[ChILd_ReBoRn]

thnx archie for stepping up olready copied the wiki link for PCB. PCM is pulse code modulation

But the main thing is we understand each other. ... I'm going to dissasemble it ASAP

 

[ChILd_ReBoRn]

Ok.. here it is. I have a problem, and that problem is easily solved, but requires soldering. Not sure how much heat can the battery take and not get damaged. I believe it wont heat up much, but.. opinions? I have to cut the BM contact in order to turn the protection circuit around.

The cells are pink. are they samsung.. LG or some chinese knockoff?

The voltages are pretty consistent, one 2P is 4.10V, the other 4.14V

 

[ChILd_ReBoRn]

f... it..

I broke it of, solder it later...

can't make a better macro. my camera is crappy, and phone hasn't got a macro...

now I have to make some kind of a glove...from a surgical glove

blah, no macro option on my phone, but a magnifier app on the phone so good it would make awesome macros

the smallest IC says 2120 CB, and two other are marked 8205A 1545

 

[tigris99]

Looks like corrosion on one pair of cells???

 

[ChILd_ReBoRn]

Dunno. I packed them away. I think it was some kind of soldering paste..

edit:

Yup, 'twas corrosion. Cleaned up most of it, and repacked the batteries.

 

[tigris99]

Get rid of those batteries, they are already leaking.

 

[ChILd_ReBoRn]

hmmmmm I wouldn't be so sure. The only corroded part was the top of the battery ( it looks like a metal dome on 4 "legs" atop of the battery. The flat part on which it resides is nice and shiney. I would sooner say that the corrosion occurred due to the glue with which the top foil was glued

 

[ChILd_ReBoRn]

https://g02.s.alicdn.com/kf/HTB1ewHHHpXXXXXCXXXXq6xXFXXX8/lg-18650-flat-top-battery-3-7V.jpg

this is what I'm talking about.. the 4 point "dome". Underneath it, the metal is absolutely clean without signs of corrosion

 

[ledoman]

The cells are Chinese estimating based on previously seen at about 1100-1200mAh each so up to 2400mAh for the pack at best.

Voltage would be consistent if the difference was 0.01V or less.

Since there are no markings on the cells I can only guess but those cells behaves quite well at very low current. At the higger currents around 1A and above they have prety low capacity. Take a look at http://forums.mtbr.com/lights-night...terproof-bicycle-battery-packs-gb-982688.html

I would use this pack for very short rides and with weak lights only. They are also good for limited testing purposes.

 

[ChILd_ReBoRn]

ok, so I have to charge them at about 0,75-1A max. even at the lowest setting the light is pretty bright for my kind of riding...

the seller refunded me half the price, so at 9,5$ the light and the pack is awesome

 

[tigris99]

hmmmmm I wouldn't be so sure. The only corroded part was the top of the battery ( it looks like a metal dome on 4 "legs" atop of the battery. The flat part on which it resides is nice and shiney. I would sooner say that the corrosion occurred due to the glue with which the top foil was glued

You'll find out soon enough that the battery pack needs to be disposed of and its already leaking. That corrosion is either due leaking cells, not the adhesive used to assemble them.

Just a heads up cause the crap they leak is toxic.

 

[ChILd_ReBoRn]

k.. wont lick them

 

[-Archie-]

From time to time, ultra-cheap Chinese batteries and chargers could be really dangerous:
http://forums.mtbr.com/lights-night...ight-nearly-burns-down-guys-house-997922.html

 

[ChILd_ReBoRn]

listen guys, let's not get overly excited. I'm not some economics graduate who hasn't got a clue about anything other than numbers. No offense to economists. I'm an electrician, and I'm well aware of LiION dangers. I was charging my battery by my side, in a metal pot, covered with a metal lid. I was by her side all the time, constantly checking the battery/charger temperature. I will change the pack first chance I got, but I'm no Gates, and I don't have any excess money. Momenterally.. 30$ is as much as 3000$. After my paycheck, IF there's anything left after my mortgage, and gas/electricity/garbage disposal/phone/ineternet/mobile phone/water/all kind of crap bills, I'll get the better pack.. OK? then.. the spring will come, longer days, and I won't need the light until next winter...

 

[-Archie-]

Ok.

 

[ChILd_ReBoRn]

Good, I did my first controlled discharge using the turnigy charger. The Voltage shown on the LCD was 6.xxV. Forgot was it .37 or .73V. Besides the point, anyway. Why can't I measure any voltage with my voltmeter? Could it be that the PCM cuts off any voltage drain as to prevent battery damage? I tried to plug the pack in the lamp, and all three leds are turned off. If the lack of voltage isn't PCM's doing, what has happened?

 

[tigris99]

What LCD is showing that voltage because if it cut off and your reading that high, the pack is way outta balance?

 

[ChILd_ReBoRn]

the charger LCD. I was doing a discontinued discharge, since I was fiddling with the settings. But the longest one ( from somwhere around 7,8V to the end) was the one that was the final one. So the discharge went on 0,6A ( although I set up a 1A, but the charger went to 0,6A and stopped), and when I woke up 6 hrs later, the LCD was shoving as follows:
blinking END 2S, voltage (aforementioned 6,37 or ,73 I forgott ), discharged capacity ( around 1580 mAh, plus around 900mAh discharged at the first attempt), and discharge time.

I could buy the balance plug, solder it on the battery connectors and plug it into the charger, and see what happens. Does the plug have some kind of a code name? I knoe I need a male 3 pin connector, but don't know the size...

 

[tigris99]

I never use a balance plug, but just get one for a 2s lipo battery set up. I use the clips that I have for my charger with the pack open, charge the low side till its voltage (resting, tested on a DMM, not charger) matches that of the side that was higher. THen finish charging pack normally, check each bank again to make sure their in balance and done.

You should set your charger to discharge to 3.0per cell (6V in this case), discharge then fully recharge. Will give you a better idea of the actual capacity.

 

[ledoman]

He has his sharger set to 3.0V. Charger has only 5W of discharge power so 0.6A is the best it can do.

I agree, one more full charge/discharge cycle would be good. But anyway I can predict you'll get around 2400mAh out of crapy chinese battery pack with unlabeled pinky cells.

ChILd_ReBoR, after 1st charge phase, you can run few short charges with 0.5A to top up the pack. Then you should measure voltage of the pack. If it is still below 4.35V then it is very likely unbalanced. Disassemble pack and charge each pair separately as 1S (single cell). Be careful when making contacts not to make a short.