Connecting a BMS Quick Guide [How-to]

Hey eSk8!

Just want to share how I connected my BMS to LiPos. In this case I will be using two 4S Lipos in series to an 8S BMS… However this guild should work out for any LiPo config you would like to use.

You will need: BMS LiPo Batteries Soldering Skills

So I did not think about making this guide until I had already soldered all my components… I will update when I do this again but until then hope the pictures help.

This picture shows how the BMS is supposed to be wired.

You will need to solder the negative leads the the B- and P- locations. As well as the last black wire on the balance leads from the battery will need to be soldered to the B- Location.

For wiring in series, it is very important you follow this chart so nothing gets shorted when connecting your batteries.

You can see I have all five balance leads on the battery with the positive wire but i only have the last 4 on the battery with the negative wire(red wire removed). With the last black wire going to the B- location.

Make sure you plan how you are going to connect everything before actually connecting it as you will only have one chance, if you short any of your components they will not work again and just lost your money.

Once you have double checked everything. YOU MUST FIRST plug in the negative wire to the B- location.

After you can go ahead and connect your balance lead to your battery and then connect them all together to the BMS.

When you are done you will have your positive lead coming from the battery and your negative lead coming from the BMS. This will allow you to charge and discharge keeping your battery balanced.

To charge you will need to get a compatible charger(Voltage varies on your LiPo config) and DC-plug to solder… I Soldered all my connections on the a Switch. One side of the Switch has an LCD and the other side had the charger leads.

After your charger should indicate when your battery is chargeing or full. (Red=Charging, Green=Full)

In the End your build should look similar to this, all that is left is securing the electronics and organizing them on the board to your taste!

Hope this helps, feel free to ask any questions.

Check out some of the components used in this build at !


Where did you get the charger

@oriol360 thanks for this excellent write-up!

Bookmarked! I’ll be using this soon :beers:

You can get a similar charger here

I’ll just leave this here :wink: It’s my diagram for a 9S Setup, but it’s is the same thing!


The Charger @Hillso Linked is the charger I bought for 8S this is the 8S BMS I bought: Here

@oriol360 What female DC connector did you buy? Your solution seems much better than mine :stuck_out_tongue:


I actually got this female DC Jack that comes with a long wire already hooked up ready to solder on to your build:

1 Like

What did you wrap your BMS in? Shrink tube? What diameter?

I just wrapped it in electrical tape. It’s easier for me, As I don’t have to cut out the parts I need exposed.

Glad to see you in here @oriol360 after you basically saved my ass this weekend.

@longhairedboy Awesome Man, Glad it worked out for you! Yeah I’m trying to get on more often I just don’t have time to post as much as I would like :confused:

made an account to ask this question. I have a 12s BMS + 50.4v 4A charger. I’ve wired everything up correctly from what I can tell, but it only charged 6 of the 12 cells to 4.2v, the rest are left at 3.8v. What could be the reason for this?

Hey @help,

Do you have any pictures of your setup we could take a look at? Also what BMS did you get? Sounds like one of your batteries isn’t hooked up properly :confused:

Hey… I hook…up everything they way I read…and went over it over n over…battery shocks you…thank god they didn’t burn up…can u please make a video …it would be a big help I tried…dude I tried

@Das53 Hey can you post pictures of your setup without actually hooking it up, to see where your connections are. I think you might be connecting your balance plug before connecting the negative terminal. or you might be getting a short somewhere.

Grab the balance plug was plugged in first…so I should plug in the …negative lead first…then the balance negative wire…then the positive lead…the the balance?

When I connect the positive to the bus it shocks up…and the balance leads isn’t even connected yet