Subaru's small battery

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Donald

Donald

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The battery in my Forester is small like many others in Subaru vehicles. Its rated for 390 CCA.

I tested it last night with a Solar brand conductive battery tester and it came out as 470 CCA. It was a little above 50F outside where I tested it.

Maybe the battery is rated for more than the label.

The Solar tester has my Jeep battery about 150 CCA below label for a 2-3 yr old battery to I am pretty sure its close.
 
http://www.bobistheoilguy.com/forums/ubb...is?#Post3941668

My battery tester is similar.

The 2011 battery never tested over 390CCA (even in 2011)
and was down to 280CCA at 2 years.

The 2015 battery tested 397CCA and its 1.25 years old.

Apparently some of the newer outbacks came with a 356CCA battery.

The current plan is to trade in the 9 year old pontiac g6 battery in my tractor put an Autocraft gold in the subaru and the subaru battery in the Deere 212 tractor.
Amex blue has a 20$ off 50$ credit that stacks with AAP coupons.
 
I've gotten a rating on brand new batteries about 20% better than label rating from both my HF tester and from a Midtronics.

If battery temp were an issue, the instructions for your tester would mention it. It may have an internal sensor and assume air temp is battery temp, for example. Midtronics has an IR doohickey you're supposed to point at the battery case.
 
My OE battery went 5 yrs in midwest winters, no issues. It was doing fine but I replaced it out of pre-caution because I don't trust pretty much any battery beyond 5 yrs. Installed another Subaru OEM. Does crank slower in cold below 20F (-7 C) or so, but it cranks steady and the engine always fires over quickly so it's not like it has to power long cranking episodes anyhow.

Now that I have said this it will probably strand me. Because that is how my life works.
 
For some reason, most of the manual-equipped Foresters came with this smaller battery. For me, it's started at -20F, but just barely. I have a jump box at home, and I'll replace it with something better the first day it doesn't start.
 
Originally Posted By: eljefino
I've gotten a rating on brand new batteries about 20% better than label rating from both my HF tester and from a Midtronics.

If battery temp were an issue, the instructions for your tester would mention it. It may have an internal sensor and assume air temp is battery temp, for example. Midtronics has an IR doohickey you're supposed to point at the battery case.


I looked into a bit and you have to pay a lot for a Midtronics tester that is temp compensated. The base level Midtronics for under $400 are not. Nor is my Solar. But knowing that if the battery tests good, then I know its good plus a little. Now if it tested bad I might bring it to warm up or bring it to a shop with an expensive Midtronics tester.
 
Originally Posted By: LoneRanger
My OE battery went 5 yrs in midwest winters, no issues. It was doing fine but I replaced it out of pre-caution because I don't trust pretty much any battery beyond 5 yrs. Installed another Subaru OEM. Does crank slower in cold below 20F (-7 C) or so, but it cranks steady and the engine always fires over quickly so it's not like it has to power long cranking episodes anyhow.

Now that I have said this it will probably strand me. Because that is how my life works.



It would be a Texas summer that kills the battery not a midwest winter.
 
Don't feel bad the new Accords have tiny batteries as well. Also starting in 2012 the Toyota Camry has a cheaper battery. Instead of a sealed maintenance free one with a green eye indicator they are now the low maintenance type where you can fill them up with distilled water and no more green eye.
 
manufacturers generally put the smallest battery read cheaper + lighter that works in "most" but not all conditions. my X wifes brand new mustang refused to start in the mornings at her new residence on top of a windy hill + sub freezing temps, as soon as the sun rose along with the temperature all was good. in other words those living in colder areas may need a battery with more CCA which vary even with the same physical size
 
My car is a little older than the OP's.. But I attached the factory service manual specs for my 2009 Legacy anyways.
48AH in the MT's, 52AH in the AT's.

Not sure of the exact starter spec you're looking for, but I'm reading starter voltage and output: 12V - 1.6kW.

Replaced the battery in my 2009 Legacy at around 135k after around 5 or 6 years as a precaution. The autocraft gold battery I put in lasted like 8 months, figures. Maybe that was my fault, though. Group 35's are a tight fit in my 2009 legacy, so I think I went with a group 85 instead, since I read online that fits much better. The group 85 has maybe 50 cca's less than its group 35 counterpart, just a tiny bit smaller than the group 35. Anyways, AAP denied the warranty on the battery since their computers say to use group 35, and I used 85. Wasn't too happy, but oh well, no more AAP batteries for me.

*One more thing, both AAP batteries were at least 100cca more than my oem subaru battery.

 
A Lead acid battery's lifespan is largely dictated by how close it is kept to 100% charged through out that lifespan.

So the vehicles voltage regulator plays a HUGE part in the ultimate lifespan of the battery as well as ow long it gets to apply those charging voltages . Generally the VRs are too timid and do not hold a high enough voltage long enough to get that battery from 95% to 100% charged, which can take an hour or more no matter how powerful the charging source might be. A battery nearing full charge simply cannot accept much charging current and it takes a long time at absorption voltages to complete this task.

The worst constructed battery kept 100% charged will outlive the best constructed battery kept 75% charged, and retain much more of its CCA while it degrades slower.

Heat does accelerate the degradation of batteries too, but usually it is the cold reveals this loss of capacity and cranking amps.

If you want maximum battery longevity, use a maintainer when parked for more than a few days without driving, and every so often, remove the surface charge by applying the lights to bring the battery to 12.6v or below, and start the automatic charger with an amp rating ~10% of the rated AH capacity of the battery and top off the battery, as the it takes significant time to get a battery from 80% to 100% charged, and the alternator is not great at this task, except on 4+ hour drives.

AGM batteries tend to have significantly higher CCA ratings than their flooded counterparts and they like to use a "Pulse" cranking amps figure as CCA figures are determined at 30 seconds, and what vehicle these days requires 30 seconds of cranking to start?

I have a group 27 NorthStar AGM battery rated at 930CCA and 90 AH capacity( 74 lbs), and it starts my overnight cold 318 in well under a second and stays above 12 volts when doing so. I find it dang impressive at both engine starting and deep cycle duty, as long as it is high amp recharged when deeply cycled and absolutely fully charged as often as possible.

It is over 2 years old and has over 200 deep cycles( to 50%) on it. A regular flooded starting battery would have failed long ago in this dual purpose usage.
 
Originally Posted By: wrcsixeight
A Lead acid battery's lifespan is largely dictated by how close it is kept to 100% charged through out that lifespan.


+1

Since my car does a lot of sitting (don't drive to work) and shortish (30-60 min.) trips about 2x a week I give the battery a full charge every 3 months.
I count a road trip of 4 hours or more as a full charge.
I remove it and charge on an adjustable power supply set to 14V for about 12-16 hours, then do an equalizing charge for an hour at 16V.
Been doing this with last 3 cars for 25+ years.
Recently replaced the 9 year old battery in my Matrix.
It was still going strong, but didn't trust it to go through a 10th winter.
 
Originally Posted By: sxg6
My car is a little older than the OP's.. But I attached the factory service manual specs for my 2009 Legacy anyways.
48AH in the MT's, 52AH in the AT's.

Not sure of the exact starter spec you're looking for, but I'm reading starter voltage and output: 12V - 1.6kW.

Replaced the battery in my 2009 Legacy at around 135k after around 5 or 6 years as a precaution. The autocraft gold battery I put in lasted like 8 months, figures. Maybe that was my fault, though. Group 35's are a tight fit in my 2009 legacy, so I think I went with a group 85 instead, since I read online that fits much better. The group 85 has maybe 50 cca's less than its group 35 counterpart, just a tiny bit smaller than the group 35. Anyways, AAP denied the warranty on the battery since their computers say to use group 35, and I used 85. Wasn't too happy, but oh well, no more AAP batteries for me.

*One more thing, both AAP batteries were at least 100cca more than my oem subaru battery.




Perfect info!!!

A 35Ah battery should be around 6mOhm, a 54Ah around 4.5mOhm per data Ive collected from various sources.

So one can do the math and determine if voltage drop under a 1.6kW load at low SOC is manageable by the battery, if the minimum cell voltage shall not go below 1.67V per cell.
 
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