Dual Batteries or one single

[Mitch.mccabe]

So for our camping needs, we might go 3 days without power( would be charging every 3 days, so I want to figure this out with your help and Please mind my lack of expertise in this area, So here is a question could you wire 2 x 95 amp batteries to give 190 amps, instead of using a single 130, thus giving more ampage? Would you have to run the 2 95's with a dual battery system or just a smart charger. A local nrma here in town, sell new 95amps for $130, they don't sell anything bigger,
Any thoughts or ideas would be good, I would be running lights, maybe some tunes, a water pump and maybe a fridge

[happygu]

Mitch,

I can flatten my battery in one day, by just having the radio on whilst working on the truck....

I would definitely look at the dual battery option, especially with a fridge on board - or at the very least, some sort of solar panel for daylight charging whilst you are still.

I have a dual battery system, so my natural inclination is to head for that and I have never been stuck ..... but we will see what the others say too

[threedogs]

If those 95ah batteries are out of an UPS, or for one leave them alone , they will rattle to bits
All I use is a 115 AH wet cell Trojan and an 80watt solar panel, its simple and it works.
This battery runs my 40 ltr Engel and some LED lighting which pulls very little power.
As I said been using this set up for 20 years and NEVER ran out of battery.
I have a camper with a 100ah battery for tunes at camp and additional lighting if need be.
Keep it simple.
I take an Ice box for every ones cool drinks, Engel only for food,
a good ice box will retain Ice for 3 days easy imo. If travelling you'll need fuel every day so you can top up ice as well
Water pump wouldn't be running for any extended periods I would think.
If those 95 batteries are ok you could install one under the bonnet ,
the other you could put in a plastic battery box, this way you can move your lights to say down by the river

[Drew]

Just remember that if you charge solely by the alternator they won't be fully charged so best use solar and/or a smart charger to get the most out of your batteries.

One setup I saw was have 1 battery under the bonnet topped up by portable solar panels and the 2nd battery charged while driving using a 240v smart charger via an inverter.

Maybe a ctek d250s that can be used to charge using panels and when driving its a dc/dc charger (no need for an inverter running in the car)

[Mitch.mccabe]

Sorry I probably should have mentioned that this is for my camper, I will be getting a decent system in the patrol,
So every 3 days I would be able to charge the batteries in the camper

[threedogs]

No problems then , a bit of LED lighting will use very little power.
later on get a dc to dc charger

[Cuppa]

At 12v 2x95Ah in parallel will give a total capacity of 190Ah (Amp hours, not amps).

If your batteries are 100% charged this will give you a useable capacity of about 100 AH, (less if you are drawing large currents from it). It is possible to use more, but if you take the batteries below 40/50% capacity you will be severely reducing their lifespan each time you do.

However as Drew says your alternator alone will not fully charge your batteries, it will only charge them to about 70% capacity, or 75 to 80% capacity for AGM’s.

Lets be generous & say you have new AGMs & that your alternator can get them to 80% capacity. This means you would have an effective total capacity of 152Ah. If you discharge them to 40% (of 190Ah/76Ah) this gives you a useable capacity of just 76Ah. (152Ah - 76Ah = 76Ah). So by following Drew’s advice & fitting a dc to dc charger & thus being able to fully charge your batteries you gain an extra 25% useable capacity, as well as ensuring that your batteries will have a much longer lifespan.

Ctek & Redarc both make good dc to dc chargers.

[Drew]

Cuppa always the literary genius , couldn't have said it better myself suck suck grovel grovel

I have 240Ah in the van, charged with a DC/DC charger while on the road, can connect solar to it if I want (same charger) and then if I really need to, kick the genny in the guts and stick the 25A charger on it. Did you see the pic TD :P

Ultimately it comes down to what you connect up. I use a CPAP so that takes 20-30Ah (amp hours) out a day (or night) or even more if i have a nanna nap . That's why I'm a bit fussy coz if I run out of juice I don't sleep. As TD says, LED's take nothing.

So for me at 240Ah & CPAP & lights I could squeeze 3 nights out before I hit 50% charge and need to charge (Assuming batteries were at 100% at the start). 5-6 nights with 120w portable solar panels charging during the day. If the batteries were at 80% then I lose a night

As far as what/how many batteries it comes down to what you run off them, for how long and how long you want to go before charging.

The other thing is what space you have and type of battery. I have sealed AGM in the van and can lay them on their sides if need be. I don't know where you are but guys like Batteries Direct deliver to most places I think so don't limit yourself if you can avoid it.

Just remember what Cuppa said, there's total capacity then there's usable.

This might help http://www.fridge-and-solar.net/agm.htm

[Mitch.mccabe]

Wow this is all mainly going over my head lol. Those weblinks are an awesome read Drew. Thanks aswell Cuppa, I have read quite a few of your posts and you seem very much in the know for auto electrics/batteries.
I think with what I'm going to be using in the led lights, and being able to use either 240volt ctek smart charger or my genie every 2-3 days I don't think I would go under the 50% capacity. Although may come close.
I'm going to get ARB to hook up a dual battery system up in the patrol with a better rated 12 volt plug for the fridge in the back( as I've read that the standard 12 volt cord/plug to the rear may be a little under powered for a full time fridge when it is on) , and also hook up a Anderson plug. (for a later date. To be able to charge the batteries in the trailer whilst we are driving)
My only problem might be with my genie, I only have a 1kva inverter genni, Would that be enough to use the ctek charger to charge the batteries? I read most of this link http://www.fridge-and-solar.net/gen_charge.htm but couldn't find out how big a genni I'd need
Also can you use the power (leds) as your charging the batteries?
Any more answers would be great if you can understand what I'm saying,
P.S Cuppa, How good is Copeton Dam

[Cuppa]

My only problem might be with my genie, I only have a 1kva inverter genni, Would that be enough to use the ctek charger to charge the batteries? I read most of this link http://www.fridge-and-solar.net/gen_charge.htm but couldn't find out how big a genni I'd need
Also can you use the power (leds) as your charging the batteries?

The 1Kva gennie is fine for use with a multi stage battery charger. I have a Honda Eu10i 1Kva which I bought in a rash moment & have only used it when our bus alternator died a long way from anywhere. I used it to charge our crank batteries every two or three days via a Ctek 14Amp/24v charger (equivalent of 25amp/12v Ctek) without any difficulty until I could get a replacement alternator sent to Broome).

Yes you can use power whilst charging.

If you are going to change plugs for the fridge (a good idea) replacing it with an andersen plug gives the most secure connection.

We enjoyed Copeton Dam, but it was bloody freezing when we were there, got down into minus temps. great whilst the sun was out, but like a freezer as soon as it went in.

Val at Fridge & Solar who wrote the article you linked to is a good mate of mine, top bloke always willing to help folks out.