12V battery replacement poll

[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.

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[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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