12 volt battery success ?

[chriserx]

But it'll die as soon as you pull or insert the J1772 (why oh why does pulling the J1772 take the truck out of ready?!?!?), or use the power button to take the truck out of ready on purpose....

That's actually good information on several levels to me. In case it happens to me and gives insight to the design and programming of the truck.

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[chl]

Forgive me, but I can't recall if this accessory port has un-switched (always hot) power going to it?

I like your idea of using the charger as a visual indicator of voltage level.

No it shuts off, might be a delay period.
And the manual says NOT to use it for trickle charging the battery (in essence - not exact wording).

 

[chl]

The good news is it takes just a second or two of power from my little jump pack (or a second 12V battery) to wake the truck up enough that it can get to ready, even with a low voltage battery that's down around 6V. But it'll die as soon as you pull or insert the J1772 (why oh why does pulling the J1772 take the truck out of ready?!?!?), or use the power button to take the truck out of ready on purpose....

Ford gets an "F" for 12V system design to be sure.

And when that low, the charge currents are high from the DC-DC converter (no apparent charge current restraints from what I've read anyway) which is another bad thing for the 12v 35ah AGM.

 

[chl]

The good news is it takes just a second or two of power from my little jump pack (or a second 12V battery) to wake the truck up enough that it can get to ready, even with a low voltage battery that's down around 6V. But it'll die as soon as you pull or insert the J1772 (why oh why does pulling the J1772 take the truck out of ready?!?!?), or use the power button to take the truck out of ready on purpose....

Ford gets an "F" for 12V system design to be sure.

The 12v system is used for the J1772 L2 charging in at least two ways (my educated guesses):
to produce the J1772 signals, and
to close the HVB contactors and connect the HVB (if the truck is off).

So the 12v battery would be used for those if the truck is off.

If the truck is ON, the DC-DC converter should be providing 12v charging current to the 12v battery and the 12v system to perform those functions.

 

[djwildstar]

The 12v system is used for the J1772 L2 charging in at least two ways (my educated guesses):
to produce the J1772 signals, and to close the HVB contactors and connect the HVB (if the truck is off). So the 12v battery would be used for those if the truck is off. If the truck is ON, the DC-DC converter should be providing 12v charging current to the 12v battery and the 12v system to perform those functions.

This matches my experience with a marginal 12V battery.

If the truck is OFF, the 12V battery needs to be able to provide enough power to power-up the battery energy management system (BEMS) including signaling with the charger and closing the correct contractors to connect the high-voltage battery to either the on-board charger or to the DC charging pins on the CCS coupler.

One of the first problems I ran into with the marginal 12V battery is that the trutck would not initiate a charge when off: just before departure, when plugged into L2, it would not wake up and charge on schedule. During the trip, it failed to start DC fast charging when plugged into a charger but switched off.

Until I got the 12V replaced, I kept the truck running while plugging into both L2 and DC fast chargers. This did the trick -- charging started, even at the charger that failed when the truck was off.

 

[chl]

This matches my experience with a marginal 12V battery.

If the truck is OFF, the 12V battery needs to be able to provide enough power to power-up the battery energy management system (BEMS) including signaling with the charger and closing the correct contractors to connect the high-voltage battery to either the on-board charger or to the DC charging pins on the CCS coupler.

One of the first problems I ran into with the marginal 12V battery is that the trutck would not initiate a charge when off: just before departure, when plugged into L2, it would not wake up and charge on schedule. During the trip, it failed to start DC fast charging when plugged into a charger but switched off.

Until I got the 12V replaced, I kept the truck running while plugging into both L2 and DC fast chargers. This did the trick -- charging started, even at the charger that failed when the truck was off.

I decided a while ago that the only solution to avoid 12v battery issues was to keep it on a trickle charger maintainer when not using the truck.

A $40 or so charger is a lot less hassle than a dead or dying battery, even if the replacement is covered by the 3yr b-to-b warranty.

At least a few other owners came to the same conclusion.

Of course Ford could solve the problem with some programming changes to keep the 12v topped off (to 100%) all the time (apparently Tesla decided to do this for the same reason - dead 12v batteries).

But don;t hold your breath for that, alas.

 

[michael coffeen]

I waited until just past my 3 year B-T-B expired last August to evaluate and decided to replace my 12v LVB.

The Advanced Auto sales dude tested it, the results indicated it was still serviceable but I decided to err on the side of caution and replaced it with another H3 battery (Diehard)

Install of the new battery went fine in the store parking lot, no issues since the change.

What was the exact battery model?

 

[TaxmanHog]

What was the exact battery model?

https://shop.advanceautoparts.com/p...-60-minute-reserve-capacity-h3-xev/50001096-P

 

[djwildstar]

https://shop.advanceautoparts.com/p...-60-minute-reserve-capacity-h3-xev/50001096-P

This is the one I got, too.

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