Replacement Battery Question

[big911fan]

No answer on my first post so I'll try another question.

My 2006 Boxster S uses a Group 94R battery. I can get that battery at several places but none of them come with a vent port to attach the vent hose to. In fact the Group 94R batteries have two vent holes (one on each side of the battery).

I'm reluctant to use that type of battery since I can't attach an external vent tube to it. Since these batteries are "sealed", do I need the external vent tube that's on the car? The Moll battery is sealed and it still has an external vent tube.

Any thoughts?

[Wayne 962]

Can you get an Interstate battery? These have the vent port in the proper location for the Boxster. See my article here for pics: Pelican Technical Article: Boxster Battery Disconnect Switch / Battery Buddy Installation - 986 / 987

-Wayne

[big911fan]

Thanks for the info, Wayne. Seems like you're single-handedly keeping this Forum moving. Must occupy an inordinate amount of your time but keep up the good work as long as you can.

I did read your post about the Interstate battery. I can get one locally (up here in the Gold Country) but might take a day or two. The generic Group 94R's were easy to come by and they have better CCA stats and warranty than the Interstate. There were some posts about people not liking Interstate batteries so I didn't pursue them. (I guess nothing is ever unanimous, though).

I'll go with the Interstate since it sounds like external venting is not optional and a Moll is double the money, has about 1/2 the CCA's, and lasted only 4 1/2 years with a near full time Battery Tender hooked up. (What a deal, huh?)

[Wayne 962]

Originally Posted by big911fan

Thanks for the info, Wayne. Seems like you're single-handedly keeping this Forum moving. Must occupy an inordinate amount of your time but keep up the good work as long as you can.

There are a lot of other really good people on this forum - it's just not as quick as the other 911 forum. What is it they say, quality over speed? Don't worry, when the book comes out, there will be *tons* of people here.

I like the Interstate batteries, also Genuine BOSCH ones too, but you can't ship them, so you have to find a place that sells them direct.

-Wayne

[mikefocke]

Sealed batteries aren't really sealed unless the ad states they can be run upside down...Optima comes to mind.

I've posted a list of 986 compatible batteries but the 987s are so new there haven't been the same "I used exactly x brand of this size and paid y and it has 999CCA" kinds of messages so I'm not yet able to pick up exactly what people are using for 987s...the size is slightly different.

[big911fan]

Wayne- Can't wait for the book to come out. I'll be one of the first wave of buyers. There is a definite void in tech info for the 987's. There were enough changes and idiosyncrasies between the 986's and the 987's that the older manuals ( ie- Bentley) need some updating.

From a practical standpoint your guide should help fill that void.

[big911fan]

For those of you with unlimited discretionary income, Porsche has just announced a new lithium ion battery for some of the new models. I saw a reference to it being $1800 (if you have to ask....)

[big911fan]

Mike- Here's an update to add to your files on batteries. I just ordered an Interstate for my 2006 Boxster S (987).

The Interstate model that fits and has the vent tube is MTP-H7. Cost about $185.

When ordering, make sure they order/give you a vent tube adapter with with it.

24 month free replacement period, 85 month warranty, 640 CCA. It's the Interstate equivalent of the Group 94R batteries.

Thanks for the help.

[OptimaJim]

big911fan, it is wise of you to make sure your battery is properly vented. Even though our batteries have a “sealed” design, all lead-acid batteries can vent gas. Under normal operating conditions, an AGM battery will not vent gas. Since alternators or chargers can fail, the safest and correct mounting method for trunks and passenger compartments is to make sure that any possible gas venting will escape to the outside of the vehicle. All vehicles with original equipment battery locations in trunks or passenger compartments will have a vent provision that should be used.

Our group 27, 51, 78, 34C, and 31 batteries all have ports for connecting a vent hose. Although people do it anyway, we would never recommend installing an unvented battery in any enclosed space, because there’s a legitimate, albeit unlikely, safety risk involved.

For example, IF there is a voltage regulator failure, and IF the battery is severely overcharged, and IF this goes unnoticed, and IF the battery vents because the internal pressure exceeds the release pressure of the vents, the gasses are both flammable and toxic. This may sound like a lot of “ifs,” but attorneys and engineers get paid to plan for every worst-case scenario. Although our batteries can be mounted in a variety of orientations, we do not recommend mounting them upside down. If anyone has any questions about our batteries, I’ll do my best to answer them.

Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
Optima Batteries | Facebook

[JMatta]

Have had an Optima "red top" in my '73 911 for the last 7 or 8 years without a single issue (mounted in the smuggler's box, unvented). Car has a battery cutoff switch, so unconnected when not in use. Have never used a maintainer or charger in all these years, even after winter storage...still works perfectly.

One of the best I've owned and another will go in the Box S when the Moll dies again.

[big911fan]

Thanks for the info. I strongly considered an Optima battery but went with something more traditional for two reasons.

One, I didn't want to mess with a different size battery and the subsequent battery hold down issues as well as the battery cable issues.

Second, I'm not sure about charging an Optima with a standard charger or a Battery Tender.

The bottom line is I went the easy route.

[mikefocke]

I charge my Optima with a maintainer when I don't use it for weeks at a time. Winter for example. Never let it run down to where I needed a charger.

First I've heard of a venting capability for an Optima. Jim, how about some more info for the Red Top..say a picture of where it connects. I sure don't recall one and took off the vent connection to the old failed battery when I installed my Optima.

[OptimaJim]

Hi Mike,

The only RedTop we sell with venting provisions is our group 78 battery. The 3/8" tubes are on either side of the battery lid, as indicated below-


If you have any other questions, please don't hesitate to ask.

Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
Optima Batteries | Facebook