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YOUR RESEARCHbattery info for 996
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interior lights
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Leading evidence: 'interior lights' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'interior lights' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Recommend interstate battery #mtp-h7' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion · Original poster
I am at the point I need to replace my battery in the 99, 996 cab.
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I am at the point I need to replace my battery in the 99, 996 cab. I am trying to decide which way to go. Several people told me interstate MTP91 ($150.00) others say OP red top ($189.00)...others say stay original (part #99961108020) ($210.00) not sure original is worth the money not sure what mods are need for the other choices. I can buy a new Porsche brand battery part # 99961108820 but not sure, it will fit. Any advice, especially regarding the 99961108820?
I have always done well with Interstate in my Porsche's. Used the MTP91, also have one in my wife car. The "Porsche" batteries I have been told to avoid.
The Interstate will fit and can be secured. The Optima Red Top will need a special bracket to hold it in place. If you go Interstate make sure you get the right model - I think the MTP91 is correct but verify the dimensions.
I got a new one at Sears for $135. Diehard Group 48. I don't remember all the specifications, but am sure it has higher ratings than the Porsche battery.
Here's a link to my Optima install about 2 years ago
https://rennlist.com/forums/996-foru...a-battery.html
Yellow Dog sells a plastic or aluminum mounting plate. FWIW I like my Optima, pretty much problem free. I did have a battery draining issue but it had nothing to do with the Optima. Turned out to be the interior lights.
Another option for even more weight savings is an Odyssey battery.
Just bought a 49-1 from Wally world...$69! Bought a battery tender w/float from Harbor Frieght $8(?) Been accused of being cheap, but I prefer frugal...afterall I own a Porsche with money I've saved
Having just taken my battery out, I can tell you that there are several "mounting spots" for the bolt-down bracket. This
should
mean that you can use a battery of a different length - as long as the terminals are on the right sides.
By all means, DO NOT waste your money on a Porsche battery. I have made that mistake in the past. The last one made it less than 2 years! Yes, I use a battery maintainer.
I recommend the Interstate Battery #MTP-H7. This is the
DIRECT
replacement in terms of size and location of the vent hose attachment point. You will NOT need the vent hose adapter kit. It uses one of the existing clamp points on the battery tray. It's an 800 amp (640CCA) battery compared to the stock Porsche's 380. The engine turns over much faster then before.
It also comes with an 85 month no-questions asked warranty. The Porsche one does not.
.
The Sears battery is a direct replacement. It fits perfectly and has a vent tube. I looked for the Interstate battery but couldn't find one conveniently.
+1 They are a bit lighter too. Maybe 10lbs? I have an odyssey PC295 (25lbs) which I have been afraid to put in b/c of the way these cars seem to drain battery life when not driven.
Thanks, there seems to be almost as many different opinions as there are people responding. I will probably look at both the sears and the interstate. I did pull my battery out...standing in the trunk to lift that heavy sucker out. I did notice the adjustable hold-down bracket but it appears maxed out with the current model size of approximately 12 1/3 inches. I am interested if anyone knows the actual dimensions of the Porsche battery part # 99961108820, the original battery part # is # 99961108020. I can pick up a new (the battery has never had electrolytes added) 8899961108820 for $50.00 any thoughts? I tried a couple of dealers but no one wanted to give me an answer...go figure.
See post 15 for Interstate direct replacement...the first part number you gave is for these apps:
911SC / Turbo (1978-1983) 1
911 Carrera / Turbo (1984-1986) 1
911 Carrera / Turbo (1987-1989) 1
928 (1978-1982)
Sorry don't know if it will fit.
The Interstate H7 does look like a direct replacement, but then how come their website recommends the MTP-91? Indeed, the latter looks somewhat smaller from the photo. However, the H7, when clicked on for more info, brings up a broken link. Is it no longer being manufactured?
+1 on the Optima red top.
The main advantage is that it's completely sealed, you could even mount it upside down.
1. No vent needed.
2. No leaking acid to corrode where you can't see, even with big cornering.
3. No water/electrolyte replacement.
The main disadvantage is that you have to either make or buy a mounting plate - I made mine out of 1/4 inch aluminum plate (cheap!). Once you get one, you can just get your red top at Autozone...
Good luck,
Tonger
This is the same thing I discovered via the website. Totally prepared I walked in and said "I need the MTP-91". The guy looks at my $225 22 month old POS Porsche boat anchor and says "why do you want a physically different battery,
the H7 is the IDENTICAL case, handles, and location of the vent tube connection
whereas the -91 is not". I had him bring both to the front and sure enough, two different animals.
Don't pay any attention to the website. Go to your local Interstate location and put your dead one next to them and you will see.
I have the OEM battery with no problems. Make sure you get a battery trickle charger. Ctek makes the new version by Porsche for 60-70 on ebay or 130 from you dealer.
I replaced mine with a NAPA battery that, although a little shorter and required using the narrowest hold down adjustment, seems the same in all other regards. Same style handles, same style flush screw on caps, obviously the terminals are in the right place, and the vent hose lined up. It was, however, $150... so maybe not much cheaper than a dealer. But I supported my local indi and it works perfectly.
Thanks Aviatorx and bgrpph. I'll be sure to get the H7. My battery isn't dead yet, but I've had the car for almost 4 years and will probably replace it soon to be on the safe side rather than the stranded side (like my father in his C4S two weeks ago).
Interesting thread. I will probably need a new battery after draining my battery over the winter and having to boost it a few times.
I read about a cheap device that you stick into the cig. lighter socket to maintain slight power for the computer and radio. What was that batter powered thing called???
It's a Porsche Techquipment Battery Charger. Here's the link from SunCoast Porsche in FL. NO ONE knows better about this one than I do!!
http://e-partssales.com/Merchant2/me...de=95504490054
Yup, I probably need what Phil suggested. And the "memory" 9volt battery thingy is what I was asking about!
So thanks to both of you!
PS--I thought there was a $5 version of the memory maintainer, someone mentioned buying it at one of the auto store chains...?
I just bought the charger Phil has. Hopefully I can re-charge my battery and be done. I figure I'll leave the car plugged in during the week, and be able to start and drive it without issue.
Do our cars have a cut-out in the door for the chord to pass through, without me keeping a window open all week??
There's a little cut out in the weatherstripping along the bottom of the door but it's too hard to line up the cord to the slot in the rubber. I use a maintainer and the cord doesn't get damaged by closing the door on it.
Good luck.
Sorry for dragging you back into this thread Phil! These guys are relentless! Finding a photo of a German defib machine!? Photoshopping their own German onto a USA version - when will the madness end!?
PS--Dertickerkicker - awesome!
