As mentioned I have the Shorai LFX36L3-BS12. Think its that model or perhaps the one with the polarity flipped. But in terms of the specs they are the same.

I hated the thought of a mini battery being that my car sees 4 seasons and leaving work at 6 with the car sitting in the parking lot after snowing all day or a frigid day it was a concern for obvious reasons. I wanna say it was Evodan who mentioned the Shorai and when my stock battery finally died, which lasted forever btw, I decided to pull the trigger on the Shorai. 5# no need to re route the battery to the trunk and given I was after weight savings that seemed like the best option IMO.

I hacked up the stock battery tray and bought a baller ebay tie down for extra bling factor and have loved the battery ever since.

Im thinking back now but I wanna say I installed in Jan of 2013 and here I am now with the same battery. I've had no issues starting my car in literally 0 degree weather after the car sat outside all day so the oil was nice and thick too. we shall see how long it lasts but given I needed a new battery I was quite happy with the 33# weight savings without having the aggravation of a poor performing mini battery.

One thing I will add is that if the car sits for an extended period of time a trickle charger would be recommended. Last year I had surgery and my car sat for a few weeks and when i went to finally start it, it was a no go. I jumped it drove to work 10 minutes away and when I went to leave that night it started up fine. So I don't really know what happened there but other than that no complaints whatsoever.

 

5 lbs.. insane. I'm looking at this one, IDK if it is the polarity flipped version or not but does it really matter if you're gonna mount it whichever way anyway?

 

I'll let you know tonight which one I bought. Technically it doesnt matter but the ground wire is very short so if you have to flip it it may end end up being a lil short and/or the battery tie down will end up on the wrong side.

Disregard my stupid grounding kit I made year ago (young and dumb) but you can see the way I have mine oriented with the tie down to the left of the terminals. If you look on the shock tower and look down directly to the right of where the + battery terminal cap is there is a bolt right there where the ground wire gets bolted to. Its not where the wire terminates but its another attachment point to ground out the wire. If you look in some mini battery installation guides people just unbolt that and let it hang to give it some extra slack. I didnt like that so I opted to decrimp the lug, flip it around recrimp it and bolt it back down. That gave me just the right amount of slack I needed to get the battery to work and also keep it grounded in multiple points. Was it necessarily mostly likely not but I felt it was the right thing to do and was worth the aggravation decrimping it.

 

Sent Shorai an e-mail and got some pretty good feedback here -

firstly, they are working on a higher capacity, higher amperage battery for cars & trucks to be released in 2017.

next, they are aware of the reported success in cars like the nsx, rx7, and miatas (props to them for that) in using the LFX36L3 (- +) & the LFX36A3 (+ -).

however, they don't recommend this battery at the time, because of two main concerns:

1) low capacity - similar to any small battery obviously, the added drain from a car's accessories

2) high starter current amperage - this one they are more concerned with (lots of highlighting) - the starter/ignition should ideally be designed around an amperage draw which is 25% of the CCA & never more than 50% CCA. So I guess, they are worried about overcurrent/voltage from the alternators.

That said, I have no idea what our alternator specs are. They want 13.3V at idle, 13.6-14.4 @ 2000rpm. nothing more than 15.2, and anything over 14.8 can lessen lifespan. Battery shouldn't fall below 12.86V (very specific).

They've also had some customers use two in parallel, but they usually end up imbalanced & damaged from overcharge/overcurrent. They also attached a user guide in case I decide to go with the battery anyway.

That said, given Eric's success with it, I think they can safely add the Evo to the list of cars it's worked with. 5 pounds for a battery at $250 is hard to pass up.

 

It will be interesting to see what they come out with specific to cars. I knew it was a risk when I pulled the trigger years ago being that it was a glorified motorsports battery. But given the fact that thousands of people use the PC680 or the Deka equivalent both of which are more than 1/2 the CCA and over double the weight it seemed like it was all positive and the better route to take. What's the average life expectancy of a car battery anyway? 5-7 years maybe? My stock battery lasted around 7 years I want to say which I think is excellent if I might add, but if I can get at least 4 years out of the battery, which knock on wood Im close already then I'd say its proven. Small sample size sure but its worked for me and I'd not hesitate to put another one in my car.

I'd have to look back to get exact figures on timeframe and miles I've driven with this battery but I drive my evo almost everyday. The other thing is its not liek the battery doesnt have any power where it cranks really slowly. The car fires up as if it had a normal battery on it. When it was 0 degrees out the car cranked slower sure, but at the same time a lead acid battery would probably crank a lil slower anyway.

While me dd'ing the car has proven that it can work well in various weather conditions multiple starts and stops in short trips, I will admit that it may not be the best test candidate for someone who plans to have the car sit for weeks at a time.

Ill give you the specific model tonight when I have a moment granted if you look at my pic and compare on their website youll be able to figure it out. But I'll do you a solid and take a look and if I have extra free time, Ill even bust out the DMM and give you some readings @ idle and 2000rpm.

 

Our alternator meets those specs.

 

sweet, sounds good. honestly I think a daily-driven car has a lot of things going for it, and battery health is definitely one of them, though some of that can be mitigated via a trickle charger. does make me curious on the evo's alternator specs though, as well as how that whole system interacts when we're going 7500rpm.

not to derail the stu thread too much, though, this is a great battery choice for STU.

 

Assuming the voltage regulator in the alt in working properly it shouldnt spike too high at high RPM's. My limiter is set to 8300 and I've revved to over 8 grand probably thousands of times now and no smoke out the battery yet. With a trickle charger you should be fine. OK no more talk about my battery bc Im getting paranoid that its going to strand me tonight after work as Im over here praising it.

 

After running mini batteries for years, I'm tired of dealing with dead batteries or worrying about it. Just mounting a battery in the rear seems like the right thing to do. Big deep cycle and never worry about it again.

 

Man you guys are on a different level to justify the work and headaches of saving 20-30lbs. I've had two events this year where STU was determined by .0xx, one in my favor one against. Would a battery change the outcome by saving 20-30lbs.....I don't care enough to go through with it.

 

Seem to me that you are seeing a side of the "serious business" approach...today you are asking about hundreds of a second, but tomorrow subject could be thousands. Would that be worth enough to justify 20 - 30 lb of weight savings?

 

After going through two 13 lbs dry cell batteries that lasted 1 year each and a 3 lbs lipo battery that exploded in my trunk at an AutoX… I just got a nice big 25lbs battery and don’t worry about this anymore.

I had small batteries before in other cars without any problems, (I took care of these batteries, used a special lipo charger etc) but my Evo X kills them…

 

I'm not a srs bzns guy - I would not care if my battery were in the trunk. but mounted up as high as possible in front of the axle, that's a solid mass that's up there. the shorai is a solid 5 lbs. that's a solid 30 lbs of weight savings, lopped off. For me, only driving the car like once a month & car sits on a trickle anyway, even with my deep discharge yellowtop... why not

that's gotta be the alternator?

 

You would think…I tested the alternator a few times, I even have a battery voltage meter display… after getting a bigger/ more powerful battery I had 0 problems, and since the Evo X has the battery in the trunk, I figure I could use some weight back there

 

no I agree - if relocating the battery to the trunk were the easy button, I would do it. otherwise, can't hurt to cut 30lbs from the top upper left of the car.

I meant the alternator as far as it overcharging the battery/being too strong. That was one of the cited concerns from Shorai (posted above) as far as running a small battery. The 8/9 alternator, per LGTD, falls under appropriate spec for even a small battery - perhaps it is weaker/slower charging.