John in CR
100 TW
My ebike charging station has been on hold due to a lack of electronics at what I considered reasonable prices, and refusal to go the high loss route. I want to charge my packs with an 82V cutoff using solar power. For a portable solution it makes no sense to charge a 12V pack to run an inverter with a charger plugged into that.
Now that I've sourced some small 12V solar panels I can finally get up above pack voltage, and I was going to try running a cheap low charger using DC directly from the panels. Then it dawned on me, why not run the solar output directly to a BMS. As long as the open circuit voltage from the panels is higher (significantly higher looking at cell output graphs) than pack voltage, then I think it should work well and charge and balance my pack in the process with an appropriate cutoff, as well as no issues cycling on and off when panel output drops off due to clouds.
FWIW, in the interest of safety I'll do this with used A123 M1's that could use regular balancing anyway.
Panels, diodes, BMS, battery pack is it. I'm guessing that the max voltage of these 12V panels maxes out at 16-18V, so I plan on 7 in series and add parallel strings to increase current, limited by the area of panel I want to go for, though I'd want to stay well below the BMS's charge limits.
John
Any holes in the plan.
Now that I've sourced some small 12V solar panels I can finally get up above pack voltage, and I was going to try running a cheap low charger using DC directly from the panels. Then it dawned on me, why not run the solar output directly to a BMS. As long as the open circuit voltage from the panels is higher (significantly higher looking at cell output graphs) than pack voltage, then I think it should work well and charge and balance my pack in the process with an appropriate cutoff, as well as no issues cycling on and off when panel output drops off due to clouds.
FWIW, in the interest of safety I'll do this with used A123 M1's that could use regular balancing anyway.
Panels, diodes, BMS, battery pack is it. I'm guessing that the max voltage of these 12V panels maxes out at 16-18V, so I plan on 7 in series and add parallel strings to increase current, limited by the area of panel I want to go for, though I'd want to stay well below the BMS's charge limits.
John
Any holes in the plan.