I thought about using the Batcap 8400 because it would save weight over conventional batteries. It weighs 70 lbs vs several hundred lbs for yellowtops. Its capable of 8400 amps @16V and up to 9600 amps@12V. Anyone have experience with these and how they compare to batteries? Any issues w/these things?

Im not too sure if they are made to be a daily battery or not check termpro maybe

Termpro makes no mention of them. I was told by someone who sold them that they feed some sort of a "backcharge" into the electrical system that leads to alternator and battery failure, and they only last 2 years. They cannot be charged correctly by the vehicle, you have to buy the 350.00 charger for them. So basically I'm better off with the extra 500 lbs of batteries because it's better than replacing $2,000 worth of alternators and electrical components that would fry in six months.