Anyone using a Battery Maintainer?

[will13k7]

driving the car once a week doesn't seem to be enough to keep the battery at least half charged, so I grabbed a CTEK battery maintainer, I was wondering if anyone around here is using one and if they have tried using the jumper connections under the hood or if they had to connect directly to the battery in the trunk?

[mjfloyd1]

I have a griots garage battery tender and have been connecting to the under hood terminals for about the last 7 years. Works great.

[doug97gxe]

i have a charger i used for my bike.. it will charge a battery that's down to 0.2 volts ... never had to use it on the car though.. your battery shouldn't be dying once a week though.. are you sure something else isn't drawing current? or is your driving mostly city so its not getting a chance to charge

[will13k7]

thanks guys! mostly city driving, the battery hasn't died yet, but the battery meter in MMI was down to two bars yesterday and only went up one bar after 40mins of driving, so I figure its a matter of time before it dies.

[doug97gxe]

how many years on the battery? i would have an auto parts store test the battery and alternator

[will13k7]

4 years, probably getting close to replacement, going to see how it goes with the battery maintainer before taking other steps though.

[will13k7]

from the manual:

When jump starting or charging the battery,
Never connect the negative ground cable to the battery negative post because the battery manager system must be able to detect the battery's state of charge.
Always connect the negative ground cable to the negative ground post of the battery manager control unit.

huh? Sounds like I should always use the jump start connections in the engine bay.

Then in a figure showing the engine compartment, it says:

Engine Compartment: Connections for jumper cables and charger.

So I guess so.

[b8audis4]

from the manual:



huh? Does this mean I should always use the jump start connections in the engine bay?

Yes, I always connect it under the hood, and jump start as well.

[MrFunk]

Driving once a week should not drain your battery. My guess is you need a new one. They only last about 4 years (remember who knows how long it sat on the shelf at Audi before going in the car).
I have used a battery tender on mine one winter I didn't drive the car. Connected directly to battery in trunk.

[will13k7]

Driving once a week should not drain your battery.

its probably almost done-for then. It's not in horrible shape, the maintainer went into the second mode right away, the first mode is for severely drained or faulty batteries.

[Usa]

New battery yo

[jsh139]

from the manual:

When jump starting or charging the battery,
Never connect the negative ground cable to the battery negative post because the battery manager system must be able to detect the battery's state of charge.
Always connect the negative ground cable to the negative ground post of the battery manager control unit.

huh? Sounds like I should always use the jump start connections in the engine bay.

I read this to mean that you shouldn't pull the negative lead off of the battery terminal when charging because doing so would disconnect it from the "system". I doubt it matters where you connect a battery charger, so as long as the battery itself remains connected to the car's computer systems.

[PerimeterJones]

The Desulphatioin mode of the CTEK MUS 4.3 is the best thing to extend your battery life by years


Just received my B8.5 and the first night in my garage I put it my CTEK 4.3 on it to find it took a full day to bring up to 100%


Moral: just because the car is brand new does not mean the battery is topped off.

[will13k7]

The CTEK went through all the cycles, charged it to 60%, didn't indicate that it thinks the battery can't hold a charge, and now is in maintenance charging mode. It was at 60% earlier in the year when I was still daily driving it. Maybe I have about a year left, but I'll probably get it replaced within a year. Anyways, the CTEK did its job and nothing got fried!

[will13k7]

Wasn't expecting this:



This was all I did:

12/6 around 4pm: put the ctek in normal mode, left it plugged in. This got it to 60%.
12/7 around 6pm: power cycled the ctek and put it in normal mode to get it to start another charge cycle. This got it to 70%.
12/8 around 6pm: disconnected the ctek. no driving until:
12/12: charge was still at 70%, it held!, drove the car for about 30 minutes. Didn't check the level again. No driving until:
12/15: drove to work this morning, about 20 minutes into the drive, check the battery level, it's at 100% now!

Seems to have come back to life, for now at least.

[jokingjimmy]

Wasn't expecting this:



This was all I did:

12/6 around 4pm: put the ctek in normal mode, left it plugged in. This got it to 60%.
12/7 around 6pm: power cycled the ctek and put it in normal mode to get it to start another charge cycle. This got it to 70%.
12/8 around 6pm: disconnected the ctek. no driving until:
12/12: charge was still at 70%, it held!, drove the car for about 30 minutes. Didn't check the level again. No driving until:
12/15: drove to work this morning, about 20 minutes into the drive, check the battery level, it's at 100% now!

Seems to have come back to life, for now at least.

You need a new battery. It will false charge you at this stage. 4 years not an unheard of timeframe for battery replacement hehe.