How important is it to trickle charge the 12v?

[Jarratt]

I've heard that the 12v battery gets run down and when that occurs, all manner of bad things happen. I assume that this does not occur if the truck is driven regularly. I've also assumed that when I'm charging at home with truck off that the 12 battery is recharged. Is this wrong?

I can anticipate weeklong periods in which the truck is neither driven or plugged in. Perhaps longer. Do I need to trickle charge in these circumstances? If so, is there battery powered trickle charger? Alternatively, can a conventional trickle charger be powered from the truck itself?

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[TaxmanHog]

You would need to have the truck "ON" to run pro-power, so practically speaking a trickle charger should be powered from an external source.

Persistent trickle charging ~might~ confuse the trucks onboard BMS monitoring of the SOC of the LVB, Ford does not encourage us to trickle charge the LVB, let the truck managing it on its own.

 

[Jarratt]

Thanks That sounds right.

Like you I have the Lariat ER max tow

 

[RickLightning]

The 12v will charge from the HVB has needed.

 

[Monkey]

These 12V lithium batteries in EVs are notorious for inconvenient failures. Tesla is doing a lot better with it lately, so is VW. I think it's still too early to see how Ford's solution holds up. If you have a failed 12V, it's often an indicator of another deeper problem. The 12V will charge as needed from the main pack and will try to predominantly do it as the vehicle is on or being driven. But should also do it when necessary, especially if the truck is plugged in. Connecting the truck to 120V charging isn't really considered "plugged in" IMO as it can't properly precondition and be ready to go with desired charge from 120V (12A from the Ford mobile charger).

Best thing to do is drive your truck and keep it plugged in if it's going to sit for a while.

 

[Lightning Rod]

One of the mods I am anticipating this spring is a MAJOR audio upgrade and I was considering replacing LVB with a deep cell battery like an Optima Yellow Top. I wonder if that deep cell would confuse the truck's computer? I've used Yellow Tops for decades for my ice vehicles.

 

[Bandit216]

These 12V lithium batteries in EVs are notorious for inconvenient failures.

The Lightning's 12v battery isn't lithium.

 

[JC688]

If you remove the passenger side plastic panel next to the frunk, you will see the positive charge and grounding terminal for charging the 12v battery. Since ford provides this, I would think it’s ok to charge the 12v battery as needed.

 

[viennaxmas]

Even our 2009 Prius has an issue with the 12 V battery. If it sits for more than 20 days, the battery is dead and we cannot even open the doors. Means opening using the manual key, crawling into the trunk, opening the trunk, open the battery compartment, disconnect the battery and charge it. Quite a painful procedure.

I don't think the Lightning charges the battery when turned off. There are way too many reports of dead 12V batteries. I would have always expected that an EV can at least keep the 12V battery charged from the main battery pack (within reason of course), Maybe something Ford can fix via software upgrade in the future.

 

[TaxmanHog]

If you remove the passenger side plastic panel next to the frunk, you will see the positive charge and grounding terminal for charging the 12v battery. Since ford provides this, I would think it’s ok to charge the 12v battery as needed.

I think they provide the jump terminals to get the truck "STARTED" so that it could be moved and to perform testing of the systems and AGM LVB for defects, then repair or replace as the diagnostics call for.

 

[Jarratt]

Thanks for the great info.

 

[jazzmanmonty]

Here's a question..when I'm fast charging during winter for an hour or so, and im running the heat and radio while sitting there, is it pulling power from the 12V or the main battery? You cant start the trucj while fast charging, and usually when its not on its using accessory power. I always fear I'll run down the 12v and be stuck if I keep the heat running.

 

[Jim Lewis]

Don't have my truck yet. Is there a direct readout anywhere in Settings of the 12 v battery voltage? I should imagine the Lightning doesn't have a "cigarette" lighter outlet in the cab. In my 2007 Honda Hybrid, I have a dual USB car charger with a voltmeter, like this (the OEM model I got is no longer sold): https://www.amazon.com/Charge-Charger-Socket-Outlet-Voltmeter/dp/B0BM3S5463/. The voltmeter on my device reads about 0.3 volts too low. Still, it provides a good indication of how my 12 v battery is doing without reading the voltage across the terminals directly. Although my Battery Tender trickle charger is not supposed to boil or bubble off liquid, I notice a little acid spray around the refill/check cell port plugs on the top of the battery, so I wonder how much long-term good I'm doing with my battery tender. It goes through its normal LED display cycle when I use it with no warning lights. Are there good ways of checking what the tender is doing? I guess, for starters, I could just read the voltage across the terminals in different stages of the battery tender cycle or sit in the car and read the same off the USB charger plugged into the auxiliary power 12 v outlet.

 

[TaxmanHog]

Don't have my truck yet. Is there a direct readout anywhere in Settings of the 12 v battery voltage? I should imagine the Lightning doesn't have a "cigarette" lighter outlet in the cab.

No dash read outs, yes there is a CIG lighter plug to the right of the center stack 15" screen

 

[jimfigler]

Even our 2009 Prius has an issue with the 12 V battery. If it sits for more than 20 days, the battery is dead and we cannot even open the doors. Means opening using the manual key, crawling into the trunk, opening the trunk, open the battery compartment, disconnect the battery and charge it. Quite a painful procedure.

I don't think the Lightning charges the battery when turned off. There are way too many reports of dead 12V batteries. I would have always expected that an EV can at least keep the 12V battery charged from the main battery pack (within reason of course), Maybe something Ford can fix via software upgrade in the future.

My Kona EV would charge the 12V battery plugged and unplugged. It had an indicator light inside the Hyundia front badging the glowed orange while the 12v was being charged.

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