Raising the Alternator's voltage to properly feed your AGM Battery!

[rigtec]

Hello Tech-team!

(My apologies for the poor IMG urls; I've had to avoid "Photo-Bucket" and try IMG-BB today)!

I recently did Another mod to my L.E. that I thought may interest some of you, particularly if you're using an AGM Battery! An AGM (I recently learned), will need a regular system charge of "no less than 14.50V feed" for it to provide a FULL rated CCA output. If it doesn't receive it's required feed source at 14.5V, it's life span is 'mildly' diminished, and may not be capable of some of these "Off-road" travels e.g. night time lighting, a fridge, TV...etc, as it was purchased to do; it might, but you may be surprised/(disappointed)!

Now I just did this mod tonight (10/15/20), but I am impressed at the results! My concern was that the voltage may be "TOO HIGH"; an do harm to the can-BUS system, or even the processors that enable these Gen-5's to be road worthy! Okay, what this mod is, is adding a resistor (Diode) to the Alternator's feed-back sensor circuit, at the 7.5A S (for sensor) fuse, in the Engine Room relay/fuse-box! I watched "The Lion's Share" of you-tube videos on the subject before I decided to consider it, but once I was satisfied, that was it!

You don't need to have a HIGH OUTPUT Alternator; the factory unit will do just fine! And the best part is that this mod only set me back... $7.00 bucks, including S&H; I'll leave the ebay url down below, as well as the "How To" video, for your convenience! This time I remembered to snap a couple of pics of the NEW fuse and the Diode Arrow pointing in the right direction! So you can do this voltage increase with you stock alternator, or if you're using a High Output unit like I am; the end result will be the same; just a lil' more voltage (NOT MORE AMPERAGE), follow(?)!

The only mistake the tutorial giver made, was he thought that the resistor tricks' the ECU into feeding or exciting the charging system to increasing the voltage. But that's not what's happening! The resistor is in the fuse that's in the alternator feed-back sensor circuit! So the resistor reduces the voltage source that feeds the alternator's sensor/exciter circuit, causing it to believe that the voltage regulator needs to be adjusted because voltage is low;

so it increases the voltage about 2/3'rds of a volt! My voltage from my 270-XP was ALWAYS sitting at 14.01V (the .01 = 100'ths of a volt), but now it sits at 14.62V! If I needed more voltage, I could very easily run two of the same Diodes in series, causing the voltage regulator to increase it's output to meet the "perceived" voltage output shortage, but I don't need to push the envelope; just wanna meet the tough demands of the Odyssey AGM battery!

Click to view image Diode-in-proper-direction — ImgBB14.62 volt image

14-62-volts — ImgBB /bHSg1Jw14-62-volts — ImgBB[/url]/bHSg1Jw[/url] Click url to view image

Click url to view image (see pink arrow)main-fuse-box-arrangement — ImgBB

Please see the ebay url link below for shipping and handling details:

New Genuine GMC (S)Diode 12135037 / 12135037 OEM | eBay

'Best to you',

rig, cheers!

Please view You-Tube video below:

4Runner Voltage Booster Fuse for Under $10 to Properly Charge Your AGM Battery. - YouTube

 

[jhguth]

It is important, and there's a 24 page discussion about it already in this thread:
"Voltage Booster" for 31M AGM Battery

Also that "no less than 14.50V feed" is not universally true, be sure to check the stats for your particular battery.

for example my AGM which was made by DEKA requires 13.80V to 14.60V @ 77 F and adjusted 18mV per every 1.8 F (add voltage for temps colder than 77, subtract for temps above 77)

AGMs will in general all require a higher voltage, but the proper charging voltage will depend on the battery you pick

 

[Xtremluck]

I've seen first hand multiple cases where voltage boosters have caused electrical issues including problems on the trail. No thanks, get a battery that your alternator can charge or in the case where you are running a secondary AGM battery (like me) use a proper DC to DC charger.

 

[delloro]

Keep in mind that you no longer have fuse protection in that alternator circuit. That diode is not a fuse.

That diode may fail open at some point, but I have no idea of how many amps.

 

[fkheath]

Just keep in mind that any higher voltage will shorten the life of the light bulbs, although 2/3 volt won't make a big difference.

 

[jhguth]

I've seen first hand multiple cases where voltage boosters have caused electrical issues including problems on the trail. No thanks, get a battery that your alternator can charge or in the case where you are running a secondary AGM battery (like me) use a proper DC to DC charger.

just keep replacement fuses in the glovebox, changing the alternator won't increase the voltage

Just keep in mind that any higher voltage will shorten the life of the light bulbs, although 2/3 volt won't make a big difference.

increasing the 4Runner's voltage puts it inline with other vehicle, it has a fairly low voltage as stock compared to other vehicles. the voltage change is negligible

 

[rigtec]

Keep in mind that you no longer have fuse protection in that alternator circuit. That diode is not a fuse.

That diode may fail open at some point, but I have no idea of how many amps.

Hi delloro,

Just remember that no Actual Current is drawn through the alternator 'feed-back' sensor circuit; provided that the wiring isn't harmed or cut! And diodes DO have a "Must-Trip" Amperage rating 'by design' (usually listed on the nomenclature tag), so it can behave much like a fuse, IF... too much current is allowed to pass through it! Thanks for the thoughtful feed back delloro,

'Best to you',

rig, cheers!

 

[nerfkhat]

Arclights makes a drop in voltage booster just for this. He has a 3 stage switch you can set the amount of boost you would like and it still retains the fuse in his chip. But its if you want to spend 7 dollars to 60 bux. This post is perfect timing for me because i just ordered the interstate agm battery from costco. My oem panasonic battery just died last night.

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

 

[mrblah]

this thread feels like de ja vu...

 

[[email protected]]

I did this "mod" about 5 months ago. Havent had any issues whatsoever.

 

[bring_it_on]

Arclights makes a drop in voltage booster just for this. He has a 3 stage switch you can set the amount of boost you would like and it still retains the fuse in his chip. But its if you want to spend 7 dollars to 60 bux. This post is perfect timing for me because i just ordered the interstate agm battery from costco. My oem panasonic battery just died last night.

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

I really like this product. Have been using it for a few months and like the fact that it accommodates the factory fuse and allows you to bypass the diodes and run it in stock setting without removing the device is a really good feature. I don't deep cycle my AGM but its good to know that if I needed to, I wouldn't have to drag out a AC-DC charger in order to get it back to close to full charge.

 

[nglayton]

This thread should be merged into the other one since it's basically a duplicate.

FYI, I've been running the archlightled booster since April of 2019.
I've also been running all 3 of his interior LED light products just as long and can't recommend them enough. All 4 items are excellent quality products that I wouldn't want to live without.

I have an XP270 alternator feeding a group 31M AND group 65M Northstar AGM's.

In the last 19 months, the T4R has been used multiple ways, hunting, fishing, camping, on the trails, daily driver, pulling a trailer and it sometimes sits 2 weeks at at time with no usage at all. it starts right up EVERYTIME. No electrical issues of any kind that I can recall.

19 Months....ZERO issues. arty:

Of course now that I have mentioned this out loud.......I need to knock on wood. I'm getting ready to head out for another trip next week :usa2:

 

[03_4x4Runner]

I have had my Odyssey battery for 4 years with zero mods and zero issues. In my opinion no mods are needed.

 

[jhguth]

they void the warranty if you don't have proper charging voltage for a reason, you just haven't had any problems yet (or the problems aren't noticeable yet). It also helps that you are in a climate where you actually may have sufficient charging voltage for parts of the year when you factor in temperature compensation.

 

[AMLOR]

I've seen first hand multiple cases where voltage boosters have caused electrical issues including problems on the trail. No thanks, get a battery that your alternator can charge or in the case where you are running a secondary AGM battery (like me) use a proper DC to DC charger.

THIS!!^^
DONT go cheap on electrical...the 4runner you save may be yours!

 

[03_4x4Runner]

they void the warranty if you don't have proper charging voltage for a reason, you just haven't had any problems yet (or the problems aren't noticeable yet). It also helps that you are in a climate where you actually may have sufficient charging voltage for parts of the year when you factor in temperature compensation.

As I posted in another tread several years ago I called Odyssey and asked about warranty issues I have read about on this forum. If the battery fails in its warranty period they will replace it. They said the voltage is not an issue and they have not had any problems with 4runners in general as long as the alternator etc. is working properly. I pretended not to know about the voltage boosters mentioned on the forum. I asked them how to boost the voltage and they did not know. Then they said not to overthink the voltage issue and just use it as normal which I have done.

 

[nglayton]

I have had my Odyssey battery for 4 years with zero mods and zero issues. In my opinion no mods are needed.

I can't argue with this. I too ran an AGM for 3-4 years, maybe 5 with no mods in my 3rd gen and 5th gen before I went dual battery in the 5th gen and got sucked into the endless rathole of mods, new alt, B3 wiring upgrade, voltage boost etc. I personally feel the B3 upgrade and possibly the voltage booster are very snake oil'ish, but I was curious and for the few bucks it cost me to try them, I figured why not. And as noted above, it hasn't hurt me one way or the other.

they void the warranty if you don't have proper charging voltage for a reason, you just haven't had any problems yet (or the problems aren't noticeable yet). It also helps that you are in a climate where you actually may have sufficient charging voltage for parts of the year when you factor in temperature compensation.

I thought voiding the warranty was what this forum was all about? :shrug:

 

[BackOff]

I always kinda wondered about these but never tried.

Anecdotal evidence... 4th gen.
First toyota battery = 7 years.
Replaced with agm optima yellow top = 6.5 years.
On the 2nd agm now.

No booster.
Am now hitting the battery every 3-4 months with a Noco 7200, just because.
The battery never seems to be low.

 

[TRUSTYAXE]

Hello Tech-team!

(My apologies for the poor IMG urls; I've had to avoid "Photo-Bucket" and try IMG-BB today)!

I recently did Another mod to my L.E. that I thought may interest some of you, particularly if you're using an AGM Battery! An AGM (I recently learned), will need a regular system charge of "no less than 14.50V feed" for it to provide a FULL rated CCA output. If it doesn't receive it's required feed source at 14.5V, it's life span is 'mildly' diminished, and may not be capable of some of these "Off-road" travels e.g. night time lighting, a fridge, TV...etc, as it was purchased to do; it might, but you may be surprised/(disappointed)!

Now I just did this mod tonight (10/15/20), but I am impressed at the results! My concern was that the voltage may be "TOO HIGH"; an do harm to the can-BUS system, or even the processors that enable these Gen-5's to be road worthy! Okay, what this mod is, is adding a resistor (Diode) to the Alternator's feed-back sensor circuit, at the 7.5A S (for sensor) fuse, in the Engine Room relay/fuse-box! I watched "The Lion's Share" of you-tube videos on the subject before I decided to consider it, but once I was satisfied, that was it!

You don't need to have a HIGH OUTPUT Alternator; the factory unit will do just fine! And the best part is that this mod only set me back... $7.00 bucks, including S&H; I'll leave the ebay url down below, as well as the "How To" video, for your convenience! This time I remembered to snap a couple of pics of the NEW fuse and the Diode Arrow pointing in the right direction! So you can do this voltage increase with you stock alternator, or if you're using a High Output unit like I am; the end result will be the same; just a lil' more voltage (NOT MORE AMPERAGE), follow(?)!

The only mistake the tutorial giver made, was he thought that the resistor tricks' the ECU into feeding or exciting the charging system to increasing the voltage. But that's not what's happening! The resistor is in the fuse that's in the alternator feed-back sensor circuit! So the resistor reduces the voltage source that feeds the alternator's sensor/exciter circuit, causing it to believe that the voltage regulator needs to be adjusted because voltage is low;

so it increases the voltage about 2/3'rds of a volt! My voltage from my 270-XP was ALWAYS sitting at 14.01V (the .01 = 100'ths of a volt), but now it sits at 14.62V! If I needed more voltage, I could very easily run two of the same Diodes in series, causing the voltage regulator to increase it's output to meet the "perceived" voltage output shortage, but I don't need to push the envelope; just wanna meet the tough demands of the Odyssey AGM battery!

Nice work, it’s not for me I just do the occasional maintenance charge but appreciate the write up. What spare fuse kit is that in the video? I’d like to find one that covers my added circuits and original fuses. Links are appreciated by all.

 

[rigtec]

"...I pretended not to know about the voltage boosters mentioned on the forum. I asked them how to boost the voltage and they did not know..."

Hi 03_4x4Runner,

I'm glad you didn't let on that you know about "AGM Battery Booster Theory", but I'm sorry that they (...DC POWER ENGINEERING/NATIONS STARTER & ALTERNATOR..., said that they no nothing about a booster, cuz I've spoken to them a while ago, and they have an adjustable voltage regulator kit, should you need it!

I think they said to ask for the "Ford Mustang" Voltage regulator Kit", and they would install the kit in your alternator e.g. set-up the internal wiring with the regulator control harness on the exterior, ready to be plugged in! 'Best'

rig