Help with charge only BMS wiring

Ok. So the instructions seem pretty straightforward for wiring this bad boy up. The problem is that I bought a 45A continuous BMS without thinking when I meant to buy the 60A. By all means… If you think the 45A is enough let me know. I’m running two sk3 270kv 6354 motors with 6s car ESC and a 6s4p lithium ion pack.

Basically I want to figure out how to wire this up for charging only so I can charge with laptop style charger.


You might be okay with the 45A continuous as the BMS allows for higher burst current, but I’d be more comfortable running a 45A BMS on a 10S setup. I don’t think there’s anyone here who knows 100% whether it’ll work or if you’ll get constant overcurrent problems because it depends on a lot of things such as your riding environment and weight.

As for the diagram, it’s pretty self explanatory, the battery positive (red wire) also goes to your charge port, and the BMS (P-) port goes to the charger negative.

Judging by the balance cable I’m assuming you have the positive lead (red) and 6 negative leads (blacks). The red lead should go to balance slot ‘6’ and the rest will be paired to 5,4,3,2,1. The last black lead is a duplicate of the battery negative so you don’t need that. The discharge negative (thicker black wire) goes to the BMS (B-).

1 Like

Off topic, but how long did this take to ship and did you buy it from their ebay store or their site? Thanks.

#2 on the instructions gave me the impression that the N- port would be used for charging only.

I bought from their site and it took a friggin month.

Put a space before the # sign to avoid big text. I edited my comment with more instructions, check it out. I think it’s saying don’t use N- when you’re charging/discharging from the same port (P-).



guess I won’t be riding before summer ends :frowning:

I think you can probably run your board for a month or 2 without a BMS. Just be careful to err on the safe side with your charging, set your discharge voltage cut-off with the VESCs and maybe check the voltage of your cells every week or so to make sure they aren’t too far apart.

I’m also waiting for a BMS from China. Through eBay.

1 Like

When did you order? Let me know when you get yours :slight_smile:

I will probably ride without BMS if possible, but I am having an issue with one of my cells. It drops very quickly compared to others. I am hoping the BMS helps to keep this cell in balance, otherwise I will replace it.

I ran some tests recently with 6s and dual 6355 230kv motors. 16/36 gears and belt drive 185lb rider going up 10% grade at full throttle Real time measurements as follows: 37.38 peak amps 863 peak watts So, I would highly recommend that you connect the BMS for discharge as well as charge To get the full protection benefits that it will give to the battery. You probably won’t go over 45a but if you do, The BMS has over current protection so it will cut back and You could also put a 40amp inline fuse between the battery and the ESC for extra protection.


Thanks for the info! Maybe I will go ahead and wire it up.

sure, try it with the inline fuse at first and if it never blows, then you got it!

Really, its just a good idea to have a fuse anyway incase you get a short in wiring or Esc.

Get an ATC/ATO fuse holder. There not too big and you can get 40a ATC fuses on Amazon or Ebay ATC fuses are sealed ATO fuses are not sealed

Hey does this wiring look right to you guys?

You want the charge port connecting to the BMS otherwise you won’t be balance charging, so make sure charger negative goes to P- on the BMS. You may also want an anti-spark switch/loop to avoid nasty sparks when connecting the battery.

As for the ESC’s you’ll want to wire them in parallel instead of series so have two cables from the BMS and battery positive go to each ESC. Make sure balance lead voltages are right!


Holy smokes. I did it all wrong. Let me re draw this thing.

Like this?

1 Like

The other charge cable should be going to battery positive not the bms. Throw in an anti spark and you’re set.

1 Like

Great thanks!