Trickle Charge idea for Winter.

Post by **mecheng** » 04 Jan 2018, 07:06

Hello guys, haven't posted in a while, been busy with my new to me E90 BMW, it is such a great driving experience, the handling and steering feel can only be described as insanely good. Just learning all the hidden features of this car has been a full time experience.

This has relegated my S70 to occasional use duty, so I'd like to hookup a Solar trickle charger so I don't have to worry about running extension cords in my driveway. From what I can tell, the cigarette lighter turns off with the car and therefore I can't use it to charge my battery is this correct? Can I find a constant power wire nearby and modify it? It would be really convenient to use as the charger has a lighter adaptor.

I'm thinking of using a fuse tap into a fuse somewhere in the cabin, any ideas which one is constant power, perhaps the hazard lights or any other ideas?

I don't want to have to pop the hood and hook and unhook the charger, I want something I can have inside the car all the time.

This is the charger I have, thanks!

http://www.canadiantire.ca/en/pdp/colem ... p.html#srp

skloon · Post by **skloon** » 04 Jan 2018, 09:10

Could just run a wire through the firewall grommet - I had one of these in my motorhome - sadly snow covered it so the battery froze

Klausc · Post by **Klausc** » 04 Jan 2018, 20:26

The glove box light is always 'on'. Pull out the glove box, connect the wires and let them rest inside the box.

Post by **jvl** » 04 Jan 2018, 23:05

If it's the same as my V70, there should also be an 'accessory plug' located in the drivers footwell, on the left, in between the latch for the hood and steering column. It has several pins. The red wire is constantly powered and has a 20 amp fuse.

See the picture attached, I stole it from another MVS thread.

Joost

Post by **jvl** » 04 Jan 2018, 23:12

And here are two links with more info.
First thread also contains a post on plug pinout.

viewtopic.php?f=1&t=79253

viewtopic.php?t=69527

Post by **abscate** » 04 Jan 2018, 23:51

In the winter I trickle charge three of my cars if the kids are away, and every year I lose one more, it seems

I put a Schumacher charger in the engine compartment, zip tied. Then run the AZc wire to the cowling so you can plug in an extension cord. That leaves the plug electrically dead.

You don't want a DC connection live on the cowling unless you fuse it at the battery, at least.

Post by **mecheng** » 05 Jan 2018, 06:40

abscate wrote: ↑04 Jan 2018, 23:51 In the winter I trickle charge three of my cars if the kids are away, and every year I lose one more, it seems

I put a Schumacher charger in the engine compartment, zip tied. Then run the AZc wire to the cowling so you can plug in an extension cord. That leaves the plug electrically dead.

You don't want a DC connection live on the cowling unless you fuse it at the battery, at least.

So you keep in your engine bay year round even when driving?

Yes, all connections to the battery must be fused!!!

Post by **mecheng** » 05 Jan 2018, 07:02

jvl wrote: ↑04 Jan 2018, 23:12 And here are two links with more info.
First thread also contains a post on plug pinout.

viewtopic.php?f=1&t=79253

viewtopic.php?t=69527

Awsome, thanks, I just need to find a male terminal blade.

My trickle charger is only 0.5A so I will use one of the 1A connections, I assume that won't be an issue?

Post by **Rattnalle** » 05 Jan 2018, 07:10

The solar charger linked above is. 0.16A "under ideal conditions" according to spec. Will it actually be able to charge the battery or just make the battery go flat more slowly?

Normal idle consumption of a parked P2 is something like 0.02A. I'm assuming it's roughly the same for a P80. 0.14 A left to trickle charge with. Assuming there's no frost or anything on the window blocking the light.

Not to criticise the concept, just curious.

Post by **mecheng** » 05 Jan 2018, 10:49

Rattnalle wrote: ↑05 Jan 2018, 07:10 The solar charger linked above is. 0.16A "under ideal conditions" according to spec. Will it actually be able to charge the battery or just make the battery go flat more slowly?

Normal idle consumption of a parked P2 is something like 0.02A. I'm assuming it's roughly the same for a P80. 0.14 A left to trickle charge with. Assuming there's no frost or anything on the window blocking the light.

Not to criticise the concept, just curious.

Yes I am aware it is low wattage but to maintain the battery you don't need much current. If the battery is weak, it won't help much. I just need something to compensate for the parasitic drain.

If it doesn't work, I will hook up my trickle charger which I believe is 0.5A.