Battery charge wire connectors melted

Hey guys,

Opened up the enclosure on my deck to check some stuff and replace a failed battery charge status display and noticed the connector between my battery and the charge input plug had melted. Wires are all still connected with the metal crimps so charge was still happening so I’ve no idea exactly how long it has been like that.

I replaced the connector and tested it out hoping the connector itself had just corroded and resistance was local but the wires got too hot to touch. The wires are 24 gauge so should be rated for 3.5amps and my charger puts out 3amps. There doesn’t appear to be any corrosion in the charger plug or connectivity issues.

My feeling is that’s it’s likely a faulty charger? Pushing out more amps than it should? The charger is correctly testing at 50.4 volts but I’m not game to run my voltmeter in series to check the amperage.

Initially I thought the wires were just too thin and I should replace them but the rating is within spec and until I rule everything else out I’d rather not open up the battery.

Anyone have any insight? And if you agree with the diagnosis, can anyone suggest a good charger for li-ion 12s4p nominal voltage of 43.2?


I use 50.4v charger on my 12s. Maybe it was humid, or moisture inside the connector. Use multimeter to test charging port for short.

Hiya, thanks for the reply. The voltage is correct on the charger but I’m wondering if it’s pushing too many amps? It came with the battery and feels very flimsy and cheap. I’m wondering if maybe it either pulse charges so ends up putting out an average of 3 amps but actually spikes much higher than that which the cables are not rated for or if it’s just faulty.

Because even though I’ve replaced the connector, the wires leading to the battery get extremely hot. Like too hot to hold hot.

I’ve tested the terminals resistance and it’s like .2 ohms so that’s not the problem (I don’t think…).

What kind of charger do you have?

Normally that means that the wires isn’t rated for the running current. If it’s rated a bit higher or close to the running charge current, It will get hot. You will need to change that wire to handle the current you’re pushing. A too hot to touch wire is a huge no no.

Do note to add a fuse to protect your battery just incase it’s not the wire that’s giving issues.

Absolutely! I’ve stopped using the deck since I identified that it was happening. The wires are definitely pulling too many amps but my question is why. I mean I can replace the wires but if my charger is putting out more amps than it should, replacing the wires isn’t addressing the root cause.

My charger should be putting out 3 amps and the wires are 24 gauge therefore should be rated for 3.5amps. So if they are heating up to that degree doesn’t that seem to indicate that the charger is at fault? .5 of an amp is large enough margin of error that heat should not be building up to that degree, right?

Fuse is definitely a good idea and I’ll install one no matter what.

This really depends on the charger itself. If it was cheap, yes. But this is why a fuse is necessary. Just incase the wire was never the fault, as stated here:

All i know is that if the wire is rated at a certain amps, it can still heat up to a large degree depending on the continuous amount of amps being pushed or drawed.

Ok, thanks for your input.