I'm not sure how commonly aware of these the aviation community is. Here's my automotive experience, in the hopes that it can help some of you on here. I'm sure most of you would do unspeakable things to take 20lbs of dead weight out of your airplane, so I thought I should share this. I put one of these in my sports car last spring and I don't think I'll ever buy a lead acid battery again. It's a motorcycle Lithium Iron (LiFePO4 - not Lithium Ion) battery I bought on amazon for about $90. YTX14L-BS was the biggest one I could find. It cranks/starts my 6cyl no problem despite being designed for a motorcycle, I'm sure that a pair of them would crank just about anything. It is definitely a much smaller capacity than a regular car battery, I'm sure if you left the headlights on for 20 minutes it wouldn't start the car. I did that once and had to jump the car. They are designed to work with a regular charging system, don't need special hardware. It's all internal to the battery. I had my battery in the trunk before, and a 0GA cable ran from the front to the back of the car. The old cable weighed 6.2lbs. The old battery, an Optima Redtop, weighed 43.5lbs. Battery mount and misc. hardware was another 3.1lbs. Total old setup weight 52.8lbs The new battery is so light I thought the box was empty when it arrived. It's 2.2lbs. I mounted it in the front, and so could use a much shorter and lighter cable, .8lbs. so 3 pounds total, almost 50! pounds lighter. This is the easiest 50lbs I've ever taken out of anything, ever. I just looked up cessna 152 batteries and they're 30lbs, 160CCA, 8.5AH@ 24V. Works out to 204WH The battery I bought is rated at 250CA (no CCA rating given), 64WH@ 12V. Using a pair would give you 128WH @ 24V, and weigh 4.4 LBS. Since most of you guys are using smaller engines than what a 152 uses, that should be plenty of battery - I just used 152 numbers since it was something to compare with.