Battery Trickle Charger

[R84ME]

On page 73 of the US Owners Manual, regarding the cigarette lighter use, it states "The vehicle battery must not be charged with a standard small charger that plugs into the cigarete lighter or outlet."

I'm wondering about the "standard" - is this a reference to a standard high amperage battery charger, not a 0.5A trickle charger like Porsche's battery maintainer?

Is anyone using a trickle charger on their R8? If so, what kind?

Thanks in advance!

[R8 England]

You cannot trickle charge through the lighter socket. The lighter socket switches OFF with the ignition, so you would have to have the ignition on to trickle charge, which defeats the whole purpose.

I have trickle charged mine with an electronic car battery charger (£20 - $30). Charges the battery to full, then switches itself to trickle charge mode. I just leave the charger in the front bonnet connected directly to the battery.

If you want a real trickle only charger, you can buy them in the UK mail order from electronics company CPC at around £10 - $15. I'm sure you can get something similar from Radio Shack in the US.

[R84ME]

You cannot trickle charge through the lighter socket. The lighter socket switches OFF with the ignition, so you would have to have the ignition on to trickle charge, which defeats the whole purpose.

In the US manual, right above the same sentence, if further states "When the vehicle is off and accessories are still plugged in, the vehicle battery can still be drained." This leads one to believe the socket is hot all the time like Porsche & most US cars.

I just checked the UK manual and on page 72, it states "The cigarette lighter will not work when the ignition is on."

Clearly, a discrepancy between US & UK so I tested the power socket in the luggage compartment with a 12V/110V coverter with the ignition off - dead as a door nail. UK Owner's Manual is correct - US is incorrect.

I do have a "regular" charger that behaves exactly as you state so I'll just remove the battery cover & use it.

GREAT example of why this forum is so valuable.

Thanks!

[mngolfer]

I checked with the Audi dealer about the trickle charger for the R8 battery. It took AOA three days to come up with their recommended trickle charger. They claim there is a "special" charger required. The cost is $415. I checked around and found the same charger for $324. It only outputs .4 amps.

Unfortunately, after I decided not to get the charger I tossed the information on the charger. It may take some time, but the dealer can advise on the "recommended" charger. If anyone is interested PM me and I will contact the parts manager at my dealer.

[R8 England]

Sorry, but that's absolute bull**** from AoA !!!!!!!!!!

The car uses a standard lead-acid battery. I don't remember the exact capacity, but think its around 110 Ah. You need something that will give an output of around 0.4 Amp to 0.6 Amp, at no more than 14.4 Volts.

You can use ANY charger designed to charge small capacity (1.2 to 12 Ah) lead-acid cells, or lead-acid sealed gel cells. For a large car battery, the charger output is effectively a trickle charge.

For a trickle charge, you can leave the unit plugged in almost indefinitely. As battery charge [voltage] rises, the power it takes from the charger falls, just like when the car is being driven.

These are small units that plug straight into a 110 or 240 Volt wall socket

Example:
http://cpc.farnell.com/jsp/level5/mo...cpc/467212.xml At only £9.50 !!!

Just be sure of one thing. Apart from the factory fitted car alarm or a Tracker/Lojack, nothing else must be running or using power on the vehicle.

I plug mine in, run the wires to the battery and close the front boot, taking car not the crush the cable.


That's it. Simple, cheap, effective.

[R84ME]

I have a v1 Porsche Battery maintainer (black with a single red LED) and I'm sure it will work fine. I just need the battery clamp adapter for the cigarette lighter receptacle since Audi switches the power at the ignition. I found the part number 000-043-202-55, about $10-$15 US - but I swear I have one laying around somewhere, never used...

Thanks everyone!

[swansailor]

I use this:

http://www.autogeek.net/btjunior.html

[mngolfer]

I found a thread I had previously posted on the battery charger. This is what AOA recommends and sells at the dealer.

http://www.tooldiscounter.com/ItemDi...up=MDTPSC-550S

[09R8]

that's what I have.

[Stewart W]

I use this:

http://www.autogeek.net/btjunior.html

*******
I have used this Battery Tender Jr. for all my cars over the years...never disappointed.