Help with Solar Trickle Charger

[NY65912]

I have a 2010 Audi Q5 that I hardly drive. I put in a new battery in late Dec and it went flat last week. It being an AGM battery I was able to bring it back with a long slow charge.

I purchased a 4w solar charger to keep it topped off since it is outdoors.

I wanted to charge thru the cigarette lighter but it is a switched circuit.

I do not want to use the jumper posts in the engine compartment.

I was thinking of making the cig lighter always powered, but how? Or attach direct to the battery in the rear well.

Any ideas how to hook it up? Thoughts?

Thanks in advance,

[EC900]

Rather than trying to tap into a circuit to power a battery maintainer, why not just add charger leads to the battery? You will need a multimeter to find a powered circuit, perhaps a glove box light would be closest.
If your charger came with both battery post clamps and the power port/cig lighter plug, then it should have a universal adapter, extending the cord is easy enough to run it back to the interior so your solar charger can stay dry if it’s not weatherproof.

[NY65912]

Capital idea. I was concerned about attaching the leads direct to the battery. But, I think direct would be better than running thru circuits and possible the battery management system.

Thanks

[darrin]

Originally Posted by NY65912

Capital idea. I was concerned about attaching the leads direct to the battery. But, I think direct would be better than running thru circuits and possible the battery management system.

Thanks

FWIW, you only need to attach the positive to the battery (or jump terminal) -- negative simply needs to ground to chassis (somewhere)

[pampadori]

My Mercedes E500 has a rather handy solution in the fuse box to change whether you want the cig lighter powered all the time or just when the key is on.
The fuse holder has three female points for the fuse (which only has two prongs of course). If you plug the fuse in 1&2 you have switched power. If you take the fuse a s move it to 2&3 you have full -time power at the lighter. Genius!

So having said that, could you just run a jumper to the cig lighter fuse from a source of constant 12v power to do the same thing?

[NY65912]

I thought about the jumper to the cig lighter but I would rather not screw with the fuse box. Hooking up to the battery is not that difficult and eliminates (I think) any possibility of the battery management system not being happy.

Cheers

[EC900]

Just one more point -
“I put in a new battery in late Dec and it went flat last week. It being an AGM battery I was able to bring it back with a long slow charge.”

Seems to me a brand new battery discharging over a 2 month period would be indicative of a phantom or parasitic draw. A 4-5 yr old battery, I’d say if it went flat it would be expected, especially if there’s an alarm system. Would be worth checking into that, including the charging rate of your alternator as well as connections.
Good luck !

[NY65912]

I'm thinking the dash cam is the cause of the parasitic draw.
Will check

Thanks

[blucille]

Originally Posted by pampadori

My Mercedes E500 has a rather handy solution in the fuse box to change whether you want the cig lighter powered all the time or just when the key is on.
The fuse holder has three female points for the fuse (which only has two prongs of course). If you plug the fuse in 1&2 you have switched power. If you take the fuse a s move it to 2&3 you have full -time power at the lighter. Genius!

So having said that, could you just run a jumper to the cig lighter fuse from a source of constant 12v power to do the same thing?

Sounds clever. I'll bet the 2010 audi has a setting in the dealer computer to enable cigarette lighter always on. Porsche SUV's of the same period had constant power there. Yet my 2015 VW GTI shuts off the lighter.

Checking a quick google, it does seem that some Audi products have the 3-point fuse holder discussed above, but by 2010, it seem unlikely.

[NY65912]

Yup, no 3pt fuse. Checked, but I will go in thru VagCom and see if there is a setting.

Thanks