I have a 48v lipo4 battery that I would like to keep within a min/max range (let's day 50%/60%) while in storage.
Hoping to find something within $100 - $200 USD range?
We would need to know more about your specific 48V lipo4 battery pack
...because different manufacturers, build 48V battery packs, in different Series configurations (like 14S, 15S, 16S etc.)
...& also, use different Parallel configurations, for different applications. (2P, 4P, 8P etc.)
Sounds like your looking for something like a "Trickle Charger" like used on Lead Acid battery's
...but, "if" you have a good quality Lipo4 battery pack it shouldn't need to be "maintained" while in "short term" storage (like over a winter)
Most good quality Lithium cells have a pretty low self-discharge rate (while in storage)
...but, the most important "thing" is to make sure there isn't any Parasitic Draws, draining the battery pack, while in storage
...so, make sure the battery pack is "electrically" disconnected from...everything while in storage
Like make sure the main cut-off switch or Circuit breaker is turned off
...or (if you have to) manually disconnect (1) of the battery cables
