I wonder if we're trying too hard here. Let's take it back to basics and see if the price makes sense. Here's what I'm thinking based on 1.5 times safety factor
36v*10Ahr Li-On bicycle Battery
< 100w Li-On charger
150W invertor
12V * 45Ahr lead acid batteries
Solar BMS to 12V batteries
??? W Solar
That should give a 12v battery system capable of one complete bicycle battery charge taking them down to 30% charged or so and so not completely flat. Questions:
- How cheap can you assemble 45-50Ahr of 12v lead acid batteries?
- How much solar power cells do you need to trickle charge them so that 1-2 days of sunlight is enough for one bicycle battery charge. is one or two of these enough?
SolarPowered 12V 12W Battery Charger : Solar Battery Chargers : Maplin (12w battery trickle charger)
With a bit of 2nd hand scrounging, it might just be possible to bring this in under £100