ScootCherHienie

So I can't even get a straight answer about this from Battery Tender themselves. I have a medium sized Battery Tender "Sr." that's probably from around 2005 or 2006. It "knows" wet batteries and agm, don't think it was designed for Odyssey/Optima batteries though. It has a Red LED for charging, when the battery nears full charge, the green LED flashes and when the battery is fully charged, the green LED is on all the time.

With my 08 957, if I connect the Battery Tender immediately after parking the 957 in the garage, the Red LED lights and stays lit for 45-70 minutes, the green LED flashes for 45 minutes or so, then the green LED comes on solid indicating the battery is fully charged.

The question is... is this sequence NORMAL every time you connect your Battery Tender to your 957 (or even other cars that have been driven a distance, parked, then connected to the Battery Tender)? I'm not sure if what I see is correct for a Cayenne just after driving it or not... on the one hand, you might reasonably expect the alternator to fully charge the battery if you have been driving the car for 30 minutes or more and the battery is in good shape (I have a new AGM installed in Sept 2016). Or is what I'm seing just the normal behavior for a Battery Tender? Does it take the Battery Tender 2 hours or so to figure out the battery in the car really is already fully charged OR perhaps the Battery Tender's slow charging put more of a charge in the battery even when the alternator has been charging the battery normally? The only other car we have is Electric so I can't test this Battery Tender on the second car... wondering if anybody else has noticed the same thing or would be willing to check with your own similar Battery Tender model to see if you experience the same thing.

I don't THINK I have a problem, but this is making me scratch my head a bit. I can't be the first person to notice this if it is "normal". I would expect the Battery Tender to immediately turn solid green when connected to a car battery after the car had been driven for some reasonable period of time (like 30 minutes or more) with a battery in good condition -- but the Battery Tender may require some connection time to figure out a battery is fully charged... OR maybe the Battery Tender packs more charge into the Battery than an alternator/regulator setup in a Cayenne or other vehicle? Or maybe the 2 hour (or so) time it takes for the Battery Tender to get to "full green" mode is indicating the Cayenne's system isn't fully charging the battery? I just don't know which scenario is indicated. THX in advance if you can offer your observations.

ScootCherHienie

I'm adding a SiriusXM tuner to our 957. The instructions with it indicate a number of locations where the antenna might be mounted. The "above windshield" location won't work because the 957 windshield doesn't have the rubber-gasket-around-the-glass, it appears to be glued in only. That leaves installing the antenna (sticks to body of car with a magnet, you just have to route the wire back to the SiriusXM tuner that will be within reach of the driver) just forward of the lift-gate and running the wire along the edge of the headliner to the dashboard (I think) or doing some odd off-center install like putting the antenna right above one of the passenger doors, and running that either along the headliner edge or down at the floor back to the dash.

Any advice from anybody else who has already done this? Is the installation at the edge of the lift gate doable?

Related questions.... 1) our 08 957 has the Bose audio system. I don't see a reference anywhere in the Entertainment/Nav manual to an AUX input for the analog stereo mini-jack plug from the SiriusXM tuner so I was planning to tune the Cayenne's FM radio and the SiriusXM tuner to the same FM radio frequency and receive Sirius programming that way, but if there is an AUX connection, that would make for a "cleaner" and better-sounding install if there's a way to use that AUX connection and not disable any other features of the system. 2) Our Cayenne does not have a CD changer in the cargo compartment (either side). Does that mean we have a single-disc CD player or will the dash slot accept more than 1 CD? Haven't tried playing CDs at all and don't want to risk sticking a second CD in if the dash slot only accepts a single CD.

Petza914

I use Battery Tenders on all my cars and they all have Optima AGM batteries, except the Cayenne, which has a Napa AGM battery. The behavior you're seeing is pretty normal. Sometimes on the other cars it will go from the red light to flashing green pretty quickly, but usually takes a little time to get solid green and the Cayenne takes longer to get to the flashing state, maybe because it has more electrics.

hahnmgh63

I have multiple Battery tenders, mostly use the "Jr" and this is normal. Optima is just an AGM battery with funky Spiral cores, Oddysey is a starved cell AGM (dry) and a better design.
Once you shut down your Cayenne there are a number of systems still running in the background in addition to things like convenience lighting, parasitic draws for memory and alarm, etc... So there is a draw on the battery as soon as you shut it off. The Battery Tender is a float charger maintainer, the "Sr" like you're using only uses a little over 1amp I believe, the models have changed recently and I don't think they even list the Sr but still have the Jr, although it looks different now. They now have Gel battery chargers and ones for Lithium batteries. Anyways, the tender being that it isn't very powerful, takes a while to get the battery topped off again fighting against the systems that are a constant parasitic drain and the convenience features and housekeeping functions the onboard computers are first doing right after a shutdown. The actual charge it gives is variable and probably only a little over an amp for the first few minutes then it tapers down to less than an amp and finally when it starts flashing green it is probably about 1/4amp, really for all purposes the battery is fully charged when it flashes green.