LiFePo4 off gassing during charging

[OCD Garage]

I've been running the same V-power 48 volt, 20 amp battery pack for about 3 years now, had to change the BMS once about a year ago due to a burnt connector on the BMS plug. Lately, I have been noticing an electronic smell when charging the battery. Not an alarming, choking you odor, but a "wouldn't leave it under my desk at work to charge" smell. I'm using the same motor, charger and going approximately the same distance. The only thing that has changed is I built a new bike this year and the battery is now inside a non-vented box away from the elements, but I open the battery box door when charging. Any ideas or suggestions? As it's still working fine should I be concerned? I don't want any horrendous surprises on my morning commute...

Thanks

 

[mateusleo]

Check if the cells are puffed, might be gas leak?

 

[davec]

Check if the cells are puffed, might be gas leak?

lifepo4 never gasses- if it does there's something really wrong with the cell
the venting mechanism is only there for emergencies

 

[OCD Garage]

Thanks guys:

I have to learn not to panic-post. Upon disassembly (unwrapping duct tape) I see the plastic BMS box has altered its shape somewhat due to being in such close proximity to the battery. I see now the new BMS needs a larger box. Just not enough air flow taped to the battery pack and now it's summer, the extra ambient temp is making the difference.

 

[r3volved]

Ya my Vpower bms gets pretty hot at times.
I haven't noticed any deformation of the box or any smell, but it's a good thing to note for future. (Currently 1yo battery)

 

[dogman dan]

I was going to predict it was a bms melting something. When cells leak and gas, they smell like solvent, sort of sweet smelling.

 

[mateusleo]

I was going to predict it was a bms melting something. When cells leak and gas, they smell like solvent, sort of sweet smelling.

Leaked cells smell good? That's tempting...

 

[ColinB]

Great looking bike! I assume you custom built it? Hope your battery will be ok.
Colin

 

[OCD Garage]

Thanks for the advise guys!

Yes the bike was built in my workshop at home. I had the kit on a Walmart quality mtb previously and besides being extremely top heavy, I got tired of changing the V-brake pads once a month. The battery seems fine, still working well. I had to replace my BMS about a year ago and the new one took up more space inside the plastic box than the original one did. I assume as it's jammed up against the battery inside the new battery box there was no cooling in between. The inside panel warped and now touches the BMS which gets hot when I charge the battery. I need to find/make a larger box for the BMS where it does not contact the inside of the box. :wink: