I have an off-grid campervan with Victron mains charger and MPTT solar controller.
I have a 36V Ebike. The bikes 240V mains charger output is 42V 2A. Can I safely charge directly from a 42V output solar panel?
I would say no!
The ‘problem’ is that your solar panel will blast like 10 or 12 Amps into the bike battery. That is most likely too much. Without protection of said battery. Possibly resulting in a damaged battery.
I am still hoping for a more positive response. My thoughts were to parallel from the output from the existing solar solar panel, before it reaches the MPPT controller. I would not have expected the output current from a single panel to be as high. The difficulty is finding a 42V panel with a more compatible output.
You will not get a more positive response, ebike battery fires are surprisingly common from poor charging. A solar panel with a 42V output when it is running at peak power will rise to 50V when the battery gets full and limits charge current, especially if the panel is cold. When the battery is full, what is going to stop the solar panel from overcharging it.
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It’s a shame.
The only alternative is to use my inverter and the dedicated charger. Perhaps some enterprising manufacturer may design a dedicated charge controller.
There are a lot of ebikes out there!
Best Regards
Richard Bradbury
[Moderated to remove personal info]
Li- Ion batteries are notorious for failing when overcharged. A (cascade) thermal runaway from 18650’s is not something that you want to witness. I’ve seen homes being destroyed after a battery charger failed. Three families homeless for months.
Please. When you charge your battery. Don’t do that in house. Never unattended. Keep a close eye on it. Just yesterday another e-bike owner got the scare of a lifetime. He was lucky. This time. Threw away the battery into his garden. Just in time. That could have been a real disaster.
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