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Agm battery charging..

Discussion in '2.5 Gen Tundras (2014-2021)' started by Mrf1987, Nov 2, 2021.

  1. Nov 2, 2021 at 9:29 AM
    #1
    Mrf1987

    Mrf1987 [OP] New Member

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    Agm battery questions….

    I’m swapping in an x2 power 31agm to better handle all of my camping electronics.
    *fridge/lights etc etc
    As we know the oem charging system doesn’t fully charge an Agm battery. Has anyone in here performed the gm or ford diode in the alt-s fuse spot to up the voltage seen?
    I have the gm diode ready to go but wanted to see if anyone else has seen and negative effects on their electronics like dometic etc etc? Thanks guys.
    upload_2021-11-2_12-28-17.jpg

    85E52085-50AF-4C15-9F84-566672627F77.jpg
     
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  2. Nov 2, 2021 at 9:30 AM
    #2
    timsp8

    timsp8 Member

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    I’ve been using the gm diode for about 6 months with no issues.
     
  3. Nov 2, 2021 at 9:32 AM
    #3
    Mrf1987

    Mrf1987 [OP] New Member

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    good news, which direction did you place the diode? Also did you just install the diode or did you install 2 fuse taps to protect the circuit with the factory fuse as well?
     
  4. Nov 2, 2021 at 10:51 AM
    #4
    NewImprovedRon

    NewImprovedRon Hey! Get off my grass!

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    I just slap a trickle charger on my 27F AGM battery once a month and all is good.
     
  5. Nov 2, 2021 at 12:00 PM
    #5
    Jhon

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    If you haven’t bought the battery consider a separate house battery.

    I have a Dometic PLB40. It ended up being cheaper than a dual battery system and more versatile. It’s a 40ah LFP battery with built in charge controller. I like it because it allows me to swap the fridge and battery between my Tundra and the wife’s Subaru. Since both have keyed 12v sockets I didn’t need to worry about any wiring and no worries about draining the starter battery. My ARB fridge will run for 2-3 days without charging the battery. With a portable 100w solar panel it’s pretty much indefinite.
     
  6. Nov 2, 2021 at 12:07 PM
    #6
    timsp8

    timsp8 Member

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    Arrow pointing forward. I put it straight in, no taps. Most I’ve seen is around 14.5, then after driving awhile it drops to 13.8-14 or so.
     
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  7. Nov 2, 2021 at 12:08 PM
    #7
    e30cabrio

    e30cabrio I'm e30cabrio, I'm a modaholic

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  8. Nov 2, 2021 at 12:08 PM
    #8
    Mrf1987

    Mrf1987 [OP] New Member

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    I’m going to move forward with this route of running a single battery. My factory Toyota battery can’t keep up with everything f i have onboard currently. My arb compressor/fridge/lighting puts a big hurt on it. I may also add mother house battery but i want to go this route first. Thanks for your input it’s appreciated.
     
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  9. Nov 2, 2021 at 12:18 PM
    #9
    g6t9ed

    g6t9ed Novice Tundra Modder

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    You didn't have to trim the edge of the diode? It's been a while for me but I thought i remembered I couldn't get it to fit without trimming it first?
     
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  10. Nov 2, 2021 at 12:18 PM
    #10
    timsp8

    timsp8 Member

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    Yes I had to trim it. I used a box cutter and took a little off both sides.
     
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  11. Nov 2, 2021 at 12:19 PM
    #11
    g6t9ed

    g6t9ed Novice Tundra Modder

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    Ah, okay. I misread your post then. It made it seem like no alterations were needed.
     
  12. Nov 2, 2021 at 12:20 PM
    #12
    Mrf1987

    Mrf1987 [OP] New Member

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    the diode does have to be trimmed from what i can see. If i recall i think the does diode is a direct fit.
     
  13. Nov 2, 2021 at 12:21 PM
    #13
    g6t9ed

    g6t9ed Novice Tundra Modder

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    Right, I had to trim mine. I just thought that maybe @timsp8 may have found an alternative diode other than either the trickle charger or the HKB.
     
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  14. Nov 2, 2021 at 12:23 PM
    #14
    Mrf1987

    Mrf1987 [OP] New Member

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    my voice to text is on the fritz. I believe the ford diode is a direct fit. Others on tacoma world have used the ford part and have said it’s a direct drop in.
     
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  15. Nov 2, 2021 at 12:23 PM
    #15
    timsp8

    timsp8 Member

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    Sorry. Yeah it just took a few minutes to scrape enough off. I thought I was going to get down to the metal before it would fit too.
     
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  16. Nov 2, 2021 at 12:27 PM
    #16
    g6t9ed

    g6t9ed Novice Tundra Modder

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    That is good to know. I'll have to look into it. Always good to find alternatives if this one decides to have issues. So far, so good though. Although, I don't use anything extensive. Funny enough, the reason for going AGM for me was because of the Android radio. That thing uses quite a bit of juice when the engine's off and, like you, the factory battery didn't cut it after a while.

    I know what you mean. I had the same worry. At the time, I even bought a spare in case I messed up. I've been monitoring mine and I'm getting around the same as you.
     
  17. Nov 2, 2021 at 12:37 PM
    #17
    timsp8

    timsp8 Member

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    I ordered mine off Amazon. It was in a pack of 5 or so for like $10. I was worried too but glad I had spares. I carry the stock fuse in my truck too in case something goes wrong with this one.
     
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  18. Nov 2, 2021 at 1:28 PM
    #18
    Tundradrenalin

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  19. Nov 3, 2021 at 10:32 AM
    #19
    Vr0ck

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    Thanks for sharing this link.
    My 2016 stock battery is finally acting up....looking into AGM replacement. The hkbelect.com site seems to be down.
     
  20. Nov 3, 2021 at 12:04 PM
    #20
    Vr0ck

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    What is the part# for the GM diode? Thanks!
     
  21. Nov 3, 2021 at 12:26 PM
    #21
    BCTRD

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    Does this setup have any negative affects on a later model Tundra.
    The eBay listing mentions beware any that don't retain the factory fuse which isn't a bad plan...
    Following
     
  22. Nov 3, 2021 at 12:28 PM
    #22
    Rodtheviking

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  23. Nov 3, 2021 at 12:29 PM
    #23
    Vr0ck

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    Not sure. Still trying to wrap my head around all this.
    Ideally you want the increased voltage, but keep the protections in place.
     
  24. Nov 3, 2021 at 12:43 PM
    #24
    timsp8

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    F142ECF6-7C6A-4615-AE92-0A1AB749AA46.jpg
     
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  25. Nov 3, 2021 at 12:53 PM
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    BCTRD

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    Agree on the protections. My concern is letting smoke out of the electrical on a truck under warranty, not that I'm opposed to the idea.
    Wonder what the additional amp/voltage output is and has anyone put a clamp on Fluke or Hioki to test amperage.
     
  26. Nov 3, 2021 at 1:04 PM
    #26
    Terndrerrr

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    Last edited: Nov 3, 2021
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  27. Nov 3, 2021 at 1:20 PM
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    Vr0ck

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    Thanks.
    How is everyone monitoring the charging while on the move?

    Ive seen a couple cig lighters showing voltage output.
     
  28. Nov 3, 2021 at 1:26 PM
    #28
    Terndrerrr

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  29. Nov 3, 2021 at 2:03 PM
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    timsp8

    timsp8 Member

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    I use my scangauge. It’s already there for trans temps. I just use one of the blocks for battery voltage.
     
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  30. Nov 6, 2021 at 12:12 PM
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    PWMDMD

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