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Discussion Starter · #1 · (Edited)
*** December 2017 Update ***
I got a GrimmSpeed battery mount kit and a PC-680 lightweight battery back in October. See the bottom of this post for details. Works fine in winter and cold temps!

*** Original Post Below ***

My 2013's factory battery was getting long in the tooth. Overnight resting voltage was 12.0, running voltage was 15.1 or higher, and the past two days starting the car after work the turnover was not as "energetic" as it should normally be.

All signs are/were pointing to an imminent battery failure; certainly the factory battery was way down on capacity. I suspect given the age of our cars, others will soon be finding themselves in this same situation, hence this post.

The car is a daily driver, so I didn't need to shed pounds for competition's sake, and I attend rallies where my 75W ham rig taxes the battery, so I wanted a deep-cycle-friendly AGM battery replacement with at least as much capacity as stock -- and I didn't want to have to do a lot of fabbing to mount the thing nor be unable to use the factory battery case and covers.

Guess what? No one makes an AGM battery in our car's BCI Group 96R form factor.

After literally weeks of searching, the best I could find was an Odyssey PC1200T AGM battery that was the same height as the 96R. So I ordered one and installed it last night.

The results?
  1. It fits in the stock battery case, with the stock battery hold down and the stock battery covers!
  2. As the posts are closer to the edge of the battery, the ground mount needed to be rotated 90 degrees.
  3. The height is identical, but I found I needed a little rubber between the battery top and the factory hold down to keep the battery shifting fore-aft (it's not as long as the factory battery).
  4. I took the opportunity to remove the battery box and clean up the two chassis rail grounds underneath the battery box.

Here are some photos:

Be sure to remove oxide buildup from the car's lead terminals:
CleanTerminal.JPG


Cleaned up the grounds and used some bulb grease to help keep them clean:
FixGrounds.JPG


Reality check: Yes Virginia, the batteries are both the same height, but, the Oddyssey's terminals are close to the edge of the battery:
Height.JPG


As a a result of the Odyssey's terminals being closer to the edge, I had to rotate by 90 degrees the ground cable terminal. But as you can see, the back case cover clears the higher height of the terminals just fine (and the front case cover clears too).
RotateGround.JPG


One side benefit is that my idle is now much smoother. I don't think it's because of the grounds cleaning; they were pretty good and clean when I took them apart. Instead, I suspect it's because the alternator no longer is trying to put out a gazillion amps to try to revive a near-death, dying battery.

Hope that helps others, and YMMV!
Mark


*** EDIT 31 July 2017 ***

I wanted to add that Grimspeed now offer a replacement battery hold down to support smaller, lightweight batteries. If it's time to replace your battery and you don't need the amp-hour capacity of the PC1200T, you can save quite a few pounds.

http://www.grimmspeed.com/grimmspeed-lightweight-battery-mount-kit-2013-ford-focus-st-2016-focus-rs/

You can order an Odyssey PC-680 with terminals at the same time; that's a very popular battery size and a well-proven unit.

Hope that helps,
Mark

*** EDIT 31 December 2017 ***
I've been running the GrimmSpeed mount now for a few months with the Pc-680 battery. Works great!

Some had questioned whether the battery would hold up in cold weather. The past week it's been single digits both above and below zero degrees F here in Maine. I drive the car a short distance to work each day and it gets parked outside all day.

Starting the car after work this past week has been fine. Sure, it turns over a little more slowly (did the same last winter with the PC-1200T), but fires right up within 3-4 seconds. ADDENDUM: 8 January 2018: Car was parked outdoors in NH this weekend for three days/nights in single digit above/below temperatures. Started right up no problem!

Note that Cold Cranking Amps spec on the PC-680 is much less than the on the 1200T it is true, but that spec requires 30 seconds of cranking at a cold temperature. Let's be honest, if your car isn't starting in 30 seconds of cranking, you've got bigger issues that a bigger battery isn't going to solve.

So except for very extreme cold weather conditions, my experience has been that the smaller PC-680 battery holds up adequately in cold weather.

Hope that helps,
Mark
 

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Have you used these batteries before? Do they last longer compared to a standard battery?
Deep cycle batteries generally last quite a bit longer than standard batteries. Normal car batteries are designed to deliver short, high current bursts of power for starting the car, and then the alternator is designed to do the rest. A deep cycle battery can run all the electronics, like the sound system, for much longer and be nearly depleted and charged time and again and still deliver the best power supply. That's why people that put high powered sound systems often use Optima (or other brands) deep cycle batteries. On the down side, they weigh a hell of a lot more, so if you are one of the guys on here going for the lightest possible setup, it wouldn't be ideal.
 

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Discussion Starter · #5 ·
Deep cycle batteries generally last quite a bit longer than standard batteries. Normal car batteries are designed to deliver short, high current bursts of power for starting the car, and then the alternator is designed to do the rest. A deep cycle battery can run all the electronics, like the sound system, for much longer and be nearly depleted and charged time and again and still deliver the best power supply. That's why people that put high powered sound systems often use Optima (or other brands) deep cycle batteries. On the down side, they weigh a hell of a lot more, so if you are one of the guys on here going for the lightest possible setup, it wouldn't be ideal.
Yup!

In this case, this battery weighs about the same as the factory battery.

All the best,
Mark
 

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Oh, I've never used the Odyssey batteries, but I had an Optima red top in the past and that sucker was probably 50% heavier than the stock battery.
 
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I have used Odyssey PC680 batteries in my track cars for years as well as my '03 Cobra weekend car. The battery is much smaller than stock and weighs 13lbs. They lasted 5-6 years before dying down. In a daily driver I would use a couple sizes larger. They are great batteries.
 
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This still a decent recommendation? While the Grimspeed seems like a good idea, not sure its for us in the NorthEast if your ST is a daily. Mine is starting to show a little age and 1200w of car audio doesn't help either. Only getting a few minutes before the 'smart' system shuts it down so im thinking its about time.
 

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Discussion Starter · #9 ·
This still a decent recommendation? While the Grimspeed seems like a good idea, not sure its for us in the NorthEast if your ST is a daily. Mine is starting to show a little age and 1200w of car audio doesn't help either. Only getting a few minutes before the 'smart' system shuts it down so im thinking its about time.
Funny you should ask!

My Mom bought me the GrimmSpeed unit with the 680 for my birthday, and I'll be moving the 1200 to my daughter's Focus SE shortly.

So far voltages seem fine with the 680, even with my relatively short 15 minute each way daily commute. But the proof will be when it's -10 out this winter! We'll see!

I'll post an update later this winter.

All the best,
Mark
 
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I'd be tempted to use a Lithium battery this day and age. You can get one that has the a high CCA rating and will be about 20% the weight of a regular battery. The Odyssey 680 has a CCA rating around 350 if I remember correctly. The price of the lithium batteries are pretty high though.
 

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Discussion Starter · #11 ·
I'd be tempted to use a Lithium battery this day and age. You can get one that has the a high CCA rating and will be about 20% the weight of a regular battery. The Odyssey 680 has a CCA rating around 350 if I remember correctly. The price of the lithium batteries are pretty high though.
One day soon I expect. Prices are coming down.

Lithium batteries don't like being deep discharged and their output drops a lot when cold (like here in Maine). That's where AGM batteries still shine. See FAQ about replacing lead acid with lithium battery for example.

With best regards,
Mark
 

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I'd be tempted to use a Lithium battery this day and age. You can get one that has the a high CCA rating and will be about 20% the weight of a regular battery. The Odyssey 680 has a CCA rating around 350 if I remember correctly. The price of the lithium batteries are pretty high though.
Think i saw lower like 230 which would worry me in new England without a battery tender. Perfect for the toys, unsure about a daily.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

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Discussion Starter · #13 ·
Think i saw lower like 230 which would worry me in new England without a battery tender. Perfect for the toys, unsure about a daily.

Sent from my SAMSUNG-SM-G935A using Tapatalk
One thing to consider is that the CCA spec requires output for 30 seconds. Back when cars came with carburetors, it wasn't unreasonable to expect to have to crank an engine for up to 30 seconds to get it started. Nowadays if a car doesn't start within a few seconds, it's likely not starting at all. Consequently, the battery makers are starting to make noise that CCA requirements are a little overkill in many cases.

I'm going to try running my Odyssey PC-680 this winter in my ST as a daily here in Maine, and we'll see what's what.

Best regards to all,
Mark
 

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How dare you post that link lol my battery is on its way out, going to make me spend more of my money on a beautiful battery mount lol :money:
 

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Discussion Starter · #16 ·
How dare you post that link lol my battery is on its way out, going to make me spend more of my money on a beautiful battery mount lol :money:
And... the red Odyssey battery matches our Race Red cars perfectly! Spend Away there Bradley! LOL!

Mark
 

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Clicked on the link and watched the videos. The actual weight difference between the factory battery and associated hardware, and the new Grimmspeed battery and associated hardware is roughly 31 pounds. This saves more weight than a carbon-fiber hood. My original battery lasted just three years and if the Odyssey PC-680 lasts 5-10 years it is well worth the cost of transition. $270 total cost isn't that much in the grand scheme.
 
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Clicked on the link and watched the videos. The actual weight difference between the factory battery and associated hardware, and the new Grimmspeed battery and associated hardware is roughly 31 pounds. This saves more weight than a carbon-fiber hood. My original battery lasted just three years and if the Odyssey PC-680 lasts 5-10 years it is well worth the cost of transition. $270 total cost isn't that much in the grand scheme.

That battery in the video is an RS battery. The battery in the ST is much lighter if i remember correctly it’s closer 29 factory
 

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That battery in the video is an RS battery. The battery in the ST is much lighter if i remember correctly it’s closer 29 factory
I just looked up replacement batteries on Autozone and they use the same battery.
 
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