Camper trailer charging, not as simple as I thought

[GeoffV]

I'm driving a 2013 WK2 and yeh you're right Scarps, it's cause of all the new techy stuff that means it won't charge properly through with a regular Red Arc SBI12 or SBI12D battery isolator. Because the variable voltage alternator drops the voltage down when not needed, it won't get enough charge (it will get some) to charge the CT batteries. It will take twice as long to charge them, and it it drops low enough it will trip the battery isolator and not send any charge to the camper. This is direct from the Red Arc guy. Not sure why yours is working Yoda. Perhaps your variable voltage alternator isn't as variable as it should be?? Bonus, I'm not sure. But I'd like to know the camper is getting the full charge while I'm cruising. Hate to pull over for the night and find the fridge isn't cold anymore (It's in the camper).

[Jasman]

Mine seems to charge fine.....have you tried driving with your lights on, this should convince the alternator to charge from what I understand.

[paul mac]

We have an early 2013 WK2 . I was told due to the variable rate alternator it would not charge aux batteries without a DC-DC charger by several people as well .
So we tried our old trusty Redarc SBI12 from our WG , with 6 B+S wiring to both the 2nd battery in the cargo area & to the anderson plug for the 3rd battery on the camper trailer also wired up with 6B+S . All 3 batteries charge fine on the road.
Remember the Grands have a VRLA AGM battery in them anyway , if the alternator is only pushing out 11-12 volts it would never charge the starting battery properly anyway .
The other point one auto electrician pointed out , with the agm battery & the other electronics on very late model cars , is the alternator is variable for a reason & detects added load (Well the ECU does ) .
This is the same sparky who wired in a resistor on my late model falcon work ute to keep the alternator charge up ,not drop down when the car got to running temp.
(Please note This is only my experience on my own car(s) )

[scarps]

Hhmm, I'll try and get a pic tomorrow, but in my 2012WK2, I have a volt guage sitting on the dash that's wired to the 2nd battery, (which is after the Piranha isolator). Prior to ignition, the guage is usually reading 12.8V (voltage of second battery and fridge in car turned off) and the isolator usually opens up approx 10 seconds after I start the car and the volt guage then sits on 14.4v while driving.

When I connect up the CT with another 2 x 105amp batteries (via the 50amp Anderson plug), the volt guage is then reading all 3 batteries (as they're linked on the other side of the Piranha), and sits around 12.7V (with ignition off) and this obviously drops overnight as I use the fridges, LED lighting and waterpump. Lowest it's gone to date was 11.8v after a week bush camping.
With all 3 batteries linked, once the isolator opens up, (again approx 10 seconds after ignition), I still get the volt guage to read 14.3 or 14.4v, depending on what lights I have on, plus aircon.

I'll also have to double check my reference, but I know in mine I have a 220amp alternator which has no trouble charging up all 4 batteries after a 2hr run.

Not sure if this helps you, but I have had an owner of a new 2014 WK2 tell me the charging system is different on the later models.

[Numb Thumbs]

I have an early 2013 WK2 and a campertrailer with 2 x 100 Ah Gel batteries plus I put another 100 Ah Gel battery in the back of the car to run a second fridge there on trips.

I use a Ctek D250S Dual in the camper and one next to the removable auxiliary battery in the back of the car.

Car/camper connection is by 6B&S (~ 13 mm squared) cable and 50 Amp Anderson plugs.

It seems to work very well.

Cheers
Numb Thumbs

[GeoffV]

This is the set up the Red Arc rep is saying I need, and this will allow me to charge back to the car with the solar panels.

[IMG][/IMG]

[scarps]

Here's my volt guage readings from this morning.
Pre ignition,

Not fully charged as I've had the fridge in car running last 2 days.

And post ignition