2Pcs 3S 11.1V 12.6V 25A W/Balance 18650 Li ion Lithium Battery PCB Protection Board

Inexpensive BMU (battery management unit) that works and manages batteries to charge and discharge when in use. I've purchased other BMU's for different voltages, using 18650 batteries that I've recycled from old laptop batteries.

This PCB is installed with 18650 cells in a 3S4P configuration for a 12V portable system. This model was placed in a dead HECO 58V lithium battery and fits perfectly. Charged battery recorded 12.3V dc and discharged to read 10.1V dc. I would Continue to monitor for performance on the build-up and report any update. Beside, seems to work within anticipated parameters. It's important to note that, this board is not a BMS - but a balancer, and therefore selecting the charging source should not be far greater that 13V to get the battery possibly fully charge. At best use a 12V dc charger, will possibly provide a decent control and prevent over charging. If a charging source is solar, bear in mind that Li -ion charging settings are strongly required if buck converter is being used. If a charging source is via BMS, Li-ion setting is a must-have! Don't just fault the balancer, when preliminary settings on the user are not appropriate.

This is a 3S 12V 18650 Li-ion Lithium Battery 25A Battery management system board (BMS) which is a *must* to have if you are building your own Li-Ion battery packs. This one is needed for "over-voltage protection" of your 3S battery pack. The over voltage protection ranges between 4.25~4.35V ± 0.05V, Also, this BMS prevents over discharge of your battery pack when the individual cell group voltage ranges between: 2.3~3.0V ± 0.05V. So what does actually BMS portion of this board actually do?, Well the so called "balancing" is handled by the BMS circuitry of this board, remember your 12v battery charger sends out constant voltage & current especially if you have dumb charger. So, when the first cell group reaches full capacity, the BMS cuts off the charger and drains the highest cell group(s) slowly using its on-board resistors. Once its lower, it allows the charger to turn back on. It repeats until all cell groups are full and are at the same levels as the other groups in the (|3S|) configuration it supports. It does offer short circuit protection (The main reason why you must have this) I did try it and it worked but just because short circuit protection is there do not try to deliberately short circuit too often as it does provide up-to 25A and it does self recover after a temporary short circuit and protects the battery from overheating and catching fire when there is deliberate permanent short circuit at the output terminals. This alone is worth having this board. FYI, Just like any other DIY battery pack do's and don'ts you must adhere to rules and make sure that when the batteries are connected in series with 3 groups (|3S|) please ensure that the voltage of each battery is the same. If not the same swap out the batteries and ensure all the batteries are of same voltage in the group this will ensure better balancing operation. The life of a this DIY rechargeable battery pack using this 18650 Li ion Lithium Battery PCB Protection Board can be further extended through the use of an intelligent charging system at the battery terminals but that generally costs a lot of money. Rating the product with five stars!

There are 2 different DIY project for this purchased: 1st board I made it as a power bank for a low battery power laptop by using 6 lithium flat batteries (2p of 3s) to have 12v - 5200mAh. I got 0.03v different for each cells on 3s pack (photo 1) and 0.04v different for each cell on 2p of 3s pack (photo 2). After full charged, the power for all cells are not exactly equally but the board is really do great job for balancing the cell before start charging and the rang is lower than as it described (+/-0.5v). By add volt meter next to it, I do see the board stops charging when power almost reach to 4.2v for each cell and cutting off output to protect all cells when total voltage drop at 9.5v. This project helps my small laptop can last couple more hours longer than its original build in battery. 2nd board I made it as 12v charger station to charge 18650 batteries 3s pack which I try to salvage all old hand tool model that I could not find a new batteries for replacement. Because I use same board to charge for different batteries pack from 3s 1500mAh pack to 3s 2500mAh pack - of cause overloading protection function will not avail for this project as my purposed, so using volt. meter that I monitor the power balancing during batteries charging and I do see it is doing same job with good balance range about +/- 0.05v different. All my hand tool are back to working same as using its original batteries. Without this production all my hand tool is likely going to trash, my laptop runs just an hour with no AC power supply..., it is saving me a lot of money - Highly recommend this production for a small DIY job ….

I got bitten (like others - sigh...), this balances any load between three batteries so they discharge as a unit & makes it easier to recharge. Does NOT bring output voltage to 12.6V! It looks to me like it's useful for multicell power (such as from solar panel storage). Gotta Google the board part number (on the board) to see how to connect it. Good feature: it's inexpensive so you get what you pay for. rjs

Great BMS battery management. Interestingly, you put your input voltage and load on the same pins, so it really just stabilizes your power. What's great is that you can pull power from 1 or 2 or all 3 batteries as needed and this board will float all of them as required with a single 12v power supply. For example, I am using 2 batteries for my USB outlets and all 3 for my 12volt out at the same time

When used correctly, these BMS boards work perfectly on a 3s system. I used it on a 3s x 10p 18650 build and they kept the batteries in top shape. I spot welded my leads, but these can be easily soldered.

alot safer with these in my packs