Solar battery charger

[ph001]

Standby drain current from the battery with the car fully locked should be 10 - 100mA (depending on how much ancillary crap you have running) which equates to between 0.12W and 1.2W. So you need at least this to stop your battery going flat.

You have to remember though that the panels specified power is typically in direct full sun and that's not to common in the UK in winter, and of course you are only generating about 7hrs a day in December (the other 17hrs is discharge so you need to put around 2.5 times the current in compared to what goes out). A typical overcast day produces around 1/10th the quoted power so you should be looking at a minimum 30W panel + charge controller.

 

[BeeEmm]

If your car is in a garage then why not use a mains powered trickle charger?

That's like saying "Why don't they eat cake". Lockup garages do not have power.

 

[Usel]

If your car is in a garage then why not use a mains powered trickle charger?

That's like saying "Why don't they eat cake". Lockup garages do not have power.

Oh I see, well my suggestion of a 20w solar panel and a trickle charge will suit there needs perfectly.

 

[Status]

Don’t have power as it’s in my paddock,I put the garage up last year also the car won’t be locked and it won’t get nicked before anyone comments on that because of where it is

 

[kis]

Does it have windows?
Most solar car chargers are designed for "on dash" use as they're not waterproof?

 

[Status]

Yeah got a window but it’s facing away from the sun but might still be ok just wondered wot sort would be best

 

[ph001]

You'd defo need 30W minimum on the inside of a north facing window, even that might be a bit hit and miss to be honest. The panels output drops off massively in the shade.

 

[Status]

I’m thinking I can mount it outside on the garage door and hope the lead will be long enough

 

[ph001]

Bit of speaker wire or two core mains cable and a couple of screw terminal choc blocks will sort that problem easy enough. I would defo recommend a charge controller like the one listed above as well though.

 

[Jembo]

How’s everyone doing with their solar chargers?

Started mine up the other weekend after nearly 4 months, span up really nicely, well impressed!!!

 

[ErrErrminator]

My Optimate 20W solar, mounted on a pole on the gable end of my garage, is doing a fine job. I think my battery is past its best and fades quite quickly when the car is unused for a few weeks (car unlocked in and no parasitic drain detected), but this thing is keeping it nicely topped up.