10s BMS wiring? (from first group buy)

I haven’t touched this project in a while and have not only misplaced my manual, but also the picture @longhairedboy sent me.

Long story short, I need to wire up this BMS and am not sure what goes where. -the e switch is the two prersoldered wires -the balance leads are already hooked up because I did that when I had a manual…

here’s the link to the BMS: http://www.bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D223V1.html

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I’ve been wanting to buy that bms to try it out but I hear there was a bad batch going around and they were burning up.

I’m sure it’s the same as any other bms but I don’t want to be wrong and confuse you further

P- is for negative wire to Esc’s C- is for negative wire to charge port B- is for negative wire from battery The positive wire from battery goes directly to Esc’s positive wire and charge port positive wire. I just hooked mine up a few days ago and so far it works like a dream. Note: it won’t even turn on unless you have the balance wires connected


Balance ports are the same as lipo except no lead for main negative terminal.

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You got a manual? Did you have to pay extra for it? :slight_smile:

@cmatson I’ve still got the data sheet from the group buy if you want to me send it to you.

Nope, I just got one with the bms that told me what terminals were what, and all about the cutoffs etc.

Didn’t really pay much attention to it, and when I needed it, I had already lost it


if i had seen this last night i would have posted another pic of the chart mine came with.

This BMS is great, i’ve got one in a customer build and its working really well.

Where were you able to buy the BesTech BMS from?

I want to upgrade from my current $15 BMS (which I am bypassing for discharge) as I want to feel safer when leaving it on the charger over night

use the link above, and contact Bestech about purchasing the BMS.

I think they had a minimum order quantity of two… but I may be mistaken.

Thanks. I just sent them an email.

If the minimum order quantity is above 2 I might start a group buy for them.

Also, what does the ‘E-Switch’ thing mean? Is it an ON OFF button?


Yep, on off switch

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So if just for fun i plugged in the balance wires before i wired the main wiring in the bms, could i expect it to heat up? Not that i did that…

I don’t think it matters which you connect first. Just have all the wires connected correctly when you turn the bms on. If you have the balance wires connected in the wrong order, That will damage the bms.

On my very first build with Li-ions and bms, I connected the main wires first and tried to turn the bms on without connecting the balance wires. ( How Dumb Was That) The bms would not turn on. ( obviously because it saw zero voltage from all cells) So I connected the balance wires and then it turned on and the whole episode did not damage the bms.

Does that look about right? @Namasaki ?

Looks good to me.

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@Namasaki still have this bms? If so how is it holding up?

Been running them on 2 builds for long time. Never a problem yet

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Awesome thanks I’m definitely gona get a set

@Namasaki what’s preferable if i want to use BMS for charge and discharge (no bypass!)…to have a BMS with the same port for charge/discharge or with different ports? What’s the difference and impact on the the design to have one or another (if any)?

I don’t know if it makes much difference whether there is a separate charge port or not. I’m not an electronic engineer though so I can’t really say for sure.

I prefer the Bestech bms mainly because of other reasons.

  1. It’s ability to handle high peak amperage.
  2. The heat sinks
  3. Twice the balancing current of other bms’s
  4. And most of all, the built in E-switch which saves you from spending an additional $40-$60 for an external E-switch that would likely fail.