Solar charging

[unclejam]

Hi everyone.
I have been thinking about solar charging for my ebike recently but most internet discussions about this topic fall apart when the pack voltage is larger than say, 36v, as the charging input power must be higher than the pack voltage for obvious reasons (unless a booster-type circuit is used apparently.)

Anyone have any leads on new solar developments, or how best to build a home charging setup? (My current battery is 19S6P - 79V and charges in about 2hrs with a 400W charger)
Thanks in advance for any input.

 

[dogman dan]

Charging as you ride, or a home based charging station?

Couldn't multiple 24v panels charge sections of a larger battery? I don't know if that can work or not, while the pack is still parallel connected.

 

[unclejam]

Hi, probably home-based - the array you would need to get useable charge into an ebike battery in the middle of the woods would be too big to carry!

 

[dmwahl]

Why do you want to do it? Unless you have a very unreliable power grid or are off the grid, it's unlikely to offer you and real benefits over plugging into the wall to charge. If just for the fun factor, and I totally understand that one, then multiple panels in series would be easiest, but you'll still have to monitor the power and cut it off. You might be able to rely on the BMS to do that, but if the open circuit voltage of your panels exceeds the spec of the charge controlling FETs, then you risk damage. A 24V panel may have an open circuit voltage of twice that, so to charge a 79V battery you might have an open circuit voltage on your panels of over 100V, past the limit of most FETs used on a BMS. One option would be to replace the parts with some higher voltage parts, but that won't be easy.