Low battery symptoms

[KevinH1990]

My Boxster failed to start once last winter and I had to jump start it. During the last few weeks if I drove a short distance the car sounded like it was barely turning over when I restarted it. I checked my records and the battery was 7-years old.

I decided that I was risking another failure and replaced it with an Interstate AGM battery in size H7 (94R.) The H7 is larger than the battery I removed (Bosch 48-690B.) The H7/94R Interstate battery is rated at 850 CCA. Consumer Reports tested a smaller H6 Interstate AGM battery which the manufacturer rated at 760 CCA. It rated the life expectancy as 5/5, the CCA as 4/5 and the reserve capacity as 4/5. They rated an Optima H6 ($290) and an Odyssey Performance ($260) slightly higher than the Interstate.

The AGM batteries are more expensive. I paid $175 at Costco. However, the information I've been able to find indicates that they are better able to tolerate a situation in which the car is not driven for an extended period. Although I normally drive my Boxster several times per week, we had some ice and snow during the winter and I didn't drive it for about 10 days. That is when I had the starting issue. The AGM battery also has a 3-year full replacement warranty.

[Seal1968]

Great information, thanks gents!

[Steelepuls]

Originally Posted by KevinH1990

My Boxster failed to start once last winter and I had to jump start it. During the last few weeks if I drove a short distance the car sounded like it was barely turning over when I restarted it. I checked my records and the battery was 7-years old.

I decided that I was risking another failure and replaced it with an Interstate AGM battery in size H7 (94R.) The H7 is larger than the battery I removed (Bosch 48-690B.) The H7/94R Interstate battery is rated at 850 CCA. Consumer Reports tested a smaller H6 Interstate AGM battery which the manufacturer rated at 760 CCA. It rated the life expectancy as 5/5, the CCA as 4/5 and the reserve capacity as 4/5. They rated an Optima H6 ($290) and an Odyssey Performance ($260) slightly higher than the Interstate.

The AGM batteries are more expensive. I paid $175 at Costco. However, the information I've been able to find indicates that they are better able to tolerate a situation in which the car is not driven for an extended period. Although I normally drive my Boxster several times per week, we had some ice and snow during the winter and I didn't drive it for about 10 days. That is when I had the starting issue. The AGM battery also has a 3-year full replacement warranty.

Kevin, I had the same issue with my 01S, where the first start is cold it has no problems turning over, but after a short stop to get gas or pickup food, the restart is slow. When I leave it for over an hour or two inbetween stops, the problem is not as noticeable. It isn't a battery issue or alternator, since those two were replaced recently with new parts. I've read here that the alternator wiring harness is heat soaked and causes the slow turnover.
I haven't confirmed that since i haven't fixed this yet in my car since it has always started, albeit slow. The harness is not too expensive, but I've heard it is a bear to replace.

[blue62]

Originally Posted by Steelepuls

Kevin, I had the same issue with my 01S, where the first start is cold it has no problems turning over, but after a short stop to get gas or pickup food, the restart is slow. When I leave it for over an hour or two inbetween stops, the problem is not as noticeable. It isn't a battery issue or alternator, since those two were replaced recently with new parts. I've read here that the alternator wiring harness is heat soaked and causes the slow turnover.
I haven't confirmed that since i haven't fixed this yet in my car since it has always started, albeit slow. The harness is not too expensive, but I've heard it is a bear to replace.

Please explain to me how the alternator wiring harness is involved in the starter circuit.???

[JFP in PA]

Originally Posted by Steelepuls

Kevin, I had the same issue with my 01S, where the first start is cold it has no problems turning over, but after a short stop to get gas or pickup food, the restart is slow. When I leave it for over an hour or two inbetween stops, the problem is not as noticeable. It isn't a battery issue or alternator, since those two were replaced recently with new parts. I've read here that the alternator wiring harness is heat soaked and causes the slow turnover.
I haven't confirmed that since i haven't fixed this yet in my car since it has always started, albeit slow. The harness is not too expensive, but I've heard it is a bear to replace.

The alternator and its harness play absolutely no role in the starting process; what you are describing is a classic case of voltage drop cross primary battery cables that are corroded either internally or at the terminals and showing increasing resistance when either warm or hot. You can prove this to yourself by simply running a voltage drop test on the cables; anything more than 0.5 volt drop and the cables need to be replaced.

[blue62]

Originally Posted by JFP in PA

The alternator and its harness play absolutely no role in the starting process; what you are describing is a classic case of voltage drop cross primary battery cables that are corroded either internally or at the terminals and showing increasing resistance when either warm or hot. You can prove this to yourself by simply running a voltage drop test on the cables; anything more than 0.5 volt drop and the cables need to be replaced.

Yes and when he says the "restart is slow" with engine warm.
Does he mean the starter spins the engine over slower when warm then it does when the engine is cold???? Which would be caused by the voltage drop situation you describe.
Or does he mean the starter spins the engine over for a longer period of time before it starts when warm versus cold.???? Which often times is caused by an issue with the EVAP. system. Things like the purge valve being stuck open.

[JFP in PA]

Originally Posted by blue62

Yes and when he says the "restart is slow" with engine warm.
Does he mean the starter spins the engine over slower when warm then it does when the engine is cold???? Which would be caused by the voltage drop situation you describe.
Or does he mean the starter spins the engine over for a longer period of time before it starts when warm versus cold.???? Which often times is caused by an issue with the EVAP. system. Things like the purge valve being stuck open.

Easy enough to find out: Run a voltage drop test………

[Seal1968]

Update: picked up a new Delco battery yesterday. 780 CCA, fits nicely, starts like a champ.

$228 CAN with a 30 month warranty included.

I changed the battery in the parking lot and they even took my old one for free.

One less project!