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914World.com _ 914World Garage _ 914 Battery
Posted by: JamesJ Mar 17 2023, 12:24 PM
Hello World,
I am needing a new battery for my 2.2 four cylinder 914. I have read many of the battery threads from recent years. I know many of you have had success with Optima, but I've also read about the quality concerns in recent years. The Odyssey seems like a good choice as I've not read any threads addressing quality concerns with this brand.
The Odyssey Group 42 standard size battery for our 914s is 600 CCA, is as heavy as a lead acid battery at about 40 lbs., but it is a plug and play(no extra bracket required). I am not opposed to this option, but like the idea of a much lighter battery.
Odyssey sells a PC925(330 CCA at 24 lbs.) and a PC680(170 CCA at 15 lbs).
My mechanic friend recommended that I stay within 100 CCA of the standard size Group 42 battery, which would mean at least 500 CCA.
My car is stored at a remote storage facility that does not have power, so a battery charger/tender is not an option for me. I currently disconnect the negative battery cable when not using the car, but will purchase a disconnect switch when I purchase the new battery. The car is not a daily driver, and it's not unusual for the car to sit for a week or two at a time without starting or driving it. I have a/c and a CLA for my cell phone, but no radio or other electronic gadgets and I don't run any of the above with the key on.
I've read where several of you have the PC680 or PC925 and have not had any starting issues, but I don't know how often you start your cars or if you use a battery charger/tender to keep it from draining down. I live in California, so CCAs are not as critical as other areas in the country.
Any thoughts on CCA ratings or other issues I should consider? For terminals, do you use the SAE battery posts or the M6 receptacles? Other AGM brands recommended?
Thanks!
Posted by: rjames Mar 17 2023, 12:46 PM
I have the Odyssey PC925 with SAE posts and love it, but depending on the voltage your alternator puts out, I wouldn't recommend one if you aren't able to keep it on a battery tender (and one that meets the requirements by Odyssey). The PC925 also requires coming up with a way to keep the battery in place as it's smaller than a standard battery.
Posted by: mlindner Mar 17 2023, 12:51 PM
I've had Optima's for the last 20 years, never an issue. In the 914-6 GT Tribute for the last three. Best, Mark
Posted by: Root_Werks Mar 17 2023, 01:19 PM
I'm running a PC1200 for 3 years on my 2.7 six with high torque starter. Works like a charm!
Posted by: yeahmag Mar 17 2023, 04:02 PM
Just bought an AntiGravity ATX20-RS
https://antigravitybatteries.com/products/starter-batteries/restart-oem/atx20-rs/
Only time will tell.
Posted by: zoomCat Mar 17 2023, 05:57 PM
Group 96R is a drop in, new Die Hard AGM is 31 lbs.
https://shop.advanceautoparts.com/p/diehard-platinum-agm-battery-96r-group-size-590-cca-735-ca-80-min-reserve-capacity-best-for-high-electrical-demands-96r-agm/12102917-P?source=certona
Posted by: nditiz1 Mar 17 2023, 07:43 PM
Running the PC680 on my 6 conversion. Over winter it probably did at least a 2 or 3 week stint in between runs. No issues at all. I'm running a hi-torque small starter. 
Posted by: PlaysWithCars Mar 17 2023, 11:48 PM
PC680 for me as well on a 2.4l six with a high torque starter. It has sat for months over winter and started fine afterward, but that isn't an ideal situation for the battery. It would be much happier if you used quick disconnects and took it home with you to put on a charger. (its a good theft deterrent too if there isn't a battery in the car)
Posted by: oakdalecurtis Mar 18 2023, 02:46 AM
i use an Optima Red, got about 8 years out of my last one, maybe because of this modification. Since I drive my teener in fair weather only and often on short trips, I put a tender on it whenever it's in the garage. I got tired of opening the engine cover and attaching it all the time, so I did the following modification. Now I pull in the garage and "plug in" the car...
http://www.914world.com/bbs2/index.php?showtopic=300866&hl=battery
[attachmentid=818750]
[attachmentid=818751]
Posted by: slotty008 Mar 18 2023, 10:29 AM
I have the PC680 since 2 years now. It's very light and the car starts every time from the first time. But I always disconnect the battery if i don't drive the car for more than a week and from time to time I use a battery tender since the weather here in Belgium is too bad to drive a lot during wintertime.
To disconnect the battery I have the little green wheel at the negative of the battery. Very easy to install and very cheap. I also had to buy a bracket to hold the battery in place. Until now , I'm very happy with it. I have no radio and no AC, probably you will need a bigger battery or a really good alternator if you have them and use them a lot.
I only did this to reduce weight and I think the AGM's keep their charge longer ( when disconnected).
Posted by: nditiz1 Mar 18 2023, 11:11 AM
Slotty from this angle it looks like that positive terminal is so close to the metal tray. I'd feel worrisome, but it's probably further away in actuality.
Posted by: rudedude Mar 18 2023, 11:43 AM
I have an odyssey pc925 that is in one of my 911s. It had sat for 4 months and was down to about 30% charge so I took it out to charge it. Put it on a ctek trickle charger and came to the garage a couple days later to the worst smell. It had exploded. Talked the the vendor I bought it from and they said it had sulphated and was over 2 years old and I was out of luck. Called odyssey and they are sending me a new battery. It was less than 2 1/2 years old. I am now leery of trickle charging while in the car. No one has any idea what happened. I use the charger rotating to all my batteries and never had any issue. Very nice of odyssey to replace although I haven't seen the replacemnent yet.
Posted by: slotty008 Mar 18 2023, 11:48 AM
Slotty from this angle it looks like that positive terminal is so close to the metal tray. I'd feel worrisome, but it's probably further away in actuality.
Looking at the pic, I was thinking exactly the same thing, but in reality it's not that close. Maybe I'll put some insulation in between, just to be sure.
Posted by: technicalninja Mar 18 2023, 01:42 PM
I've used the Optima batteries in quite a few projects.
For vibration resistance, no gassing, and no acid leaks they are hands down the best.
My problem is they haven't lasted over 3 years for me, and their warranty is for 1 only.
They also have to be either charged in parallel with a lead acid battery or charged with a special AGM smart charger.
I will use an AGM battery in my 914s but it will probably be a normal mass-produced battery like the MTX/MTZ line from Interstate.
It helps that I am an Interstate dealer and can get these as cheaply as anyone else.
The MTZ line has the longest warranty from Interstate (48 months free replacement) and I'd expect one to live 6-8 years.
Interstate batteries is an Optima wholesaler, and I can get those at bottom price as well.
I'll still go normal over Optima for a street-based vehicle.
Posted by: ClayPerrine Mar 19 2023, 05:58 AM
I have Optima batteries in every single vehicle I own. They are all the same size too. Never had an issue with them at all. But if I do, I can pull the battery from a 914 and put it in the daily drivers and keep going. And I can walk into a FLAPS and buy a new one there.
The factory size battery for our E34 BMW was over $300.00 for a lead acid standard battery, and had a 3 week back order. The optima was less, had a higher CCA, and was available immediately.
Posted by: mepstein Mar 19 2023, 06:30 AM
Just bought an AntiGravity ATX20-RS
https://antigravitybatteries.com/products/starter-batteries/restart-oem/atx20-rs/
Only time will tell.
I really like the idea of a 4 lb battery.
I’m also using a high torque starter so that saves another 5lbs.
I’m going to try the cheap version first.
https://forums.pelicanparts.com/porsche-911-technical-forum/861770-lucky-mans-lightweight-battery.html
Posted by: jim_hoyland Mar 19 2023, 06:46 AM
Great discussion of batteries, thanks for the info. I have a question though:
I have am Optima 34R red top.Its a least 10 years old. I wonder ifI should replace it even though it still starts the car. The car is driven 100 miles a weaken average and I attach a battery tender when it sits.
My only complaint with the Optima is its weight......
Posted by: ClayPerrine Mar 19 2023, 07:17 AM
If you are interested in a lighter weight Optima battery, this is on their website:
https://www.optimabatteries.com/products/orangetop-quad30/
800Amp Lithium Battery.
Brand new, so no one has any experience with it yet.
The red top 34R is 38 LBS. The Orange top is 7LBS.
I don't know if it will work, but it is something to think about.
Posted by: technicalninja Mar 19 2023, 09:23 AM
The Li-ion batteries scare me enough to not run them in anything but a track car.
My youngest, Michael, was a track marshal for MSR (Motor Sport Ranch).
If any of you have video where a young blond "punk" made funny faces in your camera just before you left the pit area, that's my son...
One of his duties was fire suppression.
A Li-ion battery fire is very similar to a magnesium fire. Nothing but burying them puts them out. 20 minutes AFTER you think you have it out it starts back up.
A lithium-ion battery fire almost always takes the entire car with it.
These are NOT cheap batteries either. A 200K track car usually gets the very best equipment.
Owners are pissed when this happens...
They have lost multiple cars and garages to Li-ion battery fires at MSR.
I do see the benefits to the Li-ion batteries but until these becomes less flammable, I'll stay with heavier batteries.
I wish my Optimas lived as long as Clay's and Jim's...
10 years is a shitload for any battery.
Had mine lived longer I'd recommend them over everything else.
Optimas can fail but when they do they just barf their guts out of the cases.
I have not heard of any fires being associated with this.
The usual reason for Optima failure is long term trickle charging with equipment that is not specific for Optima batteries.
The Optima smart chargers are a bit on the expensive side and don't work seamlessly with lead acid batteries.
Out at MSR, Porsches gained the title "fire lizards" due to the fact when they leave the track and slither into the grass they catch it on fire far more often than any other brand of car...
PCA and Porsche events at MSR were always super professional with extremely friendly people. Michael loved to work when the fire lizards were running.
The motorcycle crowds were exactly the opposite...
Posted by: campbellcj Mar 19 2023, 10:27 AM
I've used the PC680 for years now with good results. My car has a minimal electrical system and I disconnect the battery when not in use. Mine is on its side but flipped the other way around vs the photo above to give more clearance from the battery tray lip - it's still a bit close for my comfort but I have an insulated cover over the + terminal as required by racing rules.
Posted by: horizontally-opposed Mar 19 2023, 11:43 AM
Have had Optima red tops in my 914 since ~1992.
I think I have only had 2, maybe 3…so easily 10 years per. The big attraction back in the 1990s was avoiding hell hole rust. But they are heavy, so I think about an Odyssey or Anti-Gravity. Or that new orange top from Optima. For both of my fun cars, as I value less weight over more hp.
Having just lost a fair bit to a house fire (electrical, but not car related), @http://www.914world.com/bbs2/index.php?showuser=27135 has me rethinking the value of 30-40lbs saved vs having the car/garage/house.
Posted by: Highland Nov 10 2023, 04:26 PM
I need to buy a new battery. Is the Odyssey PC925 the best replacement for stock/street driving? (I know it's a recent post, but things change quickly)
Like the original poster, trying to go lighter than a group 42, but don't want to sacrifice performance or longevity.
Posted by: Root_Werks Nov 14 2023, 01:00 PM
I need to buy a new battery. Is the Odyssey PC925 the best replacement for stock/street driving? (I know it's a recent post, but things change quickly)
Like the original poster, trying to go lighter than a group 42, but don't want to sacrifice performance or longevity.
Go bigger than the PC925 if you can. You have plenty of room, I'm still running my PC1200 in my 914-6. Nice to have the extra umph. We've been stuck in the Ferry line, 914 off, radio running, even charging a phone for a few hours. PC1200 had plenty of reserve juice.
Posted by: Justinp71 Nov 14 2023, 01:06 PM
I was trying to put my car on a diet so I went with a PC680, works great so far. I do have a hi-torq starter and starting relays which both help the typical starting issues.
Posted by: rjames Nov 14 2023, 01:53 PM
I’m still running an Odyssey PC925 with zero issues. If going this route make sure to look up which battery tenders are compatible. Not all of them are, and using the wrong one will shorten the battery’s life.
Posted by: campbellcj Nov 14 2023, 02:32 PM
I was trying to put my car on a diet so I went with a PC680, works great so far. I do have a hi-torq starter and starting relays which both help the typical starting issues.
I've used the PC680 successfully for many years though my car's got a very minimal electrical system and load. For a more stock/street car I would lean towards the 925 or similar.
Posted by: VaccaRabite Nov 15 2023, 06:31 AM
I had a PC925 in my car.
I went back to a standard battery.
The PC925 just cant store enough energy if the alternator doe not perform at its peak for some reason at night. I got left stranded on a 20 minute drive when the alternator was not charging at full power. The PC925 was at full charge when I left the house. it lasted 15 minutes and died.
Standard or Gel batteries are heavier, yes. But most of the can sustain a car for 30 - 40 minutes in the event of a charging issue to get you home or to somewhere safe.
I would NOT put Lithium batteries in my car without special chargers built for them specifically. Also, I'd look for LiFePo4 batteries instead of L-Ion batteries.
Zach
Posted by: 930cabman Nov 15 2023, 12:08 PM
Great discussion of batteries, thanks for the info. I have a question though:
I have am Optima 34R red top.Its a least 10 years old. I wonder ifI should replace it even though it still starts the car. The car is driven 100 miles a weaken average and I attach a battery tender when it sits.
My only complaint with the Optima is its weight......
I had an Optima in my 356, lasted 16 years.
Posted by: euro911 Nov 15 2023, 12:55 PM
I had a Odyssey PC925 in the 'BB' from 2011 until I sold it in 2018, never had any problems starting a 2.1L with 9:1 C/R 
Posted by: scallyk9 Nov 15 2023, 04:48 PM
I installed an Interstate Group H5/47 AGM in my 3.2L conversion last Summer and it was a perfect drop-in fit for the stock battery tray. This replaced an Optima. I had been shopping batteries for a while then impulse purchased this when I noticed it while walking by the tire area at Costco. Less than $200.00 after I returned the core Optima.
Posted by: tygaboy Nov 15 2023, 06:09 PM
I'm running a Braille in my LS car. 17 lbs and 475 CCA. Very happy with its performance:
- It sat for over a year before I installed it. Put it on a Battery Tender to top it up and BOOM! Fired up the LS just fine.
- I accidentally left my ignition in the "on" position on when trailering home from WCR, plus a day or two before I unloaded. Totally drained it to ZERO. Put it on the Battery Tender and BOOM! Back to full function.
- Length (in.): 6.8 in., Width (in.): 4.0 in., Height (in.): 6.1 in.
- I'll likey go with the same thing in the 914 Ferrari build
- Buy on Summit Racing, $199 and free shipping to your door:
https://www.summitracing.com/parts/brl-b2317
- You can get a super cool, aluminum mounting frame, too. See pic.
They also offer an 11 lb/360 CCA, if that'd work for you.
In any case, Braille batteries: At The Red Barn approved!
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Posted by: Spoke Nov 26 2023, 08:51 AM
I had a PC925 in my car.
I went back to a standard battery.
The PC925 just cant store enough energy if the alternator doe not perform at its peak for some reason at night. I got left stranded on a 20 minute drive when the alternator was not charging at full power. The PC925 was at full charge when I left the house. it lasted 15 minutes and died.
Standard or Gel batteries are heavier, yes. But most of the can sustain a car for 30 - 40 minutes in the event of a charging issue to get you home or to somewhere safe.
I would NOT put Lithium batteries in my car without special chargers built for them specifically. Also, I'd look for LiFePo4 batteries instead of L-Ion batteries.
Zach
@http://www.914world.com/bbs2/index.php?showuser=1435
Zach, what battery did you end up buying? Was it AGM? I need to replace my Optima red top. After 20 years the first start up of the day is very slow.
Posted by: raynekat Nov 26 2023, 11:20 PM
I went with this battery for my six conversion build.
It fits in the stock factory tray perfectly and has tons of power.
Posted by: VaccaRabite Nov 27 2023, 10:07 AM
I had a PC925 in my car.
I went back to a standard battery.
The PC925 just cant store enough energy if the alternator doe not perform at its peak for some reason at night. I got left stranded on a 20 minute drive when the alternator was not charging at full power. The PC925 was at full charge when I left the house. it lasted 15 minutes and died.
Standard or Gel batteries are heavier, yes. But most of the can sustain a car for 30 - 40 minutes in the event of a charging issue to get you home or to somewhere safe.
I would NOT put Lithium batteries in my car without special chargers built for them specifically. Also, I'd look for LiFePo4 batteries instead of L-Ion batteries.
Zach
@http://www.914world.com/bbs2/index.php?showuser=1435
Zach, what battery did you end up buying? Was it AGM? I need to replace my Optima red top. After 20 years the first start up of the day is very slow.
I went backwards. Standard lead acid AC Delco. I’ve not bought a Red Top in about a decade. I’m sure that they have fixed thier issues from 10 years ago. But modern batteries don’t really leak anymore, so I don’t see the point in spending the extra money.
Zach
Posted by: Spoke Nov 27 2023, 08:13 PM
I had a PC925 in my car.
I went back to a standard battery.
The PC925 just cant store enough energy if the alternator doe not perform at its peak for some reason at night. I got left stranded on a 20 minute drive when the alternator was not charging at full power. The PC925 was at full charge when I left the house. it lasted 15 minutes and died.
Standard or Gel batteries are heavier, yes. But most of the can sustain a car for 30 - 40 minutes in the event of a charging issue to get you home or to somewhere safe.
I would NOT put Lithium batteries in my car without special chargers built for them specifically. Also, I'd look for LiFePo4 batteries instead of L-Ion batteries.
Zach
@http://www.914world.com/bbs2/index.php?showuser=1435
Zach, what battery did you end up buying? Was it AGM? I need to replace my Optima red top. After 20 years the first start up of the day is very slow.
I went backwards. Standard lead acid AC Delco. I’ve not bought a Red Top in about a decade. I’m sure that they have fixed thier issues from 10 years ago. But modern batteries don’t really leak anymore, so I don’t see the point in spending the extra money.
Zach
Thanks. Stopped at Autozone and picked up an AGM battery.
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Posted by: infraredcalvin Nov 27 2023, 09:37 PM
Another optima guy here, I’ve been using since late 90s, I replace them at about 7 years, still have one from 03 and another form 06 still going strong, they are backups.
I’ve used battery tenders with no issue previously, but now have an optima specific charger, it brought a dead lead acid back to life when nothing else worked.
I use a 3 cell yellow top in my track car, I disconnect when not in use, it’s been over a month since I’ve started it, still at 100% when I throw the smart charger on it.
Posted by: GBX0073 Nov 27 2023, 10:28 PM
Napa Did not exclude batteries from Cyber Monday 25% off so picked this up.
plus earned another $10 off in rewards.
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Posted by: 914rrr Nov 29 2023, 08:43 AM
The Li-ion batteries scare me enough to not run them in anything but a track car.
My youngest, Michael, was a track marshal for MSR (Motor Sport Ranch).
If any of you have video where a young blond "punk" made funny faces in your camera just before you left the pit area, that's my son...
One of his duties was fire suppression.
A Li-ion battery fire is very similar to a magnesium fire. Nothing but burying them puts them out. 20 minutes AFTER you think you have it out it starts back up.
A lithium-ion battery fire almost always takes the entire car with it.
These are NOT cheap batteries either. A 200K track car usually gets the very best equipment.
Owners are pissed when this happens...
They have lost multiple cars and garages to Li-ion battery fires at MSR.
I do see the benefits to the Li-ion batteries but until these becomes less flammable, I'll stay with heavier batteries.
I wish my Optimas lived as long as Clay's and Jim's...
10 years is a shitload for any battery.
Had mine lived longer I'd recommend them over everything else.
Optimas can fail but when they do they just barf their guts out of the cases.
I have not heard of any fires being associated with this.
The usual reason for Optima failure is long term trickle charging with equipment that is not specific for Optima batteries.
The Optima smart chargers are a bit on the expensive side and don't work seamlessly with lead acid batteries.
Out at MSR, Porsches gained the title "fire lizards" due to the fact when they leave the track and slither into the grass they catch it on fire far more often than any other brand of car...
PCA and Porsche events at MSR were always super professional with extremely friendly people. Michael loved to work when the fire lizards were running.
The motorcycle crowds were exactly the opposite...
I worked, very breifly, for a LI battery "manufacturer" in Clearwater, FL. 98% of their batteries are made in China and they merely slap a "Made in USA" label on it. Most LI battery sites claim plug n' play / direct swap compatability for lead acid batteries. DO NOT BELIEVE THEM! I quit over their objections to my suggestions of CYA language to add to their website, woefully inadequate fire safelty / supression in their building (they didn't even have a sprinkler system!), "made up" date codes on batteries, numerous "off the books" settlements for battery fires / explosions (one boat battery took out a $MM garage and house), etc etc.. DO YOUR HOMEWORK before choosing a LI battery for anything other than a track car. LI batteries run at different voltages, require LI specific chargers, don't like cold or really hot weather, thermal runaway safety concerns, etc, etc. Read articles below for more info:
https://www.ien.com/safety/news/21136518/fire-triggers-call-for-stronger-battery-rules
https://www.batteriesplus.com/blog/power/lithium-starting
Posted by: rjames Nov 29 2023, 02:24 PM
Napa Did not exclude batteries from Cyber Monday 25% off so picked this up.
plus earned another $10 off in rewards.
Get the right battery tender for your Odyssey. Here's the list I found online:
ODYSSEY_approved_12V_chargers.pdf ( 52.61k )
Number of downloads: 37I have the BatteryMinder 2012-AGM and have been happy with it.
Using one that doesn't meet the battery's requirements of a charging voltage of 14.4-15v may prematurely shorten its life. This did give me some concern after I purchased my PC925 as I'm betting the stock 914 alternator may not be putting out that much, but so far so good, and I always put the battery on the charger when it's in the garage.
Posted by: fiacra Dec 5 2023, 09:52 PM
Napa Did not exclude batteries from Cyber Monday 25% off so picked this up.
plus earned another $10 off in rewards.
The Odyssey 96R-600 is the battery that came with my car when I bought it. At 12 years old it was still running strong, kept its charge even when the car sat for a while, and when last I saw it the battery was still giving dependable service. Because it had such good performance I stayed with Odyssey and got a PC925 for my other car. That didn't work out so well.... Three years in, and two months out of warranty, it will no longer hold a charge and I have to replace it. I'm thoroughly disappointed in that decision. I just ordered another Odyssey 96R-600 yesterday. Yes, it's 40.3 lbs., but if I want to carry less weight in the car maybe I should put myself on a diet
. Honestly, I never had any complaints about how my car drove with the heavier battery in it and I noticed no difference in performance with a lighter battery. Granted most of the time I drive like I'm in touch with my inner grandmother, but even when doing more "spirited driving" I don't think the few lbs. of extra battery weight made a discernible difference. Running a PC925 did however make a difference in the reliability of my car. Add in the weight of the jump box you'll have to carry with your PC925 and you might as well get the PC1200 or the 96R-600.
Posted by: mlindner Dec 6 2023, 05:24 AM
Optima, love it.
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