12 volt inverter 12 volt sealed deep cycle battery system

Plenty of advice on here mate, but you'll need to say what you want to do with the set up.

On a different tark now. There are perfectly good 12 volt tellys and lighting solutions around. The extra complexity of an inverter could be avoided quite cheaply, probably for about the same as it'd cost you for an inverter.

G'day gizza
I would be using a 12v tv and LED lights so no inverter is needed, as mentioned above.
Also would use the 40L Engel as a freezer unless you really have a bullock to keep frozen. And have both the 80 and the 40 well insulated and a fresh air supply for the condensers to get rid of the heat. No good having fridges stewing in a pool of their own hot air or they will run all the time and still may not cool or freeze.

Do you have a decent high output charger to bring the batteries Back Up when on 240v?

Probably need two 100ah batteries because if used in hotter weather April will be 30 or a bit more, the fridges will still be eating battery power each night as well as the tv etc.
Inside the vehicle the temp will be more and that is the temp the fridges feel. So run times and overall amp use may be about 100ah/day. That is what two 100ah batteries would only like to deliver in a day. ie 1/2 discharge. 50 ah each.

Make sure you have a digital battery monitor which you can switch on, or leave on, most of the time to check the voltage of the batteries to see how it is all holding up and when you may need to charge them.

Cheers
Ross M

Two things you need to do, both of them involve reading.

1. Read This;Electricity for camping

2. and this;Building a 12V DC power system


Cheers Mick

First as has been said......you may be able to avoid the inverter all together.

Second...as has been said many times before.....there are realities about off grid refrigeration that some people simply don't grasp...or don't want to hear.

Big fridges realy need large batteries and a solid sorce of supply...more than many people want to know......reduce your refrigeration and reduce your costs dramaticly.

Say the word "FREEZER" and the power consumption increases dramaticly....like by a factor of 4 to 6 times the consumption of the same fridge run as a fridge.
Realy consider the need to run a freezer....particularly a big freezer.

Contrary to what all the sales people will try and tell you AGM may have no advantage what so ever.....a good quialty wett cell battery will cost less and have better temperature tollerance.....AND a good wett cell battery will tolerate fastrer charge rates than some of the AGM batteries.

Again, contrary to what all the sales people will tell you....a DC to DC charger may have no advantage whatsoever..particularly if tyou are not running an AGM that has a limited charge current.

Remember people always underestimate how much battery capacity is required......considerably so.
All too often people complain that either their batteries Do not hold up their requirements long enough and/or their batteries have a short service life.....due to insufficient capacity for their needs.
100Ah is sufficient to reliably stand up a 40 litre fridge run as a fridge for a couple of days. ...a 100AH battery will not hold up a 40,litre fridge run as a freezer for 24 hours in a hot environment

In addition people frequently do not understand that it takes time to recharge batteries regardless of the size of the charger.
6 to 8 hours is required to recharge a battery fully ...from any source...from a deep discharge.....particularly once the batteries get some age.

because of all the above, a very large portion of people are running on insufficient battery capacity, cycling their batteries too deeply and failing to fully recharge them day after day...resulting in very short battery life.

cheers

I agree with most of what has already been said. No matter what frigs or freezers and teles you are running, the important thing to remember is that the energy to run these appliances, ie taken from the battery(s) MUST be replaced. The battery(s) MUST be large enough to supply the overnight load with reserve. While you are driving charging not a real issue. However, would strongly support the use of a DC-DC charger, otherwise the batteries don't get fully charged. Being able to fully charge the batteries is most important.

I doubt that you will be driving every day. Therefore you will need some other other means of charging and/or running the load. Add 1 solar panel, the largest you can fit in your kit. 200watt min. Don't fall for those little 40watt units 'cause they'll do jack s**t.

My own experience started running a 40ltr engel as a freezer with a 75ah Thumper charged from the main battery. It would not run the unit overnight. In the morning I found the battery voltage below 10volts, dead flat. I then linked that with the caravan batteries for overnight which was OK to a point. After 2 years the thumper was bulging on the insides. Solution 130ah AGM charged via a 20amp dc-dc charger and topped up with a 140 watt solar panel when we a stopped for few days. In the event we have a few overcast days then we fall back to a 230v charger from the generator.

An Engel run as a freezer will draw 4-5 amps and it will run for around 20 hours in a day, particularly in the hotter weather, which means you need a minimum of a 100ah battery just to break even. As I said before that 100ah must then be put back into the battery.

Cheers

HI
Avoid an inverter if you can
They waste what may be limited available energy from the alternator
They DO ADD the risk of ELECTRIC shock if more than one appliance /device requiring /fitted with, a THREE plug is CONNECTED.

PeterQ

They are excellent chargers,have used 2 for 5years.

There's lots of good advice above.

My experience over 5 years of CTing has been to go entirely to 12v for reasons of efficiency and simplicity (and I can fix the faults myself - have had to learn).

As for batteries, I'm a fan of calcium hybrids. Got 5 years out of 2 x 100 aH units.