Replace or Recharge Battery - 986 Forum - The Community for Porsche Boxster & Cayman Owners

KevinH1990 · 10-20-2008, 06:37 PM

I have a 2000 Boxster. The previous owner installed a new battery in February 05. (He paid over $200 at the dealer.)

I have had to store my car temporarily while I'm having a garage added to my house. The facility I'm storing the car in does not have electricity available for a battery maintainer. I usually drive the car 3 or 4 times a week and average about 7000 miles per year. The previous owner only used the car on weekends.

When I visited the car on Sunday after not driving it for two weeks, it wouldn't start. I'm fairly confident that it is the battery since all I heard was a clicking sound and the lights on the dash were dim when I turned the key. So, I popped the front trunk and came home. The light in my front trunk doesn't work due to a faulty switch, so I don't think leaving the front trunk unlatched will cause an additional drain.

Here's my question. Should I replace the batter or recharge it? I won't be able to bring the car home for another two months, so realistically I may only be able to drive the car once or twice a week. I'd hate to put a new battery in and have it discharge. On the other hand, my experience is that once a battery lets you down, you can't rely on it.

blue2000s · 10-20-2008, 07:00 PM

Take the battery out of the car, bring it to a auto parts store or battery store and have it tested to see if it can take a charge. That should tell you whether you need to recharge or replace. There's no reason to replace a battery that just needed a charge.

Either way, if it's going to be sitting for a month or more, take it out of the car and put it on a battery tender. This will keep the battery from being ruined.

cas951 · 10-20-2008, 07:01 PM

Since you still have battery power it's probably normal drain. I suggest you have the car jump started asap and take it somewhere where you can fully charge the battery. If the battery dies comepletely you may not be able to open the trunk unless you have a trickle charger that plugs into the Cig socket.

jmatta · 10-21-2008, 05:40 AM

Personally, I wouldn't trust a three year old battery. These cars are very finicky when it comes to power supply, as my friend found out earlier this year in his '02 S. A low battery can cause all sorts of havoc with the ECU, let alone alarms, etc. Upon removal from storage, I would replace the battery, but you will need to drive the car for about a week before all systems are go again (DME ready codes).

blue2000s · 10-21-2008, 05:44 AM

Quote:

Originally Posted by jmatta

Personally, I wouldn't trust a three year old battery. These cars are very finicky when it comes to power supply, as my friend found out earlier this year in his '02 S. A low battery can cause all sorts of havoc with the ECU, let alone alarms, etc. Upon removal from storage, I would replace the battery, but you will need to drive the car for about a week before all systems are go again (DME ready codes).

Do you replace your battery every 3 years?

There is no set age to replace a battery, too many factors influence it's life. You use a battery until it can no longer hold a charge. The battery isn't meant to run the car's electronics, it's meant to provide enough energy to spin the crank, provide enough spark and operate the fuel system until the car starts and the alternator can take over. There's nothing special about the Boxsters needs.

Topless · 10-21-2008, 06:10 AM

Whenever a battery goes flat it shortens it's life. A three year old batt that is going flat is probably a goner. Maybe this is your opportunity to get a new lightweight Braille battery.

blue2000s · 10-21-2008, 06:30 AM

Quote:

Originally Posted by Topless

Whenever a battery goes flat it shortens it's life.

100% agree

Quote:

Originally Posted by Topless

A three year old batt that is going flat is probably a goner.

"probably" is the key there. There are simple tests for holding a charge that will tell if the battery is truly a goner or not. And the test is free. So why replace the battery if you don't know if it needs it?

jmatta · 10-21-2008, 03:25 PM

Quote:

Originally Posted by blue2000s

Do you replace your battery every 3 years?

There is no set age to replace a battery, too many factors influence it's life. You use a battery until it can no longer hold a charge. The battery isn't meant to run the car's electronics, it's meant to provide enough energy to spin the crank, provide enough spark and operate the fuel system until the car starts and the alternator can take over. There's nothing special about the Boxsters needs.

Why risk your car not starting or having problems for a simple maintenance item that costs a hundred or so dollars?

blue2000s · 10-21-2008, 05:57 PM

Quote:

Originally Posted by jmatta

Why risk your car not starting or having problems for a simple maintenance item that costs a hundred or so dollars?

Why spend $100 or so dollars before even finding out if there's a problem?

vath2001 · 11-26-2008, 03:42 AM

Get a new battery ... from where ever, will cost you $100. When in doubt, change the battery. You own a Boxster, its probably the cheapest thing you'll put into the car.

mikefocke · 11-26-2008, 05:03 AM

what was happening that drained the battery enough in 2 weeks that there wasn't enough juice to start the car.

It seems to me that there can be 3 things happening, either you put the car away with a battery that wasn't fully up to charge, the battery itself will not hold a charge or there is something in the car draining the battery.

I regularly don't use my car for 2 weeks at a time and it starts right up. And my battery is at least 4 years old. I only maintain the battery if I know I have (or will) not use the car for more than 2 weeks.

And if you have to replace the battery, there is no reason to spend $200 at the dealers when there are a dozen batteries just as good that fit perfectly. I don't go to the Honda dealer for a Honda labeled battery, I go to a discount store and buy a well regarded name brand battery. For a list of batteries known to work/fit in a Boxster, go here .

So lets deal with the "drain" causes one at a time:

1. Your driving right before you parked the car was such that there were multiple starts or you played the radio for 2 hours by washing it or something else that caused the battery to be already at low voltage when you parked it. It then further discharged.
2. The battery electrolyte had "burned" off so the battery wouldn't fully charge. You have a not fully sealed battery. And then the normal drain drained the rest of the juice.
3. You have something in the car like a broken switch that is keeping something on or an after-market GPS or cell phone adapter or radar detector or ?? that is on even when the car is parked and is draining the battery of its juice.

If #1, don't do that...in fact make sure you've driven the car 20 miles with the lights and a/c off just before you park it so it gets parked fully charged. If you think this is it, just jump the battery for at least 10 minutes with the donor car running at 3000RPM to get the battery back up to charge, don't start the Boxster, disconnect the battery now and prepare to reconnect and jump the battery in the spring.

If #2, then take the caps off and fill with distilled water to the mark or over the top of the plates. Then jump start the car after leaving the jumpers connected for about 10 minutes. Then drive it those 20 miles. If the temperatures or conditions don't allow that, then take the battery out of the front trunk and to an auto service place and have them test and charge the battery (make sure you have your radio code handy when you go to reinstall the battery if your model year requires a code).

if#3, then once the battery is fully changed, measure the voltage and come back a day later and measure again. And in a week. See a significant downward trend over a day or week and you have something draining more than a normal Boxster and are going to have to either solve the problem or maintainer the battery if you ever leave the car for more than a few days. You can either take the car to a mechanic and expect a big bill for the diagnosis or figure it out yourself by measuring the current draw and pulling fuses one at a time to see what circuit the draw is coming from.

vath2001 · 11-30-2008, 04:28 AM

One little thing I do to every battery I put in a car is write (use a Sharpie) on the top of the battery when you installed the battery. I could dig throught files to find the receipt / date, but this is quick. We've done this on boats for years.. rather handy when you talking about multiple batteries and you have no idea which is older/newer.