More confused I think...2nd battery blues.

Hi Wazza.

I know what you mean. I gave up on the forum and went to a local battery factory who was recommended by a rather well to do acquaintance. I read so many conflicting recommendsations that I also was lost. All well meaning but conflicting.

I started to explain what we have in our car and lost my point and then deleted it all. Go and talk to the local battery specialist and an auto electrician that you can believe. Hopefully someone that is recommended. See what they say. Luckily Canberra is still small enough and you can usually trust a recommendation. Bad work stories spread quickly. Luckily, so do good ones.

We have a Redarc 200 amp isolator, three batteries and two fridges that last more than two days without any recharging.

Also nothing beats a face to face chat. Even beats asking Google!!!

Phil

Wassa,

Firstly, you need to understand that a 100Ah AGM battery, whilst a good size capacity wise, is a bloody heavy mongrel and needs a strong mounting bracket to hold it.
AGM batteries are also not the best for under bonnet use due to the heat generated by the engine and exhaust.

If you want to have the battery in the engine bay, a 100Ah wet cell battery would be a better choice, plus heavy duty twin core wiring (8 B&S) run back to the rear cab of your vehicle. A Merit type socket is the best to use for termination. A dual battery isolator should be mounted in the engine bay to isolate the starting battery from the auxiliary, but still be able to be charged by the alternator.
A 10 amp fuse should be installed close to the starting battery. This circuit would not require a dc-dc charger as the auxiliary battery is close to the alternator and voltage drop would not be an issue for the run back to the rear cab.

When the time comes to connect a camper trailer, a second heavy duty cable installed between the auxiliary battery and the rear of your vehicle, again protected by a 20-30 amp fuse or breaker, terminating in an anderson connector.
This is when you would employ a BCDC1220, or BCDC1240 which would be located at the end of the longer cable run, close to the camper battery/batteries which would be of the AGM style.

wazza : I dont think it needs to be that difficult ....

I'v got 100ah deep cyl battery & redarc smart switch ( never had a problem with it ) . The battery supplier can sell you the right battery for under bonnet .

If it was me I would spend less on unnecessary gadgets & invest in solar panel .

In gegards to replies / forum , you get some very good info here ,have a look at links

Articles


Blog by john & Val

cheers

The purpose of the isolator seems to confuse some people. Its only purpose is to automatically disconnect the starting battery from your ancillary loads (eg the fridge) while stationary. That means that you will be able to start the vehicle after your long weekend at that beautiful camp spot.
The purpose of the BCDC.... devices is to provide a proper charging current and voltage to batteries that are a long way from the charging source (in terms of wire length and voltage drop) or to properly support batteries of different chemistry to the standard starting type battery.
As has already been stated, the best battery types for under the bonnet installation is the standard wet cell starting batteries because of the heat that they have to withstand.

For your purpose a standard wetcell starting battery installed as the second battery and a redarc SBI12 connected between the main and auxillary batteries would be perfect. As far as fuses and circuit breakers are concerned, there purpose is to protect the wiring (and battery)from excess current so I would suggest something like a 50-100 amp fuse or circuit breaker on each end of the wire between the 2 batteries ( in case the wire rubs through and shorts to the chassis somewhere), and maybe a 20 amp fuse from the second battery to the rear cig lighter socket.

My only concern is your comment about 'the stereo'. If you mean the car radio then I would be concerned because it will be connected to the main starting battery by default and having it on for 4-6 hours/day for several days will flatten the main battery. I would look at getting this rewired to run off your auxillary battery.

It seems that this subject can be as simple or as complicated as you make it.

Our previous tourer was a 1996 petrol/auto 80s that had 2 wet cell batteries and an isolater and we never needed any more than that for running our 50litr fridge, a fw lights and occasionally a laptop for 20-30mins.

Any more than that is overkill unless you are going to stay places for weeks at a time and then if you are worried about battery level, just run the engine for half an hour on a short drive to top them up.

I think as long as you have the isolater to protect the cranking battery from being drained unexpectedly you will be fine.

When you get your trailer you can revisit your power requirements but you should only need to upgrade if you are planning on taking a few power hungry accessories.

Hi Wazza,

If the "cig. lighter socket in the back (already there, not sure of wire thickness)" is an original auxiliary power socket fitted to 100 series cruisers (not sure about others), you'll probably find that it will only work when the ignition or accessories switch is on, anyway.

That'd be the FIRST thing I'd check, otherwise, I'd suggest that it won't matter what battery set-up or charging regime you have, you still won't be able to run the fridge with the ignition off, unless that wiring is disconnected from the accessories switch and fed direct (through an appropriate fuse or circuit breaker) from your aux battery (or main, if you don't want to go anywhere after a day or so).

I'll leave others to give advice on the actual wiring set-up, but I'm pretty sure Home of 12 Volt still warrant AGM Redback batteries for under-bonnet use.

Mind you, they are HUGELY heavy, so make sure the cradle you intend using, and how it's fitted, are up to the task, if that's the way you eventually go.

Regards,

Charlie

Wazza
Look at all the bits and bobs people are collecting to go camping in the bush.
I went for a week with my caravan and a second Dometic 3 way fridge. Wet cell in the van running the lights and the radio and gas on both fridges.
No solar, no nothing. We ran out of water was the only snag.
Dice the 12v electrics and run your power hungry fridge on gas. Cheaper, more efficient and more reliable in the long run.
Why do you need TV when camping? Getting away means exactly that.

Bill

Wazza,

There is an Engel socket available to terminate the cable run, if you want to use the supplied Engel plug. They are a very good solution but what do you do when you wish to plug something else into the circuit?

You either need to have an Engel plug on every piece of 12 volt equipment, or standardise on a commom plug/socket combination.

The Merit socket is a robust solution which will prevent a merit type plug from vibrating loose. Just to confuse you a little bit, A Hella style plug is the type I use.
It has a removable red collar which enables the plug to connect to a standard cigarette socket, or with the collar removed, into the Merit socket.
Very easy to connect to a cable too. No soldering required as the wire ends clamp into the plugs connection terminal.
I cut the Engel plug off the end of the Engel fridge cable and added the Hella plug in it's place.