Any solar experts?

[winchman]

I keep the Range Rover at Winchboys. As its rarely used and I keep killing batteries I was thinking of fastening a solar panel to the fence and with a controller sticking it on the battery to keep it in good shape?
Am I talking rubbish or would this work?
200W panels are buttons used on Market place I do have a spare MPPT controller but no instructions!

 

[JOEPRO]

I'm not a solar expert.

However I used one of these in my w140 s class and it charged the battery+ is keeping it full. All contained inside the car so issues at all.




This is the solar charger kit

https://amzn.eu/d/9TfLswu

 

[winchman]

Unfortunately it’s not easy to get electricity to the place it’s parked in so that’s why I looked at solar

 

[hotponyshoes]

Yes, as long as its in the light it will work fine

I've got one on a van I don't use/start over the winter and it keeps up with the drain from the alarm and the interior lights when I open the doors every couple of weeks or so.

I've also got a couple on a boat which will run quite a few electronics all day and keep it topped up the rest of the time.

I have them all roof mounted, I used the flexible ones (etfe?). The adhesive probably cost as much as the panels but you can walk on them and pressure wash them off and they cope with partial shading fine as well.

I've also mounted plenty of them on horseboxes and a fair few in stables.

Best way to work out what you need for a car is lock it up, leave it for an hour, then see how much drain it's pulling from the battery.
Add that figure onto 2% of your battery size and get a panel with 4-5 times that output.
Should keep it topped up just fine.

The charge controller probably has pictures on the front for the wiring but will be fairly simple. You don't need a controller if you keep the solar panel below 2% of the battery capacity, just connect it directly.

 

[winchman]

Thanks

 

[Nomad]

I bought a couple of dash top solar chargers from halfrauds.
1 is hung outside the garage, if I’m parking the car up for long term I disconnect the battery and hook it up to the panel.
Then other is left on the dash if the car is being parked outside for a few weeks.
I think mine were mid-range (10w ?) under £30 each. The ones they are selling now look different- new version??

https://www.halfords.com/search?q=Solar+battery+charger

 

[winchman]

I bought a couple of dash top solar chargers from halfrauds.
1 is hung outside the garage, if I’m parking the car up for long term I disconnect the battery and hook it up to the panel.
Then other is left on the dash if the car is being parked outside for a few weeks.
I think mine were mid-range (10w ?) under £30 each. The ones they are selling now look different- new version??

https://www.halfords.com/search?q=Solar+battery+charger

Thanks but the Range Rover drain just sat I feel would be too much for a 10w panel

 

[RWD3M]

Thanks but the Range Rover drain just sat I feel would be too much for a 10w panel

Really? I would have expected the parasitic drain to be in the mA (<100mA) range rather than amps. 10w is not far short of an amp at 12v. Might be worth measuring the drain you have.

 

[hotponyshoes]

Really? I would have expected the parasitic drain to be in the mA (<100mA) range rather than amps. 10w is not far short of an amp at 12v. Might be worth measuring the drain you have.

Range Rovers / Discovery are about the worst cars I know for this.
I've seen a newer one with the keyless drain the battery in a couple of weeks.

 

[dobbslc]

This is the solar charger kit

£58 now!

 

[winchman]

Really? I would have expected the parasitic drain to be in the mA (<100mA) range rather than amps. 10w is not far short of an amp at 12v. Might be worth measuring the drain you have.

Its only 10w on a very sunny day I would have thought it to be a very small current on most UK days, I was looking at a 200w + panel as loads on market place for around £50

 

[aesmith]

Aside from questions about solar, does the battery run flat if disconnected from the vehicle?

 

[hotponyshoes]

Its only 10w on a very sunny day I would have thought it to be a very small current on most UK days, I was looking at a 200w + panel as loads on market place for around £50

On the cheaper/generic panels I have tried, they produce about half the stated power on an average uk day. Then half of the day is night. Plus losses in the cables/controller.
A panel rated 4-5 times the load is about right.

Correct sizing is only really important if you want to mount it in/on the vehicle though.
If you have a fence and a charge controller you can just use a bigger panel and know it will do the job in the middle of winter.

Use a controller with 2 outputs and you could use any surplus power for something else. (If you can think of anything!)

If it's not in the car you'll have to clean it occasionally.
You'll also have to un/plug it each time to use the car but I guess you don't use it often or you wouldn't need the panel anyway.

 

[hotponyshoes]

Aside from questions about solar, does the battery run flat if disconnected from the vehicle?

Battries do discharge themselves even if completely disconnected.
One of the ways of testing the condition is to measure that rate.

Plus, on a car, you'll loose the clock time, radio presets, central locking and so on if you fit an isolator.

 

[winchman]

Aside from questions about solar, does the battery run flat if disconnected from the vehicle?

Running the battery flat on a P38 Range Rover is a big no no as it locks you out and recovery is more luck than good management even with the codes to un isolate it.

 

[minimutly]

Look at motorhome chargers and panels. The controller on mine is dual output, cost around £40. No idea on panel costs...