Increase alternator voltage without needing a tune?

Hello,

Recently took delivery of a 2022 TRD OR. So far loving it, but I've got a laundry list of small modifications I am working through to make it my own. One of items is adding some car audio equipment. Due to the size of the amplifier I will be running, one of the mods I want to make is the dead horse of adding an AGM battery. I feel like I have researched it up and down and may know the answer, but wanted to post it directly....

Is there a way to increase the alternator output voltage without the need of something as heavy and expensive as VFTuner or OVtune (rebranded recently?). In my 4Runner, I was able to mod the Alt-S fuse, which I really miss. I don't really have any desire to apply a full custom map or anything to this truck, just want to squeeze another half volt is all.... At the moment I am taking the road of plugging in a CTEK charger once every month or two to top off.

 

Sorry, but no. A tune is the only way as the voltage is 100% ECU controlled.

But, you could have someone modify a Stock tune to bump the voltage up. If it were from me, I would do that and only charge the cost of the vF Credits necessary to Unlock your VIN.

 

Is that something that's out there? A list of vF tuners that do side work like that, if so that sounds like something that would be right up my alley as all I want modified is the ECU control for alternator voltage. I really don't want to fork out the ~$600 or so to get fully setup with vF just to make that one change. I am in SE Michigan.

What are your thoughts on remote tuning with screensharing/take over made available to you?

 

Heck yeah. A lot of folks would / could do this.

It isn't $600 for a tune. That is usually for a shared tune setup. Basic vF Tunes, which are really good and about to get better, are in the $300 to $350 (my price including future support) region.


@Shellshock is in central Iowa?


Remote Desktop is one thing, but Remote Tuning has higher costs associated with it as you'd need a vF License and Tactrix adapter. That is currently $399:
https://vftuner.com/collections/vf/products/vforest-tuner-software-flash-cable

 

Maybe I'm wandering quickly into the weeds, but is the cable itself tied to the laptop, as in only able to be attached to a single hardware ID kind of thing? I used to do edits on VW's years ago and used a licensed cable called vag-com and the license was attached to the cable, not the device the cable was plugged into.

So.... Would it be possible (with a deposit or similar) that I could use your cable for example (mailed to me), then through my laptop and a remote connection we make the modification. Wrap it up, put the cable back in the box, mail it back and deposit is refunded (or even kept if it's the fee for making the change? )

 

You are correct. The vF License being tied to the adapter was a very recent change to the vF Software. It is too new of a situation to know if that is allowed or not, as it has not come up yet. Given the scamming that has happened in the past for vF though, I have a suspicion that it would violate the Terms of Service. I would be happy to check in on that.

 

If that floats, you got your first customer

 

I'm not a big tuning fan because of the potential warranty risk, but if you are going into your ECU and altering the stock tune anyway to get your AGM battery hooked up, why not just get completely tuned and take advantage of the performance gains that goes with it and get your voltage adjustment for AGM at the same time? Just a thought Sounds like it would cost about the same.

 

The alternator change is pretty light weight in my simple mind as far as mods go, at least in regard to voiding warranty. Maybe in the future once the factory warranty is up I'd look into doing a full tune, but at the time being all I want is ~ half a volt Good thought though, and the thought did cross my mind already

 

Upping the charge voltage (permanently) is not the ideal way to charge an AGM. Once an AGM is fully charged it needs to drop to a lower float voltage to avoid burning the plates. I’d invest in a Redarc or similar smart charger with an AGM charging profile. Otherwise you won’t get the maximum life out of the AGM.

 

I think that's similar to the plan I am executing against at the moment. I have CTEK chargers here at home that I stand behind pretty firmly, and it has an AGM profile on it: https://smartercharger.com/collections/car-battery-chargers/products/ctek-mxs-5-0

And this is where I am at now, either upping the voltage of the alternator and be hands free. I assume with the voltage increase, temperature regulation and all still occur? Meaning the voltage will still decrease/increase slightly when needed but just with the higher offset. (Maybe this is where my assumption is making an ass of u and me)

Or, I wire in a pigtail lead (quick disconnect) to give myself a way to plug in and charge every so often without having to have my hood popped.

 

This is exactly what I do with my Honda Goldwing. Since I mainly only ride on weekends it's on a battery tender every time I pull into the garage and park it. I have a pigtail permanently installed on the battery that I tuck away when I'm riding.

 

Yeah...... Just my laziness...... Would be pretty nice to just have the truck setup for AGM vs having to spot charge, especially since the truck will not be garage kept and will be a daily.

 

The only compensation is for ambient temps and throttle angle. The maps associated with throttle are not edited for the voltage increase. The battery temp is not monitored. Stock values shown:

 

Solar panel with charge controller to top off the battery

 

Thanks, but I don't want to go the solar panel route. I've seen that mentioned a few times.

 

Apologies, when I mentioned "temp" earlier, I was referring to ambient and not the actual battery itself.

So what you are saying is that the modification we could make via a tune is pretty much the same as the stock values, only for my simple understanding, we could increase the voltage. So if we were to raise the offset by something like 0.7 volts (on average my system floats at 13.8, so if we raise by .7, that puts me at 14.5), my system would, all things equal, now be at 14.5 and then increase and decrease based on ambient temp and throttle angle, right?

Just trying to fully understand if it's worth it or not, as this would put the battery into a constant state of cyclic and never drop into float.

 

Ah! I get you.

That is correct. It will maintain a set charge voltage for different temps. There is always the recommendation to monitor the voltage during the first few temp swings to be sure it is all good.

The files that I have were created by @Shellshock with his voodoo to set them at 14.2v. I think he will have to jump in here for higher outputs.

 

14.2 would be an interesting value as that damn near is sitting right in the middle of cyclic and float for most AGM batteries. I assume that's why he chose that.

 

Yes. I believe so.

That is also where most MOSFET R/Rs charge motorcycle AGM batteries to.