I pulled the trigger on a lithium battery unit. I considered building my own but just thought, "Someone's already done this and done it right" so I went the pre-built route. Bigbattery.com makes several power units for boats, campers, home, etc. This one is the "Owl Max" and is in a stainless case with 202ah of lithium. It's got a battery management system, fused, and fire suppression device internally mounted. It's nice in that it has Anderson connectors. I'll be doing double duty with it. It will stay on my electric boat a lot and then moved to my cargo conversion when I need it. The weight is 47 lbs and it has handles for toting (not shown in the picture below). It's not cheap but it's very well made after looking at some take aparts on youtube.
Justifying the cost of something like this: I've got two 100ah agms in the camper, and two 100ah agms in the boat. And all of them are weakening after 4 years of heavy use and charging/discharging. With 200ah I can only get max about 100ah as at 50% they act pretty much dead. They're older so now it's much less than that. The drop off is linear.
With the lithium I only have to get 200ah instead of 200ah for the camper and another for the boat as the lithium is movable from one application to another. Still costs more than 4 agms but you can get nearly 80% out of it before it needs to be charged and it has a 10 yr warranty and thousands of charge's in it. Considering their longevity they should prove more cost effective that what I'm currently using. And the unit is about 12"x10"x7" in size.
With the Victron charger I'll be using, I can monitor it on my iphone, and the charger can act as a power source for the camper when plugged into shore power while it's charging the battery.
Anyway, that's my current battery story. (Current) get it? Oh well....Fingers crossed.
