dporto

It should also be noted that the terminals are turned around (negative on left front of battery as situated) for the Porsche spec. batteries, so it's "not just size that counts"...

jhbrennan

It doesn't matter - the OEM battery has a standard terminal placement. With aftermarket you just have to make sure you put the battery in the tray correctly...you just turn the battery around so that positive is on the passenger side and negative is on the drivers side. See the picture in post #1 - that's exactly the way the Porsche Moll OEM battery is set up.

wyovino

Pep Boys charges $15 to install the battery. I was going to have them do it just to save a trip to return the old battery. I just noticed that they add on another $10.50 because it's a "Difficult installation". What's difficult about it?

jhbrennan

Maybe lifting the battery onto the tray...otherwise it's one of more simple installations I've ever done. If you're going to let them install I'd watch pretty closely to make sure they don't install the battery backwards and end up reversing polarity when they hook up.

dporto

Seriously? What the hell is "standard terminal placement"? Yes it does matter, you're wrong...All batteries of the same case size DO NOT have the terminals oriented the same or an the same sides of the battery i.e. positive on right, negative on left... Nor do they all have the terminals in the front corner or the rear corner... Why does this matter? The terminal cables are cut to tight tolerances, and they won't reach the terminals unless they're in the right place...

jhbrennan

OK your opinion...but the Wal-Mart Everstart Maxx, Interstate, Bosch, Moll, many others all fit in the tray and the terminals (assuming you put the battery in correct) are positioned properly that the cables reach the terminal with no issues. Here are some pics of some of the popular replacements. Show me an H7 battery not configured like this and I'll happily agree with you.

Plus two pictures of Porsche batteries/

Long Islander

I've been wondering about how to use the unthreaded 4th hole so that next time I can use an H8 battery. What I've come up with is (a) get a body shop to weld an M8 nut (same size as the current hold-down bolt) to the bottom of the unthreaded 4th hole; or (b) use a tap to thread the 4th hole so that you can use an M10 bolt in there. Any other ideas?

Also, is there a Porsche battery tray from a model other than the 996/Boxster/997 where the 4th hole is threaded?

jhbrennan

Check with Quadcammer - I believe he modified his tray. I recently replaced my tray and the part I received had all the holes threaded. Here's the part number:

99750415100 BATTERY CARRIER

Replacement went into a 2004 996 C2.

Long Islander

Great. I see that this part supercedes a part # that begins with a 996, so it looks like they started making them with threaded 4th holes.

DrMEMS

In my 2003 996, the new battery only extended one hole wider and that hole was already tapped.

If you like working with hand tools, I recommend buying a metric tap and die set. I have one from Craftsman and have used it a lot to tap new holes and to clean up the threads on existing bolts and holes on Porsches, Toyotas, and VWs. You'll have to remove the battery tray to screw the tap in far enough. I removed mine to access the gas tank to install a new fuel pump and it was easy. When I put the battery back in, I put an absorbent battery mat from Pelican under the battery. Due to the added thickness, it was hard to get the clamp back onto the battery. It's worth catching any overflowing sulfuric acid, which isn't supposed to happen, but did on an earlier battery. And my new Bosch AGM battery does appear to have a vent hole.

wyovino

"And my new Bosch AGM battery does appear to have a vent hole. "

Did you hook it up? I was under the impression that AGM batteries were sealed and didn't need venting.

How can something as simple as replacing a battery be so complicated?

jhbrennan

AGM may not gas as much as a flooded battery but they should be vented. Only AGM that I know of without venting are the Optima's and there are some battery pros that will tell you that the Optima isn't 100% sealed just doesn't have any vent outlets.

Long Islander

It is simple. But because those of us on this forum are car enthusiasts, we relish the distinctions between various things automotive and want to know more about them. Like for me, since there's an extra hole for the battery hold down, I want to figure out how to use that to put in an H8 battery. The average person, when their battery dies, just asks for a new battery, and they get charged a huge sum for a battery that is a piece of junk, but they don't know any better.

FastM96

Ummmm, yeah. Don't let Pep Boys change your battery. Always seems like the guy with the least amount of shop experience is the battery & windshield wiper guy -- do you want him working on your Porsche?

Quadcammer

taping that hole will not work. there is really nothing to tap. I tried this and the one thread or so I got on there stripped immediately.

That said, this is very simple.

Find a bolt that fits snugly through the hole in the hold down bracket, drill the hole in the tray to match, and then put a nut under the tray and hold it in place with a wrench as your tighten down. You'll want a bolt approximately 25mm long.

Alternatively, you could take the tray off and either weld or epoxy a nut onto the tray.