e9stibi

Hi,

after my car was sitting for almost 3 weeks I experienced a dead battery this morning. After jump starting and driving 90 minutes it was dead again late afternoon. After jump starting again I drove another 75 minutes.

3 hours later I took the following measurements:

- 11 Volt
- 100 mA (with hood light pulled)

What are reference values?

The only change I recently did is the install of a CDR 220 with aux input.

Thanks,
Erik

epj993

Since it was dead after just three weeks, doesn't hold a charge after 90 minutes and reads only 11v, I'd say the battery is shot.

black ice

Just for peace of mind make sure your getting 13V plus across the battery terminals when the car is running. If it's charging then I'm with Eric putting my money on your battery being shot. texas is hot and puts a beating on those things - wouldn't be surprised to have to replace one every few years.

dave

e9stibi

Thanks for your replies so far. Is a current draw of 100 mA normal? What battery brand do you recommend?

Erik

Robin 993DX

When every single one of my original Porsche battery dies I replace them with ones from Costco and they have all out lasted the original battery with no issues what so ever.

The voltage seems a little low, also it is the cranking amp that you need to look at to see if a battery is good or not. But that should be a difficult test unless you have a special battery tester. I have a Snapon battery tester with heavy coils that loads up the battery in order to test for the amperage.

jimbo3

100 mA is a little high, but only pulling the hood light still leaves the interior lights AND the engine compartment coutesy light on. Also, remember to take the key completely OUT of the ignition. After opening the trunk, manually push the latch to the "closed" position so that all the lights are off and then take a battery load measurement. PUT A RAG OVER THE LATCH to remind you to open the latch before closing the hood.

IIRC, the draw spec is 30 to 100 mA, but around 40 is typical. You might find that the Porsche battery maintainer (~$50 from Sunset) is a great investment.

e9stibi

I just replaced the battery. It was 6 years old which is not a bad lifetime for Texas heat. The alternator should be ok. With engine @idle I have +2 Volt.

I will get me the charger from sunset. What is the model number? Does it connect to the cigarette lighter?

Thanks for your help,
Erik

jimbo3

It's about a 1/2 amp automatic charger that plugs into the lighter and the other end is simply a 120volt plug-in "wall wart" with a 25 foot wire that is about 20 gauge. The wire is small enough to easily run over the door threshold and close the door over it. Simple and effective. Part number 980-611-981-00.

After much frustration, I finally broke down and bought one. Best $50 I spent in a long time.

-Jim

Robin 993DX

FWIW, not sure if it is battery tender related or battery.... I have read several horror stories from the Ferrari side of pond that several Ferraris have caught fire from battery tenders, I am sure those were just isolated cases as I never heard of that issue with the Porsches.... But scary thought.... I use the tender from time to time if the car is to be parked for over 3 weeks, I know that with the current new battery I can go on more than two weeks without starting and the car will starts just fine.

texas911

I got the Optima battery when mine became weak. I personally like it in that you don't need to vent it, thus there is no corrosion worry.

LarryN

My 95' 993 killed 3 batteries within the last year when I was not able to drive it very much (due to back
surgery). And I mean KILLED DEAD - measuring <2V, and my 6 amp charger would not bring it back. The batteries were Autolite from Kragen (never again). I could start the car after one week but not much longer, but 2 weeks or so would cause this problem. I finally got a battery minder and this worked great... until I got lazy and didn't plug it in and did not drive the car for 2 weeks... Arrggh@! I have yet another totally dead Autolite.

I assume that there is something wrong with the electrical system and will go through the testing after stopping by Costco today to see if I can get a replacement battery.

I have to say I am puzzled as to how my car can run fine, crank strong and start after 1 week with no battery minder, no indicator lights showing a problem on the car or the battery minder - and still kill a battery completely dead. Any ideas???

Bruce SEA 993

I also replaced my original Porsche battery with a Costco battery 9 years ago and just put it on an on board trickle charger/tender (Schumacher) that limits the voltage input and shuts off once the battery is up to charge.

Next time I need a battery I may go to Autozone and get a Duralast. They provide the venting kit for it.

Cheers!

allill

When my car was in the body shop for 7 months I thought I'd need a battery for sure. The car wasn't started at all the whole time it was there. We charged the battery overnight and it's been good since! I believe it's an Interstate battery. I have Interstate in two of my other cars and can only say good things.

LarryN

I just installed a Costco battery and measured the current at 1.6 amps, this was with the hood open so there were 2 interior lights on - I don't really know how much those lights draw, but I don't think that two of them are going to approach 1.5 amp. Sigh. Now to track down what my gremlin is this time.

jimbo3

Larry- See my post #6 above.