Hi Searching,
Don't forget that flooded lead acid jars used to be used for welding.
Sorry to hear about the salesman hype, particularly on number of cycles.
Does that hype include the energy density?
Searching_Ut wrote:
Even the somewhat safer LiFePO4 batteries can rapidly discharge in a quite spectacular manner when damaged or abused. Electronics utilized to prevent over discharge, over recharging, and keeping the battery pack balanced make a huge difference from a safety perspective. As you're learning though, for the most part there aren't any standards to speak of, so it's hard to know what you're getting.
As a side note, from what I've seen there is a lot of salesman hype in the marketing of lithium batteries. I wouldn't expect anywhere near the cycle life performance claims you see being made.