LVB heavy use

[chl]

since the 12v only charges while the HVB is charging

It will also charge the LVB anytime the truck is ON.

Also will charge if the LVB gets down to 40% while the truck is OFF after 48hours or immediately if it goes to 30%.

Pretty bad idea to set the levels so low (40% and 30%) since AGM batteries should never be below 50% for battery longevity. Already seen posts about LVB fails within the 3yr warranty period.

Also Ford apparently assumes it is "after market loads" that are draining the battery down to low (<40%) levels, but from all the posts it seems like it is just the Ford stuff doing it.

Besides wearing the battery out prematurely, updates won't install if the LVB battery falls below about 80% or 85% (I have seen both numbers mentioned).

I had a hell of a time getting the last update - I had to leave my truck ON n drive ready mode, plugged in to the FCSP (for an overnight charge to 90%), and schedule the update for the next day after the HVB was finished, to get the LVB up over the threshold for the update to go through.
Just driving around for 1/2 to 1 hour as Ford customer service recommended did not get the battery topped off high enough - it went up but not enough.

I had already had the CSP 23B70 done to replace the LVB sensor - didn't change the update not installing.

BTW, the system has the ability to send out a top-off code before OTA update, but they don't seem to implement that for whatever reason - probably because it could tie up the truck for longer?

"...While ignition status is off, DC-DC is normally off and 12V battery supports the 12V loads.

While ignition is off, if 12V battery reaches 40% state of charge, then vehicle waits 48 hours , before the DC-DC transfers 300 Watt-hours of energy to recharge the 12V battery. The HV power comes from either HV battery or wall power while on plug. If the 12V battery state of charge reaches 30%, then this HV to LV energy transfer happens immediately with no delay.

Note:
• This system was designed to recharge 12V battery while the vehicle was left parked for many days either on or off plug or occasional drain from customer usage. The 12V battery will wear out if this energy transfer is completed daily due to aftermarket loads draining the 12V battery down to 40% or lower.

• Vehicle has 35 Amp-hour AGM 12V Battery..."
----
NOTE:
35Ah x 12v = 420Wh
40% of 420Wh = 168Wh
30% of 420Wh = 126Wh
so the 300Wh charge should be sufficient to get the battery to 100%
(the recharge is stated to be 300Wh above)
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"ENTRY CONDITIONS FOR HIGH VOLAGE TO LOW VOLTAGE ENERGY TRANSFER (continued)
Special Conditions:
• 1.) If Customer On-Demand Request is detected (e.g. OTA On-Demand)
• Then request will be honored with any LV Battery SOC.
• [Overrides LV Battery SOC <= 40% condition.]
• But other conditions must apply before sending energy transfer request
• OTA (Over The Air) On-Demand Request provides option for LV battery energy top off before OTA software update
• 2.) If LV Battery SOC =< 40% and detection of any of the following special error conditions:
• Battery End of Life (EOL)
• High Key Off Load (KOL)
• Park Lamps Active / Hazard Lamps Active
• Then will initiate energy transfer request.
• [Overrides 48 hour delay limit]
• But other conditions must apply before sending energy transfer request.
• Special error conditions and customer on-demand noted above are excluded from 48 hour lock
out period.
• 3.) If LV Battery SOC =< 30%; extreme threshold - will initiate transfer request
• [Overrides 48 hour delay limit]

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