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

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?

Brucelee · 10-21-2008, 06:36 AM

If it is a stock Porsche battery, they are simply put, junk. I find the Costco battery to be much better at about $60.

Save yourself some misery and buy a new one and a battery tender if appropriate.

Good luck.

mikefocke · 10-21-2008, 08:05 AM

Can a 3 year old battery go bad? Sure.

Is it the kind that has caps or plugs that can be opened to see the battery fluid level? Check and fill to line with distilled water.

Jump start. Remove jumpers. Seem to rev ok?

While running, have someone sit in the car and rev to 2k and measure the voltage across the battery posts. ~14.4V? OK, alternator seems to be working.

Drive OK? Drive for 15+ miles with a/c off and in daylight. Should now be charged.

Stop. Measure voltage. at least 12.5+V? OK.

Or drive to a battery place and get them to test the battery.

Does completely draining the battery hurt the battery life? Yes. One time fatal? Usually no.

Any aftermarket add ons that are in the car that could be draining the battery? Electronics, alarms, radar, phones, etc?

The trunk lights go off after about a half hour on mine. Been there, done that. Battery wasn't drained when I came out and saw mine the next day with the trunk (or door) still open.

I'd not just go swapping the battery before understanding what is draining it.

There is also a way of removing a fuse at a time and measuring the current drain to see what circuit the drain is coming from.

And if you do replace the battery, there is no need to pay $200 when there is a whole list of perfect fit ones.

KevinH1990 · 10-21-2008, 09:21 AM

Thanks for the comments and advice.

The car is currently in a storage unit that is about three feet wider than the car. The front is facing in, so jump starting it will require pushing the car out. I think I will remove the battery, charge it and have it tested. If it checks out OK, I'll put it on a battery maintainer at my house for the balance of the construction period.

If I buy a new battery, it definitely won't be from the dealer.

This just reinforces my belief that the car should be driven frequently.

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?

KevinH1990 · 10-31-2008, 06:41 PM

Update - I brought the battery home and put it on a battery maintainer for a few days. I reinstalled the battery this morning and brought the car home. (My contractor doesn't work on the weekend, so the risk of damage is reduced.)

I drove the car 50 miles today in a series of 10-15 mile trips. Unfortunately, the car turns over very slowly (I didn't think it was going to start a couple of times). I haven't had the battery tested yet, but I guess that is not a good sign.

I'm reluctant to buy a new battery right now because the car will be spending most of its time in storage during the next two months. I guess I could take the new battery out, bring it home and put it on the maintainer each time I return the car to storage.

Any thoughts?

blue2000s · 10-31-2008, 06:53 PM

Quote:

Originally Posted by KevinH1990

Update - I brought the battery home and put it on a battery maintainer for a few days. I reinstalled the battery this morning and brought the car home. (My contractor doesn't work on the weekend, so the risk of damage is reduced.)

I drove the car 50 miles today in a series of 10-15 mile trips. Unfortunately, the car turns over very slowly (I didn't think it was going to start a couple of times). I haven't had the battery tested yet, but I guess that is not a good sign.

I'm reluctant to buy a new battery right now because the car will be spending most of its time in storage during the next two months. I guess I could take the new battery out, bring it home and put it on the maintainer each time I return the car to storage.

Any thoughts?

It could be the alternator, but it probably is the battery.

If you have the car sitting for 2 months at a time, you should at least disconnect the battery, but if you want it to last as long as possible, it probably should come out of the car and be on a maintainer.

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.