Dual batteries

[Jimbo092]

Hi I'm new here! Can find any thread but have just bought a d22 2013 and and looking at putting a redarc dual batteries in it, my problem is to isolate one under the bonnet and run fridge off that or run a 3rd battery in the tray,



Any suggestions and ideas or what you guys have done would be great!

 

[Old.Tony]

Hi Jimbo!

If you're running a cable from the front to the tub, make sure it's big - 8Ga (21 sq mm) or larger (4Ga is cool!). That's for either method - charging the aux battery or driving the fridge from the front.

Personally I do things a little differently to most. Because my Engel fridge will use 240V in preference to 12V, I bring my power in to the tub and immediately invert it to 240V, then drive both a standard battery charger and the Engel @ 240V. This allows the battery to be unladen while it's being charged.

Usually, people would place an isolator just off the main battery, then a fuse, then a long cable to the rear, then a fuse and connect the fuse to the rear battery. You could put the isolator on the far end in the tub I suppose, but it will get a better look at the actual battery voltage if it's close by.

 

[Jimbo092]

Ok sweet thanks for that!

 

[bods]

I guess it depends how you want to set it up too... I have the 2 standard ones under the bonnet separated from each other, there's a perfect spot on the drivers side I side the quarter panel that has m6 captive nuts spaced perfectly for a basic redarc/projecta or similar shape solenoid type isolator. I've got a projecta one in mine, I'm on my second one after I'm guessing frying the controller on the first one trying to jump start after leaving headlights on....

When I eventually get a canopy I'm considering putting a ctek or redarc DC - DC charger with an agm battery in the tub to use for the fridge long term, probably with a solar panel too. Then put a lead acid deep cycle under the bonnet and leave the isolator in place for running the accessories off, but leaving the agm just for the fridge, plus a bigger cranker to make up the difference from splitting the standard ones up...

The difference in doing it this way is you don't need as hard core cable running to the tub, as the DC -DC chargers don't put out as many amps as the alternator, as far as I know the redarc ones come in 25 or 40a, so less than half of what the alternator puts out...

 

[maggot3064]

So tony let me get this straight you have the battery charger running the whole time connected to the inverter while it is charging a battery in your tub is that what ya saying?

 

[Old.Tony]

Absolutely. It's a 7-stage smart charger, it checks the battery and determines what it needs to do then does it. When finished charging, it automatically goes to 'maintenance mode', keeping the battery at full charge.

 

[maggot3064]

Do you have your fridge running off the battery or the inverter?

 

[Old.Tony]

Both. The output of the inverter has a powerboard plugged in to it. From that, I have three cables - one to the fridge, one to the battery charger and one to a double-powerpoint that I've installed at the rear of the battery box (for charging drill batteries etc while driving).

The Engel fridge is also plugged directly to the battery. While 240V is unavailable, the Engel will draw power from the 12V battery. As soon as 240V becomes available, the Engel chooses that power source automatically.

 

[maggot3064]

Sorry to bump an old thread, but I'm going to put a 300watt inverter in my tub and connect it to my 12v Anderson plug that is already there. The inverter is going to run my waeco so just wanted to know do I have to put a fuse between the Anderson plug and the inverter as I already have a 40amp circuit breaker at the battery
Cheers chris

 

[maggot3064]

Sorry to bump an old thread, but I'm going to put a 300watt inverter in my tub and connect it to my 12v Anderson plug that is already there. The inverter is going to run my waeco so just wanted to know do I have to put a fuse between the Anderson plug and the inverter as I already have a 40amp circuit breaker at the battery
Cheers chris

 

[Old.Tony]

No need, Chris. Fuses go at power sources, the inverter is just another device (that is internally fused).

 

[ozstickman]

Hi Jimbo!

If you're running a cable from the front to the tub, make sure it's big - 8Ga (21 sq mm) or larger (4Ga is cool!). That's for either method - charging the aux battery or driving the fridge from the front.

Personally I do things a little differently to most. Because my Engel fridge will use 240V in preference to 12V, I bring my power in to the tub and immediately invert it to 240V, then drive both a standard battery charger and the Engel @ 240V. This allows the battery to be unladen while it's being charged.

Usually, people would place an isolator just off the main battery, then a fuse, then a long cable to the rear, then a fuse and connect the fuse to the rear battery. You could put the isolator on the far end in the tub I suppose, but it will get a better look at the actual battery voltage if it's close by.

Love your idea old tony. Bods put me onto it. What size inverter have you used?

 

[Old.Tony]

In the tub, it was a 300W/1000W surge from Powertech (Jaycar) but it blew up last week and I've had to replace it, I've now got an Aldi one in there. Inside the caravan, it's a 600W Aldi job too, providing 240V for the fridge as we drive along.

 

[ozstickman]

In the tub, it was a 300W/1000W surge from Powertech (Jaycar) but it blew up last week and I've had to replace it, I've now got an Aldi one in there. Inside the caravan, it's a 600W Aldi job too, providing 240V for the fridge as we drive along.

Cheers mate.
Would you have a thread on here about the setup by any chance? I've looked but haven't found it.

 

[Old.Tony]

Nothing yet. No build thread ... maybe I should do one, one day!

 

[Navmania]

Nothing yet. No build thread ... maybe I should do one, one day!

Now I don't feel so bad for not having one yet.

 

[ozstickman]

Nothing yet. No build thread ... maybe I should do one, one day!

No worries.