Second battery set up for fridge freezer

Peter and JudyH · Senior Member

Second battery set up for fridge freezer

Chucker · Veteran Member

Hi Peter and Judy,
I also have a set up problem.
I have a Mercedes Motorhome with Solar Power with 2 x batteries and I have just bought a small trailer to
which I would like to carry my Waeco Fridge Freezer in. Should I run an Anderson plug from the Van to
trailer or buy a portable Solar panel and battery for it alone. Or better still, do you have a better idea to help
with a better or easier set up. Hoping for great ideas please.
Thank you.
Chucker......

Hetho · Senior Member

Hi Peter and JudyH.

I did exactly what you are suggesting. Works a treat. The only extra I installed was a circuit breaker before the 2nd battery. I trip the circuit breaker every time I stop.

This way I know the fridge is only running of the second battery, and will not draw off car battery.

Regards.

Hetho.

vince56 · Senior Member

Second batteries are the way to go to ensure you have a start battery at all times.
I would suggest setting it up with a dual battery system (or Voltage Sensitive Relay) from Ironman, Redarc, ARB, Ebay etc.
These systems automatically shut off the start battery when you stop and when restarting will only charge the second battery once
start battery has been charged. The whole idea is that it is automatic and takes away the human element in forgetting to
disconnect / switch / change a battery setting, in my opinion well worth the $120 odd dollars and very easy to set up.

Vince · Senior Member

I would consider a DC-DC charger to the second battery in the tub as it will give a higher boost in voltage as opposed to using an OE isolator,

Attached is another way of doing it.

PeterD · Guru

You say the feed to the van is only 8 mm². I would not be joining a second fridge onto that wire, I would be using a separate wire of the same size for the battery in the tub.

LLD · Senior Member

Purchased this www.supercheapauto.com.au/Product/Ridge-Ryder-12v-Portable-Power-Station/368862 plus battery. It's in the boot of the ute and runs off the 12v outlet. It can also run off solar (Anderson plug in Power Station). The Engel is plugged into the 10A outlet. When stopped, I can either run 240V from the van direct to the Engel or solar to the battery box. The battery box will last overnight depending what your requirements are. This keeps my van and 2nd ute batteries independent which I found out is a good idea. The power station can be set to cut-out so it doesn't flatten the ute battery. Have a second solar panel that I can connect to the drawbar on the van for the van battery. Seen this setup on lots of vans except that many have the van solar permanently on the van roof. Only issue I've had is the wires on the solar panel were way to thin and voltage drop was massive.

I've noticed people who just use their Engel running from solar (via the battery) and making ice during the day and using the ice in an esky to keep their drinks cold.

Hylife · Guru

Have 3 batteries.
1 Crank battery for car engine.
2 Auxiliary 100AH deep cycle battery in engine bay for 50litre fridge in back of tug. Separate wiring to a separate socket in back of tug. Lasts 4 days before charging required. Charges whilst driving.
Use 20A DC-DC charger because car is newer and has a smart alternator and they only charge to 12.8V. DCDC charger disconnects when crank battery reaches 12.5V, ie engine is off.
3 House battery 100AK deep cycle in caravan with 20A DCDC charger because wire run is long inducing significant voltage drop.
6 gauge wire to Anderson plug on drawbar and 6 gauge wire from crank battery to Anderson plug next to trailer plug. DCDC charger disconnects when crank battery reaches 12.5V, ie engine is off.

Peter and JudyH · Senior Member

Thanks all for the information. It all makes sense and is as I thought it should be

We are currently away for the next few weeks so will look at the install after we get back.