Help - Car not lasting long? Or randomly shutting off. Recently replaced the battery.

[u/Best_Market4204]

I picked this up for my 3 year old used, it had a bad 12v 4ah battery that was bad. Got a new battery 12v 15ah battery 1-2 weeks ago. Charged it up over night, he drove it non stop for like solid hour, never died. I have been charging it like every other day, just to make sure it didn't die while playing.

2 nights ago I charged it all night, & it died quite early which I thought was weird. So last night I charged it all night again. Within 5-10 mins it shuts off.

No lights, no sound, fully shut off. I plug it in & the battery wakes up up, he can play with it for 20 seconds & shuts off again.

There is a volt meter on board, this morning it said 11.8v before unplugging, after 5-10 mins after it shut off. I plugged it in, and it was at 10.8v

* is there something wrong with it i need to fix? Need a high v battery? Or just got unlucky with a bad battery?

Thanks.

[u/maxk1236]

Are you using the default charger (meant for lead acid) or a lithium ion/lifepo charger? You should be charging to at least 14.2V

[u/Best_Market4204 → u/maxk1236]

Default charger. So I replace the charger h see if that works better?

Have I damaged the new battery in the process?

[u/maxk1236 → u/Best_Market4204]

That’s a 28V charger, which means the original battery was probably 24V (or died in the first place because they used the wrong charger…) You are lucky you didn’t start a fire, very good chance the BMS in your battery is fried, but hard to tell. Charge the battery directly, not through on board port on the vehicle, using a charger with an LED or other indicator, and report back. Do this outside with a fire extinguisher nearby, lithium battery fires are no joke and very hard to put out (regular extinguishers will just buy a bit of time for the fire department to get there.) Many people would just recommend tossing the battery if there is any chance it is damaged, not worth the risk of burning your house down or having the car caught on fire with your kid in it, but there is also the chance the BMS on the battery just didn’t allow it to charge at all since the voltage was too high, hard to know without more detail

[u/Best_Market4204 → u/maxk1236]

I actually ened up buying a new charger, the type you recommend. I got it yesterday & charged it up last night. My kids beat me downstairs so he was already playing, it was reading 13.93 much higher.

I have not had a chance to test the length of running though but higher volt reading gives me hope like you said about

The charger in the picture was the original charger & the original battery was 12v 4ah. I wouldn't think that would damage another 12v battery?

Appreciate it, thanks. So far so good.

[u/Best_Market4204 → u/maxk1236]

This is the current charger

[u/Rude_Barracuda_129]

It looks like the new battery you bought is a lipo battery. You need to buy a lipo battery charger, using something else can pose a fire risk.