How do the dual OBCs work?

[djwildstar]

Then the question becomes why doesn't Ford use dual 40A chargers? Wouldn't that have been cheaper?

While it is likely that a 40A on-board charger would be slightly cheaper than a 48A unit, that savings may well be offset by the cost to specify, procure, warehouse, and distribute an additional part number. Each unique part has a certain a mount of "overhead" costs -- so you can also save money by re-using the same part in multiple vehicles (Mach-E, e-Transit, Lightning), or using one part to fill multiple roles across different trims of the same vehicle (primary and secondary on-board charger). Not only do you avoid the overhead cost of having an additional part in your bill of materials, you may also drive the per-part cost down by ordering more of them at once.

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[chl]

Looking at the wsm, it says "Some vehicles" are equipped with a secondary On-board Battery Charger Control Module (BCCM), also known as the GFM2, a liquid-cooled component that facilitates and provides additional charging capacity to the high voltage battery if a high output level 2 EVSE is utilized. The primary On-board Battery Charger Control Module (BCCM), also known as the SOBDM communicates and controls operations of the GFM2 via dedicated communication circuits. for the 25 year model.

I know mine is limited to 48A with a 123kWh what I'd call a mid range battery so there's that, only truck I'd think that would have dual would be the Pro for contractor usage? Spitballing here.

Yes, if we are talking about the 2026 model year (MY) the Pro can have the larger battery as an option primarily for contractors/fleet vehicles.

The 131kWh is also standard on the Platnumb and Lasso versions in 2026.

The Flash, Pro and STX, seem to have a 123kWh battery - they did away with the 98kWh battery.

Those are the usable kWh, the actually battery has headroom in all models.

Now what size the chargers is for the 123kWh battery I haven't looked up...but since they limit the current to the same max as the 98kWh battery (48A) I assume they used the 11.3kW charger in these as well?

 

[TaxmanHog]

While it is likely that a 40A on-board charger would be slightly cheaper than a 48A unit, that savings may well be offset by the cost to specify, procure, warehouse, and distribute an additional part number. Each unique part has a certain a mount of "overhead" costs -- so you can also save money by re-using the same part in multiple vehicles (Mach-E, e-Transit, Lightning), or using one part to fill multiple roles across different trims of the same vehicle (primary and secondary on-board charger). Not only do you avoid the overhead cost of having an additional part in your bill of materials, you may also drive the per-part cost down by ordering more of them at once.

If anyone has access to FDRS multi day pass, could you look up the part numbers for various configurations and see if there is commonality or disparity with the front OBCC amongst the spectrum of model years and ranges?

 

[I <3 My Lightning]

Used my vin to search since I have dual chargers....

You can view the tab "what this fits?"

This one is REAR of dual charger lightnings only....

https://www.oemfordpartscheap.com/p/Drive-Motor-Battery-Pack-Charger/144365373/NL3Z10B689E.html

This one is used across ALL of fords BEVs... MachE, eTransit, Lightning

https://www.oemfordpartscheap.com/p/Drive-Motor-Battery-Pack-Charger/144596944/LK9Z10B689M.html

And this one is the FRONT of the dual charger lightnings only.

https://www.oemfordpartscheap.com/p/Drive-Motor-Battery-Pack-Charger/145832294/PK4Z10B689D.html

 

[TaxmanHog]

Used my vin to search since I have dual chargers....

You can view the tab "what this fits?"

This one is REAR of dual charger lightnings only....

https://www.oemfordpartscheap.com/p/Drive-Motor-Battery-Pack-Charger/144365373/NL3Z10B689E.html

This one is used across ALL of fords BEVs... MachE, eTransit, Lightning

https://www.oemfordpartscheap.com/p/Drive-Motor-Battery-Pack-Charger/144596944/LK9Z10B689M.html

And this one is the FRONT of the dual charger lightnings only.

https://www.oemfordpartscheap.com/p/Drive-Motor-Battery-Pack-Charger/145832294/PK4Z10B689D.html

Thank you for pulling these links, looking at all three, then using the "does it fit my truck" filter, says all three would fit, ????? I think the filtering is incomplete as they don't let us define the SR vs ER configurations for the 2022 model year ( I did not try running 23, 24 or 25) I have my truck in the remembered "Garage"

They are lacking any technical specifications for any of these parts so we could infer the unit that is applicable to 44 version amongst 3 models (MachE, Lightning, E-Transit) might certainly be a 48 amp units.

 

[bmwhitetx]

Thank you for pulling these links, looking at all three, then using the "does it fit my truck" filter, says all three would fit, ????? I think the filtering is incomplete as they don't let us define the SR vs ER configurations for the 2022 model year ( I did not try running 23, 24 or 25) I have my truck in the remembered "Garage"

I noticed the same thing on my 2022. Since they don't distinguish between SR and ER, all three are applicable in theory to a 22-23 Lariat. So which one you need is in the "fine print":

[Harp music] Seems like we came to this conclusion 2-3 years ago but I couldn't find any posts with a quick search.

 

[TaxmanHog]

Leaving open the question ...... are the -D & -E units 40/40 or 48/32 ?

It was stated that the ER trucks call upon on the secondary OBCC when the there is a request for more than 48 amps, that leads me to think the front unit is still 48 amps, I wonder what is unique about it that it calls for a distinct part number? Could it be the accommodations for the interconnection with the secondary OBCC that calls for this distinction ?

 

[bmwhitetx]

Leaving open the question ...... are the -D & -E units 40/40 or 48/32 ?

It was stated that the ER trucks call upon on the secondary OBCC when the there is a request for more than 48 amps, that leads me to think the front unit is still 48 amps, I wonder what is unique about it that it calls for a distinct part number? Could it be the accommodations for the interconnection with the secondary OBCC that calls for this distinction ?

I haven’t seen a credible source say 48A is when the secondary kicks in. The workshop manual just says the secondary gets involved when connected to a high level EVSE. That might mean anything at 240V or anything above 32A (speculation). In post 15, Zach indicates the units begin to share at a very low level, maybe as low as 4kW. He and Martin are the guys behind some charging mods so I give them the nod over speculators like me.

 

[VTbuckeye]

I haven't looked lately, but I vaguely remember something about charging above 30amp as hoeing as 15 amp on car scanner. Maybe it was 40amp showing as 20, ergo at 40 amp the second obc turns on and the reported charging amperage is half of what you are actually receiving from the evse. Maybe I will experiment this weekend (plug in truck to emporia while sitting in truck with car scanner active and adjusting the charging power).

 

[TaxmanHog]

Chasing a 100% accurate answer, but the documentation on the charger system suggests the second charger is only used when input current is above 48A.

I consider this a credible statement by the source.

 

[ZSC100]

As the design engineer and reverse engineer behind EverDrive I know most everything about the chargers and how they work. What @Jesse-Infotainment said earlier is mostly accurate except the chargers ARE identical parts (as others have mentioned makes sense for Ford). The Front charger simply commands the back charger via a private CAN bus and splits the charging power in half after around 4kW on the primary. The CAN messages the SOBDMA relies on tells it immediately if it's the primary or slave charger and thus no different firmware is needed and Ford can stock one module for both purposes on the assembly line. Since both chargers are identical and capable of doing around 12kW, both could charge at 24kW, but all of that is very software controlled and limited for owner safety. As others have hinted here, they limited (advertised) the charge rate for dual chargers at 19.2kW because the NEC (America's widely adopted electric code) states you can only use 80% of a branch circuit for the load classification that EV's fall under. And as most know the North America residential market uses a split phase 240VAC power scheme which is the primary market for the Lightning. So, the 19.2kW limit has 100% to do with that math. It has less to do with the actual capability of the equipment.

This is also why EVSE's operate their PWM signal via current limits and not power limits.

If you fed your EVSE with 277AC you could push 22kW with 79.4A of AC power on a 100A breaker and still be in compliance with the NEC; and still be only using 11kW on each on board charger. Also, something no one thinks about is the DC output of the on board chargers; at low SoC's (on SR's specifically) HVB voltage can be sub 300VDC, the DC output stage of the power electronics in the charger has to pump out the maximum current for a given steady state power at these SoCs This results in actual hardware limits being reached and we've seen this with EverDrive. Once an SR's HVB drops below 15% the on board charger has to be commanded to 10kW or the output stage of the charger gets overloaded.

This means essentially the on board power electronics experience the most stress at low SoCs.

I have yet to try putting two on board chargers on an SR, but I will probably soon for testing and learning purposes if I don't sell my truck and upgrade to an ER. There is also merit in trying this because a lot of people want the 2nd charger after they removed it from the standard equipment on ERs. I say a lot of people???? I really have no clue how many actually would go through the work of removing the bed and adding it, I suspect this entire thread is about wanting to add the 2nd charger?

 

[TaxmanHog]

The Front charger simply commands the back charger via a private CAN bus and splits the charging power in half after around 4kW on the primary. The CAN messages the SOBDMA relies on tells it immediately if it's the primary or slave charger and thus no different firmware is needed and Ford can stock one module for both purposes on the assembly line. Since both chargers are identical and capable of doing around 12kW, both could charge at 24kW, but all of that is very software controlled and limited for owner safety.

Thank you, this makes sense to me now.

 

[ZSC100]

I consider this a credible statement by the source.

It's completely wrong. Have we ever seen an actual engineer that would know this kind of information engage with the community on a highly technical level. NO. I suspect if we or even the PR positions that interact with owners on platforms like this were ever able to talk to an actual engineer, that engineer wouldn't say anything for fear of breaking an NDA Also, there is likely no one at Ford who even knows half of what I or Jesse knows about highly technical aspects of the trucks like this. Because Ford just assembles the trucks, their engineers don't really know how they work on a sub-system detailed basis. This is a huge problem with the big traditional auto makers. There is likely a few select engineers within Ford R&D that are the "Rockstar" engineers that would know this kind of thing, but they aren't appreciated or compensated by the giant machine that is FMC and again they wouldn't be allowed to tell anyone here ANYTHING without fear of breaking an employer NDA. Similar situation exists with all the vendors. There are engineers, possibly on this forum that work for Delta Electronics who make the on board chargers that likely know in way more detail what I shared above, but won't say anything b/c if they did they would be breaking their Vendor NDA with Ford. in short: this is the struggle all car companies face as they grow. They can make more money being an assembler of cars than trying to make and control every component, but when you to too extreme (as with everything in life) you run into problems.

I hate Tesla, more than Ford, b/c they try to build everything themselves and thus control every aspect of their vehicles, sure OTA's may work better, but I disagree with way more about their vehicles than the traditional ones

 

[Jesse-Infotainment]

@ZSC100

They are different.. Different firmware and different part numbers..

GFM2 = Second charger
Part Number - NL3Z10B689E
Strategy - NL38-10D681-AL

SOBDM = Front Charger
Part Number - LK9Z10B689M
Strategy = NL38-14F476-AM

 

[I <3 My Lightning]

Now, who's going to get dirty, take a few things apart, is running 80 amp charging currents and has a couple of high quality Fluke clamp meters? Start at the lowest charging current, measure, and repeat at the next higher setting... I know it still doesn't answer the question. But it could if the front ramps up to 48 eventually or peaks at 40, as the back increases and then if at 80amps splits it 40/40... This means the rear is more than 32 and the front never peaks to 48... If perhaps the rear obc could be unplugged without an error to see if the front gets up to 48.

But this is all speculation as it is beyond my staying at a holiday in and pay grade.

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