I've heard LiFePo4 Batteries are good??? There are a few sellers on Ebay and they range from 150 to $300. Should these be trusted? Do they have warranties? They're coming from people in China mostly and they're covered in Duct Tape it looks like lol Go to ebay and type in Lifepo4 and you'll see what I mean. Are there any "respected" websites that sell similar lifepo4 batteries with warranties and the like?