Dual Battery Set up

[SnowMotion]

I am looking to install a second battery in my 2012 T5 Crew Van 132kw and am looking for some technical advise on the best set up.

I have read all about Split chargers with Isolators for the main battery and have now come across information about CAN-Bus equipped vehicles having variable output alternators. I have read the UK forums on this as well but all this information is leaving me unsure of exactly what I need.

My plan is the install a 100AH AGM battery under the passenger seat. This will have relatively light duties being used to run:
A cooler
Charge mobile phones
Charge computer if necessary
Maybe an inverter to run a heater
some lights

So the actual drain on a 100AH battery should be ok, my question is what is the method of charging the battery.

I have looked at 140Amp split charging systems that draw from the main battery with an low voltage isolator.
or
BC-DC battery charges like the RedArc BCDC1225LV, that is basically a battery charger drawing power from the main battery and amplifying to charge the AUX battery. This type also can run solar panels. (not doing this but maybe later)

If the 140Amp split charging system would work in the van I would prefer to go this way on a cost basis but my real question is would this work.

Any help on understanding how the battery/electrical/alternator system works would be appreciated.
I did a massive search on the weekend for this and really can not find an complete answer.

Cheers
Andy

[Transporter]

I have installed Projecta dc-dc charger in my 2005 T5 with 75AH Telecom battery and Projecta 1000W pure sinewave inverter. DC to DC charger works well with the deep cycle AGM batteries. There should be the thread with my install somewhere in the stickies.

[T5Pete]

i did a good install with a CTEK unit.

I have 2x55ah batteries installed in the rear in a box that i had around the wheel tub, one is permanently connected and one is hooked up in parallel with a mini anderson plug and is removable. I can hoy one out and use it camping, to run compressor if needed etc.

the ctek unit looks after the batteries, and can also take a solar panel in if required.

If you are in Sydney go and see Battery Business in warriewood (behind maccas). I went there, got all the bits, got a great price. we drew out what i wanted, test fitted batteries, he cut up and soldered and crimped every wire i needed to hook it all up and even lent me the hydraulic crimper to do the final crimp on the cable from the car battery to the ctek in the back. I even managed to hide the unit behind a magic panel in the right hand wall panel and have a pop off cover that hides the fuse box and ctek.

I've run my engel mt45 for 3 days with no probs. I also hooked up a ton of cig lighters and a dual usb power port in the back that is great.

pedro

[SnowMotion]

Thanks Pedro,

I work at Dee Why so not far to pop up to Warriewood and have a chat to them.
I have been leaning towards the CTEK 250S as it seem to do most things very well.

[Transporter]

Did you check the Redarc BCDC1240 ?

[SnowMotion]

Yes, had a look at the Redarc BCDC1225LV and spoke to the company and this is the unit they recommended for the van especially if I wanted to add solar power. The only downside is that it appears to be an additional $150 above the CTEK.
I have contacted an installer in the UK (who had good reviews) about what he is fitting to the T5's and he was very kind enough to have a look at my short list of items and he thought the CTEK was pretty much identical to what he is installing.

The only issue is just to finalize how much space I really have under the drivers seat (thinking of fitting seat swivel to passenger seat) to fit the battery, charger and fuse block. I will measure up a bit better tomorrow and see if I can make a decision.

[Koopa]

Hi guys.. I am also looking at installing a dual battery system in a T5. I am looking at some different setup and before I found this thread, I was leaning towards the following;

1. 100amp deep cycle connected to main battey through a diode battery iscolator. This will charge the Aux battery when the engine is running, and iscolate the main battery when it is not. Also looking at a model which has a manual override incase I need to crank off the Aux battery.
2. Off the Aux battery have
- 1000w inverter with two double socket power point wired in the van
-12v bus to power lights, fans etc.

3. Down the track..Install a battery charger for Aux battery when external power is available or for use with Solar panels.

This thread talks about installing a battery charger to be able to charge the Aux battery off the main. My understanding is that if you directly hook up the aux battery to the main, then this should charge the aux battery ( with an iscolator for the above mentioned reasons).

I'm not too electrically savvy but am I missing something here? Do you actually need a battery charger atall( except for when external/ Solar power is available)?

Cheers

[Transporter]

If you install 2 batteries in parallel, just connected with the wires and nothing else, you will put quite a load on the alternator, if both batteries would be flat and when you will use your second battery the current will flow from the starting battery and you probably won't start one day. Also, the connecting wires would have to be quite thick at least the same as the battery cables that are in the vehicle now.

The 12V to 12V charger has advantage that you don't have to run the starting cables from your main battery, you only need cables that are for 50A current. I used 150A cable from the battery positive to the 12V to 12V charger under the front bench seat, so I can use the AUX battery in emergency for the start up. The 12to12 charger also allows to charge batteries with different chemistry and it's usually 3 stage charger, much better suited in long term.

[Syncrotek]

Back in the day, aux. battery charging isolators were diodes only, most diodes introduce
a voltage loss to the connection, meaning the battery being charged through the diode(s)
will not rise to sufficient voltage to maintain the correct charge, which will lead to reduced
battery life and low capacity for use. Aux. battery charging isolators of today are more
sophisticated and (mostly) will not have voltage loss. So make sure you don't use the diode
type.
The alternators on the T5 are rated at 120 amps, (may vary on some models) so can cope with
the charging of 2 or 3 batteries without problems,... but... and this is the thing to consider...
when you discharge the aux. battery(ies) by use of accessories, it might be 3/4 discharged
when you start driving home, and due to the action of the alternator's regulator the aux. battery
will take perhaps more than the drive home to recharge, so this is the reason for the 240v
battery charger, when back home switch that charger on until the battery is fully charged,
ready for the next use.
There is a whole lot more that can be considered for auxiliary batteries, i.e. solar and other
charging systems, seperate switching, etc.

[Transporter]

The alternators on the T5 are rated at 120 amps, (may vary on some models)

...140A in 5 cylinder models. I'm not sure of the long term impact on the alternator health if someone would just connect another battery in parallel. It could work with the new batteries but once the batteries would get older, I don't know, I wouldn't do it.