Newbie needs help with solar charging. Negative terminal melting insulation.

[Fishpharmer]

Hi, I am new here, been watching Will Prowse on youtube trying to learn something. I bought two new Li Time 12v 100Ah TM batteries. I was trying to charge each battery individually with my 400 watts of solar panels and thunderbolt charge controller before connecting in parallel. The negative connector got so hot it melted the insulation. I connected it to a lead acid battery and my other Li Time battery and this did not happen. I reconnected to “hot” LiTime and it got hot again. Could my new battery be bad? The other “good” LiTime battery shows 14.8V. The “hot” LiTime shows 13.5V after a day connected to 400 watts and thunderbolt charger. Thanks for reading and any information. Should I return battery?

 

[BentleyJ]

Alligator clips like that have a very small contact area and are too thin to carry the amps. You can get battery terminals like this. Connect the wire under the wing nut with a good solid copper ring terminal.

Marine Style Battery Terminal Adapter - Top Post to Threaded Stud

www.batterycablesusa.com

 

[Fishpharmer]

Thank you @BentleyJ !! I will do that. I guess the thing that baffles me is that it did not get hot on the other 3 batteries I connected it too.

 

[Fishpharmer]

A little off topic but I just connected the two 12v 100 Ah Li Time batteries in parallel with 3 foot 2/0 ga cables. I hooked up my small 1500 watt jupiter modified sine wave convertor to it with 6 ft 2 ga cables. Next I plugged in my 5000 btu 120v Air-conditioner in the camper. It ran flawlessly. I had 13.28 V going into inverter to start. I did not time it. I had 12.9 when I turned the inverter off. The AC seemed to work fine. I don’t have enough Ah to run the AC very long. Yet, it is good to know that if I expand my battery bank I could run AC.
Thank you! I will be quiet and read a lot now.

 

[MisterSandals]

In your pic it looks like the red wire goes to battery negative and the black wire to positive.

 

[Fishpharmer]

MisterSandals you had me second guessing myself. I just enlarged the photo, all is good.
Thanks

 

[MisterSandals]

I was talking about the other end

 

[Rednecktek]

thunderbolt charge controller

There's the issue, the SCC is garbage for that size of a load. You'll need at least thicker wire to a proper terminal. 400w is about 40a and it looks like 14awg wire there which is only good for 15a.