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Anyone know how to change alternator output for AGM battery

Discussion in '3rd Gen. Tacomas (2016+)' started by ihatemytruck, May 10, 2019.

  1. Jul 20, 2019 at 12:04 AM
    #21
    crazysccrmd

    crazysccrmd Well-Known Member

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    No problems for me with AGM batteries and temps below zero for five months of the year. Even down at -50° they still started the truck.
     
    shakerhood and Grossomotto like this.
  2. Jul 20, 2019 at 12:07 AM
    #22
    Boosted_Carrera

    Boosted_Carrera Well-Known Member

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    I've never ever had a problem with Diehard AGMs.
    Never.
     
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  3. Jul 20, 2019 at 6:52 AM
    #23
    DanoT

    DanoT Well-Known Member

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    Isn't it the Lithium batteries that are not very cold temp tolerant?
     
  4. Dec 3, 2019 at 2:53 PM
    #24
    SRBenjamin

    SRBenjamin Well-Known Member

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    Never heard of a special alt for AGM. I've run them for over 20 years without issue(in Toyotas). Most last over 10 years, but one died at 8 years(diehard platinum).

    Full voltage for a car battery is 12.6~7 volts. So if a charge is higher than that, it should charge fine.
     
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  5. Dec 3, 2019 at 3:19 PM
    #25
    shakerhood

    shakerhood Well-Known Member

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    I got 11 years out of my last Odyssey, stuck it in place and didn't have to do anything special, it was good to go.
     
  6. Dec 3, 2019 at 4:56 PM
    #26
    FritoBandito

    FritoBandito Well-Known Member

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    I’ve had an AGM since May and through the Texas summer heat. My alternator has no problem keeping the AGM battery charged to 100%. I test it with my Schumacher charger on AGM mode and it won’t charge it because it’s already at 100%. Not sure this is a real problem that needs requires a higher voltage solution? I’m also not sure what my alternator output is but it keeps me charged to 100%.
     
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  7. Dec 3, 2019 at 5:10 PM
    #27
    Boss hoss

    Boss hoss Well-Known Member

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    Black chrome tailpipe tip. Black hood decal OEM. Fuel wheels and BFG K02 tires seal riser 1 1/4 in frt and 3/4 in rear
    Lipro batteries cost 80 dollars for my R/C cars and can catch fire, why would you want one for a truck.
     
  8. Dec 3, 2019 at 9:46 PM
    #28
    OregontoBajaCA

    OregontoBajaCA Well-Known Member

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    You can save over 100 pounds of weight on a group 31 two battery system by using lithium instead of lead acid.
     
    Last edited: Dec 3, 2019
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  9. Dec 3, 2019 at 9:58 PM
    #29
    OregontoBajaCA

    OregontoBajaCA Well-Known Member

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    8001336D-5BD3-482C-96A7-43F976DD3879.jpgE2C52E5A-6BEE-49B3-98D0-81301AF5349C.jpg C630714A-0619-4147-BF04-902CFDBEC3FE.jpg
     
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  10. Dec 4, 2019 at 9:07 AM
    #30
    ihatemytruck

    ihatemytruck [OP] Professional dumbass

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    The 2017's don't have an alt-s fuse.
     
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  11. Dec 4, 2019 at 10:25 AM
    #31
    Boosted_Carrera

    Boosted_Carrera Well-Known Member

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    I'm wondering if the OP is confusing "battery charger" and alternator.
    Who told you that you need a high output alternator?? My other car is over 20yrs old , stock 130a alternator and charges fine. If you have a lot of power draining accessories , then yes.
    Battery charger does need an AGM option . A normal charger CAN overcharge an AGM without an AGM option. An AGM charger charges low and slowly.
    I've had the Diehard AGM down to 2% . So low that the charger cannot detect it being a 12v . A normal battery would've been toast. I had to boost it to 12v to start charging. That was 3 years ago. The same battery is still in the car but on Battery Tender with desulfator. No problems.
     
  12. Dec 4, 2019 at 10:28 AM
    #32
    tonered

    tonered tacorider

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    No confusion. The Taco regulator is ECU controlled and tops out at 13.5V, if I recall correctly. You need north of that to not shorten the life of an AGM, like your Battery Tender does.
     
  13. Dec 4, 2019 at 10:46 AM
    #33
    Scott17818

    Scott17818 Well-Known Member

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    LiPo's and similar LiFE, and a a few other formulations cannot handle cold temps and actually drop voltage, and amperage draw available.. while they do have long lifespan (draws down below 50%, and the amount of amperage avaliable, as well as lifetime deep charging cycles it has... typically a LiPo will habdle around 2000 deep cycles before death.. where some lead acids, and AGMs will only handle 500-800 deep cycles.

    ALL batterytypes have different charge cycles for a trickle, and float charge to keep them topped up. the downfall is that the voltage required for an AGM, and LiPO battery is much higher than what our "smart alternators" are capable of. they will typically output 14.5v @ anywhere from 30-100AMPs (stock 2016 v-6 with A/C is rated for 100AMPs output) however this is an optimal output, it does not account for extra exuipment running/charging off this system.. lots of LiPO's speciffically will require 14.7v+ to reach a full charge.. while you can get away with running and charging them to 14.5v only they will eventually damage the battery, and leave you with un-usable capacity for that expensive LiPO, or LiFE battery you bought...

    one way around this is to run a dual battery setup with a DC to DC charger such as this one... this only helps if you want to run a house battery setup... which means separate batteries, and different wiring setups... not for your "starting battery"

    https://www.amazon.com/REDARC-BCDC1240D-Dc-Dc-Charger-12V40a/dp/B077JR6NH5/ref=sr_1_4?crid=67FPBPJ4MHX3&keywords=dc+to+dc+charger+redarc&qid=1575485149&sprefix=dc+to+dc+charger+red%2Caps%2C169&sr=8-4
     
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  14. Dec 4, 2019 at 11:03 AM
    #34
    12TRDTacoma

    12TRDTacoma #1GR-FZE

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    For what it is worth, I have an Odyssey group 65 AGM in my truck. I installed it back in 2015 in July/ August of 2015 I believe and it has been kicking ever since without an ALT-S mod to the circuit. I tested it recently and with a spec of 950 CCAs out of the box when it was new, it tested to 804 CCAs. Granted, this test was done with my style driving which is 10-12 of vehicle on activity highway driving, which is usually not enough time to properly charge a battery. I have the ALT-S mod in mind, but I can't really justify it at this moment because of the test results.

    In short, if you buy a quality battery, given how the Toyota charging circuitry works, you may never end up having to worry about it, as 4 years is damn good service life out of any modern day battery, and we all know how garbage today's vehicle components are these days.
     
  15. Dec 4, 2019 at 11:07 AM
    #35
    tonered

    tonered tacorider

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    What is the charging voltage on the 2nd Gen? I'm assuming the ECU controlled regulator is a 3rd Gen 'feature?'
     
  16. Dec 4, 2019 at 11:11 AM
    #36
    12TRDTacoma

    12TRDTacoma #1GR-FZE

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    Anywhere between 13.3-13.7 normally, though I do sometimes see 14-14.3 on the charge. It is sort random when it does that though.
     
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  17. Dec 4, 2019 at 11:20 AM
    #37
    tonered

    tonered tacorider

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    That might be why you are seeing the longevity? The voltage that I have seen on mine is rock solid at something sub-optimal for AGMs. It doesn't move once the motor is above idle.

    My bike with a MOSFET reg sits nicely at 14.2 according to a DMM. I have an onboard voltmeter, but it samples too quickly. It was good for spotting the OE shunt-type reg when it was dropping volts though.
     
  18. Dec 4, 2019 at 11:25 AM
    #38
    Scott17818

    Scott17818 Well-Known Member

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    Typical charging voltage is 14.2v or roundabouts.. it is controlled by the voltage regulator which is typically in the alternator housing itself (there are some ECU controlled alternators out there.. they are pricey too...) the ALT in our tacomas is designed to shutoff charging for fuel economy..... it will charge with 13.7-14.3v unitl it sees that the battery will return a signal showing about a 12.6v charge state.. it will then shut off and discontinue charging until voltage drops again due to accessories being used, radio, lights, cooling fans, etc... an AGM will like to see 14.7-14.9v to charge... it will accept the 14.2-14.3v charge, but will never "fill" the battery to capacity, couple this "never full status" as well as cell degredation (typical to see anywhere from 70-80% loss in amperage, and you have effectively negated the $300-400 you spent on that extra capacity, and or Ah storage.. add in freezing temperatures that rob amperage, and you may wind up in a no crank situation.... so be selective on what battery type you get.. its all about choice really... honestly I'm looking at the northstar 27f, or possibly getting a 31... and eventually expand my 12v system to involve the dc to dc charger, and a house battery for all my camping needs, and device charging responsibilities.
     
    Last edited: Dec 4, 2019
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  19. Dec 4, 2019 at 11:36 AM
    #39
    MonkeyProof

    MonkeyProof Power Top

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    Edit: Didn't realize this is a 3rd Gen. thread...

    this mod applies to 1st and 2nd gen only


    A 5 dollar diode and voltage sense wire relocate is one would ever need to sufficiently provide the proper voltage to maintain an AGM battery(s)...

    20190908_165900.jpg 20171008_143811.jpg 20190906_110703.jpg 20190906_121145.jpg 20190906_125817.jpg Screenshot_20190906-125538_Torque.jpg 20191204_113400.jpg
     
    Last edited: Dec 4, 2019
  20. Dec 4, 2019 at 11:36 AM
    #40
    DanoT

    DanoT Well-Known Member

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    My other truck is a '91 Dodge Cummins with a truck camper. I recently installed a CTek DC to DC charger (it takes input from both solar panel and alternator) and it has 2 separate very thin wires for AGM batteries but specifies a "smart alternator" is required. One wire goes to the batt neg terminal, the other to the truck's ignition.

    While I have 2 new AGM house batteries, my '91 Dodge has a firewall mounted, separate from the alternator, not very smart voltage regulator so I didn't bother hooking up the AGM wires. I guess I will settle for plugging in a 120v smart charger when electricity is available for the truck camper.
     

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