H8 Battery upgrade

[Snakedoctor]

Just did the H8 replacement and the truck seems better all around. Placebo, probably?

NAPA AGM is what I ended up going with.

I do need to do the reset though. I’ll dig out the forscan and get that done.

The BMS reset? That can be done just sitting in the truck. Mixture of high beams and brake presses.

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[Saturnfire]

Well i got tired of seeing these "battery low" blah, blah blah turning off to conservere...messages on a ~4 month old F150 with ~2400 miles...

Went to WallyWorld and got an H8....did not know these were made in Germany. Put it on my battery conditioner. even though it was a April 2025 battery. When the conditioner started it was at 95%. Waiting for battery jacket to arrive today. I will do a BMS restart afterwards.

 

[Gros Ventre]

That initial charge is good. When I got those funny readings on my OEM battery I just replaced it with an H-7 (NAPA). Have had zero issues since, three years ago.

 

[ebsocalmtb]

I replaced my oem h7 from my 22' over the weekend with a walmart everstart h8. I can't believe I waited this long to do this... so many little weird things the truck was doing are now resolved. My truck finished a few OTA updates over the weekend that had been failing as well. Good riddence Fomoco battery.

 

[SumGuy]

I replaced my oem h7 from my 22' over the weekend with a walmart everstart h8. I can't believe I waited this long to do this... so many little weird things the truck was doing are now resolved. My truck finished a few OTA updates over the weekend that had been failing as well. Good riddence Fomoco battery.

Agreed. That tiny, literally “made in China” battery that ford uses is a slap in the face for domestic production.

some bean counter (say that as a finance guy), pushed for the smaller, cheaper battery to increase fords margin by $12 per truck…but all of the warrantied batteries and customer complaints cannot be worth the $12 savings.

I assume their incentives are paid for finding short term value engineering solutions with zero regard for long term impacts.

 

[digitaltrucker]

I think biggest issue was availability during Covid times.

 

[Gros Ventre]

My take: going to the H-8 battery was nice, but not necessary. When I replaced my OEM battery I wasn't smart enough to do the H-8 vs H-7 thing and just took the NAPA listed H-7 battery off the shelf. I've not had a peep out of the system in three years including Wyoming winters where we see -20ºF routinely.

 

[Gros Ventre]

As an aside, I have a small pulse width power supply for added gauge illumination. Not a big current draw but likely just as much as some of the truck's modules. Its powered directly from one of the always on circuits. I've forgotten to turn it off a few times and never had a peep out of the electrical system. This is with the three year old NAPA H-7 battery.

 

[moonlanderadventures]

One thing I learned that is absolutely critical to understanding battery voltage is the temperature coefficient. For every degree below 77F, the voltage curve on a 12V AGM drops about 0.012V though its not perfectly linear but a rule of thumb. Likewise the opposite occurs for each degree above 77F. Since we only care about the low battery message, the focus is more so about low voltage. I believe the low battery warning triggers at around 11.9V. So a battery with 100% SOC at around 77F will be around 12.8V resting voltage give or take. So at 0 degrees F, it has lost about 0.012VX77 or 0.924V, making it 11.876V +/ a few, triggering the low battery warning potentially. Since its not exactly linear it may be a bit above that range. Bottom line - Make sure you factor temperature into the equation when evaluating your battery condition. The benefit of the H8 is extra storage potential, meaning we are less likely to dip below the low battery 11.8-11.9V range. Even with all of this, getting the H8 for just the boost in CCA in winter time is worth it alone.

 

[Gros Ventre]

One thing I learned that is absolutely critical to understanding battery voltage is the temperature coefficient. For every degree below 77F, the voltage curve on a 12V AGM drops about 0.012V though its not perfectly linear but a rule of thumb. Likewise the opposite occurs for each degree above 77F. Since we only care about the low battery message, the focus is more so about low voltage. I believe the low battery warning triggers at around 11.9V. So a battery with 100% SOC at around 77F will be around 12.8V resting voltage give or take. So at 0 degrees F, it has lost about 0.012VX77 or 0.924V, making it 11.876V +/ a few, triggering the low battery warning potentially. Since its not exactly linear it may be a bit above that range. Bottom line - Make sure you factor temperature into the equation when evaluating your battery condition. The benefit of the H8 is extra storage potential, meaning we are less likely to dip below the low battery 11.8-11.9V range. Even with all of this, getting the H8 for just the boost in CCA in winter time is worth it alone.

The size of the battery, H-8 vs H-7, does not influence the terminal voltage calculation you describe above. As a practical matter out here in Wyoming, when I see ambient temperatures on the order of -20º to -30ºF I do not get a warning. The H-8 provides more reserve current but does not change the chemistry of the temperature coefficient. Note that when you initiate the engine start the battery voltage will drop due to the current draw passing thru the battery. This drop will be lesser with the larger battery.

 

[Aonarch]

I just left my truck parked for two weeks. Didn't go to sleep mode, cranked right up without any issues. Infotainment fired right up, no delay.

The H8 battery is a great upgrade.

 

[moonlanderadventures]

The size of the battery, H-8 vs H-7, does not influence the terminal voltage calculation you describe above. As a practical matter out here in Wyoming, when I see ambient temperatures on the order of -20º to -30ºF I do not get a warning. The H-8 provides more reserve current but does not change the chemistry of the temperature coefficient. Note that when you initiate the engine start the battery voltage will drop due to the current draw passing thru the battery. This drop will be lesser with the larger battery.

The BMS is supposed to compensate for temperature as well from what I understand. Voltage is lower the colder it gets. Internal resistance is higher the colder it is. It's why you only get like half of your CCAs in frigid weather. It also makes sense that's why they have an insulation blanket around the battery. To keep it "warmer".

 

[Gros Ventre]

The BMS is supposed to compensate for temperature as well from what I understand. Voltage is lower the colder it gets. Internal resistance is higher the colder it is. It's why you only get like half of your CCAs in frigid weather. It also makes sense that's why they have an insulation blanket around the battery. To keep it "warmer".

The BMS compensates for charging voltage versus temperature. Just as the terminal voltage changes with temperature, so does the desired charging voltage.

 

[moonlanderadventures]

The BMS compensates for charging voltage versus temperature. Just as the terminal voltage changes with temperature, so does the desired charging voltage.

I follow you now. Makes perfect sense.

 

[Snakedoctor]

I haven’t driven my truck in maybe about 5-6 days and this morning I got the “remote features disabled” message on the App. Less than a month with my Costco H8 battery. I think my dash cam parking mode may have affected it so I turned that feature off.
Next step is a Noco Genius 5 to leave on the truck I guess. Very disappointed.

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