Thanks for taking the time to do such a detailed description of your work! When this setup is running, is there any danger in overloading the charger by running 12V accessories (lights, stereo, pump, etc.). The charger is designed to charge batteries and perhaps does not have the current output capabilities?
The charger has a current limit of 18A so you'd be hard pressed to get enough stuff running on 12v to put it over that. Even if you did get to 18A the batteries would supply anything over that as soon as the voltage dropped off without any damage to the charger.
Am about to order one of the Muvonics 3 stage chargers Dave, just to check before I do. The fan isn`t insanely noisy or anything is it Not likely to keep you awake at night or anything silly I`m a light sleeper
The fan only cuts in when necessary ie. when it's been running on the max output for a while. As far as i've noticed so far the fan hasn't even come on yet, but so far i've only been using it to keep my batteries topped up. I guess it would only be needed if it was charging some pretty flat batteries or there was a high drain being used on the 12v system for a while.
Madmyk - charger is 100 quid from a conversion parts supplier on Ebay, search for "motorhome charger" and its like the one in Irish Daves posting with the fotos. Also available from various dealers round the country, Google search for "muvonics charger" and the manufacturers have a website with dealer network on it.
Not sure on 240V relay cost from Maplin as yet, gotta get me one of them as well when I`m back in the country on Friday, posting from sunny Oz at the moment
FOUND IT
Relay is about 6 quid from Maplin, make sure you get the 240V 30A one as Dave says. Probably worth having a spare in case one blows, not easy to find a 240V 30A relay when camping in Little Snoring and you have no charger on a Friday nite
Back from sunny Oz this morning, all my charger bits waiting for me
Done the installation this afternoon, looks identical to Irish Daves picture. Been charging for about 3 hrs now, the fan cut in pretty quickly and the charger is pretty warm, so looks like the batts are a bit flat from being stood for 6 weeks, and giving the charger a good work-out.
Just checked with the meter and they are up to 13.9V. Will check again in the morning, should be stabilsed and on float charge by then.
A good way to check if the wiring is correct is to compare the voltages on both batteries on and off load with the charger running and then with the charger off.
I used the following method (engine must not be running).
With the charger off, measure the voltages on both batteries. They both should be similar (about 12.5v to 13.5v).
Then run the heater blower motor on full speed and measure the voltages again. The voltage on the main battery should be significantly less (probably under 12v) and the aux battery should be unchanged.
Stop the blower motor and start the charger, then measure the voltage on both batteries again. They both should be very similar (above 13.5v).
Run the blower motor with the charger on and measure the voltage on both batteries. They should both be very similar (over 12v).
If all this works out it means the circuit's working as it should.
Yes, that`s the relay (I`m looking at one now, I bought a spare "just in case")
Looking at the base of the relay, with the printed top face at the top:
6 terminals labelled:
1
3
4
6
7
9
A
B
(7 + 9 slots have no terminals in them)
term 1 and 3 are not used
term 4 - wire from inline fuse / red/yellow out (OE westy wire crimped into terminal with the fuse wire, thats the doubled wire into a connector you can see in the foto)
term 6 - wire red/black (OE westy wire)
term A - new wire from charger DAVE USED WHITE IN HIS FOTO (the new one you soldered in)
term B - new wire from charger DAVE USED WHITE IN HIS FOTO (the new one you soldered in)
Don`t think it matters which way the WHITE wires are connected, to A or B, it`s just energising the coil so it should work either way.
All sounds a bit complicated but it`s straight forward really. Draw yourself a diagram of what color wire to connect to what terminal before you start and it`s a piece of cake.