Testing an Aux batt solution...

[Porpoise Hork]

I have to admit that I would be very pleased to be told by someone at Ford why the fanspeed 5 voltage trigger exists. Of course that would assume that someone at Ford knows the trigger exists and it isn't something unintended or meant.

I'd suspect Ford did this to compensate for increased draw on the system from the fan. So they programmed the system DC/DC logic to increase line voltage from 12.6–12.7V to 14V+ to handle the load and prevent slow drain on the 12v reserves. Curiosity got me and I checked my mom's 23 Highlander hybrid and it supplies 13.8-14.4v continuous regardless of the HVAC fan speed. My bet is some engineers at Ford decided that having the DC/DC converter supply 13.8-14.4v all the time was not as efficient or something stupid like that.

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[scott011422]

Does anyone know if the 5 fan trick was eliminated by recent updates? I removed my 12v batteries (2) to do some wiring on Sunday. Now not only does the fan 5 trick not work, its no longer charging the battery above SOC of 70. I have not yet had the chance to plug into forscan and see if anything was reset.

 

[trabo]

Does anyone know if the 5 fan trick was eliminated by recent updates? I removed my 12v batteries (2) to do some wiring on Sunday. Now not only does the fan 5 trick not work, its no longer charging the battery above SOC of 70. I have not yet had the chance to plug into forscan and see if anything was reset.

I’m glad you asked because I wonder the same. I hope it’s no longer necessary, I hate running the fan so high all the time!

 

[M.R.F.O.R.D.]

This trick never worked on my 2024 PB

 

[Jmitchelltfo]

I just tried backing my fan down in my 2021 yesterday………still dropped the DC/DC voltage to 12.9. Clicked it back up to fan speed 5, and voila! 14.4 volts.

I don’t mind running my fan on high…….but then again, I wear hearing aids and am type of guy that has to have a ceiling fan and some sort of white noise going since I got used to artillery, IED’s, generators and all the other loud noises associated with life in the army.

 

[Snakebitten]

I use the fan-5 hack every day and like clockwork it raises the voltage from 12.9 to high 13's/low 14's.

I think the reason my DC/DC converter is determined to stay at 12.x is because the SOC is perpetually 100% these days. Which is great, of course. But I still use Fan-5 for some percentage of my driving time to make sure the LFP Auxiliary gets to eat. ?

The Ford OEM battery management shortcomings are a thing of the past on my 3+ year old Powerboost. And I'm currently on a 3 week cross-country RV camping venture and the truck is behaving flawlessly. This truck is just amazing.

 

[Snakebitten]

Video evidence of fanspeed 5 still functional. Although I have not applied the BCM update that requires dealership credentials. (I don't know if it changes anything regarding, and honestly this truck is so dialed in that I'm no longer an FDRS update junkie anyway.

 

[scott011422]

I use the fan-5 hack every day and like clockwork it raises the voltage from 12.9 to high 13's/low 14's.

I think the reason my DC/DC converter is determined to stay at 12.x is because the SOC is perpetually 100% these days. Which is great, of course. But I still use Fan-5 for some percentage of my driving time to make sure the LFP Auxiliary gets to eat. ?

The Ford OEM battery management shortcomings are a thing of the past on my 3+ year old Powerboost. And I'm currently on a 3 week cross-country RV camping venture and the truck is behaving flawlessly. This truck is just amazing.

Thats interesting. For me, Fan 5 was always 14.850 to 15.2. After pulling the batteries for the day its as you say, high 13's to low 14's. 14.2 mostly.

 

[Jmitchelltfo]

Thats interesting. For me, Fan 5 was always 14.850 to 15.2. After pulling the batteries for the day its as you say, high 13's to low 14's. 14.2 mostly.

Colder temps usually show me higher voltages like that. I haven’t seen anything over 14.6 volts since April.

 

[Porpoise Hork]

Mine fluctuates between 13.2 - 14.4v a lot. Sometimes it will hit the higher voltage and stay there until I shut the truck down for a few minutes or an hour or more (going into a store or something) then the next startup it might be in the 13's or might be in the 14v range. It's like it can't decide what the output voltage should be and switching the fan below 5 and back doesn't change what ever it has decided to be at during that key cycle.

 

[Eskram]

So I decided to join the cool kids club - battery will come on Monday.

Is my noco genius 10 ok to do the initial charge (it claims lithium charging capability) or do I actually need a bench power supply?

 

[Porpoise Hork]

The Noco's have different modes that you can select including lithium but won't maintain the needed +14.3v needed for the LifPo4 BMS cell balancing process. Or at least the Noco 5 doesn't. I got one of these chargers when I got a 50ah lithium battery for a DC backup on my saltwater fish tank to keep the DC pumps running in an outage and it does a great job at maintaining +14v so I used it on the 20ah battery for the truck too.

 

[Samson16]

Video evidence of fanspeed 5 still functional. Although I have not applied the BCM update that requires dealership credentials. (I don't know if it changes anything regarding, and honestly this truck is so dialed in that I'm no longer an FDRS update junkie anyway.

Plus you hardly drive it ?

 

[Porpoise Hork]

Got to thinking, there HAS to be a higher capacity lithium battery that would fit in the case for the AUX battery. What got me to thinking about it was the post from @Tank on the group size BTX14AH - ETX15 battery with minimal modifications to the battery tray. I started digging in on it and found one. The Precision HJTX14AHQ-FP, a 48AH lithium battery that has the same dimensions as the BTX14AH - ETX15 battery so it should fit in the tray with only minor modifications needed. Only downside is the cost. At $130 US it's a bit steep for it and I have not found much additional information about this brand, but they do boast some impressive claims on it. I'd be curious to know if anyone had heard of this brand or not.

 

[Jmitchelltfo]

The Precision HJTX14AHQ-FP, a 48AH lithium battery that has the same dimensions as the BTX14AH - ETX15 battery so it should fit in the tray with only minor modifications needed. Only downside is the cost. At $130 US it's a bit steep for it and I have not found much additional information about this brand, but they do boast some impressive claims on it. I'd be curious to know if anyone had heard of this brand or not.

Just in case you didn't notice......

48 wH is not 48 aH. You will still have an improvement on the OEM battery, but there are other options out there if you want more capacity in a lithium.

I have had a great experience with the lithium iron phosphate battery in my pickup.

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