Solar battery charger

[cagey]

Help please, want a solar battery charger initially for my car, left in airport car park( muddy field) for 6 weeks in January. Car is 12yo BMW and cigarette lighter is off when ignition off. Cheap please only wanting to maintain its charge, hopefully it will then be useful on boat.
Thanks
Keith

 

[lpdsn]

A basic 5 or 10W solar panel from Amazon. And a cheap controller.

 

[ghostlymoron]

If only 5w, you probably don't need a regulator. If the cigar lighter is dead when the ignition is off, you'll need to run a two core wire from the battery to the inside of the car terminating in a cigar lighter socket at a convenient point.

 

[sarabande]

Even if no controller is used, then an in line fuse on the positive wire is prudent.

https://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias=aps&field-keywords=car+solar+charger

£22 sounds expensive but if it stops a dead battery and saves a couple of hours when you return, it's worth it.

 

[lw395]

We were talking about this not long ago.
It should be possible to charge via the ODB socket.
I believe you can buy an adaptor.
Not got around to it myself yet.

 

[johnalison]

I got one for my wife's Polo, from Halfords. It needed an adaptor from the same store to go in the ODB socket but has been fine for the 2-3 months we've been away in recent years.

 

[RichardS]

5W panel, no contoller, no fuse, ODB adaptor, leave panel on parcel shelf or dashboard ....... job's a good 'un.

Richard

 

[GrahamM376]

Simpler still if the car's electronics allow, is to just disconnect one battery terminal. I do this on our Focus and when reconnected it starts OK after several months.

 

[RichardS]

Simpler still if the car's electronics allow, is to just disconnect one battery terminal. I do this on our Focus and when reconnected it starts OK after several months.

All car electronics will allow it ..... the problem is that the alarm system is then usually disabled.

Richard

 

[GrahamM376]

All car electronics will allow it ..... the problem is that the alarm system is then usually disabled.

Richard

No self respecting thief would want to nick my car, even if he knew the alarm was disabled

 

[dunedin]

Simpler still if the car's electronics allow, is to just disconnect one battery terminal. I do this on our Focus and when reconnected it starts OK after several months.

If the OPs BMW is one of the early iDrive generation of BMW I would not want to risk disconnecting entirely. Suspect could lose quite a bit of the settings / setup if not careful. Trickle charge should be the way to go

 

[cagey]

If the OPs BMW is one of the early iDrive generation of BMW I would not want to risk disconnecting entirely. Suspect could lose quite a bit of the settings / setup if not careful. Trickle charge should be the way to go

Thats my worry, car plays up if battery gets low.
Thanks everyone for info, have managed to find similar article in reader to reader from September, knew I’d seen one just couldn’t find it, between the two I think its on the way to solved.
Thanks
Keith

 

[TQA]

Simpler still if the car's electronics allow, is to just disconnect one battery terminal. I do this on our Focus and when reconnected it starts OK after several months.

Check with service department before disconnecting the battery. In some cars this causes expensive problems.

 

[[3889]]

Check with service department before disconnecting the battery. In some cars this causes expensive problems.

It certainly can. Destroyed my ECU when I disconnected the battery for a month on my Passat.
I now use a 10w panel on the dash, Croc clipped to battery with no controller (winscreen keeps ampage down). I leave the car for a couple of months without problems.
https://www.ebay.co.uk/i/2226394018...3D710-134428-41853-0%26rvr_id%3D1326648755849

 

[Big-Bang1]

Given that you have a BMW and most BMW's have a battery in the boot it wouldn't take too much to have a 10 or 15 watt solar panel on your parcel shelf, run the wires through the arm rest into the boot to a small charge controller and croc clip the output from it to the battery terminals. I personally wouldn't want to connect anything to my OBD socket that wasn't a decent code reader/scan tool and it seems rather pointless when your battery is so easily accessible.