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New battery time

6K views 7 replies 3 participants last post by  tym_v6 
#1 ·
My car is over 4 years old, which means the stock Motorcraft battery is probably 4.5+ years old. No problems yet, but I notice some slow cranking on very cold days and the voltmeter readout in the cluster shows the voltage dipping to ~9.5V when cranking. I don't know where the voltage measurement is being taken, but I'm guessing it's at the voltage regulator / near the alternator.

At any rate, since this is my DD and I don't want to be screwed some cold morning, I took this as an excuse to blow some holiday money and get an Odyssey AGM battery.

For those who are interested, the 3.7L takes the PC1200MJT battery. This battery is not an exact fit (about 1" shorter in the long dimension), so there is a bracket available to make it fit the factory battery tray without modification. Since the new battery is smaller, I suspect I'll fold over a bit of the battery blanket and zip-tie to keep it snug.

Battery and bracket should arrive next week; if there's any interest, I can snap a couple of photos and do a quick write-up of any issues encountered.

Benefits of an AGM battery: longer service life, holds charge better if car is left unused for a while, less prone to sulfation, no danger of liquid spills.

Downsides: more expensive, weighs ~6 lbs more than the factory battery.
 
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#4 ·
Yep, dielectric goo is a must.

There is a tab on the batt for the hold-down, and the Odyssey rep says the $30 bracket is needed to make sure the Odyssey battery fits. We'll see if that's true or if it's just good salesmanship.

There are 500 and 590 CCA versions of the factory BXT96R, both 90 min reserve capacity. I'm curious to see what's in my car once I take the batt blanket off.

The Odyssey PC1200MJT is 540 CCA and 78 min RC, so "smaller" but AGM batts can provide high "pulse" currents at warmer temps, have less self-discharge than flooded batts, and can be deep cycled.

I'm also pretty sure my old factory batt no longer supplies 500+ CCA or a 90 min RC...
 
#3 ·
Replacement batteries always seem to be a bit smaller than the original. I have always gotten a larger battery that was close to the same physical size as the last one. As a bonus, you get a battery with lot more cranking amps. You know you can never have too much power. The additional price for the larger battery shouldn't be too far out of line.
 
#6 ·
#7 ·
Quick update. Battery received today. I'll install it in the next week or so, but for the time being some pics of the battery with the bracket. I'm not sure if the side of the bracket with the horizontal "bar" should be towards the front or rear, but it should become evident when I look under the hood.
 

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#8 · (Edited)
So, Mud, you were right. The adapter bracket not only isn't necessary, it doesn't fit. The factory battery has tabs at the front and back bottom edges to lock it into the tray. The Odyssey battery doesn't, so the bracket is designed to take care of this.

Except it doesn't. The thickness of the bracket keeps the front hold-down "wedge" from fitting. Doing away with the bracket, the wedge can be tightened fully and the battery is firmly held in place (first pic). The factory strap is a little slack on top, but I don't see the battery budging unless the car winds up upside down.

Second pic shows everything back together and zip ties helping keep the thermal blanket in place.

There are removable plastic wedges on the left and right sides of the battery tray. Because the new battery is less wide, there's a gap on each side. I'll see if I can find some other wedges rust are a bit more snug.

Factory batt was 590 CCA.
 

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