This Might Save Your Life...

...or it might just get your car going in an emergency.

I knocked up a solar charger for my car battery for less than $15 (£7) using a cheap generic 20A solar controller ($11 from eBay), an Anderson plug and a piece of scrap wood.

My car has a 100w solar panel on its roof which normally charges the aux battery via a quite sophisticated charger which can use power from the alternator or the solar panel to keep my fridge running and power a 200watt pure sine wave inverter.

However I have had this el cheapo solar charger for ages, bought when I was experimenting with solar panels some time back. It's a PWM type and hence not very efficient but who cares?

Anyway I was clearing out my garage when I came across a couple of wired crocodile clips cut from an ancient Halfords half wave rectifier battery charger which dates back to the 1960s and which failed in a very exciting way many years ago.

Seeing this old wire and clips in my 'useful box' made me think that, combined with the solar charger, it could be an emergency battery charger on the road (in the middle of nowhere) or just a float/top up charger using the 40w solar panel currently languishing on the car port roof when the car is not in use.



As you can see there is bugger all to it but it works and I have set the parameters to suit the ordinary (flooded) lead acid car battery but they can easily be changed to suit a Gel or an AGM battery. I would not recommend it for a lithium battery though.

Anyway it is something light to throw in the tool box and which could get you out of serious trouble before your water runs out.

Re: This Might Save Your Life...

Interesting although tbh I can't see a need for me personally I ring my husband to bring his works van or the rac to get my Jeremy going. Haven't had to do that yet with Jeremy but had a car years ago I think I was recover more times than I had hot dinner over a period in the summer.

Re: This Might Save Your Life...

To be honest I will probably use it as a float/top up charger because in a real emergency I could start the car from my aux battery using jumper leads. That is not a good way to treat a deep cycle battery but it should get the car going in a real emergency situation if you are hundreds of km from help.

I could also carry a 20 or 40 watt solar panel in the tray just in case the 100w roof mounted panel was damaged by hail for example.

Re: This Might Save Your Life...

Bruce that's really interesting because I am wondering why we cannot have dual fuel solar charged cars. I don't mean the battery but the fuel.

Re: This Might Save Your Life...

Not many vehicles here come with solar panels on the roof.

Re: This Might Save Your Life...

They don't here either, you have to fit them yourself but no need, just carry a panel in the boot, they are cheap enough.

I have a couple of 40 watt panels thrown up on my car port roof that I use to keep my batteries charged when my camper and/or car are not being used - for example when I was recently overseas for a month.

Even on cloudy days it is surprising how much power they can provide it might be less half an amp but that is enough to float a 12v battery

Re: This Might Save Your Life...

It is not practical because the area of panels you need to run a car is enormous. just look at the cars in solar challenges. This is some shots of the cars in the Darwin to Adelaide race each year as you can see they are very light, very streamlined and totally impractical as a passenger vehicle.




My 100watt solar panel is enough to run my portable fridge indefinitely (or so it appears) but the fridge averages less than an amp off a 125A/h deep cycle battery.

However if I was stuck in the middle of nowhere with a flat battery a few hours charging in sunlight should give me enough charge to start the car.