Best lightweight battery still useful for DD'ing?

[86TOYO2k17]

Originally Posted by Irace86.2.0

I agree. I have an 11lb Braille battery, and I only drive 3.5 miles to work or the gym. I have a battery tender that is absolutely necessary. If the car sits for 5-7 days then it may not have enough juice to start. Leave the lights on for a few minutes, and the same thing.

I have a smaller/lighter Shorai battery for the motorcycle. I have let that sit for over 6 months with no tender, and it starts up every time. I would suggest an lithium ion or lithium iron battery over an AGM battery.

Yup my shorai has been amazing so far. Over double the CCA and about double the AH and still lighter then the braille 6. But a bit more $$.

[Irace86.2.0]

Originally Posted by 86TOYO2k17

Yup my shorai has been amazing so far. Over double the CCA and about double the AH and still lighter then the braille 6. But a bit more $$.

Honestly, I went with Braille for the price, and I really didn't think they were different until after the fact, and I read up on AGM. In all, I paid more for the battery and tender than if I had just bought the lighter Shorai. Oh well.

[DarkSunrise]

Originally Posted by B T

honestly I haven't ever gotten around to it. Kind of worried it will affect my OEM Audio stereo system and startup with supercharger. I would go with one of the 12-15 lb Braille pieces or odyssey when I go through with it.

Yeah I thought about the 11 lbs. Braille, but ultimately decided against it. Specs on the Braille:

Weight: 11.5 lbs
CCA: 360
CA: 486
Amp hrs: 15
RC: 25 min
Cost: $260 ($170 battery + $90 FT86SF kit)

Vs. typical specs for a light 151R battery:

Weight: 19-21 lbs
CCA: 340
CA: 410
Amp hrs: 40
RC: 55 min
Cost: $140 ($110 battery + $30 parts from jp-parts)

The Braille has the advantage in cranking amps and weight, but the 151R has more than double the reserve capacity. Since my car typically sits a few days between uses and I'm on e85, capacity was more important to me than cranking amps.

Anyway I went ahead and ordered the parts from jp-parts. I'll update this thread if the battery tray is the wrong size for a 151R battery.

[DarkSunrise]

Originally Posted by nikitopo

I am using a Yuasa 44B19L battery:

It is almost half the weight of the OEM battery and still useful in a daily driven car. It fits perfectly in the BRZ RA's battery holder (Japan spec). So, no need for custom solutions.

I replaced the following Subaru parts. Part numbers are for the new ones:

Tray-Battery
82122CA010 x 1

Rod-Battery Fix
82161AG001 x 1

Holder-Battery Fix
82182AG010 x 1


Dimensions of the battery:
Length (mm) 187
Width (mm) 127
Height (mm) 225

Any other battery with similar dimensions will work.

Ok so I used this method to install a group 151R battery similar to the Yuasa battery shown above. Some thoughts:

1) This battery tray is actually sized for a group 51R battery, not 151R. These battery groups are dimensionally similar in width and height, but not length:

151R battery dimensions (L x W x H): 7.4" x 4.9" x 8.9"
51R battery dimensions (L x W x H): 9.4" x 5.1" x 8.8"

So the battery tray is actually 2" too long for a 151R battery. That's not a huge issue, but I would recommend really securing down the battery tie-down to ensure the battery won't slide lengthwise in the tray, especially if you do track days, autocross, etc. Otherwise the tray is fine and has the proper detentes at the bottom for mounting to the car.

2) The battery tie-down is 1/4" too wide for the 151R battery, at least with the battery I used. Again, not a huge deal. I fashioned a filler using some lightweight wood I had laying around and it filled the gap just fine. Everything is snug and secure, but it took a few minutes to measure, cut and glue the wood. In the attached pic, it's the black piece (used black duct tape to wrap it) under the top part of the tie-down. You could probably get away without doing this step, but given that I use the car for track days, I wanted to eliminate all play in the tie-down.

3) I ordered a 19 lbs. Magna Power group 151R battery, but instead received a 22.4 lbs. Duracell Ultra 151R battery. My 8 yo stock battery weighed in at 28.0 lbs, so total weight savings was 5.6 lbs. Specs on the battery I received:

CCA: 340
RC: 55 min

When cranking the car for the first time, it was very easy to tell the increased cranking power over my old battery. My car had been sitting a while and is on e85 so it took 3 cranks, but each crank was nice and strong. It seems a 151R battery is plenty strong for this application, even in 50F weather.

Overall I'm pretty satisfied with this battery mod for now. It was about the same cost as an OEM battery, but with some weight savings. Later on when I stop using the car for daily driving, I'll probably switch out to the FT86SF 11.5 lbs. Braillle for more weight savings.

[solidONE]

Originally Posted by 86TOYO2k17

Yup my shorai has been amazing so far. Over double the CCA and about double the AH and still lighter then the braille 6. But a bit more $$.

I had a Shorai in my bike that I abused.. discharged several times leaving my headlight on by accident on my motorcycle. This Shorai battery took this abuse for 6 years before giving up the ghost. Surprisingly sturdy, lasted much longer than expected.

[86TOYO2k17]

Originally Posted by solidONE

I had a Shorai in my bike that I abused.. discharged several times leaving my headlight on by accident on my motorcycle. This Shorai battery took this abuse for 6 years before giving up the ghost. Surprisingly sturdy, lasted much longer than expected.

It’s hard to beat that battery for performance and weight reduction.

[solidONE]

Originally Posted by 86TOYO2k17

It’s hard to beat that battery for performance and weight reduction.

Imagine if I had maintained it properly, keeping it charged and cells balanced. 8-10 years might have gotten out of it.