not 7.2V. A 10 ohm resistor is going to give you a 370mA draw at full charge. So you could grab a 5 ohm, 10 ohm, and 20 ohm resistor and measure the mAh ratings for all 3 to give a more complete picture.

I'd use these resistors. Total cost for all 4 is $14 plus shipping.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RHRA-5.0-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RHRB-10-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RHRC-12-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RHRC-15-ND

They're rated to 25W (but you'd be using at most 2.5W) so no temperature or cooling worried at all.
[Touch Pro2, Tilt 2 Accessories] d0ugie:
in the mail

Okay just ordered the flowmeter, the charger and three of those resistors, 5, 10, 15 ohms. Thermometer sounds like overkill as the batteries will be exposed to the same resistance and that's just one more thing to keep track of. Guess we'll reconvene whenever all of this shows up.

After a first few sets of apparently successful tests of my htc battery and the andida, if things look good and I'm confident I've got the right procedure down, I'll maybe create a thread tailored more specifically for this operation, a thing on my sites as well, an invitation to mail me new unopened third party batteries to test, report and return and approach the companies selling the things to see if they're interested.

Once I've tested maybe four or five batteries total and can put up some good content wherever, maybe then I'll advise people of the $47 I just spent .. but first I want to test these suckers. I'm kind of psyched about this. You see batteries on the net that are advertised as being both cheaper and better than your battery, you think yeah right but hmm, and that makes you one of a whole lot of people so, assuming I don't screw this up, or get hammered with complaints from battery sellers saying I didn't do this or that to the battery first, that's a major contribution, at least one worth the investment, information that belongs in the public domain. Who knows, I might be looking at my first sticky thread which in the end is the meaning of xda life.

Thanks fellas.

Doug
[Touch Pro2, Tilt 2 Accessories] anit77:
I'm typing this from my phone. Once I take a shower I'll read up on what's been posted and throw in my 2¢. I do have several things to add already :)

I'm heading to Vegas in the morning for a trade show but once I get back I can help you get set up.
[Touch Pro2, Tilt 2 Accessories] anit77:
Wow, I didn't read your last post till now. You're moving fast :)

This should be a good starting point for some basic tests. However it will be critical for you to monitor the voltage closely towards the end to each test. Without knowing if these batteries have an internal cut off you can kill the battery if you don't disconnect it at 3v. This will also be how you will get accurate results. If the pack goes under 2.7~2.8 it will be trash. That is why I liked the CBA2 because it's full auto, once you start the test it will finish unattended. This would've come in handy when doing multiple tests. The other thing I like about it is the fact that it does all of the math for you giving a final amp hour reading at the end. You don't have to worry about load you're putting on the pack...

...Anyway

When you get everything set up you will want to do at least 5 tests for each pack and track the average. Let the pack cool down before recharging. You will also want to charge them all with the same charger. The charger will need to cutoff at 4.2 volts. (This is VERY important!)

Lastly LI-ion batteries

DO NOT

like being shorted. You risk injury and or fire if the happens. :eek: I cannot stress this enough, okay? Actually this goes for over charging as well.

I would recommend using a deans connector to make contact with the pack. If you want I can make this for you when I get back.
[Touch Pro2, Tilt 2 Accessories] Telek:
Anit's caution about shorting the battery is a good one - don't do it!

The Flowmeter also has a mAh display which is exactly what we need for the discharge. Yes it would be ideal to have the auto cutoff but for the added cost I'm not sure it's worth it. If it turns out to be a problem we can build a simple cut-off circuit with an opamp.

I figured that just buying a cheap $5 battery charger off eBay and using it for the connector would be sufficient - do you think that a deans would be better?

I also figured that charging the battery with the cellphone itself would probably be easiest since that is going to be the best charger (and most appropriate) other than buying an OEM external charger or one that actually communicates with the battery rather than just tracking voltage. Downside is that your phone is tied up charging the battery. I haven't had a lot of luck with cheap external chargers being reliable - do you know of any that you'd recommend for this usage?
[Touch Pro2, Tilt 2 Accessories] anit77:
With the deans, 1st off if doesn't line up correctly with the battery it can easily be bent slightly to make a solid contact. I think this will be much safer than trying to hold 2 separate probes in place. 2nd it can be glued into a plastic bowl or cheap Glad storage container. I was thinking of using a new sponge notched and cut to fit. This would be perfect to use as a spring to keep constant pressure.

edit:You can also test fit the deans repeatedly without worry of shorting.

With charging, using the phone to charge & test one battery let alone 2, 3 or more batteries would be a major PITA. Unless it was a crappy weekend with nothing else to to he'd be tethered to a wall or usb port for quite a bit of time. (I also think all of the batteries should be charged from a wall outlet for the tests) Add to that the constant swapping of batteries and restarting the phone... I think you get the picture ;)

I've never used an external charger for cell packs but it's not that complicated for a vendor to manufacture. You don't think one of those dual chargers would be good? He'll have a volt meter so he'll know when they're full, 4.2V.
[Touch Pro2, Tilt 2 Accessories] Telek:
Anit I'm confused about your comments about the deans connector. By buying a $5 battery charger and reusing the housing and connectors he gets something that is designed to exactly fit the battery with the proper connectors where they are needed and handle insertion and removal thousands of times. Why would using a deans-based custom rig be better?

The reason that I'm advocating using the cellphone to charge is:

- you get exactly the same charge properly administered and stopped

- this is how the battery is going to be charged for normal users and normal usage

- cheap external battery chargers rely strictly on voltage and many if not most either chronically under or over charge the battery as a result.

Properly charging the battery requires either communication with the on-board micro

or the on-board micro must be smart enough to detect, allow and stop charge via only the +/- terminals. The onboard micro is designed to monitor voltage, current and temperature to determine the safest way to charge and when the battery is full. IANAE but I don't think that many (if any) batteries will have the latter option, especially the dirt-cheap knockoffs that he is going to be testing. Cheap external chargers do not communicate with the onboard micro either.

Yes it is a little inconvenient, but this is neither something that he's going to be doing hundreds of times nor something that needs to be done really fast. I think that the reliability of the internal charger would be worth the inconvenience.
[Touch Pro2, Tilt 2 Accessories] d0ugie:
I'll be charging it with the phone, that makes the most sense unless the phone is known to be widely erratic in deciding when the battery's full and to ease back. I guess I should have the phone off when charging for consistency's sake but do you think that's really necessary, especially after doing five tests per? As far as not stopping the charging past whatever the cutoff point is (it looks like 3.600 give or take according to this powerguard program), no problem, I'll watch closely.

Pretending my abcPowerMeter tests are at all accurate and along with it the readings of the HTC stock battery weighing in on average around 1500mAh and in a few runs higher than 1600, whereas another company's battery purporting to be 2000 falls below 1400, is it possible that HTC's giving a usable mAh rating whereas the other company's clocking the mAhs all the way to zero volts? Or more likely just a total fabrication from the East? HTC can't really get away with fudging numbers given all the "batteries" of tests their phones are subjected to by critics field testing for talk time numbers.

I was wondering how I'd get my hands on more batteries and an idea I just came up with is a reputable company whose battery clocked a legit figure, one whose name people around here have heard of, who takes an interest in buying me batteries to test from their competitors. Or maybe that's prematurely grandiose. But it seems to me that the naughty companies are both the ones that I am particularly interested in and the ones that are the least interested in me and I am not spending hundreds on spare batteries and in case you haven't tried the donation button thing around these parts the money ... I'm getting ahead of myself here. Good night.
[Touch Pro2, Tilt 2 Accessories] Telek:
Cutoff at 3.6V seems abnormally high since that is the nominal voltage of a single lithium-ion cell. I think the best way to determine the cutoff is to actually check the voltage of the battery using external voltmeter when the phone decides to shut off (not after!) Note that the phone may not be using a voltage at all, it could be going strictly on the % remaining as based on the onboard micro of the battery.

HTC does have a vested interest in having their numbers slightly higher than real life usage, but 3rd party vendors certainly want to inflate their numbers and could be going on the entire usable range of the battery rather than the phone's determined cutoff point.

Most batteries that you will be testing are going to be less than $10 each, so you're not looking at a very expensive proposition here. You can likely recoup your losses from donations and if your site gets a lot of traffic then from ads as well. Hopefully you'll get a good reputation for this and then can start banking on that to get some free samples from manufacturers :)
[Touch Pro2, Tilt 2 Accessories] anit77:
I some how missed the part about cannibalizing a cheap charger. Sorry... That is a good idea!

I still think there has to be a good charger out there but having never used one you would know better than I. I still think once Dougie gets started he's gonna miss not having that ability.

I too think cutting off at 3.6 is way to high. I would say 3.0~3.1 would be better. I'm interested to see what the voltage is when the phone cuts off. If it's not already posted when I get back I'll find out.

Adam
[Touch Pro2, Tilt 2 Accessories] d0ugie:
Well, not having cannibalized the stock battery, we don't know if there is some kind of cutoff setup either to signal or stop charging because it thinks it's full or if the phone makes that call, same deal with cutoff for an empty tank. So in the interests of simulating a real-world condition as best as possible, why not just keep the method of charging the same and that is with the phone? Just need to take a snapshot of the battery's voltage when the charging stops and then when the phone dies. Am I going to be able to do that with the flowmeter?

As for the cutoff voltages, on the top end this software powerguard is telling me about 4010mV and 3580mV at the bottom, give or take. Those numbers aren't precisely consistent but close enough. However close the software readings are to what this hardware I ordered will reveal, we'll see. I'm pretty curious, particularly not knowing how such software works.

Parenthetically, I plotted out a full drain of the Andida battery last night, mAh and voltage. Seems the mAh add up progressively slower as the battery percentage drops (the phone's gauge drops faster as you use it more), particularly after 50%, about what you'd expect but not what you'd desire. The voltage falls off its fastest but a steady drop from 100-90%, a slower (but again, steady) rate from 90-60%, then its slowest descent begins at 45%. I wonder if the same is true for the stock battery. I'm guessing it is.
[Touch Pro2, Tilt 2 Accessories] d0ugie:
ohm?

I did a short test with the abcpowermeter thing and according to it, when I did do a heavy burn (>350mA), it cost a substantial amount of greater capacity according to the phone's power meter (and I know that neither the software nor the hardware for all we know is an accurate gauge of anything, but still).

I think I ought to be doing average-use real-world-like runs. For instance an average use for me might be starting on a full charge at bedtime, midnight, with activesync on four hour cycles, hsdpa and bluetooth (too lazy to drop to edge and no bluetooth), and at 8am activesync pushing begins, then I start using the phone as many would until it dies. The average mA by the time of death is maybe 100mA. Just during the daytime, 150-200 (data always open for email, screen frequently on high power, 3G, bluetooth, a couple calls, a little google maps action with gps here and there, you get the idea).

So I think I ought to get one more resistor, one that drains at, say, 180-200mA. According to my math using this, that means I need a 20 ohm resistor as well. Do I have that right? I realize that means a full day's worth of testing per battery, more for higher capacity batteries, and I need to be eyeballing that voltage but I am willing to do that if it will help make this stand up against skepticism and possibly threats. I did order a 15 ohm resistor but at least according to the calculator is >300mA (at 4.7V, which is labeled on the batteries) and I think that's too much. I don't want to stack the deck too heavily against these guys.

Doug
[Touch Pro2, Tilt 2 Accessories] Telek:
Sure

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RHRC-20-ND

Will work and give you 180mA draw.

This is why I suggested using multiple resistors as you will get different mAh ratings based on the draw :)

3.7V (not 4.7) is what is written on my battery, which is open-circuit full-charge voltage. Operating voltage should be 3.6V for 85-90% of the capacity of the battery.
[Touch Pro2, Tilt 2 Accessories] anit77:
4.2v is the full charge capacity for a 3.7v cell and 2.9~3.1 is the safe discharge level.

More info can be found here.

When using the phone to charge will this won't matter. I have found several smart chargers online that can be wired to the cheap charger that houses this cell. (most of them are around $20-30) a molex connectors could be used to switch between charging & discharging.

I will have the voltage that the phone cuts off at when I get home tonight.

Edit: The phone did indeed cut off at 3.5v. That leaves quite a bit of power left in the battery. I have read that it's best not to run Li-ion batteries down all the way very often but I figured they'd leave that up to the user.

I'll post the full charge voltage later.

Edit2: Full charge through phone is 4.15v.
[Touch Pro2, Tilt 2 Accessories] d0ugie:
How did you measure that? With the software I get about 4.15 tops on 100% and death by 3.60.

My stuff still hasn't arrived, hopefully soon, itching to start this mission.

By the way regarding whether or not these guys refer to the maximum usable mah number or a wider range, if discharging or charging the battery too far outside this range would damage the thing, then no one could call such a measurement's parameters legit. People are only interested in the usable range and if they are trying to get away with some other range then that, I look forward to exposing those guys.
[Touch Pro2, Tilt 2 Accessories] anit77:
I used a digital multimeter to see the voltage levels. At phone cutoff I let the phone shut down & took the voltage, after that I put the battery back in and started the phone and verified shut down then took the voltage again. At full charge I basically did the the same & came up with the same as you. Their keeping the the full charge max voltage in a safe range for safety reasons.

All batteries are rated at full usable mah (or AH) unfortunately we don't get the full usable mah from the battery due to HTC's set point. Your test will give us the ability to not only see the full usable charge but if you record the time it take to get to 3.5v along with the time at 3v we will have both sets of numbers to work with.
[Touch Pro2, Tilt 2 Accessories] Telek:
Note that to really get the true cutoff point we need to have leads attached to the battery while the phone is in operation at the point in time when it decides to shut down. Measuring the voltage after the phone has shut down won't tell us the true story.
[Touch Pro2, Tilt 2 Accessories] anit77:
Very true. It may be possible to do so but there is not much clearance in there to run leads. That and there is a much greater chance of causing a short if not done correctly. If I were going to do it I wouldn't try it in the phone but in a rig. What do you think?

I am going on the assumption that HTC uses a round number for the cutoff, ie 3.5 and not 3.47.

When I took the 1st voltage it was off for 20sec or more before I got a reading and the cell was already rebounding from being off load. The voltage was 3.54 and I watched it go up to 3.58. After I put the cell back in and restarted it cutoff in under 1 minute and I read the voltage in under 5sec. It was at 3.48 and rebound to over 3.5.