Hi all,
I have a SolarStorm X2 as the primary bike light but was wondering if the battery was balanced.
It ships with a 8.4V charger, but it doesn’t have a balance plug so $10 that it’s not balanced.
I have a similar light (a trustfire if I recall correctly) that uses an identical battery pack. On my example, there’s a circuit board underneath the shrink wrap that has what appears to be a balance lead that runs between the two battery banks. I know little about electronics, so I couldn’t tell you how (or if) the circuit functions, but I did try unbalancing the pack by discharging the banks to different levels. Even after leaving the pack for several hours and then slowly charging the pack at 100mA, the pack remained unbalanced and subsequently started overcharging one of the banks.
In hindsight, it would’ve been better if if I just ran some leads from the two banks and monitored the voltages after several cycles. The cells, for what it’s worth, were marked “TZGLLY18650-1800 L08140921”. I think they came out to be close to 1.8Ah per cell.
Awesome, thank you very much for your reply.
I guess I’ll have to cut open the shrink wrap and see if they’re balanced at all.
Edit: I’ve just torn apart my pack and it’s not looking good.
They’re very unbalanced, at 3.997V and 4.102V.
Thanks for the warning, I guess I’ll balance charge them. Thank goodness I only charged up to about 8.30V with my hobby charger because I was suspicious that these were not balanced.
I have several of these. What’s the fix? I understand they need balancing but how? Extreme detail for beginners is much appreciated.
If you don’t have a hobby charger, individually charging the battery pairs is the way to go.
Here’s what I’m currently doing:
I hooked up one of the pairs with magnets and I’m charging it up to 4.20V. After that’s finished, I’m going to switch to the other pair and charge it up to 4.20V.
If you do have a hobby charger, you can take advantage of the green rectangular PCB and solder some leads to them and connecting it to the balancing port of the hobby charger.
I was hesitant about cutting open the black shrink wrap, but after Default Username said that they were not balanced, it was a no brainer.
If batteries are low quality, and have different capacity they always will go unbalanced.
The best option is add balancing connectors like that: http://www.ebay.com/itm/10x-2s1p-7-4v-JST-XH-Connector-Adapter-plug-RC-lipo-battery-balance-charger-B6-/160899607757?pt=Radio_Control_Parts_Accessories&hash=item25765d2ccd
of course if you have hobby charger like imax b6 or icharger. And charging in balance mode.
That’s correct. The one with the lower capacity will always have a lower voltage after a discharge cycle, and if charged without balancing, the one with the higher capacity will be overcharged beyond 4.20V. I doubt these would explode as in a flashlight, but venting wouldn’t be very present either.
I’m glad I could help ryansoh3. Interestingly, the circuit board on your pack looks quite a bit different than the one present on my pack, despite them looking quite similar on the outside. Here’s a picture of what I found inside mine. The two 8-leg chips on top are marked 8205 24C1G, and the 6-leg chip is marked 3W17. The “balance” lead was connected to COM, B+ and B- to battery, and P+ and P- to output.
(Apologies for the poor macro shot)
(Link to original image)
https://farm6.staticflickr.com/5495/12703074745_c492edd476_o.jpg
Some folks on the MTBR site converted their packs to removable batteries. I had planned to do the same so I could firstly, use better cells, secondly, be able to charge the cells individually.
Kaidoman has a pack that is serviceable.
Kaidomain battery pack.
http://kaidomain.com/product/details.S023038
They emailed me back yesterday to let me know that it's wired for 8.4V.
Do you run your hobby charger open for heat management? Or just because it looks cool, because it does.
That might be explained by the internal charge leakage being higher when the cell is discharged than when it is charged, or by the lower capacity cell also having more leakage. If they were always equally efficient, in terms of the charge out equaling the charge in, they would stay in balance when charged and discharged in series, even though they had different capacity.
That looks a bit better than the one I saw. Nice
Comes with a bag/cover to strap to your bike.
http://dx.com/p/pannovo-b-c04-water-resistant-4-x-18650-battery-pack-case-for-bike-lamp-black-254957#.UwlGhajnbtI
So, if I’m reading correctly, if I have the version with the board on the top I’m OK? Assuming it is wired the same. Or not?
Edit: oh, I see the Kaidoman one has the “bag” too.
Yup, it does come with a fan but it was quite distracting so I’m running it silently. The cool part is a nice addition, thanks. 
I'm planning on using the DX Pannovo case as well (it's just taking DX FOREVER to ship my order while they wait on an item to come in stock). I was also tinkering with other DIY ideas to be able to use my own cells and pull them to charge them individually.
Question - how safe/unsafe is it to use 4 high quality BUT unprotected 18650's in a case like the Pannovo?
-Garry
I ordered some balancing plugs from eBay yesterday and I was able to fix the balancing issue.
The circuit board did seem to have some components but wasn’t able to balance the cell. Over/under voltage projection perhaps?
I soldered on some XST-XH 2s balancing plugs to the PCB tabs:
I added some heatshrink to keep the wires organized.
Works perfectly with my hobby charger.
I’m trying to do the same with my pack. I can’t get it to work though.
Can you see where I’ve gone wrong?
I think that blue wire should be connected to COM (right-botom corner)…