scott011422
Well-known member
Keep us updated on the police settings. With that new battery update the Fan 5 trick doesn't work anymore. I'm currently using some of the police mods, But they don't seem to be doing much............
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Factory battery ongoing issues
- Thread starter Nate Shango
- Start date
- Watchers 29
HammaMan
Well-known member
Once your underhood batt is 100% the fan 5 trick most certainly does work. You'll never be below 14.2 volts using it. I have the latest BCM outside of the one that just dropped literally 3 weeks ago and nobody has received OTA (I haven't seen a truck with the newest BCM to even know its software part#). Anyone that's got the BCM in the last 2 months has the AAM software that radically changed how quickly the batts are charged. Once at 100%, the fan 5 logic is very much alive.
@rugedraw have you seen the newest BCM software yet beyond AAM? It's gated behind the login thing
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Jmitchelltfo
Well-known member
I figured I was stuck with AGM unless I wanted to spend well over $100. Nice find on that one!As long as the charger can charge AGM, that's all you need and even then you really don't 'need' that. As for battery size, I put an LFP in mine and it required hacking up the battery box a little bit but here's the end result.
Yes it closes and works just fine but still needs the fan 5 trick to charge because the underhood batt is always at 100% SOC and the DC/DC sags the voltage down 13.2 v or so and it really needs to be up at 14.2 or better. With this in place the underhood batt's only job is rolling starts using the BISG. I need to play with some of the police settings for voltage so that I don't have to resort to fan 5, but I don't care.
Have a link to a thread for any specific changes you made to help fit that 30ah battery?
I've got lots of learning to do on the Forscan side!
KTM753
Well-known member
I have a Noco and it works. But the advantage of this Victron is the ability to use it in Power Supply mode if you use FDRS to update your truck yourself. If not, any charger for AGM battery will work.
That said, I respect the user that posted the Victron and shared his test results. He knows his stuff, but for the average user, any AGM charger will charge the F-150 underhood battery.
Jmitchelltfo
Well-known member
I will reluctantly admit that I used my Schumaker to charge my battery without ever confirming that it was certified for AGM use. That will be the first thing I check when I get home.
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HammaMan
Well-known member
I have a 15a charger that's more than enough to keep the vehicle alive for updates (PB). I did 90 minutes of updates to the 24 5.0 we've got and the charger shut off several times during 90 minutes worth of updates so a 10 amp unit should be more than enough so long as the truck is charged to begin with.
When doing updates make sure the headlights, AC blower, and seat heaters are off. I think some people don't pay attention to such things and the seat heater alone will draw 8 amps.
When doing updates make sure the headlights, AC blower, and seat heaters are off. I think some people don't pay attention to such things and the seat heater alone will draw 8 amps.
HammaMan
Well-known member
Try manually resetting the BMS. The truck does track the age of the battery as a variable and the manual reset procedure makes it think it got a new batt and changes its behavior. No reason a 12.7+ voltage should be triggering a service charging system.Why am I getting this message? Do I need to replace my aux battery by chance?
I bought another battery tray off ebay for $50 delivered as it was unknown territory cutting into the tray itself to make that fit. LFP battery life can degrade quickly if charged below freezing which is why I've not really suggested people to go LFP aux route due to the varied winter conditions seen across the US. That battery is touching the lid -- its fit is tight, but the lid closes / snaps in. if it was 1/8th inch taller it wouldn't close.
You could use an H8 if you pull the battery isolator out of the battery tray and just leave it chilling next to the battery under hood. The wires are sufficiently stiff to keep it in-place. Wouldn't be hard to secure it if desired -- I didn't try. The LFP affords me a 'free' 25ah worth of reserve capacity before the under hood AGM starts to get consumed which is quite considerable. Can't speak to the long-term effects of this arrangement though. Keeping the AGM at 100% is supposed to have long-term negative effects but I'm not sure when they'll show up. It's only used for starting the ICE while moving in hybrid mode so even if it degrades to 70% health it still might not show up.
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scott011422
Well-known member
LOL! im pretty sure you with your special little battery is the only owner with a fully charged battery!Once your underhood batt is 100% the fan 5 trick most certainly does work. You'll never be below 14.2 volts using it. I have the latest BCM outside of the one that just dropped literally 3 weeks ago and nobody has received OTA (I haven't seen a truck with the newest BCM to even know its software part#). Anyone that's got the BCM in the last 2 months has the AAM software that radically changed how quickly the batts are charged. Once at 100%, the fan 5 logic is very much alive.
@rugedraw have you seen the newest BCM software yet beyond AAM? It's gated behind the login thing
But good to know!
scott011422
Well-known member
Do you have any other info on this? Your not the first person I've heard say that. But Odyssey Interstate and Optima all recommend their AGM's stay as close to 100% as possible for max life.
HammaMan
Well-known member
There really isn't solid numbers on it. Temp is a variable and due to my scenario, when driving I'm around 14.2v, when parked it starts around 13.4v and then settles at 13.3 once the truck fully sleeps until the LFP starts to empty then it will eventually drop down to the AGMs voltage (LFPs have a sharp drop off as they near empty). I have no idea what the actual real-world result will end up being with this config. The truck isn't daily driven so reserve capacity is more important. I can go 2 weeks not driving it. Around town it's a poor fit due to rarely getting up to temp so the EV rules there. I try to drive it for the 20+ mile trips but the EV is significantly cheaper to operate there as well. I use the truck for longer runs and truck things as it goes 600 miles on a 5 minute fill up and it's more comfortable. 2.5yrs old and has 8k miles on it.
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DadBald
Well-known member
I did this a few times the first week with the new battery (once right at install, one or two other times after I kept getting this message). I suppose it couldn't hurt to do it again, but do you think it'll help?
I noticed the battery dips below 12.4v right at startup... would this be doing it? Seems like normal behavior to me though.
DadBald
Well-known member
Oh, yeah I can do that, sorry. The Subaru in my profile is what turned into my truck now 
It's a 2021 XLT 302A Powerboost.
It's a 2021 XLT 302A Powerboost.
HammaMan
Well-known member
The dip you're seeing I believe is you waking the truck up if you're relying on the graph above. You can test this by simply leaving your truck alone for 10m or so and it powers down, walking up to it with the key, opening the locked door then closing it / locking it. When you wake up the truck the voltage dips as everything wakes up.
DadBald
Well-known member
Right, that's my understanding too and aligns with what I typically see. Was curious though if this dip on wake-up would trigger the "charging system service soon" message if it happened to go below 12.4 (ish) volts? It seems to do that pretty regularly so I'm not certain it would.
I wish I had a better indicator of when it was going to happen or what is causing it. Everything seems normal to me, and it occurs so sporadically.
I wish I had a better indicator of when it was going to happen or what is causing it. Everything seems normal to me, and it occurs so sporadically.
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