Lithium Golf Cart Fire

[chelmuth]

For those of you who have Lithium Golf carts be very aware!!

6 Months ago I rebuilt a club car ds that we had been using at our business that my dad owns for the last 8 years and converted it to lithium cart using Big Battery Batteries with a Navitas 700kw kit, been working great for the last 6 months until disaster struck last night.

I finished work a bit late so I was in a hurry and parked the Gem cart that I had been using directly behind the club car, walked past the club car and noticed the voltage meter was showing 57 volts [it's a 48volt cart with a maximum voltage of 51 volts] I instantly thought oh boy somethings wrong and was planning on unplugging it when my brother who was with me said, oh its been doing that a long time. Just 3 weeks prior the old charger went bad because it got wet and burned out I got the correct charger for it and had charged it up multiple times just to double check that there wouldn't be any issues, went to 51volts like it was supposed to, I then returned it to service and it had been working the last 3 weeks like that.
My brother told me its been doing that every time it charges and when you unplug it it drops back down to the correct voltage I assumed it was just a bad reading... until it wasn't

16 fire trucks and absolute destruction.





So when I sat down and tried to figure out what happened this is the best thing I could come up with...


This charger that I was using was not a ip65 rated charger and the location were at is extremely dusty and and muddy when it rains, the grounds guy that used the golf cart the most just set the charger on the back little step on the cart and left it there then when he wanted to charge it he would just plug it in to a outlet, due to it being so dusty I think it messed something up in the charger and didn't stop charging.



Here is the link to the footage https://onedrive.live.com/?authkey=%...213849&o=OneUp

[CP241]

Glad everybody was okay and nobody got hurt! And I’m sorry it looks like you have one hell of a disaster left over.

I do have to say, if a 48v lithium pack would usually only read 51 volts then something was wrong with that pack from day 1. 51v is “dead” for a lithium pack. If it was run under 51v then damage probably occurred. Mine never goes below the mid/low 52’s. Resting off the charger it’s usually in the mid 53v range.

It is normal for the charger to go UP TO about 58v for lithium, but not above about 58.2 max. Anything above 58.4 is dangerous. My charger cuts off at 58.2 (programmed that way from allied, I didn’t modify anything).

Something sounds like it was wrong with your pack from day one if the voltages and conditions you describe are accurate. And if it was 57v and not charging something is wrong. If you had been charging it with a charger not designed for lithium then that would exacerbate the problem.

Guess we’d need more details surrounding what happened before, but it doesn’t sound like things were happy long before it caught fire

[Pat911]

Was the battery LiFePO4 or NMC chemistry?

[CP241]

Originally Posted by Pat911

Was the battery LiFePO4 or NMC chemistry?

Good catch just looked at their website and didn’t realize they do have a NMC battery kit that says max voltage is 50.4v

Didn’t realize they had that option. That doesn’t seem like the most desirable option… kind of expensive too

[chelmuth]

It wasn't, partly due to space

[Volt_Ampere]

Properly designed and installed BMS should protect the battery from overcharge and undercharge. Something is wrong here if voltages were that far out of wack.

[Pat911]

And LiFePO4 is more forgiving when abused compared to NMC.

[UpstateNYDS]

Were you using a BB charger or something else? I know not all batteries are the same but as for the voltages, this is what BB told me about minimum and max volts, and is different than what others are saying-

[Pat911]

That voltage info is correct for 14s NMC chemistry.

[UpstateNYDS]

Just re-reading this. Very sorry this happened and no one was hurt. I’m a little surprised that charging to 57 volts for weeks, it didn’t happen sooner. Over charging these batteries is no joke **** goes bad in a hurry. BMS aside, always trust but verify.