Ok, so question w/ my batts.

One of my batteries for my hydros keeps giving me a shit load of trouble and i can't think why it would keep doing this...

Basically the negative terminal likes to heat up or something and it just melts off a good chunk at a time? Why is this? I was able to fix it the first time with some washers and a bolt, but this just happened the second time and its completley toasted.

My question..Why is this happening? I checked the connections and they were a bit loose, could it be from the electricity arcing? Shitty batteries?

I went with these 4 batteries cause they are tiny and i can fit 4 in my spare tire well, but if i keep having trouble i might just have to switch to something else...Yellowtops maybe?

Input? Help me?

Thanks