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Discussion Starter #1
Anyone put a larger battery in the '10+ Outback? Was camping this weekend and drained it with the hatch open and charging phones. I'm going to all LED-interior lights but also thinking of increasing battery size/A-H capacity.

Ours is a Group 25 which is standard 9 1/16" L x 6 7/8" W x 8 7/8" tall.

I don't think you could go any taller, and the stock tray doesn't look like it would accept much wider, but it appears you could go a bit longer, up to maybe 11" long (don't go there).

Looking at a group size chart, Group 24 is 1/16" narrower, the same height, but 10 1/4" long: don't know about terminal orientation.

Just wondering if anyone has already done a battery upgrade or experimented with it.

Matt
 

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LED Info

As well as replacement battery info, I would appreciate the info about how to replace the current interior bulbs wirh LED bulbs - what make/model are they and where did you find them ??
 

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Discussion Starter #3
As well as replacement battery info, I would appreciate the info about how to replace the current interior bulbs wirh LED bulbs - what make/model are they and where did you find them ??
Well, I just ordered from SuperBright LED's but haven't put them in yet so don't have any feedback on fit/performance. Most of the info I gleaned from this thread...

http://www.subaruoutback.org/forums/104-gen-4-2010-present/41120-interior-led-lights.html

...including ordering the WLEDB-CWHP6-DAC for the cargo light instead of the cross-referenced 912/921 since someone had confirmed that worked. Actually, I think I ordered a 921-X12 as well which will probably end up as a spare if that previous one works as expected.
 

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Discussion Starter #4
Looking at the sizes again, Group 63 is is the same height (8 7/8"), 1/2" narrower (6 3/8"), but 10 3/16" long.

If you could go 1/8" taller (maybe without the plastic insulated box the battery looks to sit in), there's a Group 24F and 24R that are both 9" H, and 6 13/16" wide, but 10 1/4" long for the 24R and 10 3/4" for the 24F. I think the R's usually have terminals in reversed positions if we would need that. There's also a Group 46 that's the same dimensions as the 24F.

It would be super-sweet if a Group 24 would fit as there are tons of options of high quality dual-purpose starting/deep cycle or even true deep-cycle Group 24's.
 

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Discussion Starter #5
One more little tidbit... the height limitation is the height of the plastic case, not the terminals. The front corner of the battery tucks under a metal brace with not much room to spare. A longer battery will need to tuck in there farther. If I have some time this weekend I'll pull the stock battery and make some measurements to see what would fit.

For reference, Interstate has a Group 25 with an RC of 100. They have Group 24 auto batteries with RC's of 110 and 125 and a marine Group 24 with an RC of 140 (with the same CCA rating as their auto Group 25). So maybe 40% increase in storage to be had with much better tolerance to deep discharges IF it would fit.
 

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The good news. This is a fairly comprehensive list of battery physical sizes:

BCI Battery Group Size Chart

The bad news. The physical size isn't as important as the reserve capacity of the battery. This is affected by the materials and physical configuration of the plates more than anything else. Reserve capacity is the time the battery can support a 25 amp current @80F. This isn't always an easy statistic to obtain.

Most starting batteries are rated for cold cranking amps. CCA is a measure of burst capacity for starting, and has little relationship to how well the battery supports constant low level loads. The other measurement of battery capacity is Amp-hours. AH is misleading because it can be measured at any load, allowing the battery maker to choose the discharge time that makes the battery look best.

Manufacuters list some of these statistics on their websites.
 

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Discussion Starter #8
Thanks mxfrank.

I had used that Group Chart, imported into Excel, and sorted by height to determine what sizes near our Group 25 might fit.

The main thing I'd disagree with is that, within a battery chemistry/architecture, total cell volume is almost directly related to A-h capacity. Different plate configurations help with vibration resistance, dictate sustained discharge vs peak current characteristics, etc. But to get significantly more A-h at a given current draw, you pretty much have to go with a larger battery. That's the main reason the Optima style, spiral cell batteries don't have very much A-h capacity: fitting 6 cylindrical cells into a rectangular box of a given group size means they have less cell volume than a traditional battery of the same dimensions. They do have excellent surge capacity and vibration resistance, though.

The other significant item about being able to fit a larger battery, especially a Group 24 if it's possible, is there are so many more choices than in Group 25. Automotive batteries designed for higher peak output (CCA) do not handle deep discharges (say lower then 50% depth of discharge) very well at all, sometimes failing after only a handful of cycles. I'd much prefer to go with a more robust deep-cycle style battery, hopefully with more A-h capacity as well, as long as it doesn't sacrifice too much peak output/CCA to get the job done for cold starts.

Now I'm feeling obligated to get around to this this weekend ;)
 

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Discussion Starter #9
...and we're back.

For reference, here's our OEM Subie battery in its cute little jacket...



And here is the label in case yours is obscured by the hold-down or grime...



The OEM battery is approx 9" long x 6 7/8" wide x 8 7/8 inches tall to the top of the posts. The case is ~8" tall, meaning the posts are about 7/8" tall. That's pretty much right on the Group 25 standard referenced above as 9 1/16" L x 6 7/8" W x 8 7/8" H.

The battery sits in a flimsy plastic tray which just lifts out...



... which measures ~10 3/4" long x 6 7/8" wide. It has two locating nipples on the bottom and 1 drain hole but certainly provides no support. I'd be comfortable cutting the sides or ends or both or removing the tray altogether.

I think we could squeeze an extra 1/2" in length (MAYBE 3/4") beyond the length of the tray, between the windshield washer fluid neck in front and some plastic trim in back, so let's call that 11 1/4" max length.

Width I'm not so sure of without something to test fit, as I think width and length may be interdependent when it comes to clearance at the corner of a 3D box. Another 1/8" should be fine so let's go with an even 7" wide max.

Height is where we are limited by the metal structure at the front. From the bottom of the plastic tray to the structure you've got 8 1/4". Remove the tray, maybe bend some metal a tiny bit could probably get 8 1/2". Remeber, this is case height. If automotive studs are a standard length (7/8" as our OEM ones are) that would be 9 1/8". With some shoehorning, maybe 9 3/8" but we'll go 9 1/8" for now.

That give us 11 1/4" L x 7" W x 9 1/8" H.

So I think all of the groups I mentioned initially would physically fit. I thought my trolling motor battery was a G24 and I was going to test fit it but it's a G27 so I didn't even try.

One other crucial point, the + battery cable doesn't have much slack, so I think we need to OEM post placement unless you're going to mod the cables. That means the posts need to be on the inboard side (close to the engine) when the + post is positioned to the rear and - post to the front. My deep cycle G27 has that configuration so I'm assuming standard G24's would as well.

Please check my numbers above in relation to group sizes but I think we have some options as far as what will fit. I don't think we'll know for sure until someone tries it, though.

One other thing I noticed is that although there are standards for "Group 24" that are ~9" tall, most of the specs I see listed (Interstate for instance), list them as 9 1/2" tall which probably means the case is too tall to fit.
 

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txmatt thanks for the measurements, sooner or later somebody will have to be trying something....
FWIW, I put an Odyssey PC1500DT group 34/78 battery in my Outback. Had to ditch the sleeve but it does fit in the tray. Stock cables reach the terminals ok.

PC 1500 DT Odyssey batteries
 

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Discussion Starter #12
No problem. I had been reading around and it seems like some of the Jeep and FJ Cruiser crowd uses Group 34's in their vehicles and seem to like the Die Hard Platinum...

Sears: Online department store featuring appliances, tools, fitness equipment and more

Looking at the dimensions of that group 34 it looks like it would fit, and from some pictures I've seen, the terminals appear to be in the right spots, too. It's an AGM battery which are generally high quality and the FJ folks seem to be pleased with it under some severe usage (vibration, winching, etc). I think it also topped a Consumer Reports battery test in one group a year or two ago.

That's most likely what I'll go with, I just haven't decided yet if I'm willing to spend $200 to replace a battery that should have a few years of life left in it for a better battery that I may never need it's extra capacity and durability. FWIW, Interstate lists their Group 25 replacement for the OB with an RC of 100 and Sears lists the RC of that Group 34 Platinum as 135, so a 1/3 increase in capacity if he specs are to be believed. Plus it is 880 CCA compared to our stock battery which has 490 CCA.
 

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Discussion Starter #13
FWIW, I put an Odyssey PC1500DT group 34/78 battery in my Outback. Had to ditch the sleeve but it does fit in the tray. Stock cables reach the terminals ok.

PC 1500 DT Odyssey batteries
Great news! Thanks for the input. I must have been typing when you replied. Interesting that the Odyssey and Die Hard Platinum have the same CCA and RC specs and are both AGM. Now that I think about it, I seem to remember people saying the Die Hard Platinums were made by Odyssey.

One of those two is definitely what I'll get.
 

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I installed a group 34 Die Hard Platinum, no problems. The DHP is pretty much the same as an Odyssey spec 2 spec, at a little less $. Just as good. If you look at the 2 next to eachother, they're identical, copy the color.

It's shorter than stock, but that's ok.

I have it installed in my thread.
 

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If you want a really good battery that will last for years, get an optima! I had one in my previous car running a large aftermarket stereo. The battery lasted 9 years, could be still kicking since I left it in the car when I sold it. The Optima 25 should fit in the outback just fine. It's got 720 CCA, and they can be drained fairly low and still start your car just fine. I left the dome light on in my previous car for three days on a trip and the car started up, mind you not the best start i've ever seen, but it started. When the oem battery in my outback dies, I'll be purchasing a new one in a heartbeat!
 

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Discussion Starter #18
I'm personally looking to maximize amp-hour capacity. The Optima 25 has 90 minutes of Reserve Capacity compared to the Die Hard Platinum 34 / Odyssey PC1500 Reserve Capacity of 135 minutes. That's a significant 50% more capacity from the Die Hard Platinum G34.
 

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I'm personally looking to maximize amp-hour capacity. The Optima 25 has 90 minutes of Reserve Capacity compared to the Die Hard Platinum 34 / Odyssey PC1500 Reserve Capacity of 135 minutes. That's a significant 50% more capacity from the Die Hard Platinum G34.
? Are you saying Optimas are better than Odyssey / Die Hard Platinum?

Optima batteries are not what they used to be, and even then they were overpriced, and notthat great. We would Always have issues with them. IMHO
 

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Discussion Starter #20
? Are you saying Optimas are better than Odyssey / Die Hard Platinum?
No. Comparing the Odyssey mentioned and the Platinum, the Platinum has 50% more capacity, more CCA, likely comparable vibration existence, etc.
 
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