Hey guys, while at WCR a couple of weeks ago I noticed Geoff Straw (WCR host) had a pretty small battery and he said it worked great and sounded like it was under $100. I haven't been able to reach him so does anyone know what kind of battery he has? Or any recommendations on a small sized battery that gets the job done? He kept saying it saves him about 30 pounds of weight and if it does the job I want one. Thank you very much and do tell.
All the best,
gg

Please tell me it doesn't exist... I spent 250 on an optima 2 months ago...

I’ll be doing the same on my lightweight 912 build

https://forums.pelicanparts.com/porsche-911...ht-battery.html

And, who sells them ?

When you say ‘get the job done’, we are talking daily driver street car? I need to figure out where I’m gonna put a battery on my project while I’m still in body work stage - a future conversion car, so I’m leaning towards non-stock location and I’d love to save some weight… so please find out what battery it was!


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I am trying my best!! I hope Geoff is ok as I have not heard back from him for days. I have to say this guy was amazing to me as getting to WCR on Thursday my car was running way too hot. I mentioned it to Geoff on Thursday afternoon and he invited me to his house that had a lift (two lifts) at around 7:pm on Thursday. He found the problem (missing intake manifold stud) and he threw a bolt in there and darned if my car didn't cool off IMMENSELY !! Gotta' watch those air leaks. So I couldn't thank him enough and it was the classic 914 community "May I help you fix your car?" This is the heart and the glue of our group I believe. Mention an issue on your car and someone will be under there in about two minutes. Cary did this for me in Mammoth WCR and so many others are always willing to help....what a family we have!!! We are blessed to be together like we are....wooohooo!!
gg

..and you’re pretty sure it’s not the ‘Battery Tender’ (brand) battery that mepstein linked to above?


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I run one of these in my autox car

https://www.amazon.com/ODYSSEY-PC680-Odysse...y/dp/B0002ILK6I

and these in my other 914s

https://www.amazon.com/Odyssey-PC925-Automo...y/dp/B0002ILK72

Way more reliable than Optimas have been over the last 15 years.


I have ran the 680 in one of my street cars as well, it does just fine, just has less reserve capacity. I just prefer the 925 as its shorter and slightly easier to get in and out of the engine bay without nicking things. Only reason to go with the 680 over the 925 is for maximum weight savings.


Rennline makes a nice clean mount for them, and adding a battery cut off switch is nice when parking for the winter.

https://www.rennline.com/Battery-Mount-Kits/products/169/

I've had great experience with the Odyssey PC680 Uber reliable cranking my 360 cubic inch 9:1 compression airplane motor that sits for months

Made in USA . AGM technology (not lithium) not as light as lithium but absolutely no technology risk

I run PC680's in my Bugs and a PC1200 in my 914.

The new battery technology is amazing. Now a lithium-based battery can be a fraction of the weight with plenty of umph. Battery tech development is white hot right now. For deep / long store, lithium iron phosphate (LiFePO4) is so solid. Fascinating times.

Thank you for replies but we are not even close....this battery looked like a motorcycle battery....about that big....let's keep trying and maybe Geoff will surface??
All the best,
gg

How small you talking? The Odyssey 680 is 7" x 3" x 6.6"

I have an anti gravity battery- lithium 480 cca- works great its 4 lbs and $170

I use an ETX, with a Braille mount.

http://www.914world.com/bbs2/index.php?s=&...t&p=2939294

Look them up at Summit Racing. You must keep them charged and they don’t last for as long as a regular battery.

FWIW I've been using the PC680 for many years as well and they're fantastic. I turn-off the cutoff switch when the car's not in-use and they last me ~5 years

Bought a Green-Lite series years ago. Some of these batteries also will not take more than a 10-15amp charge meaning you shouldn't put them behind a 50+ amp alternator.

https://braillebattery.com/

I remember it weighed nothing and was super small. We used it to jump start cars.

Be aware that the smaller batteries do not (yet) have the reserve capacity to a good old lead acid. So if for some reason you stop charging, you have a very small window to get home before you need to call AAA for a rollback.

I went from a PC925 (which is a perfectly good battery) back to a heavy dumb lead acid after a SLIGHT charging issue left me stranded on a 20 mile drive at night. The headlights started dimming at about mile 7. At mile 15 I was coasting to the shoulder. Since I regularly drive over 100+ miles in my 914, I'd rather have the capacity then lite weight.

As long as the charging system works properly, the smaller batteries work totally fine. As soon as there is an issue, hope you are close to home.

Zach

Dumb question but do all these small modern batteries need a charger on them when not in use, like nightly? Haven’t bought a battery in a few years and certainly not one of these, but that’s the impression I’m getting on some/most of them. Can some one clear up which ones need constant baby sitting and which do not?


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Those UPS batteries can be found online or most any "Battery Store". I used them in my plane 20 years ago. They are about 6x6x4 IIRC. They don't give you much warning when they are on they way out. But very light and <$100 IIRC.

Gloss over my comment all you want, but they ARE close. Motorcycle size (smaller than my previous favorite PC680) weighs less, puts out more, doesn't have the same level of trouble with long storage....

What are we not close about? Lithium iron, lithium iron phosphate... You got something new to back it up?

You throw out the "not even close" bullshit, bring me something real that's better than Lifepo4 that we can use today.

I take it back....I was looking at a couple of the larger battery pictures so forgive me.....3" x 6.6" is pretty damn small!! How much is one and will it really act like a full size battery? Thank you very much,
gg

All right all right.....I didn't realize the sizes you guys we're talking about plus I know about this topic.....sheesh!! I apologize for upsetting you....please forgive me....so how much are the batteries you are speaking of? Thank you and have a great day:)

Nobody is upset. Dude, don't cry. It's conversation and we all brought something to it. That includes you. You deserve to buck it up.

4.5 x 3.25 x 4.25 inches (LxWxH)
360 Cranking Amps
16 Amp Hours (Pb Eq)/ 8Ah (Actual)
2.25 lbs
$219.99

Appreciate it Rand.....all good!
gg

It works just like any other car battery. Plenty of cranking amps, just a smaller reserve capacity.

They store well, can deep cycle, and dont leak acid, so better in pretty much every way than a standard battery.

The reserve capacity really only becomes an issue if you are running accessories for an extended period with the engine off, or if you are having charging system issues. I had mine in one of my "street" 914s for years, took it from salt lake to colorado for multiple RRC meets, never had an issue with the battery. Did have an unrelated charging system issue at one point (alternator was throwing belts on the way back from RRC one year due to the lower nut having backed off) but even in that case the PC680 performed without issue, other than running down on power after i threw a belt. Still got home just fine.

The PC680 runs about 100 bucks. I think between the two i prefer the PC925 for most things (its still about 1/2 the weight of a stock battery) but if you want to shed as much as possible without paying for lithium, the 680 works great.

No not if AGM they hold a higher percentage of charge way longer than lead acid can if not used a lot.
Biggest issue I have found is if they go almost completely flat smart chargers won't lift them back,I use an old type charger set to 6 volt for a while then go to 12 volt then smart charger...this may sound odd but it works every time.
I started with a very small Vision brand ( 9lbs ) and got great results for 4.5yrs until I had an short to ground and that buggered it rather quicky ,I wasn't too worried as I didn't have any other damage and a replacement was only 78 NZD.
IMO and experience I would never go back to the bulky older batteries.

Be careful about switching to lithium UPS batteries for car use, most are designed to output around 20 amps, the BMS might shut it down if you try to start a car with one. The ones designed for high current start cars no problem even though both might have the same amp hour rating.

There may be better options now, but I've been using a Odyssey extreme 30 AGM battery and it's about 20 pounds - about half of a "normal" battery. And I cut down the battery tray to make it fit nice.

-Steve

I'm not really a fan of itty bitty but more than a mouth full is a waste

Let me ask a couple questions:

1) In an industry that fights tooth and nail for every .1 mpg of CAFE fuel economy efficiency, why aren't 12 volt Li-ion batteries widely deployed in OEM vehicles? Weight is directly related to fuel economy. There are always conversations about how many $$ are willing to be paid for MPG.

2) In an industry where packaging space is always at a premium, why wouldn't OEMs adopt such small battery packages?

3) Any condideration being given to the failure modes for Li-ion batteries?

I agree with what you are saying but being a hobby car for most of us provides some leeway from the considerations that oem manufacturers have to deal with. For example, I expect my daily driver to start easily in 10 degree weather, I dont want to spend $500 for a daily driver replacement battery, I want it to work with a/c, lighting, stereo, heated seats and accessories.

The battery for my 912 has to start the car and be under 3lbs. Everything else is sort of optional.

They are available as an (expensive) option on new Porsche's

Yup! Just need to be thinking about those trades offs.

The OEM's have a wide range of issues to consider when choosing the battery. Everything from all the accessories offered on the car to the fact that your teenage daughter might be sitting in the driveway running the stereo and seat heaters on a 20 degree winter night. So they err on the side of the bigger, heavier battery for longevity and reliability.

With a 914, you don't (normally) have power windows, AC, seat heaters, or other considerations like making sure it starts after sitting out overnight in sub zero conditions. And you get to pick and choose what you want on the car, so you can size the battery for your use. You don't have to worry about what I do with my 914.

Just my $.02

Clay

yes, I agree, If you want safety and security, the oem design is usually the way to go.

I'm not sure I'd call it err . . . Let's agree to call it an engineered system.

Lots of load manament going on in the background that most people now take for granted. Even with a 12v lead acid battery.

Battery State of Charge monitoring, loads (like seat heaters) can be modulated or dumped completely if necessary to manage proper charging at all engine speeds. Way more complicated than a 914 analog voltage regulator.

The elephant in the room for Li-ion is the fire risk. Thermal runaway is real. When I worked on DoD project with Li-ion batteries we nearly lost a one off prototype to Li-ion battery failure in the middle of the night. Luckily it self extingushed. Can't count on that always occuring.

Battery Mangement Systems (BMS) have come a long way but still have a long way to go. Can only wonder what the BMS is for an aftermarket battery.

Item #3 still makes me laugh.

"Park your vehicle outside immediately after charging and do not leave your vehicle charging indoors overnight"

https://www.chevrolet.com/electric/bolt-recall

Recently learned more than I wanted to know about Lithium batteries when looking for a replacement for my motorcycle. The safer battery to use is the Lithium fe kind and you should get one with the onboard battery management circuit. Without the circuit on board the battery could possibly over or undercharge which can ruin the battery for good. And if you run a lithium battery down too far on charge (left lights on maybe) it will also become a brick. So if your charging system is not working in the required charge range for the battery it could get bricked. In the end I just got another lead acid gel battery even though the CCA and weight are nowhere near the lithium battery advantages. The price and a two year warranty were the advantages I went with. And user reviews online seemed to be reporting to many owners getting stranded.

New battery tech has evolved drastically, on an accelerated curve in recent years. There are a TON of OEM things on 914s that can be improved with aftermarket upgrades since 70s tech, but I digress.

Heck, I remember when Nicad batteries were the thing. I had a cell phone with one. It had to be fully discharged and recharged to preserve it's life because of "memory." Then there's lipoly that changed the RC world. With bigger batteries, lithium ion has crushed lead acid. More recently, the RV world which has been accelerated drastically since covid, has turned up LifePO4 (lithium iron phosphate). No more issues with storing them at full charge long term, or losing that charge. No more losing 20% of battery capacity after x amount of charge cycles. Of course none of the problems of the OEM lead acid garbage. Less weight, no acid leaks, more reliable, more tolerant to temperatures, no memory problems, less degradation over time, yada yada.

Don't get stuck in time.

I didn't see my inexpensive AGM battery here so thought I'd throw in my 2¢. I've been using this battery for almost a year and a half now with no problems. I drive the car 1 or 2 times a week and never put the battery on a charger (I am in SoCal temperatures though).

https://www.batterysharks.com/SigmasTek-STX...12-21-350-d.htm

Click to view attachment

Sorry, I've been crazy busy and haven't had time to check in on 914World. The battery I use is the Braille B129, which costs under $200 shipped. Here is a link:

https://braillebattery.com/products/b129-1

Beautiful car. BTW, disconnecting the ground is much safer than disconnecting the hot terminal.

Build your own, 4 x 3.2v cells (or multiples of 4) is perfect for 12v, lots of YT vids.
I'm going to be building LiFePO4 batteries for my RV build.

Just to add to my comment about AGM charge loss over extended periods ,here is a case in point, my car came with me when I moved house in early March and started it yesterday and got great cranking speed but I hadn't primed the fuel bowls enough and it took a while but engine started fine after that.
Something to consider if you don't drive your car much and other benefits of course.

James, is your battery strong enough to power a good sound system with a good alternator, like 120v of good?

The PC680 is fully adequate to start and run. It is ideal for minimalist light cars concerned with weight.
If that's not your goal, and you want to run accessories and sound systems, then no. Don't pimp out a 914 with a 680.

We run the 680 battery* in the 8gtt build. It's on the passenger floor mounted in a Rennline battery box. While sitting around, I have a battery tender connected to it. *Approx $200 at Autozone cash/carry *

1 watt = 1 volt amp. Let your stereo system output max. out at 100 watts rms per channel with only 90 % efficiency. The system will therefore have a max. power draw or input of 222 watts rms. For a 13.4 volt system, that corresponds to a max. current draw of 16.6 amps rms. Multiply this by 2^0.5 (1.4) for a peak current draw of 23.2 amps.

Ergo, your car's electrical system needs to deliver about 25 amps peak for just the stereo system. This doesn't take into account any power line noise filters. This is the worst case scenario.