12V battery replacement poll

[chl]

I recently replaced my LVB and added the Battery Tender. My HVB now charges up to 245 miles on 100% charge. 2024 SR XLT

That's good, but the two should not be related...unless the weak 12v battery was somehow affecting the range estimate? I have to think about that...

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[chriserx]

That's good, but the two should not be related...unless the weak 12v battery was somehow affecting the range estimate? I have to think about that...

If it's attempting to charge a bad LVB while off plug it can waste energy as heat. I estimated at highway speed an extra 6% loss if this was the case (higher at lower speeds). If correct, I estimate that @Airforce original range to have been 230 if they'd kindly verify.

Edit: The estimate is actually 3-6% depending on the DCDC being 100A-200A. I haven't replaced my LVB, anyone know if doing so gives the GOM a clean slate? That's the other possibility.

 

[chl]

If it's attempting to charge a bad LVB while off plug it can waste energy as heat. I estimated at highway speed an extra 6% loss if this was the case (higher at lower speeds). If correct, I estimate that @Airforce original range to have been 230 if they'd kindly verify.

Edit: The estimate is actually 3-6% depending on the DCDC being 100A-200A. I haven't replaced my LVB, anyone know if doing so gives the GOM a clean slate? That's the other possibility.

From what others have measured, sometimes the LVB charging current does get up to 70A but only for a brief time, the charging current not the current being drawn from the battery to run the various truck components - I forget what those numbers were but they could be significant I suppose and they'd be higher if there was less energy stored in the 12v battery because it was weak.

And if the truck is using the AC or Heat fans, pumps, etc., and other 12v system loads, it could require more of the HVB energy to run things off the DC-DC converter when the battery is weak or low as well.

So I get your point.

But since it is only a 35Ah battery, I assumed the energy to charge it / keep it charged while driving compared to the HVB battery capacity would just be at the noise level.

The loads on the 12v system when running should hardly have any noticeable effect on range by comparison with the HVB running the drive motors, for example.

But who knows how the guess-o-meter reacts to a weak 12v battery?

 

[jwrezz]

Replaced my 12v battery with an H4 size. Was hoping that this would stop the MyVIew on the IPC from resetting randomly, but it looks like that may be its own issue not related to the LVB. Anyway here are some pics of the battery tray alterations needed to get the H4 to fit.

 

[AlaskaFlash]

My 12 V battery failed after 1.5 years. Replaced at the dealership under warranty, battery didn't last two weeks before bulging and putting the truck into battery saver mode. I just replaced the replacement battery with an AMG H4.

 

[chl]

I am not positive this would apply to Lightnings, but I read somewhere that you should update the Body Control Module (BCM) with FORscan to indicate the new larger battery capacity.

It may have been an ICE F-150 forum?

Not sure how necessary it is, but in theory it should help the BMS keep an accurate coulomb count.

 

[Zprime29]

I am not positive this would apply to Lightnings, but I read somewhere that you should update the Body Control Module (BCM) with FORscan to indicate the new larger battery capacity.

It may have been an ICE F-150 forum?

Not sure how necessary it is, but in theory it should help the BMS keep an accurate coulomb count.

I think part of the rationale for the H4 and NOT updating the BMS was to trick it into not allowing the large depth of discharge that it currently allows. If it thinks the battery is getting low from coulomb counting, it will charge the battery up prior to it actually getting super low. Main thing as I see it (and I am by no means an expert, just a forum jockey) is to make sure the battery is fully charged when performing the BMS reset procedure.

 

[chl]

I think part of the rationale for the H4 and NOT updating the BMS was to trick it into not allowing the large depth of discharge that it currently allows. If it thinks the battery is getting low from coulomb counting, it will charge the battery up prior to it actually getting super low. Main thing as I see it (and I am by no means an expert, just a forum jockey) is to make sure the battery is fully charged when performing the BMS reset procedure.

Good point.

That should work after the BMS reset to keep it from getting too low, but will it really charge it back to 100%?

I still think a maintainer is the way to go - cheaper and more reliable at restoring the 12v to 100% SOC.

With a larger battery the BMC could still let it get 'low' (instead of 30% to 50% maybe 70% to 80% SOC?) and sit there not fully charged to 100%, which is the main problem with lead-acid batteries.

To fully remove the sulfates on the plates, a lead-acid battery needs to be recharged back to 100%.

Otherwise, the sulfates can become permanent and increase the internal resistance and make the battery 'weaker.'

That effect accumulates over time leading to battery 'death.'

It will also lead to increased internal heat (current squared x resistance) which can lead to swelling and electrolyte leakage/venting.

Yeah, a larger battery will last longer since it starts out with more capacity.
But it doesn't really solve the underlying problem that is killing the batteries slowly.

And the larger battery costs more and requires some work modifying the tray.

My years of experience with owning vehicles with L-A batteries is they can last a really long time if on a maintainer. My 2012 Nissan Leaf flooded L-A battery is now 14 years old for example. SOH at 80% which is about the threshold of 'good' for a L-A battery.

My 2 cents.

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