BMS getting very warm while charging?

[AxialFlux]

Just got back from a week long camping trip, and noticed that one of my 48v 13ah batteries gets quite warm while charging. Seems to be right around where the BMS is, and stay warm around the first hour or so of charging, then starts cooling down somewhat. This is using the stick 2amp charger, but I did try my 4amp charger, and that seemed to make it very hot. In fact, I stopped using the 4amp charger, as I was afraid something might get damaged. My other battery, which has the same specs, seems fine on either charger, and does not get the slightest bit warm. Is this something to be concerned about?

 

[6zfshdb]

I have the same problem with one of my batteries. It gets very hot and starts to smell but only when charging at or above 6 amps. At 2 or 4 amps, it gets warmer than my other batteries but otherwise performs normally. The manufacturer says this is normal for their batteries but doesn't recommend charging above 4 amps.

You may have a different problem though and I think it's cause for concern. I would check with the kit / battery maker to see what they suggest.

 

[JES2020]

Just got back from a week long camping trip, and noticed that one of my 48v 13ah batteries gets quite warm while charging. Seems to be right around where the BMS is, and stay warm around the first hour or so of charging, then starts cooling down somewhat. This is using the stick 2amp charger, but I did try my 4amp charger, and that seemed to make it very hot. In fact, I stopped using the 4amp charger, as I was afraid something might get damaged. My other battery, which has the same specs, seems fine on either charger, and does not get the slightest bit warm. Is this something to be concerned about?

I second what 6z says.... get the pack checked.
I will personally never charge above 2 amp for just such a reason...also the battery will last longer.
I also place a smoke/fire dectetor right above the battery/bike along with an ELECTRIC extinguisher for added safety, both during charging and storage.

 

[tomjasz]

My other battery, which has the same specs,

Who built the battery? Where was it purchased from?

 

[AxialFlux]

Battery is a Wallen Power from eBay. https://www.ebay.com/itm/283905457800

Just heard back from them, and this is their reply:

Yeah, BMS is usually installed on the left or right side of the battery. And a metal heat sink is sandwiched between the BMS and the battery case. So when the battery is charging, this area will get warm, because all the heat is concentrated in this area. Also, when using a higher current charger to charge the battery, the battery will get hotter because it transmits higher current, which is normal. And please rest assured that our batteries have not had any accidents due to warming.

I also checked the specs, and 5a is the max charge, so maybe just stick to 2a on it?

 

[tomjasz]

maybe just stick to 2a

Best practice.