250Voltage discharging turnoff circuit
This is all possible . You can make any DC mask you want . Your power is rather low so you could just burn it up in resistors and current sinks .The volt thresholds are easily done with simple compariters like LM393.If you use mosfets for your current sink be careful .Mosfets in linear mode are for people who know what they are doing .Otherwise just use BJTs .You can put them in series if you like because your currents are low and you dont have to worry about current sharing.This has all been done by others and works .One thing that I did was use an interleaved buck convertor into some elements .The idea of this is that you can vary the effective resistance of the elements to make the desired VI curve.This worked well for 110V 10A with 1.75 Vpc UVLO for testing a 50 cell lead acid bettery.I interleaved by 4 using a LM339 and used 4 cheap to220 mosfets that ran cold on no heatsink .The elements got hot of course but I run a pwm reg to drive a computer fan which kept things cool .The interleaving or polyphasing was done to keep gross ripple low meaning that huge electros wernt needed .I am told that lead acid does not like ripple but I think your batteries dont mind .I did all this last century so you might want to use a micro .