vF Tuner for the 3.5L Tacoma-AGM tuning

I don't know that we need finer control, just trying to wrap my (our) heads around what all the different tables and values do. I realize it's probably not possible, but it isn't great to charge an AGM at its charge voltage constantly. Not so much of an issue for short trips, but for people out driving all day, it may overcharge the battery. I think the best we can do now is drop the voltage down with ECT.

I'm going to be tuning a couple trucks tomorrow that want AGM adjustments.

 

I guess the trick to that would be to know when to push ETC

Correct me if I'm wrong but for AGM there are 3 states ( I am going to use my Odyssey group 34 pc-1500 as example numbers)

Charge: 14.4-14.8 @25c
Condition: once the battery has reached 14.4 it should spend 2-3 hours at 14.4 to Fully charge and condition
Float: once at full and conditioned 13.5-13.8

It's almost like to do AGM right you would need some sort of alternator-powered charge controller that can tell you the charge level of the batteries. I know with the Solar systems on my RV and trailer they have one of those and I know solar is a lot more variable so it is needed but it also controls when I am plugged into the land line.

 

Right, and we are not going to get that charge profile from the truck. So, we have to take that into consideration and make some trade-offs. I am inclined to just set the charge voltage at 14.5-14.6 and have it taper down to 13.9-14.2 at the highest ECT.

 

that would get tricky for those of us that want / use the ETC button for more vroom or tow

 

That's not at all what that table is referring to. ECT is Engine Coolant Temp....

 

.... wow I had a totally brain fart moment for some reason I thought you were talking about the button in the cab... I am just going to go hide under a blanket now.

I follow what you are saying now.

 

Lol, no worries. We're all learning together here. I just wish there was a better way to create numbers that were predictable and didn't require a guess, flash, and check method.

 

Were you ever able to figure out when specific duty cycles are selected?

right now some people adjust them, some don’t.

There’s been a couple people who have used the same settings we’ve been doing on 2016-17 trucks on 2018+ trucks, some it works fine and others get voltage drop at idle and a charging system warning error.

in typical Tacoma fashion... same settings equal different results for some reason.

 

I’ll stay in the car with you while @lapoltba gets the slurpees

 

You're buying and I don't give change.

 

First off huge shout outs to @tonered and @Shellshock their amazing help and work on this stuff has really been the best.

My truck has never been happier! A re-gear, a tune, and now the cherry on top happy batteries.

my setup:
2x odyssey pc-1500 group 34 AGM
to manage them I have a genesis Offroad dual battery kit (highly recommend)
I can view voltage of both batteries From the “G screen” in the cab that comes direct from the battery. The screen shows yellow when the main battery is charging once it’s done it turns green and charges the accessory battery.

tested @Shellshock values tonight. Holy cow what a difference. I am in cold temp 32°f and was getting 14.2-14.3v still a little on the low end for where my batteries want to be for charging (14.4-14.8v@73°f) however I think I am going to leave it to account for the cold. Went for a good test drive everything held steady and my main battery has never clicked over from being done charging so fast. I also ran a logger to verify the ecu seeing 14.3v.

turned on my ARB twin compressor saw a drop down to 12.6 as the compressor ran once it filled the lines it picked right back up to 14.3.

also tested all of my lighting at once ( it’s a lot) and saw no real negative or weird impact.

So far so good and super stoked.

will continue to test on these values as the weather warms up. I will also keep an eye on it as I do a 2 hour drive in the Rocky Mountains tomorrow.

thanks again to everyone on this thread for the wonderful information.

 

You're welcome!

I think you should see more charge at a cold start and then it should taper? @Shellshock will know.

 

It’s warm enough it’s already tapering. It’s only above that below freezing.

 

Thanks!

 

Just want to say thanks for this. No issues with these settings on 04A61. I use different settings for the other years but this seems to make 2018's happy. I wonder why it needs to be lower values on them... Lower idling? The issue someone had was when coming to a complete stop it would cause a decrease in voltage and they'd get the check battery warning light, then it would go away after resuming driving.

 

ok small update

it was 23f this morning and the truck really struggled to turn on it has a PTS (im sad i dont have a keyed ign) so when I hit the button it tried to turn and then sounded like it would if the battery was dead and shut off before turning the engine. Saw the voltage drop to about 10v. Tried a second time it had a little less struggle but this time the engine kicked on and it climbed straight to 14.4v. Drove 2 hours turned the truck on and off multiple times with no issues. Will give it a try again tomorrow morning and see if I get the same results. Im thinking maybe I have to adjust up the cold crank?

 

I'll take a look at 18+ ECUs and see if there is anything out of the ordinary. Also any ECU ID that this confirms happens on, zendesk it to us.

To get a fully idea of how the alternator control works will take some time for every little detail. Patent paperwork would be super helpful

 

Thanks Matt. Didn't want to your already full plate but I appreciate that. I can confirm that these settings make an AGM happy on 18's, but again not sure why they are different.

 

I’ve been able to replicate the low voltage issue.
Under hard brake it’ll drop down to 13.5/6 volts.
Same thing backing up and braking hard.

so I’ll have to do some checking as to why it does that.

 

I’ve done two trucks now with AGM settings and when they are using aux accessories like a fridge, high draw LED lights, winch, air compressor, etc etc they are both getting the charge warning light on the dash when their accessories are running.

one is 2018 and one is 2019