Solar vs alternator charging

John & Val

I'm always after a way to keep my camper battery charged to the max.

In your case you said "The auxilliary battery is switched by a controller to the alternator/cranking battery once the engine has started."

Do you mind telling me if this switching is automatic or is it something that you need to switch on & off yourself?

I really like the idea of SP's mounted on the roof (all the free sunshine when motoring about) but wondered iF they are likely to get damaged during travel.

I a member on this forum with a Nissan Patrol as his pic. Not too sure but it looks like he can possibly even swivel the panels on the car roof when camped or at least he can alter the angles. I suppose the car just gets moved for the best directional advantage.

So that's a great idea for maximising the solar effect and reducing all that lugging around of those heavy panels.

Now I'm reading that it's possible to combine solar panels with car alternator & wondering why my auto electrician didn't suggest it for my application.

Finally - I really like your picture. Night camp by fire next to Boab tree. Lovely.

Wayne,

My switching from the alternator to the auxilliary battery is automatic. The commercial controllers make this connection after the cranking battery has come up to voltage. Initially I used such a system, but found that this point is reached virtually as soon as the alternator starts charging. So, I now have automatic switching based simply on when the engine is running (NOT just ignition on, but when there is oil pressure.) I'll elaborate on my system and blog it when I get a few minutes.

Cheers

John

Hi Mandrake
Mandrake replied:
I don't have the luxury of Alternator power for my Auxiliary batteries (yet) - The only high drain item I have is a Waeco CF50 which runs off the vehicle when driving .
I have a pair of 26aH batteries in the back of the Jeep connected to 2 X 15 watt
Solar Panels on the roof .. When I park the Jeep I simply swap the fridge to the Aux Battery - In theory that gives me 4-5 hours fridge time''


I dont know if you actually tested this setup,but 30watts is only going to put in about 2amps in bright sun ,ON a good day your total input would probably be about 12amphrs max I believe you will be going backwards.
A cheap easy way to parallell the starter& aux batts ,in your case, is to use an ignition switch controlled relay such as a head light or preferably a higher current rating relay to auto connect & disconnect the aux with engine operation This will ensure that the aux batts do get more quickly charged when you are driving.

As I sort of stated in the blurb - I do have an 80 watt panel connected to an 85aH battery in the camper - well actually on the camper so I can with an extension lead plug the 4.5 Amp 80 watt panel into the smaller battery in the back of the jeep whilst motoring - which should perk it up fairly quickly ..

I am sure this will work but I will need to be vigilant -

But we shall see what we shall see - If I find the 2 X 15 are inadequate then I'll have to move the 80 watter to the Jeep roof and put a 140 watt over the camper -- which is probably going to be the final answer - But first there is St George and 4 weeks of "Sunny" S.A and N.T travel and camping to get through as the test ..

Energy independance ... and cold beer !!

Rgds

Mandrake