I have this build planned out but would appreciate a go/no go from others if this is a decent idea or not. I have a set of Echo cordless power tools which run "58v" 2ah or 4ah batteries. I have an extra charger and battery collecting dust, and would like to put it to use as a portable power pack similar to https://www.instructables.com/id/12v-Power-From-Ego-Power-56v-Battery/ while also retaining the battery charging capability. It charges the 2ah battery in ~30 min, an hour for the 4ah, so it opens up the possibility of topping off the battery if we go out exploring in the truck.
There is a pretty good teardown of these batteries HERE, they are 14s2p 18650 batteries (or 14s1p for the 2ah pack). If I use a 95% efficiency step down converter to 12v, that might give me a ~17ah battery [(56v/12)*4ah*95%=17.73AH]. The converters seem to have a draw even when not under load, so it would get a switch. 12v out would go to a couple USB ports, a cigarette style socket, binding posts, and maybe some sort of quick connector. I took the charger apart and there seems to be room for the converter in the base if I clean out a few plastic rib supports from the case. If I just use the binding posts and a small usb socket, I might be able to get it all in the OEM charger case. Otherwise I have a plastic ammo can that I can put everything in and would also offer some weatherproofing.
This would cost me ~$50 for the step-down converter, usb socket, switch, and binding posts compared to $325+ for a Powerwerks PWRbox + 20ah Bioenno battery + charger. Terrible idea, or go for it?
There is a pretty good teardown of these batteries HERE, they are 14s2p 18650 batteries (or 14s1p for the 2ah pack). If I use a 95% efficiency step down converter to 12v, that might give me a ~17ah battery [(56v/12)*4ah*95%=17.73AH]. The converters seem to have a draw even when not under load, so it would get a switch. 12v out would go to a couple USB ports, a cigarette style socket, binding posts, and maybe some sort of quick connector. I took the charger apart and there seems to be room for the converter in the base if I clean out a few plastic rib supports from the case. If I just use the binding posts and a small usb socket, I might be able to get it all in the OEM charger case. Otherwise I have a plastic ammo can that I can put everything in and would also offer some weatherproofing.
This would cost me ~$50 for the step-down converter, usb socket, switch, and binding posts compared to $325+ for a Powerwerks PWRbox + 20ah Bioenno battery + charger. Terrible idea, or go for it?