Dual Battery Question

[k3vin]

Hi Guys,

Don't want to sound too much of a newbie, but I will be attempting on installing my second battery this weekend, just after some advice.

I got a Baintech Dual Battery Kit (100A).

What I was wondering was, would it a bad idea to use a 130A deep cycle battery for the AUX?

I originally planned to get a 100A deep cycle for AUX, but thought for the extra few bucks, would it be suitable?

The AUX battery will be mainly powering a CFX-40 and some lighting occasionally.

 

[MjWatt]

Im looking at putting duals in my d40 soon too. my thinking was
Put a good cel 100A or something ike that where the original battery is, add a red arc controller.

Put the factory battery in the back. Run all things like fridge and lights from battery under bonnet and then install a manual override switch to engage the rear battery if I drain the main battery past start point.

Thats kinda how an auto electrician explained it to me. But still googling..

 

[k3vin]

Interesting idea. Would love to hear other peoples input on this. I thought the deep cycles wouldn't have the same cranking capacity (unless you go bigger) & are not as tolerant to environment conditions (extreme cold, hot, etc.). Also mainly designed for long constant power draw.

EDIT: Just asked a mate who's a truck electrician, he didn't say it's not possible, just told me "You shouldn't be starting off a deep cycle battery. Keep the deep cycle for aux only."

 

[Old.Tony]

Cranking power and endurance used to be at opposite ends of the battery spectrum, but now they're closing the gap. My Optima D31A is a 75Ah AGM deep cycle that can do 900CCA - it's so rugged that I can discharge it to zero and it'll still recharge and work.

If you can get a 130Ah battery for slightly more than the 100Ah it's worth doing - because as a deep cycle you'll have a fair bit of extra power. In winter, with a fridge that's cycling maybe a third of the time, that 30A represents a whole day's operation.

 

[k3vin]

Hi Tony,

Cheers for the reply mate. So it shouldn't be any issue running 130Ah battery even thought I've only got a 100Ah isolator & fuses? I guess as long as I am not drawing 130Ah worth should be fine?

 

[Old.Tony]

Yeah it's no drama. The 130Ah refers to the long-term capacity of the battery. Technically, it's measured by drawing power from the battery at a rate so that after 20 hours, the battery voltage falls below 10.75V. That rate - let's say it's 5 amps - gets multiplied by 20 giving the capacity figure that you see on the battery (which is NOT noted as "RC" - that's a slightly different way of measuring things).

The isolator will isolate 100A - it will protect the system from dumping more than 100A. It is possible for much more power to move to the aux battery - after all, it's being fed not just by the alternator, but by the cranker! The aux battery will more than likely draw much less, although I suspect that spiral AGMs could suck the life out of the cranker if it was dead - probably a good thing that I use an inverter+mains charger on mine, to avoid problems!

 

[k3vin]

Thanks again Tony, always a wealth of knowledge.

 

[4Burner]

I am using a CTEK DC-DC Charger and an AC Delco 100AH battery. It's main use is the 60L Waeco and charging the kids Ipads. The CTEK charger keeps it all running fine.
The one thing I did was put the new battery I bought on a battery charger in the garage and crank it full. You don't know how long the batteries have been sitting before you get them. It helped.

Good luck.

 

[BIGCOLL]

The AH of the battery reflects how long the battery will last eg 100ah will last an hour if drawing 100 Amps, as far as using your battery that cranks and then also tunning your auxillary equipment off it defeats the purpose of putting a secondary battery in, your starting batt is your life line, use the secondary battery for your auxillary equipment then starting the car should be as easy as turning the key. I would put the deep cycle as your auxillary batt. Your 100A batt isolater is rated just the same as a fuse, at 100A current draw it will pop. I recommend a redarc BCDC1225LV dual battery carger as they are designed for the new charging systems on the new type vehicles. Any quieries please feel free to ask.

 

[k3vin]

Cheers for the replies and responses guys. Was an interesting weekend on the install

 

[MjWatt]

pics and story

 

[k3vin]

Haha, mine setup quite crude, but I'll do me best maybe on weekend to get some pics.

 

[k3vin]

The Build

Hi Guys,

As per requested by MjWatt, here is my crude build. (Be gentle).

Started with:
- Supercheap toolbox
- Baintech 100A dual battery kit
- Century 100Ah deep cycle
- Projecta dual battery monitor
- Projecta battery tray
- 2 x 100A fuses and holder
- Battery clamps
- Narva 12 port fuse board
- few rocker switches
- few marine cigarette lighter & USB combos.
- Various terminations & wiring.
- Silicone
- 5mm bolts

THE BUILD:

1. Started by connecting the fuse holder to main battery in first image (top red wire), then running that through firewall, through the drivers side down to rear where I have mounted the tool box.

2. Terminated it to the Baintech relay in this image.

3. This is the terminal of my AUX battery, which runs to the Baintech relay also. You can see I have use another 100A fuse on this terminal also.

4. Image of how it all looks in the back with the Narva fuse box and few things connected to it (tray lights, awning light & usb/cigarette sockets). I know its messy, but a few cables times should do the trick.

5. With the Projecta dual battery monitor, simple run it to each battery & earth.

Other images are the rocker switches, external & internal usb/cigarette lighters.

 

[k3vin]

The Build Pt.2

With the internal socket, it is just wedged in there for now, still contemplating where to put it. Either around that similar area or possibly on the seat belt cover between driver and rear passenger.

Not that great at write ups, but will answer anything I've missed.

TOOLS USED:
- Clamping tool for the terminations.
- Power drill
- Dremel
- Socket set
- Screw drivers
- Aluminum stripes (got from bunnings to mount toolbox down to rails)
- BEER!

 

[MjWatt]

Nice. I like the USB power outlets

 

[ninorc]

Hi Guys,

Don't want to sound too much of a newbie, but I will be attempting on installing my second battery this weekend, just after some advice.

I got a Baintech Dual Battery Kit (100A).

What I was wondering was, would it a bad idea to use a 130A deep cycle battery for the AUX?

I originally planned to get a 100A deep cycle for AUX, but thought for the extra few bucks, would it be suitable?

The AUX battery will be mainly powering a CFX-40 and some lighting occasionally.

just a problem I had was my deep cycle battery never fully charged while even on long drives. Now using a AGM battery is getting up to near full charge, I've only got a smart solenoid system (the deep cycle is great until charging required, ok with my older 4WD or generator)

 

[ninorc]

just a problem I had was my deep cycle battery never fully charged while even on long drives. Now using a AGM battery is getting up to near full charge, I've only got a smart solenoid system (the deep cycle is great until charging required, ok with my older 4WD or generator)

 

[k3vin]

Haven't had a chance to really test it out, will in about a month tho. Will report back

 

[Old.Tony]

That's where DC-DC chargers (or inverter+AC-DC chargers) shine.