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Battery Monitor

Discussion in '2.5 Gen Tundras (2014-2021)' started by 2point5seconds, Jan 27, 2022.

  1. Jan 27, 2022 at 7:00 PM
    #1
    2point5seconds

    2point5seconds [OP] Wish I didn't have so much money

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    2019 Tundra 5.7l 4WD DC

    Just replaced the original battery that came with the truck. Lasted only 2.5 years. Got a X2 AGM battery from Batteries Plus. Hopefully will be able to support my winch, light bar, and ditch lights.

    Got a battery charger. Read that the factory alternator doesn't charge the larger AGM battery 100% .

    What does everyone use as a battery monitor? I know there are Bluetooth ones with an app. Just want to keep an eye on the battery since it cost me $300+.

    Thanks!
     
    Wallygator likes this.
  2. Jan 28, 2022 at 8:44 AM
    #2
    frichco228

    frichco228 Valued Member

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    You need to change some diodes I believe to run an AGM battery. It will not fully charge and cause you issues without that modification to the factory alternator. It has been discussed here, try a search.
     
  3. Jan 28, 2022 at 8:45 AM
    #3
    Saltyhero13

    Saltyhero13 Throbbing Member

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  4. Jan 28, 2022 at 8:59 AM
    #4
    DEboater

    DEboater New Member

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    If you head over to boat forums, like thehulltruth.com you’ll get good feedback on AGM and other batteries, keeping them maintained, charging. Those folks use them for trolling motors and a lot of other stuff. I don’t know much about it but do know if they’re not set up to charge right you’ll be in for a world of hurt.
     
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  5. Jan 28, 2022 at 9:05 AM
    #5
    Saltyhero13

    Saltyhero13 Throbbing Member

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  6. Jan 28, 2022 at 9:17 AM
    #6
    Cruzer

    Cruzer Wheeling Full Size

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    You could replace one of your cigarette lighters for a USB charger that also displays your voltage. Just search Amazon.
     
  7. Jan 28, 2022 at 5:42 PM
    #7
    2point5seconds

    2point5seconds [OP] Wish I didn't have so much money

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    Yeah. Looked on YouTube and on here before buying everything. I decided not to do the diode and just got a charger. Thank you for the input!
     
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  8. Jan 28, 2022 at 5:43 PM
    #8
    2point5seconds

    2point5seconds [OP] Wish I didn't have so much money

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  9. Jan 28, 2022 at 5:44 PM
    #9
    2point5seconds

    2point5seconds [OP] Wish I didn't have so much money

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    I saw that. I already changed both my cig lighters for dual USB chargers. I did see that one though. Thank you!
     
  10. Jan 28, 2022 at 5:51 PM
    #10
    Brownsfanhere

    Brownsfanhere New Member

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    Seems like a total pita to go AGM. But that just me. Put a battery in and forget about it . Was interested in the batteries plus agm but will never babysit a battery. Got better things to do.
     
  11. Jan 28, 2022 at 6:39 PM
    #11
    HulkSmurf14

    HulkSmurf14 ...Weighted Average...

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    No need to babysit anything if done correctly with an $8 diode...just replaces the factory 7.5A Alt-S circuit and tricks the ECU to enable the alternator to charge between 14-14.4 volts...no monitor needed unless you like distractions
     
  12. Jan 28, 2022 at 7:06 PM
    #12
    2point5seconds

    2point5seconds [OP] Wish I didn't have so much money

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    I was looking at one of the other threads that showed the diode. Does that get plugged in with an add a fuse to the 7.5?
     
  13. Jan 29, 2022 at 7:40 AM
    #13
    HulkSmurf14

    HulkSmurf14 ...Weighted Average...

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    Negative...Lexus GX can be configured with an add-a-fuse, you just need to put the diode in place of the 5A-7.5A ALT-S fuse on the Tundra...works like a charm.
     
  14. Jan 29, 2022 at 8:59 AM
    #14
    Sonicbluerider

    Sonicbluerider New Member

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    So want happens if you Don't add that diode in the system???
     
  15. Jan 29, 2022 at 9:53 AM
    #15
    pdf256

    pdf256 New Member

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    Without the diode the charging voltage will be too low to fully charge the AGM battery. Over time you will kill it from the under-charging.

    pdf
     
  16. Jan 29, 2022 at 10:51 AM
    #16
    Saltyhero13

    Saltyhero13 Throbbing Member

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    It was incredibly complex for me.

    The monitor is plug and play, IMO it should have just attached itself on command as soon as I opened the box. Once I found the battery I had to remember "Lefty loosie, righty tighty!" I held my hand up in the shape of an "L" for this part.

    To view the battery log I tried speaking binary and Spanish to the device but I was forced to download an app that allowed me to connect to the device via Bluetooth. The device has a "QR" code that will take you to the app download. Once connected it gives you access to current voltage and a historical log of the battery's charge state. The connection range is about 30 to 50ft depending on where you are standing and it takes less than 10 seconds to get into the logs. It has very low draw on the battery as well.

    The voltage mod required incredible finger strength to pull out the fuse (once I located the fuse box, whew!) and replace it with a diode/voltage boosting HBK device. If you garage your vehicle the three prong trickle chargers are more difficult to plug in than a two prong; whew take it from me! Someone also recommended a quick disconnect cable (crazy bastard) and surprisingly it worked. No one died! Off grid I use a solar generator battery to plug in when I'm not driving.

    You guys may have an easier time than me as I'm a few beers short of a six pack if you know what I mean ;)
     
    Rodtheviking, nlaroy, hagrid and 3 others like this.
  17. Jan 29, 2022 at 12:02 PM
    #17
    Sonicbluerider

    Sonicbluerider New Member

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    So is that diode needed for all tundras? Or older ones. I was under the impression mine had the best alternator with high output available in 19
     
    2point5seconds [OP] likes this.
  18. Jan 29, 2022 at 12:09 PM
    #18
    HulkSmurf14

    HulkSmurf14 ...Weighted Average...

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    Only vehicles that do not come from factory with an AGM battery. If you're "upgrading" your battery, other items should/need upgraded as well to make it worth doing...hobbies are expensive :spending::transformer:

    The ecu determines the output it will use from alternator...we're just tricking the ecu into unlocking more charging potential with the diode...all alternators can pump out more juice safely...
     
  19. Jan 29, 2022 at 12:19 PM
    #19
    Saltyhero13

    Saltyhero13 Throbbing Member

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    Its not an issue with the alternator's amperage. Stock voltage is about 13.7V, AGM batteries are happiest at ~14.5 volts. The diode tricks the ECU to have the alternator produce a more acceptable output. The GM diode is a flat .5V bump for $8, the high end HBK device gives you more control with .2V adjustments and some protection for ~$150 or so. You can put a fuse in series of the diode if you want the extra protection. I'll see if I can find the write up someone posted.

    The big risk is if you go too high with volts but I'm not sure what that threshold is. I've had voltages as high as 14.7 with no issues. Others have reported no issues or long term effects.
     
  20. Jan 29, 2022 at 12:45 PM
    #20
    2point5seconds

    2point5seconds [OP] Wish I didn't have so much money

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    That's what I was wondering if the diode would create issues for the alternator. Other threads said no or they weren't sure.
     
  21. Jan 29, 2022 at 12:48 PM
    #21
    Saltyhero13

    Saltyhero13 Throbbing Member

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    A few people have had this on long term with no issues. I would be more worried about overvoltage frying something vs the alternator. Toyota overbuilds their products and the alternator is pretty beefy.
     
  22. Jan 29, 2022 at 2:07 PM
    #22
    Sonicbluerider

    Sonicbluerider New Member

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    HKB Electronics0
    MK2 Micro blade 5A (Electronic fuse version)---- anyone have a place that have them in stock. Hkb website sold out.
     
  23. Jan 29, 2022 at 2:21 PM
    #23
    Wallygator

    Wallygator Well Zippedy Da Do!

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    Replaced the cig lighter with this....

    https://www.amazon.com/gp/product/B08LDC86Z9?ie=UTF8

    I throw my X2 AGM on the battery charger about once a month, sometimes more. It's not a pain in the ass cuz I like taking care of my truck. Maybe one day I will do the fuse thing but so far it's been fine. I need an AGM for my application so that is why I have one. YMMV.
     
  24. Jan 29, 2022 at 3:10 PM
    #24
    Saltyhero13

    Saltyhero13 Throbbing Member

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    I'm fairly certain they are the sole vendor.
     
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  25. Jan 30, 2022 at 5:51 PM
    #25
    2point5seconds

    2point5seconds [OP] Wish I didn't have so much money

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    Sorry. Haven't drive my truck in awhile. But while starting it I realized that's the one I installed. Don't see the display because I have two USB cables going up the dash. I have to bend over to see it. Do you find it to be accurate?
     
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  26. Jan 31, 2022 at 4:44 AM
    #26
    Sonicbluerider

    Sonicbluerider New Member

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    My problem is we spend a lot of time Boondocking, 158 days last year with zero electricity available.
     
  27. Jan 31, 2022 at 4:52 AM
    #27
    timsp8

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    Ive had the gm diode in for about a year with no issues. When i first start the truck, it’s between 14.2-14.7v. After driving awhile, it’ll settle to 14-14.5v. I got a 5 pack on Amazon for $20. You also need a knife or box cutter to trim the side so it’ll fit. Not hard to do.
     
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  28. Jan 31, 2022 at 5:57 AM
    #28
    Vizsla

    Vizsla Don’t eat the brownies!

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    Had to remove voltage booster, know a few others as well due to killing batteries. Not sure why, but after watching a proper AGM charge cycle think it’s due to holding 14.4v ish too long, but all had more than 1 battery so idk.. End up in some really remote places where reliability is important, so booster went in the trash can. My solar controller does a proper AGM charge, so just let it keep the batteries happy now.
     
  29. Jan 31, 2022 at 6:38 AM
    #29
    DSLKSL

    DSLKSL New Member

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    I used the "GM diode fuse" I noticed when I start my tuck the voltage goes to 14.4v after about 10-20 mins it drops to 13.8. So I don't think the diode is hurting anything.
     
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  30. Jan 31, 2022 at 6:58 AM
    #30
    AZTundra

    AZTundra No Longer a New Member

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    Was this with the GM diode or the HKB?
     
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