Vicl

I'm really sorry for such question, it is not directly related to A8, but I was talking to my father today and he asked me what type of battery charger do I have? I told I never had one. He was really surprised. He said everyone needs one.

So, question #1: Do we really need one? Even in my old car I've replaced my battery when it was 14 years old and sometimes I had to drive only 1.5 km (about 1 mile) one way in the morning in the winter with -30C ( -22F) and the same distance back and I had to leave the car for a month in the garage in the winter to travel south. I never had a problem starting it. This car is 5 y.o. and I use it a little more often, but still during the week it is mostly short distance travel, when on the weekends more long distance travels.

The question is do we really need one? And if we do how do we use it?

According to my father the battery should live longer if it is kept fully charged. Is it the old school?
Thanks for any info.

Quetion #2: if we do need one what we should look for in it?
I found 2 chargers at Canadian Tire with discounts. Are they worth it? Thanks!

http://www.canadiantire.ca/AST/brows....jsp?locale=en

http://www.canadiantire.ca/AST/brows....jsp?locale=en

MP4.2+6.0

First, your links are on a WAY different page than 90% of what I say below. See the very end for those kind of chargers.

I get the sense what your father is referring to is a "trickle charger," sometimes called a maintenance charger and things like that. Or if not, what you should consider. Net, if you leave a vehicle for an extended period it is a good idea. How long is extended? In this age, days, a week or two is a "No," clearly. If the battery can't hold up, something is wrong; that's just a typical leave for a week or so vacation or car at airport for extended trip scenario. Your one month scenario from your post, then maybe it starts to get at the edge of it making sense, especially in colder weather scenarios where batteries struggle more.

When it clearly makes sense is full season storage--months at a time. Second/third or spare vehicles can fall into this category too. I use this approach on my now 14 season boat w/ a 115HP outboard and a very conventional (for boats) Group 24 starting battery. My boat spends its winter in an enclosed garage in a cold winter climate (Tahoe, 6700 feet) and is trailered. Typically it first hits the water about Memorial Day at end of May and is done by Labor Day in early Sept; once in a while it gets an off season use. Basically, when I used no trickle charger, it would often marginally start or needed a pre charge at the beginning of the season. The batteries lasted 2-3 years and then catastrophically failed. After that, I hooked a small trickle charger to it--about the size of a large box of camp fire matches. Max charge is 2A and it has auto maintenance/shutoff. Since then I went > 5 years on the next battery and zero issue ever starting. I just plug it in sometime in the fall and unplug it when I pull it out of the garage come Spring. It has a few LED's that tell me when it is either charging, is fully charged or there is an issue--very simple: "Green" [LED] is good. Trust me, last thing you want to do is either show up at a launch and find your battery is fried, or worse yet push it off the trailer and then find out! Briefly, similar experience w/ a Vespa 150 scooter (or most any motorcycle). If ridden rarely and not in winter, I could lose the battery. Put the same charger set up on it, and never an issue since. Not endorsing this one, but just an example I quickly pulled:


The charger ideally has a pigtail that you leave attached to the battery area/vehicle. You leave only the connector exposed (like sticking out from under the installed side panel in the A8 trunk, from a bike seat, boat compartment, etc., and then off season hook the charger to that and plug into wall.

Whole separate discussion on conventional wall chargers (10-20A @ 12V and then should cut back as it charges, often with a shorter higher amp quick charge and/or starting cycle). More for the home shop guy and those who don't want (or have) something like AAA with older DIY maintained vehicles. Your links have the smaller one that is the typical home mechanic type (my own is a Craftsman), and the wheel based one is more the semi pro/gas station type one for heavy duty use.

ltooz_a6_a8_q7

To me since I had mine, I always have a use for it and it paid for itself many years ago.

Get an inexpensive one - 2-6AMPS/hr minimum, 6V options is better, just in case.

Search on EBAY.

Here is the deal with A8,
Open the trunk with auto trunk - electrical use.
Open the door electrical use...
If you park the car for a few days, open doors and trunk many times to get stuff - you're draining out the battery. I checked mine. It was from 12.8V went down to 12.22V in a few times going back to the trunk, open it up and test stuff.

To me with a DVM, I'll check and charge when it's needed. The car is in the garage, the extension is there, charger is there, pop the trunk and start charging for a few hours - When the voltage gets up to about 12.8 to 13V, I'll unplug it.

Cheers,

Louis

jakematic

I concur 100% with MP4.2+6.0, and Schumacher is one of the better names.

Spend the money to get a quality one you will have forever.
It's simply not worth cheaping out on something this important that could damage your systems.

I spent 30 years of my life in a dealership and have seen a lot.

pfishwacker

What's the best way to connect a trickle (float) charger to an A8 battery in the trunk? Will be in a cold garage out of service for 3 months.

nathanwind

Get a Ctek...it's what my buddies that have much higher end cars than me use:

pfishwacker

Thanks. But I am also concerned about how to connect the float to the car. In other vehicles I connect direct to the battery under the hood where good ventilation is not a problem. Can't find any guidance about the trunk.

zedbyers

i just took my car out of storage a week ago. used a Schumacher i picked up at walmart for about $35. placed charger outside of car and ran cable to battery in trunk, with trunk closed.

sat like this for 6 months. no issues, no accumulation of gasses or fluids.

i use this brand of charger on all the vehicles i have stored (Z06 also had battery in rear, but wasn't a trunk so to speak, in the cargo area of the passenger compartment. same story as the audi, no issues.

currently have set up in my GT500 going through the cig lighter (as most american cars leave that circuit closed to battery even when ignition is in off position). truck is going directly to battery.

been doing this for a few years now and life is good.

zedbyers

the other point is these Schumacher chargers are 'smart' chargers. if it sees something it doesn't like it is going to stop charging. not like the old days where you might come out to the garage and find quite the mess....

MP4.2+6.0

As before, +1 on a Schumacher or similar "smart" trickle charger.

I would also use the extra "permanent" wire jumper they give you with the charger unit (or at least did mine). Hook the positive end directly to the terminal, probably right along side the other small wire piggybacked to the + terminal already (under the 10mm nut). I would get the negative wire under the larger jumping terminal (the big hex rod sticking out laterally above the battery area). You would have to unscrew it first (simple) to get the hard wire jumper under it--hopefully the terminal lug on the hard wire jumper is right; if not just crimp on the right one. It fits my boat battery fine, but that's the typical side terminal w/ wing nuts. Specifically I would put the - connection there instead of directly at the battery on the negative side because that is what they tell you to do on a standard/heavier charger. That puts it on the far side of the power management module as I recall so the car system knows what is going on charge/discharge wise. Now w/ the permanent wire jumper in place, you can easily attach and remove the trickle charger--literally just open the compartment and 10 seconds to plug the charger to the jumper at the supplied connector.

On venting, the battery itself is vented into a factory fitted tube--unless you went pretty far non-OE without a vent fitting. The tube typically looks like aquarium air hose. Audi type (group) aftermarket batteries I have seen in the last 10-15 years have the vent fitting to attach the hose, and Audi batteries have had it back to my 73 100LS. Hopefully no issues with your vent tube/system. That then vents the hydrogen outgassing through the tube and out underneath. Then back to the electronic type trickle chargers, it should automatically regulate the optimum charge, plus charge at a low rate to minimize any bubbling at the internal plates anyway.