Lightweight Batteries

[longislandwrx]

The group 35 battery that Subaru runs weighs about 38lbs. Personally I plan on running a lightweight battery, lb for dollar it seems like its a smart way to save weight especially since most of the donors I've seen will be requiring a new battery anyway.

In the past I have used a Braille b2015 at just about 15 lbs. for about $175, you are instantly saving 23 lbs. I've had no problem starting the car above 50 degrees and I imagine it would work well in colder areas with a battery warmer/tender. Since this is a summer car, I'm not too concerned.

braille.png

it will also give you the option of mounting the battery back in the engine compartment and shorten up the heavier power cables.


The Odyssey PC 680 is very similar to the Braille, is a little cheaper @$120... I have not used it though

odyssey.png

I've also heard of people running the PC545 on BRZs/FRS but no reason you couldn't run it on a WRX

That one weighs 11.7lbs

Braille also has a new lithium version at 6lbs but for $1500 that's ridiculous.

The Shorai LI batteries are up and coming too but again, I have no experience with them.



here are some helpful lightweight battery threads:

http://www.iwsti.com/forums/2-5-lite...a-battery.html

http://www.ft86club.com/forums/showthread.php?p=802933

http://www.iwsti.com/forums/gd-membe...america-3.html

http://www.ft86club.com/forums/showthread.php?t=32544



Anyone else want to post their lightweight battery of choice?

[kabacj]

I use Braille B3121 to start the LS3 race motor in my GTM. Works just fine. Im not goingto crank the thing for 10 min without killing it, but the small size and weight savings are worth it.

John

[StatGSR]

the braille is just a flashy Deka Powersports battery. I ended up getting a rebadged deka at the local Batteries Plus labeled as an "X2 Power" battery. http://www.batteriesplus.com/t-motor...batteries.aspx

All you need to buy in addition to that is the automotive terminals. and you can save about $100 bux. I use this in my track/summer only Integra. I think i got the 14 or the 16, but I will check the size i bought when i get home.

[Mechie3]

I've used the PC680 year round in NY in my WRX. Even in freezing temps it started it, though it was a little slow.

[CHOTIS BILL]

Here is one that is only 3.4 pounds. A little pricey though.

http://www.aircraftspruce.com/catalo...se4battery.php

Bill Lomenick

[JeromeS13]

+1 for Deka.

[BipDBo]

If you opt for a really light battery, would you still want to place it up front as they did on the prototypes? With less weight, there's less of an impact on the distribution, and you may save a little bit of extra weight and $ by not running a big red wire to the front of the car.
Do FFR kits typically use the chassis to ground or is the negative fully wired?

[longislandwrx]

Yes, one of the links I posted gives the equivalent deka batteries.

[mattster03]

I have gone thru 2 and just about my 3rd PC680 on my LS-powered RX-7. Not impressed with the battery to say the least.

[longislandwrx]

If you opt for a really light battery, would you still want to place it up front as they did on the prototypes? With less weight, there's less of an impact on the distribution, and you may save a little bit of extra weight and $ by not running a big red wire to the front of the car.
Do FFR kits typically use the chassis to ground or is the negative fully wired?

true, but it also depends on where you put your fuses etc. I think shortening it is a good idea, but I wont know for sure until I strip and lay out the harness.

[flytosail]

Also this could free up some room for a small storage compartment.

[Zodiac]

had my braile battery in my evo 8 for about 5 years now and never had a problem

[bnr32jason]

Assuming we aren't running a stereo system, one of these batteries should be just fine for the 818 right?

I'd rather have the battery in the back with the engine so I can have a storage compartment in the frunk.

[SStrong]

Battery should ground to frame and engine on any application. Then add grounds from your wiring harness to the frame near where you have powered components (lights, radio, etc.). This will save you lots of problems in the future. You can overload a ground wire if you connect too many components to it.

[Rasmus]

It's back from the dead!

I've used and had success with Odyssey brand batteries. Specifically the:

PC545 - Pulse Cranking Amps 460 - 12Ah - 5.2 kg - $99 &


PC625 - Pulse Cranking Amps 530 - 17Ah - 6.0 kg - $110

The PC545 can have issues starting the EJ motor on colder days. And by cold, I mean Vegas cold, so ~40 Fahrenheit. The PC625 doesn't seem to have the same issue. With the longer distance to the starter on the 818 vs WRX I imagine the PC545 would struggle even more, even if you installed the battery in the passenger foot well. The PC625 I run on my daily driver. No issues in Vegas. Starts the WRX right up, everytime, going on three years now. That stated, the PC625 (and PC545) will not start the car if I leave an interior light on overnight.

There's also the LiFePO4 battery from EarthX


Model ETX36E comes with a built in battery management system. 680 Pulse Cranking Amps. 36 (Equilivant)Ah (I don't really trust that 36 rating). Weighs 1.8 kg. But costs $350. I don't have any experience with this battery.

[Boog]

Has anyone tried the StarkPower 'Ultra Start' line? 12V-36AH-US5 Advertises 36Ah and 1k CCA at ~2kg.

[DMC7492]

Hi guys my last project was a rotor way helicopter, we ran a odyssey PC 680 and they worked, but the longevity was only 1 Season!! Then some of the other builders from colder climates like Canada started using the Deka EXT 16 AGM battery with great results and lasted many seasons, I went with the EXT 18! 15.5 lbs!
This battery in the helicopter with higher compression spinning the complete rotor system before firing up was awesome compared to the PC 680.
I have no doubt this battery in our Suby motors with even 9.0:1 compression will fire it up most excellently!
Here is a link,

http://www.etx18l.com/

[Santiago]

the braille is just a flashy Deka Powersports battery. I ended up getting a rebadged deka at the local Batteries Plus labeled as an "X2 Power" battery. http://www.batteriesplus.com/t-motor...batteries.aspx

Hell man even Duracell doesn't make their own batteries?!? I feel so naive... I'm sticking to Deka from now on... =)

[Rasmus]

Braille even goes so far as to wrap Deka (Penn East) batteries in carbon fiber. They'll then claim it's a lightweight battery, that they just added weight to by wrapping it in an unnecessary layer of carbon fiber.

[Rasmus]

The Deka ETX15 or ETX15L looks awfully good.

??? Pulse Cranking Amps -14Ah - 5.0kg - $73

[billjr212]

That Deka ETX18L battery also appears to be rebranded as BigCrank.com on Amazon. (unfortunate naming, same specs)

http://smile.amazon.com/Big-Crank-ET...dp/B002ZEYTR4/

[Frank818]

I can't figure out what the "L" stand for.

So the 15, 16 or 18 would work? L or non L?

[billjr212]

the L or no L has to do with which side has the + and -.

makes a big difference for people trying to match up existing terminals, shouldn't make any difference to us.

[Gary Livingston]

I would suggest that if you want a light battery to build one from lithium cells. I would use a high C rate LiFePo4 like A123 for safety reasons and balancing issues. I used model 32113 in a 4 series 3 parallel configuration. I bottom balanced them. It has worked well in my electric truck. I was using a lead acid AGM lawn tractor battery. Granted I don't need cranking power, but you could build a stout battery at a fraction of the weight. These cells are available from China. Get them with screw studs. I think mine weighed around 7 lbs complete. Does anyone know the cranking amps required? You may need a 4S4P configuration. There are some already packaged lithium based 12 volt batteries available also. You can save a fair bit making your own if you know how. At 3.2 volts nominal, you will need a 4 series configuration to get the voltage . . . then parallel to get the required amperage.

[JeromeS13]

Uggghhh... Just as I was sitting back thinking to myself as I was reading this thread lately, "Man. I've had great luck with my Deka ETX-14." I came home today (after not driving my car for a week or so) to a COMPLETELY shot battery. The voltage is practically zero (0.3 volts to be exact). Ughhh.. Now I need a new one...

[Rasmus]

"Man. I've had great luck with my Deka ETX-14." I came home today (after not driving my car for a week or so) to a COMPLETELY shot battery. The voltage is practically zero (0.3 volts to be exact). Ughhh.. Now I need a new one...

How many years did you get out of it?

[JeromeS13]

How many years did you get out of it?

It's been in the car since late November of last year... So, not even a year. Granted, the car sits in the garage a lot and doesn't get started every week.... Maybe I just need to get a battery tender.

This is the 3rd one that I've had, though. I got about 2 years out of the one in my old STi. I replaced it with another just a few months before I sold the car.

[longislandwrx]

The battery tender plus has been a great friend of mine. I used to have problems with DEAD batteries in my 68 Firebird that doesn't get driven as much as it should. I got the one with the quick connect terminals and it starts every time now and I haven't had to replace the battery yet.

http://www.amazon.com/Battery-Tender...ry+Tender+Plus


also

Braille did weigh in on this once and never denied that the batteries are the same, they are pushing the fact that they rate them higher and guaranty them for that higher rating.

http://www.evolutionm.net/forums/evo...ml#post3574425

I do agree with them for $50 you get someone in the US you can call on a telephone.

[tirod]

O'reilly sells the etx line in their motorcycle batteries. About as pricey as regular car batteries, which doesn't help the average local biker who thinks $40 is high.

Yes, a battery tender is needed for ANY vehicle which sits for long periods. Exactly what the guys at the boat dock do - nobody wants to show up on Friday night for a fun weekend on the lake and discover a dead battery, right? I've even had the U1L's from riding lawn mowers reported lasting as long as five years if kept on a battery maintainer. They cost less than a new battery and generally pay for themselves in a year's time - you don't buy another battery because it has .3 VDC after 6 months. Which every one made is prone to do.

Keep the "tank" filled up and the battery lasts at least twice as long. Deep cycle discharge it and you cause it to fail twice as fast. It's your money.

As for a lightweight, the Miata uses a smaller battery and it's commonly available with an automotive warranty. Finding an AGM version is a bit tough, they usually have to be ordered in.

[Frank818]

The battery tender plus has been a great friend of mine.

I plug my red Optima on my AGM/Gell Delran battery tender all the time. Every time I come back in the garage, I plug it. I was using a non-gell tender before and it shot the optima, I was able to get a new one under warranty and since then, 2009, I use a gell tender and the battery is still strong according to the snap-on battery/starter load tester I used.

[JeromeS13]

Here's what I ended up going with. It's a Duracell (I'm pretty sure it's the exact same battery as the Deka). It's available at your local Batteries Plus and carries a two year warranty.

http://www.batteriesplus.com/product...M--14--US.aspx

Edit: They tested my new one at the store. At room temperature, it was putting out 425 cranking amps.

[Gary Livingston]

I don't seem to have a pic of the battery finished in it's box, but here are the cells connected into a 12 volt battery, connected to my Powerlab8. The two tabs connected +/- are what stick out of the little box once complete. I made the interconnects out of soft copper tubing hammered flat and drilled. Each one of those little cells will put out about 270 amps, so this light weigh 3P battery would put out about 800 amps. 4P would do over 1000 amps.

It seems rather "interesting" to be discussing lead acid batteries in a thread for "lightweight" batteries. If your handheld phone used lead acid, it would weigh more than you'd like, be much larger larger than you would consider practical and last until first coffee break..... if you were lucky. lol
edit. . . oh I almost forgot, lead acid has a cycle life in the 200 to 500 range. With good LifePo4, you could add a zero to those numbers.

Regards,
Gary

[Frank818]

If you are selling a good cranking battery fully built for our 818s, since you are in Canada and in ONT, I might get one from you.

[Gary Livingston]

I'm not selling Frank. . . I have too much to do now. lol But you can make your own. . . I can give you a few pointers if you like.

[Frank818]

Sure I'll take them and see what's best for me from there.

[Rasmus]

Gary, I'd love to be able to construct a LiFePO4 battery for my 818 from scratch. But I don't know what I'm doing. You seem very knowledgeable in this subject. So much so, that in your first post in this thread I knew you were communicating in English about batteries, but that it. You seem far more knowledgeable than I am with this topic.

Could you type up or provide us a link to build plans for a battery that would start an 818?

[tirod]

I found this and fell into the deep end of the pool. http://americansolarchallenge.org/AS...cell_count.pdf

Seems sourcing enough batteries is a monetary issue. How to hook them up seems far more important. Getting them to discharge in a balanced manner has a lot to do with it.

As for actual plate construction, etc. be advised you are working with a reactive material and there are hazards with it. Consider placement of the power source and what it will do if it goes into a "chain reaction" and cooks off while in the car. It will be a pretty big thermal burn, not unlike the batteries that actually are made to do that in munitions.

https://www.google.com/search?q=ltit...s+fire&tbm=vid

Which includes the thinking behind an airplane crash caused by it. Since it's at the beginning stages of development it might be the cautious person's best decision to wait until things are scienced out at the user level. Not unlike the early years of turbos, can you afford to blow it up, or would you rather keep running the car without the drama?

There are sources for the street strip crowd: http://www.dragzine.com/tech-stories...-lithium-pros/

And no doubt the electric drag bikes and cars are pushing the envelope. Overall, tho, it seems to be tech that is a lot further along than, say, 3D printing a firearm.

[Gary Livingston]

Amazing. If you want to put it into some kind of perspective, google number of vehicle fires per year in the USA. It ranges between about 170,000 and 450,000 with over 500 deaths most years and several thousand injuries. Just doesn't make the press list of dirty laundry after a while. . . gets boring. Lithium fires on the contrary, its new, exciting and scarily misunderstood. . . black box nightmares. lol People have no problem carrying around a few hundred pounds of highly explosive and combustible gasoline. lol

Anyways, talking about lithium batteries in a group is kinda like talking about trees. There are many species. Some are much more challenging related to taming them. The Lithium cobalt group I would stay away from. This is why I mentioned LiFePo. This is Lithium Iron Phosphate. It is the safest and you can find many examples on the infamous youtube I would imagine of nails puncturing them and bullets piercing them without incidence.

The main cause of the fires in almost every case is a faulty BMS. (Battery Management System). Some chemistries of Lithium require an active balancing circuit as they tend to get out of balance easily. Others, like Lifepo, doesn't suffer this to any great extent. If you know which chemistry to select, how to prepare your cells and how to charge them. . . there is no problem at all. I wouldn't charge lithium polymer cells of any chemistry in my house unattended.

The listing on the one link supplied lists lifepo as having a nominal voltage of 3.45. This is not correct. The generally accepted nominal voltage for Lifepo is 3.2 volts per cell. A123 specs theirs at 3.3 volts. It's definitely not 3.45. 3.45 or 3.5vpc is a very good and safe upper charge voltage. I'll explain more on this later.

As for some of the terms. . . C rate refers to the charge/discharge capability of a cell. All cells have a rated capacity usually spec'd in Ah (amp hours) or mAh (milli amp hours) for smaller cells. A cell like the A123 (brand) 32113 has a capacity of around 4.5Ah IIRC. It has a continuous output rating of 30C and a burst rating of 60C. So 4.5ah x 60 is 270amps.

When you connect cells in series, you add the voltage. We call this series connections. 4S would be 4x3.2 volts = 12.8 volts nominal. This is a bit different than lead acid as 12 volts is where a 12 volt battery is pretty much empty of capacity. 3.2 for lifepo on the other hand is where the cell spends most of its time at during a modest discharge rate.

If you connect them in parallel, the voltage remains the same, but the capacity is added. 4P would be 4 x 4.5Ah or 18Ah.

So then if you connected a pack of 4S4P you would have a nominal voltage of 12.8 with a capacity of 18Ah. You can try this with primary batteries around the house. (primary batteries are common non-rechargeable cells)

Next I'll talk a bit about the BMS thing. This is (or at least use to be) a very hotly debated topic on some of the RC, battery and electric vehicle sites. There are still die hards that will argue with me and others that every lithium based battery system requires a BMS. Now that they have been around a while, there is plenty of proof related to the safe operation of LiFePo with no BMS. I have a had a large pack in my truck for several years with no imbalance issues. No BMS. No problems. Again, there are all kinds and designs of BMS's. The issue i have is primarily related to top balancing BMS's and particularly those which control the charger. More later.

[RM1SepEx]

Gary, you have a source for these cells at a reasonable cost? @25 per cell we are looking at a $200 18 AH battery without figuring in a box to contain them... I can buy a 20 AH lead acid gel cell for $50 with a 3 year money back warantee and I've pulled 20C out of them quite a few times with a reasonable life expectancy

http://www.ebay.com/itm/271508236100...%3AMEBIDX%3AIT

[Gary Livingston]

Hi Dan.
I have several sources that i have purchased from but if you want to buy an inexpensive battery, I would recommend to stay with lead acid. I thought it was about weight.

The last ones I bought was low volume and I paid $12 each for them.
I actually prefer the 32157 cells, but they don't seem to be available anymore with screw studs. These have about 8ah. I have purchased several hundred of this model.