Further from my original post on "Positioning Aux Battery". An auto sparky explained it in simple terms to me and was hoping to get your thoughts.
Run Heavy cable from main battery through an isolator switch mounted close to the main battery. Cable runs via alternator to the dcdc charger and aux battery in the back tray of the 2012 Navarra for optimal charging. From here it runs to the grey anderson plug at the towball end of the Navarra."
Does this make sense?
darjak said
12:09 PM Jun 22, 2021
Most DCDC charges have an inbuilt isolator so you might not need it.
If you also run solar thru DCDC charger youll have to bypass the mppt on the back of solar panel
as it will not charge battery. I have set mine up that way using pushin joiners as use my panel on caravan
on really overcast days.
IMHO would not run less than 6b&s twin cable. Cheapest place to by cable and Anderson plugs is Jaycar.
Darjak
oiddad said
12:15 PM Jun 22, 2021
Thanks Darjac. On the solar panel I have already removed the regulator and the dcdc charger is a Redarc 1225amp positioned right alongside the aux battery if that helps?
oiddad said
04:49 PM Jun 23, 2021
Just reporting back....
So I hooked the car up with the van (Just the wiring not the coupling) took the fridge vent off to get to the wiring at the back of the fridge (see pic attached) Armed with my multi meter started taking measurements with the car running and not running. Now as I understand pin 1 & 6 shows volts from car battery .... pin 5 &10 is ignition switch from car and pin 3 & 8 is the caravan battery. As soon as I hooked up the car the AES thetford fridge in the van powered up. Voltages at the back of fridge.... Car battery 1 & 6 ignition on and fridge on Under load 12.5 to 12.7v ... no load 13.3v.
Ignition off .... Fridge turns off Car battery 1 & 6 13.1 to 13.2v 5 & 10 ignition switch 0.0v with car off. With car on 13.9 to 14.0v With car running aux battery read 13.2 to 13.3v while main battery 14.1v (bit of voltage drop there) Previously the mobile 12v guy who first worked on my set up stated that the van had to be physically hooked up to create an earth .... i proved today that this is false and i will be letting him know this. .... DOES NOT need to be hooked up for fridge to operate.
If you also run solar thru DCDC charger youll have to bypass the mppt on the back of solar panel
as it will not charge battery. I have set mine up that way using pushin joiners as use my panel on caravan
on really overcast days.
IMHO would not run less than 6b&s twin cable. Cheapest place to by cable and Anderson plugs is Jaycar.
Darjak
Just reporting back....
So I hooked the car up with the van (Just the wiring not the coupling) took the fridge vent off to get to the wiring at the back of the fridge (see pic attached) Armed with my multi meter started taking measurements with the car running and not running.
Now as I understand pin 1 & 6 shows volts from car battery .... pin 5 &10 is ignition switch from car and pin 3 & 8 is the caravan battery.
As soon as I hooked up the car the AES thetford fridge in the van powered up. Voltages at the back of fridge....
Car battery 1 & 6 ignition on and fridge on
Under load 12.5 to 12.7v ... no load 13.3v.
Ignition off .... Fridge turns off
Car battery 1 & 6 13.1 to 13.2v
5 & 10 ignition switch 0.0v with car off. With car on 13.9 to 14.0v
With car running aux battery read 13.2 to 13.3v while main battery 14.1v (bit of voltage drop there)
Previously the mobile 12v guy who first worked on my set up stated that the van had to be physically hooked up to create an earth .... i proved today that this is false and i will be letting him know this. .... DOES NOT need to be hooked up for fridge to operate.