Safe MsuperX charger voltage

[ryny24]

I have the 84v MSuperX, which comes with a 1.5A charger and it measures 84V exactly on a volt meter.

I recently purchased a 84v 3A charger, but the volt meter shows 96.7V (with no load). Does the msuperx have a BMS with a safe voltage range? I can't find any specs except for the 84V included charger. Obviously the safe option is to return it lol, but I've already cut the connector off.

Thank you!

[Chriull]

@ryny24 - you can look if your charger has a trim pot to adjust the output voltage to 84V like described here 

If there is no voltage sensitive part in the BMS, one coul theoreticaly use this 96.7V charger for a 84V battery. While the constant current phase of charging the voltage is lower than 84V and once the charger reaches this 84V the BMS will cut off charging once the first cell reaches the overvoltage threshold (something around 4.23V)

But this is absolutely not recomendable since it will soon degrate your battery pack until its not usable anymore (no balancing and stressing of the/some cells). Additionally one should have an increased risk of fire hazard by stressing the cells on a regular basis...

Edit: ps: although very presumably a gotway bms has overvoltage cutoff on individual cell basis, i have no proof for this.

[ryny24]

I did not even think of checking for a trim pot. Thank you @Chriull. Unfortunately, I checked last night and I do not see one. I will not use this power supply and get the right one. Thank you again!

[mrelwood]

Sounds like you got a wrong model. Good decision not to use it! In my understanding a 84V charger shouldn’t put out more than perhaps 84.5V under any circumstances. The trimpots are usually for fine tuning the output voltage, but 96V sounds like it’s for a different cell count all together.