Battery pack charging problems please help

ESK8 Electronics
1

Hi i have made my battery pack of 50 LG HE4 batteries. I have them in a 10S 5P configuration ending up with max 42V and 12.5Ah.

I have a 10S 60A Suunpower BMS, which i have connected the right way to the pack. The battery leads reads the right values from 3.6V up to 36V

I have also bought a 42V 4A power supply, With a fuse.

I have the two connected via a XT-90 Anti Spark plugs.

My problem is that the pack wont charge.

The powersupply blinks when red to green indicating that the power is cut. I can measure it goes from around 4A to 0 and over and over again. So something is wrong.

I can press the XT90 connector half in and the power will flow constant with 1A. But then the XT90 will get hot, so i pulled it fast.

I can not seem to figure out what is wrong. I have bought and changed the BMS, no smoke or nothing comes from it. So i think it works.

Can it be the resistor in the XT 90 that makes it work weird or what can i do?

2

I never heard of using an anti-spark connector to connect your charger to the battery. It may be messing with the charger’s sensing circuit. The charger negative to the bms P- pad The charger positive straight to the battery positive Usually, people wire a DC connector that matches the plug on the charger

3

Its because the BMS uses same port for discharging and charging. Can it be why it got hot?

4

oh man my charger has some wierd port like an xlr but a lot smaller, would it work normally if i put an xt90 on there

where can i buy one of these ports

5

I just removed the plug and soldered a XT90

6

Nope it was not that. What the hell can it be. I have changed the connector to XT60 to test.nothing changed.

7

Maybe the resistor is messing with your charger

8

I use the same 3 pin connector. It’s the size of a CB mic plug.

9

I changed the connector to a standard XT60 but the same problem persisted. What do i do wrong?

10

Your XT90S is probably bad. Did you replace it with an XT60 loop key?

Here is how I would troubleshoot it:

Bad XT90S Loop key: Replace both connectors with new ones.

If problem persists then it’s either, BMS or charger.

Bad BMS: Remove the BMS from in line, if the board charges fine then the BMS is the problem.

If problem persists, then it’s the charger.

Bad charger: Replace charger.

If problem persists, then there is something wrong with the battery.

Bad Battery: Check all voltages followed by welds and solder joints if it was DIY.

11

Hi everyone, after months of waiting for new bms, then seeing that it was not a problem with the BMS. i bought a new charger and now it charges flawlessly. But weirdly enough with only 1 Amp but the charger is 2A