Solar trickle charger

[M3GX]

I bought a couple of the Project Farm recommended solar trickle chargers and just got it today. It has a few different connector types: direct to battery, cig lighter, and ODB port. Either the cig lighter isn't constant, or I forgot to hook it back up when doing the HU upgrades. It doesn't charge through that with the engine off. But it does through the ODB port. It even charges through that with the engine on. I've read that it's ok to do that, but have my doubts. I'll just unplug it before driving. I'd prefer it was direct connected to the battery, though. I need to see exactly how much cable I have to work with, and if I can run it through the firewall.

I plan to use the other one on my JK. Thinking of doing a semi-permanent install on the hood and direct connect it to the dual battery system.

https://www.amazon.com/dp/B0DMN1CVS2

 

[Rednexus]

I'd suggest some Anderson connectors wired straight to the battery. I have them connecting my camper to the GX, and they have yet to disconnect or get water in them (although I did add waterproof boots on them). I think you can smaller-gauge ones as well (mine are 10 ga).

 

[folivier]

I put one last fall since my GX was going to be parked all winter. Direct connection to my battery and sitting tilted about 30º on the dashboard. Either it wasn't enough charge or not enough sun but my battery is dead, down to 2.5 volts. So I'll replace the battery when I get back up next month.

 

[M3GX]

The kit did come with a connector for the he battery also. I wired it directly on my E46 M3. Trying to see if I can get away with two chargers for my three vehicles, and just swap a panel out between two of them. I'll either order another battery connector or just get a third panel kit. They were only $33. This was rated at the top of Project Farms list.

Also the fact that it charges through the ODB port with the vehicle off, leads me to believe part of my battery drain issue was leaving the Joying HU ODB reader plugged in. At least others have pointed to it being an issue. Haven't had a dead battery since removing it. But can't say 100% that was it until I start testing for parasitic draw

 

[Rednexus]

I rigged my OBD2 reader so it's only powered with the ignition is on. Had to custom make a OBD male-to-female cable to do that, and I have the power pin ran off of a fusetap on the interior fusebox.

 

[Pighead]

Thinking of doing a semi-permanent install on the hood and direct connect it to the dual battery system.

Maybe not like this though...

Thread 'Flexible solar mount on hood: BEWARE!!!!!!!!'

Nov 29, 2025

I'm sick to my stomach to post this, and I assume this is the right location.

I purchased this solar panel kit from a vendor and applied it just as instructed. Seemed like a great idea. It worked very well for me for several years. I never had a dead battery and had a lot of questions about it in parking lots all over the place.

Lately I've been considering selling my 200, so that's been on my mind a little and a friend sent me an instagram story showing someone removing this same setup leaving the paint and hood underneath it completely trashed. It took me about 10 seconds...

• concretejungle
• Replies: 16
• Forum: Power Systems

• 

 

[zzyzx85]

The kit did come with a connector for the he battery also. I wired it directly on my E46 M3. Trying to see if I can get away with two chargers for my three vehicles, and just swap a panel out between two of them. I'll either order another battery connector or just get a third panel kit. They were only $33. This was rated at the top of Project Farms list.

Also the fact that it charges through the ODB port with the vehicle off, leads me to believe part of my battery drain issue was leaving the Joying HU ODB reader plugged in. At least others have pointed to it being an issue. Haven't had a dead battery since removing it. But can't say 100% that was it until I start testing for parasitic draw

Are you me? lol. I saw the same video a little while ago and bought the same FlexSolar panel for my M3. I think my battery needs to be replaced soon (3 years old) but this is a convenient way to keep it topped off.