Thread: Auxiliary battery installation

Can any one advise me how to easily access the main battery to install cables to a second battery installed in the spare wheel space. If i must take it from the main battery, how do I remove the seat,is their any room for cables in that tight space, or can it be taken from the front live terminal.Any advice gladly accepted
Armdlo

Mate I'm going through this now.

I've got the battery fitted, just waiting on delivery of a special charger from NZ and them I'm doing it. Will post pictures and a guide in the next few weeks.

Cheers

Bob

PS. Nothing's easy on this car

Here's a link to my post on how I did it.

http://www.clubtouareg.com/forums/f6...tml#post115851

Cheers

bob

Hi, bobzed57
What special charger did you use, if I can ask?

MRL T5

Here's the blurb from the email the maker sent me. It's called an ABC unit.

"I developed this unit in order to overcome the shortcomings of the existing charging system in our ex-rental Transit - a relay between the batteries which connected them together when the motor was running- and I installed current & voltmeters to track what the problem was.

It would seem logical that simply connecting the two together would allow the full charged [main] battery to fill up the flat [aux] battery, in the manner of two water tanks being connected with a hose, but unfortunately lead-acid batteries don't work that way.

It became obvious pretty quickly that it was impossible to charge them fully in this manner. Charging a lead acid battery requires extra energy to push the chemical reaction backwards, and at best, the reaction is only 80% efficient.

To charge at 25 Amps a 12v battery requires a voltage of about 4v more than the battery at rest. The main charging system limits at about 14.2-14.4volts, and to charge the Auxiliary battery at 20 Amps requires the charger to be able to generate up to 16 Volts.

This is what the 12-12v ABC does. - A switched mode inverter generates a controlled voltage which is added on top of the motor battery voltage to charge the aux. battery at more than 25 amps.

As far as the motor battery/ alternator system is concerned, it has the same effect as turning on the headlights - the alternator senses the battery voltage drop and produces a charge to keep the motor battery voltage up.

Meanwhile, the ABC is generating the difference voltage and adding it on top of the motor battery voltage, all the while controlling the charge to and voltage across the house battery.

The beauty of the system is that we are not generating the whole 25 amps at 16 volts, only say 25A @ 4 volts. Monitoring circuits keep an eye on the motor battery voltage [ so that the ABC will not run while the main battery is too low], the current going into the aux battery, the voltage across the battery, and the internal temperature of the ABC.

Once full charge is approached, the current is applied in short pulses inversely proportional to the capacity remaining. This prevents the battery gassing by allowing the bubbles formed on the plates time to re-combine back into water.
The cycle is repeated every 10 seconds.

Efficiency is better than 85%

It may be configured either to be enabled by an ignition input, or allowed to auto- detect that the alternator is charging.

There is provision to connect a remote reference line to the aux battery if it cannot be close to the ABC. [Greater than about 0.5v drop @ 20A - usually means further than about 2m for 5mm2 wire]

This doesn't mean that the charger will not work properly if the aux battery is too far away, just that it will take slightly longer to charge to 100%

Remote leds can be connected to show [green] that the ABC is enabled and [red] that the charge is being limited to 20A. This led also indicates that the battery is approaching 100% when the ABC begins to charge in the pulsed mode. These are supplied as part of the charger, with the cable at a length specified by you.

There is an internal fuse to protect the inverter section, but not for the common-mode current from the main battery - experience has proved that there is no need to do so, and that common automotive fuses are totally unreliable for a constant current which is more than half of their rating - the
fuseholders tend to fail thermally."

As I said a few guys in club are installing this system. I geuss the proof of its effectiveness will be how long the beer is cold for.

Cheers

Bob

Hey Bob
How difficult was it to remove the seat and what about the covers on the internal panels, do you have time for a step by step guide for us. I just hate buggering the carpet looking for clips etc. Thanks for the great photo shots.

greg

Greg

The instructions for getting at the battery are at club Touareg.

With the trim, I just worked it out.

B-pillar trim comes off first. There's a torx screw under the airbag label. Then you have work the trim out of the rubber. There's also a plug for the vent motor, which'll need disconnecting. There's also a cover on the seat that covers the seatbelt anchor. Take this off then simply push down on the seat belt anchor with a screw driver and it'll come free. Thread the belt through the B-Pillar and there you have it. The install is the reverse. Just make sure that the belt height adjuster is the same as when you pulled it off otherwise the belt will bind.

Door sill trim next. Lever the two plastic strips out of their recesses. When you gently prise these covers up, you'll see one end is a tag the other a clip. Free the trim from the clip end. Undo the 4 torx screws and prise trim out of seals. You will now also be able to prise the wheel arch trim just a little to give you the access you need to the boot.

I don't know how big the piranha et al isolators are, so I don't know if one will fit under the seat at the battery. There's a fair bit of room in the channel so you shouldn't have too much trouble running 4 gauge cable to the rear if that's how you decide to go.

All in all, I'm pretty happy with my install. Now if the Treg just holds together for another couple of years, the T3 might be the replacement

Cheers

Bob

Hi Armdlo
have you considered the other alternative of a portable full size battery pack - I think Waeco and Engel both market these. The battery can be charged from your auxilliary 12v sockets and can also be placed anywhere in the car. When you don't need it you can leave it at home. This involves no mods to the car which will ultimately detract from its value and doesn't add dead weight.
Having had a Range Rover fully kitted with dual batteries + many other built in options for many years these days I prefer not to modify the vehicle.

Cheers T Rex

Thanks T Rex,
I have actually( National Lunar which is pretty smart)but still requires two heavy cables from the primary battery, like you (previous RR) you end up leaving to much gear on the vehicle so this portable battert box appealed to me.Cant quite imagine how the required current flows thru such a low rated( thin) cable? unless it boosts the minimal voltage received into something decent. more info would be good

Armdlo

Hi Armdlo
My guess (I'm no expert) is that charging from your 12 outlet would be the same as charging from a normal 240V battery charger which also has quite thin wires. The National Lunar unit may suggest heavy cables to allow you to use the battery to feed power back to the vehicle. I would tend to use the auxilliary battery to power a fridge and as a spare should my main battery fail (using jumper leads). I hope we have as many great outback adventures in the Touareg as we had in the RR. Cheers

T Rex