Help! 3rd Gen voltage booster

[Iva]

Hello,
I’m Running dual battery system with bluesea acr between starting battery red top and aux battery yellowtop optimas. Getting problem of not fully charging my agm yellow with alternator of 3rd gen tacoma.
Now plan to add solar panel to charge yellow top properly with 14.8v using a solar.
but still want to do something to give needed voltage to yellowtop battery from alternator.
Maybe someone knows what is the easiest way to charge agm battery with 3rd gen tacoma alternator at 14.8v ???

 

[DaveInDenver]

I've experimented with using diodes to bump voltage from my 2nd gen Tacoma with limited success. It seems to me the way to describe using the diode is it slows the discharge and aging but you have to be very careful of temperatures. Running >15V on an AGM at high temperatures (e.g. under hood, summer) is going potentially do as much harm to them as running them persistently undercharged.

One thing to note is AFAIK the 3rd gen Tacoma has a smart alternator so a simple diode bump trick may not even work. The ECU controls the profile so will just compensate for the diode and end up doing whatever it does, which is to charge what it thinks is well enough while minimizing engine load (e.g. increase MPG and reduce emissions, the primary goal).

The sure way to keep your batteries healthy is to consistently use good chargers, be that a charger you plug in at home, solar controller or an on-board DC-DC charger and not rely on the alternator and stock charging system alone.

Even the best systems can only be right under ideal conditions so I view the alternator as a bulk charger that keeps you at 80% or maybe 90%, which is good enough for a few days traveling. But to really perform absorption and conditioning you need something that can be on the battery for long periods uninterrupted and ideally temperature correctly.

 

[Sentry7]

I am working to tackle the same issue as well. I have a dual battery setup on order with the new Redarc dual battery manager and planning on adding two AGM batteries. As for boosting voltage from the truck side, the only way that I have seen or heard of, is thru tuning the ecu with software like VF Tune (formerly OV Tune). I have an email into their CS since I have the OV Tune kit for my 2019 Tacoma. I will gladly report back when they respond.


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[Winterpeg]

I use the following one from HKB.

HKB Electronics

The Alternator Voltage Booster was the first of its type on the market and is the only unit available that was has been purpose built for alternator voltage boosting.

www.hkbelect.com

Dirty Parts also sells them:

Dirty Parts

dirtyparts.com

It's the easiest mod I've ever done.
Remove the ALT-S fuse... replace with the one with the diode.

 

[4000lbsOfGoat]

Clearly you have 2 different batteries there, which is not ideal, but are they actually different chemistries? You mention that only the "yellow top" is AGM. It is best for any dual battery setup to use 2 of the *exact* same battery. If you are using batteries with different chemistries altogether, that is not likely to work well under any conditions since the batteries will have completely different charging profiles.

I have no trouble with charging both AGM batteries in my Tacoma and I'm using the same BlueSea charging relay. However, the most I see while charging is 13.7-8v. Why do you want to be all the way up at 14.8?

 

[DaveInDenver]

Why do you want to be all the way up at 14.8?

Trickle is OK at 13.8V, just that a 3-step is preferred for cyclic charging to make sure you fully charge given limited lengths of time.



Odyssey suggests a higher voltage 3-step to maximize battery life based on test data.

 

[Deleted member 13060]

The only way to boost the charge output on a third gen (that I've found) is through OV Tuning. The Alt is ECU controlled and they can "flash" your ECU to charge at a higher rate to keep the AGM battery happy.
Best to have both batteries match or you'll be slightly overcharging the Red Top.

Tacoma 3.5L vF Tune Pack

Tune Add on tune file package for vF tuner for the Tacoma 3.5L *This is 'ADD ON' package. Does not include cables, VF tuner or registry file(system ID). This is an additional pack for VF tuner customer. VF TUNER SOFTWARE LICENSE AND FLASH CABLE IS REQUIRED TO USE THIS includes OVTuned tune...

vftuner.com

YMMV RON

PS you'll probably want to change the Walmart battery connectors on the Yellow top to something better/more reliable.

 

[Adam_Cole]

Not sure the similarities if any between a 5th gen 4runner charging system and a 3rd gen Tacoma but I installed this voltage booster and see upwards up 14.7v and average of 14.3v.

Triple State Voltage Booster - 5th Gen 4Runner — ArcLightLEDs

IMPORTANT: VOLTAGE BOOSTERS ARE NOT COMPATIBLE WITH 2020+ 4RUNNERS DUE TO CHANGE IN FUSE BOX LAYOUT Did you know a AGM Battery (eg Odyssey, Optima, Northstar) requires a higher voltage output to properly charge? Odyssey states in their warranty booklet that: “…applications where an alternato

www.arclightleds.com

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