Diode for solar-car-battery-charger (protection while starting the car)

Thread Starter

hroldan

Joined Oct 12, 2016
16
Hi, instead of buying I put together some solar panels I have at home, this setup works fine and keeps the battery charged (I can improve this). Naturally there is a protection diode to avoid the energy going back to the panel when there is not enough sunlight, BUT I would like to start the car with the panel still connected, I know starting the car will produce a high energy bounce in both voltage and amps, and I don't think a single simple diode will work for protection. Anyone happens to have some advice on this???

- A stronger diode?
- 2 or more diodes in parallel?
- Any ideas?

I'm working from home and rarely use my car, this means battery slowly looses charger naturally, the car alarm and electric doors also drain energy while in waiting mode. Been disconnecting the battery but till I don't use the care so often and the cold makes everything worse.

Thanks in advance.
 

LowQCab

Joined Nov 6, 2012
2,188
To figure this out,
You need to know the maximum Current that the Panel can produce,
and, is the Factory installed Diode capable of continuously withstanding that amount of Current ?,
if it is capable,
You shouldn't have to worry about Starting the Engine with the Panel permanently connected.
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.
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Thread Starter

hroldan

Joined Oct 12, 2016
16
To figure this out,
You need to know the maximum Current that the Panel can produce,
and, is the Factory installed Diode capable of continuously withstanding that amount of Current ?,
if it is capable,
You shouldn't have to worry about Starting the Engine with the Panel permanently connected.
Thanks, these are small 6V (3watts) panels in series producing 14.something v max in full sunlight, they came without diodes because were part of something else. I just added a simple (one) diode (random) that I had on my stuff-box. Was about to put a big one (diode) but instead placed a small one. The spares I keep come from broken charger units with full rectifier bridge of diodes, chargers rated about 14v.
 

DickCappels

Joined Aug 21, 2008
8,858
The 40V diode in this datasheet should do it. Make sure the panel is connected close to the battery to assure that the battery helps keep the voltage down.
 

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