JackOlsen

My apologies for basically copying this over from Pelican. But I thought some people here might be interested. At this point in my car's development, dropping 15 pounds for under $200 is pretty good.

I've been using an 18-pound AGM wheelchair battery in my old Porsche for almost a decade, now. I've replaced it twice -- the last time when the price dropped to $30. More than anything, I'm a cheap bastard.

Now, my garage recently won an award in the Classic Motorsports 'Show Us Your Shop' contest. The prizes for the contest ran the gamut of usefulness. I got a $500 worth of degreasers, brake cleaners and other chemicals from CRC. I got a (Chinese-made) TIG welder from Eastwood. And then… $500 worth of Battery Tender products.

Now, I already own and use a battery tender. I like it. But once you've got one of those $30 beauties, you don't really benefit from having 15 more.

But I looked up the company, and found out that they also have a line of lightweight LiFEPO4 (Lithium Iron Phosphate) batteries. The biggest one has 480 cold cranking amps and weighs 3-1/2 pounds.

The last time I'd noticed this battery technology was when Porsche Motorsports offered it in a 12-pound version for $2,950.

I don't know if it's because of laptops or all the Priuses out there or what. But now you can get a Lithium Iron Phosphate batteries pretty cheap. The Battery Tender one lists for $300, but can be bought from Amazon for under $200.

So now I don't have 16 battery tenders. I've got one extra, a cool battery, and then a LiFEPO4-specific battery tender.

Here's the new guy on the scale:



And as you can see here, it's about the size of the popular 16-pound Odyssey battery. It's just that when you pick it up, it feels like they forgot to put the guts inside it. (It's actually less than 3-1/2 pounds.)



I had to downsize the bracket I use in the car's smuggler's trunk. Normally in a 911, the batteries (yes, two) would have been up in the nose. For racing, you move them inboard. But repositioning the battery to this location really wouldn't be necessary if I'd started with a battery this light.



And here's the old guy back on the scale, along with the portion of the tie-down I was able to chop out. My net weight savings was 14.7 pounds, and the cost to me (because of the contest, of course) was zero. That warms my thrifty heart.



The Battery Tender LiFEPO4 battery can be got from Amazon for $185 and the LiFEPO4-specific charger/maintainer for it is $27. .

The upsides? Unlike other lithium-based batteries, this one is not prone to catching fire. It has a very long lifespan relative to many other battery technologies. Unused, it will hold a full charge for about a year. It's environmentally safe -- I'm pretty sure it doesn't need any kind of special disposal. It holds its nominal 12-volt charge between 13 and 14 volts until it runs out. As such, it runs your starter like it's on steroids.

The downsides? Reportedly, it loses a lot of its umph below freezing. (I'm not sure what that means in practice, but I'm in a warm climate here.) In real-world use, it might be more susceptible to parasitic drain issues.

Matt Romanowski

Very cool. The price seems very reasonable versus a Braille or similar too.

zadar

That looks pretty similar to Shorai battery, wonder if it is same.
I am Shorai dealer and sell a lot of this for motorcycles.They do have one that is higher than this battery tender one. Shorai one is 36Ah and 540cca.

kgorman

Have you used it yet? Do you have a feel for how it retains a proper charge over time? Interested to know.

zadar

Usually cars will have some drain on battery from gauges or people using aftermarket gadgets. You want to keep this batteries on charger or disconnected if car is not used daily.

JackOlsen

kgorman, I just put it in, and have done maybe 8 starts with it. So no real data. It cranks the engine faster than my AGM, maybe because its voltage is a little higher than other batteries for this kind of application. As an illustration, this is how this battery 'runs down.' It is near full voltage (and above 12V) right up to the point where it runs out of juice.



Zadar, I got mine paired with a tender-type charger, although that's something of a misnomer since this thing will hold its charge for a year if there's no load. But if I do have any parasitic issues with the car, this charger will prevent the battery from discharging.

JackOlsen

As I understand it (and my electrical knowledge is very low), a battery's CCA rating is at 0°F/-18°C. So this technology, which is best above freezing, might end up with misleadingly low CCA ratings. I know of guys running these in their race cars with the 300CCA and 360CCA versions.

This graph is for 3V cells, but you can see the effects on Ah ratings as the temperature drops.

zadar

Yea, it will hold charge for year or so with no load, key word no load. Reason we disconnect them when bikes are not in use for long time, and most race bikes sit for month or two.
You don't want it to fall under 13V.
I did sell few to the car guys and so far they hold fine.

LuigiVampa

Ahhhh, just replaced my Braille battery a month ago! Good info for the next time around.

Battery technology has been getting better and better. I have one of those jumper batteries that can crank my truck if the battery dies. It is the size of a remote control for the TV!

BlueBarchetta

I have the large Shorei in my race car. It goes 1-2 months without needing a charge. I have also been able to start the car in below freezing weather.

However I got too used to the battery being relaible and invisible. unfortunately I left it unattended for 3 months this past winter. I put it on the Shorei charger (which is really a conditioner/charger), and it showed almost dead. Luckily the charger revived it and so far all is well. My understanding is that if these batteries get too discharged, there is no bringing them back.

Overall, I'm very satisfied, especially considering the weight loss in the car.

Ritter v4.0

I got a new car in Nov and the battery, which has always been an issue in other cars at one point or another, wasn't. We run elec steering pump, Coolshirt, blower etc.

I just looked at it- FWIW it's a Shorai and it's brilliant.

breljohn

I like the price/benefits ratio
Thanks Jack for sharing

wanna911

I was set on getting a Shorai, but this is an option as well now.

XPC5

I've had a shorai fail, but it was over charging. Lots of start cycles, lots of fans running, and little cool down. The case swelled, and it lost cranking power. They are cheap, carry a spare!

smarlow2

Was very interested in this battery until I talked with a Battery Tender rep today when I was getting ready to order one. He said these batteries are not suitable for use in automobiles because the max charging rate is 10 amps, which is obviously much lower than a standard alternator puts out. Here's their product description:

Product Summary

This unique Deltran Battery Tender® 12V Lithium Engine Start Battery is up to 80% lighter than comparably powered lead-acid batteries, making transport a breeze. The 26–35Ah long-life battery delivers 480 CCA and is ideal for use with motorcycles, ATVs, personal watercraft, lawn mowers and generators. Not for use in automobiles. CE and UN 38.3 approved.

Features + Benefits
Top of page

Super lightweight design for exceptional portability
Quad terminal configuration makes it very easy to install, allowing it to be mounted in any direction
Delivers 2000+ deep cycles at 80% depth of discharge
Lithium battery won't accumulate damaging lead sulfate on the plates like a standard lead-acid battery
Delivers up to 5X the life of a comparable lead-acid battery
Designed to operate in 32° to 140°F temperatures
Max. charge rate of 10 Amps
6.49in.L x 3.38in.W x 5.11in.H
Includes heat-resistant foam blocks for custom fitting the battery into an OEM battery box

Anybody have any thoughts on this? I'd love to run this battery in my NASA ST3 class BMW.