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A123 26650 BMS
#1
Ok had a question on a BMS for A123 batteries. The battery i'm building is for a trolling motor in a canoe, it is going to be a 4s battery but not sure on the BMS i should use.

(thread on what I'm doing in the solar charge forum) 

the batteries I'm using are..

https://www.batteryspace.com/a123-lifepo...isted.aspx

And the BMS i was looking at was..

https://www.amazon.com/NOYITO-Over-Curre...YN92NY559R

So just a few questions, will that BMS work for those batteries? The batteries are listed as 3.3v with a nominal V of 3.25 +/- .05v (average 3.2v) and the bms is listed for 3.2v. so just wanted to make sure that this BMS will work.

Second question is wiring up the charge on the BMS. The BMS has 2 different neg for load and charge, C- and P- what i want to do basically is create a battery with 2 terminals like how a normal trolling motor/car battery is set up. So the positive side terminal will have both C+ and P+ directly from the + battery. But the neg side has to go to the BMS and there is 2 tabs to solder wires, the P- and C-. can I have both the P- and C- go directly to the neg terminal? Or do i have to have a dedicated charging connection, so the p- goes to the terminal and c- has to be the connection for charging?
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#2
the other option was this one..

https://www.amazon.com/NOYITO-Protection...den&sr=1-2

now this BMS has the load and charge on the same connection so i dont need a separate charge cable. just attach to the terminals.

But this one is only a 30A rated. and the trolling motor is also only a 30A motor, normally I would want overkill and want a higher rated BMS, but maybe thats not that big of a deal?

this one also has a max of 20A charging, while the other one is limited to only 10A charging so if the 30A rated BMS is fine with a 30A motor then this one seems like the one to get?
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#3
both bms will work, they are for lifepo4. But for a motor I would want something that had good peak amp capabilities.



I been using 80a constant 250a peak 4s bms on my jump packs, they also can charge at up to 50a, they cost me about 30 dollars, you can find on ebay. This has same port charge/discharge. These have no problem running my 30a tire inflator with its high peak motor.



On the first bms in your link, that has separate charge/discharge ports. it will need a dedicated connecter to charge, its why its rated 10 amp max charge. I prefer the bms that have same port charge/discharge, easier to wire up.

The second 9 dollar 30a bms i would not use on a 30a motor. It will not run it for long before it overheats. You can add a fan to it to keep it cool if using constantly.





12v 4s 80a pcm bms peak 250a , you can see it on the bottom. The top bms is 450 peak amps, overkill for your motor.
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#4
Thanks for the feedback, I did find one that was a 50A rated that can be wired up in both split or common port. so hopefully the heat wont be a problem with having a little overkill on the amp rating. But because of what I'm using this for this year I dont think it will be an issue. I'm going to be camping/fishing up in MN and where we are camping there is no power. So I have a bunch of solar panels to recharge the batteries. My old setup that I have used in the past was a lead acid walmart trolling battery, and it worked great except for the weight. But whenever i have camped in a no electricity area I have always been very conservative on the battery. As in never going full speed on the trolling motor to conserve battery power/ shorten recharge time. Speed setting 3 vs 5 on the trolling motor does not have that much difference in actual travel speed in the canoe anyway. So other then maybe doing a test to see how warm it gets I will stick with never going full speed for this year. And if it does get to hot at full speed then I know I will need to upgrade the BMS, because the years I camp in areas that have power and easily recharging.. its full power! lol
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