12v battery replacement with LFP.

[rpritchett2]

Looking for references and watchouts on replacing my 12v battery with an LFP from Ohmmu or others.

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[ZheWiz]

Stay away from Ohmmu. I tried their LI battery (H3) for the Lightning. It went bad in about 6 weeks. They sent a replacement, it went bad in about 4 weeks. They sent a Sodium version as a replacement, it lasted 4 weeks. I am in the Northeast so weather is a factor, but if you want a good battery - DO NOT DO IT. You'd be better off going with just about any H4 AGM battery and modifying the tray to hold it. OR just get another Ford H3. I ended up going with an H4 after the 3rd Ohmmu battery died. Those things DO NOT work well in our Lightnings.

 

[Athrun88]

I think the general consensus is to get the OEM H3 12V and slap on an AGM compatible battery maintainer. I just bit the bullet and got a Noco Genius 5 which I'll 'hardwire' to the truck. I don't have the link to the thread, but there was someone who poked a hole through the charge port cover so he could plug in the maintainer that way.

 

[rpritchett2]

Thanks. I am in Houston, not much of a low temperature concern. Bought my '22 used 2 yrs ago and loving it. Low 12v battery is first issue I am dealing with. Appreciate the help.

 

[TaxmanHog]

Just put in an AGM Motorcraft battery, or your favorite third party AGM.

 

[jwrezz]

I just did the H4 size tray modifications and put in the slightly larger battery. I'm hoping not to get that low battery warning once next winter comes around!
https://www.f150lightningforum.com/...-replacement-with-h4.35340/page-5#post-664037

 

[Zprime29]

No interest in LFP or Sodium replacement for my 12v. My original will be 4 years old this June, not worth the cost or risk of switching to anything other than a standard AGM.

 

[The Weatherman]

I installed the OHMMU LFP H3 replacement for the Lightning in Nov. of 2025. It is very expensive, so may not be everyone.

I have zero issues since installing it. It has its own onboard Bluetooth status reporting and it has maintained a consistent voltage and cell variation each time I’ve checked it.

Your experience may be different, but I am happy with my decision.

No more trickle charging here.

 

[ZheWiz]

I installed the OHMMU LFP H3 replacement for the Lightning in Nov. of 2025. It is very expensive, so may not be everyone.

I have zero issues since installing it. It has its own onboard Bluetooth status reporting and it has maintained a consistent voltage and cell variation each time I’ve checked it.

Your experience may be different, but I am happy with my decision.

No more trickle charging here.

I suspect "South Central KY" is the key here. OP may be OK down there in TX, but I've lost all faith in Ohmmu.

 

[Tfarrell73]

Several manufacturers offer a slightly larger H3 OEM compatible battery. 40AH 520 CCA. Interstate, Duralast, etc

 

[chuck27p]

I think the general consensus is to get the OEM H3 12V and slap on an AGM compatible battery maintainer. I just bit the bullet and got a Noco Genius 5 which I'll 'hardwire' to the truck. I don't have the link to the thread, but there was someone who poked a hole through the charge port cover so he could plug in the maintainer that way.

https://www.f150lightningforum.com/forum/threads/alarm-randomly-went-off.34830/post-662734

 

[Athrun88]

https://www.f150lightningforum.com/forum/threads/alarm-randomly-went-off.34830/post-662734

Beauty! I knew someone would come through. Cheers!

 

[chl]

I think the general consensus is to get the OEM H3 12V and slap on an AGM compatible battery maintainer. I just bit the bullet and got a Noco Genius 5 which I'll 'hardwire' to the truck. I don't have the link to the thread, but there was someone who poked a hole through the charge port cover so he could plug in the maintainer that way.

Several of us did so there are several post here about putting trickle charger/maintainers on the battery and how to make it easier by adding a trickle charger wire:

https://www.f150lightningforum.com/forum/threads/charging-12v-battery.16979/


I did it like this:

That's an SAE type plug I had left over from a different brand maintainer, but the NOCO uses a proprietary plug so I needed their adapter.

Be sure to hook up the negative downstream of the 12v battery BMS sensor:

 

[Tfarrell73]

How did you route the cable? Did you remove frunk tub, or just remove cover on drivers side?

 

[jwrezz]

How did you route the cable? Did you remove frunk tub, or just remove cover on drivers side?

I just keep the NOCO in the frunk, connected to the battery and have the AC plug hanging out the front like an old diesel engine warmer. You could also run the AC cord out the charge door. I don't see the need to have the charger separated from the wiring for the 1 lb of weight savings.

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