12V battery replacement poll

[B177y]

I chose "other" for the poll. I'll wait for gremlins or Ford app messages to start showing up then replace it.

I live it a mellow climate, not too hot and not too cold which batteries seem to "like". I also put over 30,000 miles/year so lots of DC/DC converter charging and lots of time on my EVSE charging, so the 12 volt is generally happy.

I purchased a load tester on the advice of a post by @RLXXI so I'll randomly run a load test or be able to do one at the first sign of a gremlin.

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[klossfam]

I chose "other" for the poll. I'll wait for gremlins or Ford app messages to start showing up then replace it.

I live it a mellow climate, not too hot and not too cold which batteries seem to "like". I also put over 30,000 miles/year so lots of DC/DC converter charging and lots of time on my EVSE charging, so the 12 volt is generally happy.

I purchased a load tester on the advice of a post by @RLXXI so I'll randomly run a load test or be able to do one at the first sign of a gremlin.

Well I can confirm in Western NY where we really don't get that cold (avg Jan high is 30 F) my 3 1/2 year old 75,500 mile original H3 is showing 100% SOH, 426 CCA (rated at 380).

My only concern is the number of charge cycles. If I don't drive the truck for a day and do a real short trip, the 12V will show a SOC of only 30-35% and my Viking Charger Tester will say the battery GOOD - Recharge.

Nothing too funky yet but I got the Discharge warning in the IP a couple times and the System Off to Save Power display pretty regularly on the center screen.

I do wish these H3s were more common like H4 and H5 AGMs. We've exclusively used H5 Weise AGMs on our family Hyundai and Kia EVs. $129 delivered. If that was the H3 deal, a new one would already be in the truck.

 

[21st Century Truck]

So as per my previous post here I took a good look this past Fall at my 12V battery, noticed it had bulging sides, ordered an OHMMU sodium 12V battery (only choice then available) and popped it in in late November or early December 2025.

I also mounted the optional OHMMU 12V battery monitor Bluetooth dongle at swap time, because why not?

We just got back from a three-week trip to Newfoundland Canada, 14 Dec thru 09 January total trip time. Two blizzards, an early polar cold freeze throughout the trip including on the way up and especially back down when we stayed with family in eastern Massachusetts... multiple times between the two blizzards and after them, it got seriously cold up there on the Rock (the local name for Newfoundland).

The OHMMU handled everything swimmingly throughout, so much so that I quit monitoring the 12V battery monitor halfway through the trip.

Very glad I had made the switch. My truck had about 81 K miles on it when I did, including some hot Arizona & Utah & Nevada driving this Summer which might have (??) contributed to the 12V OEM battery sides bulging.

 

[klossfam]

Might have been mentioned but a Motorcraft brand BAGM-H3 is $102 plus approx $12 fgt and $18 core at Rock Auto. Obviously put in your discount code for 5% off.

They have stock. Just ordered one and installed. Nov 2025 date code. Perfect. Just take the core back to O'Reillys for a $10 gift card. Easy.

Made it to 75.5k miles and did it due to the deep discharge it was doing. Showed 100% SOH but at 3.5 years old, that isn't good info from my Viking tester IMO.

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