Testing an Aux batt solution...

[Jmitchelltfo]

When I turn my truck on in the morning, the OBD Mx+ is showing resting volts(because the engine isn't on) and it's always above 13.1v

The way I understand it (maybe @HammaMan, @Snakebitten, @FaaWrenchBndr or someone with more knowledge than me can chime in)
When you turn your truck "on" the DC/DC charger kicks in immediately. At least that is what I have noticed. My pickup doesn't care whether the ICE is engaged or not, it will charge the 12v batteries at whatever the low level setpoint is listed at on my MX+.

If your AGM batteries have a resting voltage of 13.1 (or above), I would be surprised. You are probably seeing 13.1+volts depending on the fan speed (and that is what your batteries are being charged at). After years of using AGMs in boats/trolling motors, and different vehicles, mine normally have a resting voltage between 12.7-12.9........ unless they were just pulled off the charger.

The only reason my AGM batteries show 13.15-13.25 for the resting voltage is due to the parallel setup that links a 20ah LFP to my OEM auxiliary battery. 10 minutes of work and next to zero modifications thanks to the efforts of Hammaman for R&D on his LFP to make sure it played nice with the DC/DC setup.

Sponsored

 

[HammaMan]

Thanks for the additional details @HammaMan, do you have any knowledge of why they switched on the 24+? Issues with the belt starter? or?

Costs less to build. The flywheel starter that's on the 21-23s is the same in trucks equipped with the ASS feature but it never runs. Mine has started the truck with it 4 times? Ford originally decided to include a pretty decent starter generator unit and only use it as a starter despite being able to deliver 280a of 12v. The belt starter is silent vs the typical flywheel starter.

Anything that puts more money in their pocket. What I'm surprised about is that they're replacing the belt starter vs flashing the PCM disabling it. Turning that belt and starter aren't energy free, plus they've confirmed it's not needed. I'd probably have a different opinion on that if I had to occasionally hear the starter while under way. Just not what I bought.

 

[Jmitchelltfo]

One month of running the parallel LFP setup and I am thoroughly impressed. Our weather has been about as cold as it gets here in the Ozarks, so I feel that unless I take a trip to a northern climate during the winter months.........I know what happened to Sonny Bono, so that will never happen.

It was 20°F this morning, and these screenshots are after driving for about 15 minutes. I didn't get a screenshot of the battery app before it was warmed up, but I did see that it showed 13.1 volts (97%) with a BMS temp of 23°F when I hopped in the pickup this morning. Batteries Plus is selling a solid product, but most of the cost is probably due to the 10 year or 2200 charging cycle warranty. I'm ok with that due to the fact that I can use this battery in my next powerboost or in another application, if for some reason I end up going with a different vehicle.

Threw in yesterday's snapshot that included lots of errands around town and I'm still noticing that by the end of the day if I have restarted my pickup several times, that I will see around 14.2 volts vs 14.8-15.1 like I get earlier in the day. If I replaced my 1425 day old battery and reset the BMS, this might change. But at this point, I will just keep an eye on it and replace my main battery if it ever gives a hint of an issue.

 

[Snakebitten]

I haven't been driving the truck, but I did yesterday to go to a wedding. I was wearing black Cowboy Boots and I don't enjoy driving the cars with my boots on. ?

Anyways, the truck has been moved in and out of the barn a few times over the last few weeks and it dragged the resting voltage down to the 12.8x range. Not too shabby for 1043 day oem Motorcraft. I'm sure that thing is well past its half life, if you know what I mean.

The wedding wasn't a long drive, but it was enough to get the Ford (proprietary) SOC back up into the mid 90's quick enough.

I'm more convinced every day that switching to an LFP Auxiliary is a great solution for me personally.

 

[Jmitchelltfo]

@Snakebitten I'd really like to figure out the PID's for your SOC and DC/DC LV. My SOC always reads 100, which I don't think can be true......so I think I'm on an incorrect PID for that gauge.

 

[HammaMan]

If he ran fan 5 trick for any appreciable time, his SOC should already be 100% as the LFP trickle charges it back up at its resting state. I 'only' run fan 5 as I don't want the truck trying to only charge based on the underhood batt's desired SOC level. LFP will change the reported SOC level by charging up the underhood batt at rest if it's allowed to charge fully.

 

[Snakebitten]

@Snakebitten I'd really like to figure out the PID's for your SOC and DC/DC LV. My SOC always reads 100, which I don't think can be true......so I think I'm on an incorrect PID for that gauge.

OBDLink 2022 Ford/Lincoln/Mercury enhanced PID library

SOC for the low voltage battery

It would be named exactly what the yellow lettering shows

In the gauge itself, I edit the "label" to whatever I desire. In this case, simply "AGM"

 

[dochawk]

I haven't been driving the truck, but I did yesterday to go to a wedding. I was wearing black Cowboy Boots and I don't enjoy driving the cars with my boots on. ?

I drove my Miata in boots for exactly a week.

At that point, I had a whole through the floor mat!
?

From then on, in my socks until I got there.
[and my left leg still doesn't quite fit!]

For a wedding I'd have to change boots when I got there; anyway: I have a set to wear with my tux, which was bought as part of my Knights of Columbus Regalia. They stay in their box, get another layer of polish the knight before, and get opened at the destination.

Now I only seem to wear my tux to my daughters' weddings. (three down, one to go!).

And for those, boots get switched as soon as the ceremony is over, and into reptile skin.

[and, no, I'm not buying the new KofC outfit. I'm just not willing to look like a third world paratrooper!]

 

[RedDragon65]

One month of running the parallel LFP setup and I am thoroughly impressed. Our weather has been about as cold as it gets here in the Ozarks, so I feel that unless I take a trip to a northern climate during the winter months.........I know what happened to Sonny Bono, so that will never happen.

It was 20°F this morning, and these screenshots are after driving for about 15 minutes. I didn't get a screenshot of the battery app before it was warmed up, but I did see that it showed 13.1 volts (97%) with a BMS temp of 23°F when I hopped in the pickup this morning. Batteries Plus is selling a solid product, but most of the cost is probably due to the 10 year or 2200 charging cycle warranty. I'm ok with that due to the fact that I can use this battery in my next powerboost or in another application, if for some reason I end up going with a different vehicle.

Threw in yesterday's snapshot that included lots of errands around town and I'm still noticing that by the end of the day if I have restarted my pickup several times, that I will see around 14.2 volts vs 14.8-15.1 like I get earlier in the day. If I replaced my 1425 day old battery and reset the BMS, this might change. But at this point, I will just keep an eye on it and replace my main battery if it ever gives a hint of an issue.

Are you planning on leaving the parallel solution in or will the X2 fit in the factory location/replace the stock AGM if you chose to?

 

[Jmitchelltfo]

Are you planning on leaving the parallel solution in or will the X2 fit in the factory location/replace the stock AGM if you chose to?

It will fit, but I would need to cut the OEM box to fit. I decided to keep it this way due to the fact that it’s less modified and more amp hours.

 

[FaaWrenchBndr]

Been thinking going with two batteries. I know so can install two 7.5 aH batteries. Would like to find two that are the same size as the factory aux battery but with a higher aH rating

 

[Jmitchelltfo]

If he ran fan 5 trick for any appreciable time, his SOC should already be 100% as the LFP trickle charges it back up at its resting state. I 'only' run fan 5 as I don't want the truck trying to only charge based on the underhood batt's desired SOC level. LFP will change the reported SOC level by charging up the underhood batt at rest if it's allowed to charge fully.

I always run over fan speed 4 (used to be 5).

That makes sense. I guess I assumed that my SOC would show lower than 100% after the starter engages, but I’ve never even seen that happen. The LFP does such a good job that it can dump back into the main battery to top it off before it can even register under 100%.

I will see the LFP for a few minutes on the few occasions where the starter is utilized.

 

[FaaWrenchBndr]

The way I understand it (maybe @HammaMan, @Snakebitten, @FaaWrenchBndr or someone with more knowledge than me can chime in)
When you turn your truck "on" the DC/DC charger kicks in immediately. At least that is what I have noticed. My pickup doesn't care whether the ICE is engaged or not, it will charge the 12v batteries at whatever the low level setpoint is listed at on my MX+.

If your AGM batteries have a resting voltage of 13.1 (or above), I would be surprised. You are probably seeing 13.1+volts depending on the fan speed (and that is what your batteries are being charged at). After years of using AGMs in boats/trolling motors, and different vehicles, mine normally have a resting voltage between 12.7-12.9........ unless they were just pulled off the charger.

The only reason my AGM batteries show 13.15-13.25 for the resting voltage is due to the parallel setup that links a 20ah LFP to my OEM auxiliary battery. 10 minutes of work and next to zero modifications thanks to the efforts of Hammaman for R&D on his LFP to make sure it played nice with the DC/DC setup.

I cheat
I use a NOCO 5amp charger at night
I’ve been using a battery tender on vehicles in the winter for at least 15 years

I need to get some “cold start voltage” pics

 

[HammaMan]

I always run over fan speed 4 (used to be 5).

That makes sense. I guess I assumed that my SOC would show lower than 100% after the starter engages, but I’ve never even seen that happen. The LFP does such a good job that it can dump back into the main battery to top it off before it can even register under 100%.

I will see the LFP for a few minutes on the few occasions where the starter is utilized.

The traction motor starts the the truck when parked. When rolling, the opening of the isolator, the start, and the rejoin is just too quick. At no point is the LFP connected to the under-hood batt when a starting event of any kind is happening. It's either done via HV, or the isolated large batt.

 

[hpwjr]

Is there any down side to leaving the AGM battery in parallel to the LFp battery?

Sponsored