Battery setup -Hypothetical

It's not difficult.. just a matter how well you want to treat your AGMs with only and car alternator to charge and also how fast you want to charge the AGMs.. If you use the batteries a lot your alternator will have to work hard.

I have a second 160amp alternator with a Balmar Maxcharge external 3 stage regulator for my AGMs because I want them to live a bit longer.

good luck
gmd

I have 2x120 amp/hr AGM's with a 40amp three stage charger and with a 75% charge state they will draw the full 40amps. AGM's have a lower internal resistance and thus will grab most of your output and also need 14.7v to get to a full charge

Voltage drop to 3-rd battery in the back of your car and especially in caravan will be substantial. Thus step-up charger highly recommended if you like to make most of your batteries in terms of their longevity and ability to charge them in full.

Cheers
Serg

The unit will do the job as far as I understand, but as my learned friend Crazy Dog pointed out earlier this year that a 3rd battery in the back of the car is no good for the occupants health wise, unless of coarse the battery is going in the back of a ute.

Cheers Steve.

Hi
All things are possible IF you go to enough trouble &$$$$
You are talking about 480ahs of deep cycle bats with a 100amp alternator, unless you use very heavy cables ,& specialised chargers they will take alooong time to charge if heavily discharged.
I know it is not the question you asked but I think you should be giving some information on your intended use ie heavy power req for a short time with long trips in between or lower power for a long time?.
The main thing is to get a balanced system based on intended use

Is it better to keep the vehicle simple and lighter and also there is the cost of replacing all the batteries at the same time..Nothing wrong with dual batteries and is it better to buy a small generator to get you going if you run out of battery power rather that the third battery option?? Something like a Christie Engineering unit or a tiny generator.. Michael

I have a somewhat similar set-up (almost).

The Chev 6.5 V8 sports a 85 amp alternator.
Under the bonnet resides one Supercharge N70ZZ battery. A very heavy cable runs through a piece of reinforced hose from that battery to the cargo box on the back of the Patrol's dual cab. That heavy cable leads to another N70ZZ Supercharge. There is NO gizmos of any sort between those 2 batteries.

Now, from the original front battery, there is a reasonably heavy cable (8mm I think) that goes via a relay, which is switched when the ignition is on. That cable also goes to the box where it enters a small plastic junction box. From the junction box I have run 2 smaller cables (6mm sq). One of those 6mm cables goes into the cargo box and powers up an Arrid Twin Charge that is connected to the Fullriver 120a/h AGM, which runs the accessories on the Patrol (fridge, Maxair, HF, inverter, side lights, rear lights etc).

The other 6mm cable runs to the 12 pin Narva trailer plug. On the camper trailer a similar sized wire goes to another Arrid Twin Charger which is connected to the Supercharge N70ZZ batteries that are used to power the camper's fridge, water pump and lights.

I have a couple of other heavy use items attached to the 2nd starter battery in the cargo box; a large Grande Boss compressor and 4 x Lightforce 170 spot lights mounted on the roof.

It all works very well and the alternator doesn't seem to struggle at all.

Cheers

Roachie

- main *starter* battery N70zz
- 120amp dual battery isolator <-- between 2 x Cranking batteries batteries ??
- second battery - also N70zz <-- What is it for ?????

this is my only 'problem' with the set-up

Mainey . . .