Here's something odd that I discovered today... But allow me to digress...

I've got a totally stock 2002.5 P5 that seems to have a battery drain somewhere. About a month ago, I left it at an airport parking lot while I was out of town for about a week and a half, and when I returned the battery was totally dead. No lights, no keyless entry. Nuttin.

I charged the battery and everything has been fine ever since, but as a precaution, I bought one of these Sunsei solar chargers that plugs into the cigarette lighter (Like this) to keep the battery topped off by charging during the day. I'm not even sure if this works, since the lighter plug powers off when the ignition turns off.

The strange part...

I walked up to my car today after work and unlocked the car/shut off the alarm and opened the hatch. When I did, I hear a radio playing....it was mine! I sat down in the car and saw that my stereo was powered up and the stereo was playing. I don't think any fans were on. Anyway, I unplugged the solar panel and everything powered off. I plugged the solar panel back in and the radio came back on again. The car started up just fine, by the way.

In the morning when I parked and plugged in the solar panel, it was dark enough that the stereo didn't turn on, but apparently it was bright enough in the afternoon to power the stereo.

First of all, is that weird or what? Second, when I shut off the ignition and plug in the solar panel to the lighter, is this thing actually charging the battery, or is the lighter plug electrically isolated from the battery when the ignition is off?

Any ideas?

Thanks!

 

moved to the correct section "audio". Maybe you'll get better responses here.

 

I figured it was more an electrical question, but I guess it doesn't matter!

 

I'd be willing to bet anything it's the way your stereo is wired. Is your stereo factory?? if so, that's odd beyond odd.

 

Yup, the stereo is the factory CD/Radio. No tape, no MD. It kinda freaked me out. More because I thought my car wouldn't start than anything.

I fibbed a bit. The only aftermarket item is a Viper car alarm that was installed by an alarm/stereo shop. That doesn't mean it wasn't installed perfectly, but I haven't had a reason to doubt it thusfar. <shrug>

 

ACtually Ive noticed a similar effect, using my portable flashlight/cig lighter powered jack.

The cig lighter will actually power up the acc line along with everything on that line. This means the radio, ac, defroster, windows, and moon roof im not sure what else is on that line. That solar panel has to be extremly efficent to power up the radio, Im impressed. However I do think that theres a chance that the battery is not being charged at all being that its on a diffrent circuit ( the acc is just disconected from the battery when the cars off).

Options to make it work pretty much involve rewireing the cig lighter to the batt. OR wiring the solar panel directly to the battery, easy stuff if you have an amp installed.

 

The solar panel is spec-ed at "135mA, 15V (2W)", according to the manual, under full sun I presume. I guess that's enough to power the radio, even if the lighting is less than optimal. I kinda have a feeling that it isn't charging the battery. It does come with battery post clamps, but wiring that up and leaving wires dangling out of the hood all day at a park and ride is an invitation for shenanignans.

Maybe I should plug in the solar panel and put in a CD of myself yelling, "Help, get me outta here!" and see what hilarity might ensue.

 

If you are powering the radio - you are not charging the battery.

If you have a drain on the battery find and fix it. Use a multi meter to see how much draw there is with the car off.

If you don't have a drain and the battery was just worn out - quit using the charger! You don't need it!