Charging an AGM Battery

Discussion in 'Dodge Challenger General Maintenance' started by SRT-Tom, Dec 19, 2019.

  1. SRT-Tom

    SRT-Tom Well-Known Member Super Moderator Article Writer

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    Here's a word to the wise on using a trickle charge with an AGM (Absorbant Glass Mat) battery.

    Late model Challengers come with an AGM battery. AGM batteries cannot be maintained with conventional battery chargers. You must use a charger/maintainer that is specifically designed for AGM batteries. If you connect a conventional battery charger to an AGM battery, the charging indicator will light but never turn off. It will simply keep charging the battery until it is overcharged and, if left on too long, will damage or shorten the life of the battery. AGM batteries require chargers with microprocessors that regulate the charge rate and have the correct logic to turn off when the battery is fully charged.
     
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  2. 2017 Redline HC

    2017 Redline HC 2017 Redline HC

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    I use a Battery Tender brand that I better check to make sure is ok for AGM’s. It does show the green light indicating it has and maintaining the charge.
     
  3. KEVIN DONOVAN

    KEVIN DONOVAN Full Access Member

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    Sorry Tom but that is not true. You DO NOT need a special charger/maintainer for AGM batteries. Unless deeply discharged (below 10.5 v) AGM batteries can be charged with pretty much any automatic charger. Below that voltage, an AGM battery may trick your charger into thinking it's bad and the charger may not even come on. This is mainly due to the unusually low internal resistance of AGM batteries. You can however trick your old charger to charge the deeply discharged AGM battery by grabbing a set of jumper cables and hooking up another known good battery in parallel with the deeply discharged AGM battery and then hooking the charger to the good battery. Charge both for about an hour and then you can disconnect the good battery and hook the charger directly to the originally discharged AGM battery. If the charger comes on and charges, you're all set. If not, chances are the originally discharged battery truly is bad and you should consult a professional to further diagnose or dispose of the battery.
     
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  4. SRT-Tom

    SRT-Tom Well-Known Member Super Moderator Article Writer

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    I am corrected. You can use a standard battery tender with an AGM battery, if you use it on the lowest and slowest setting. Still, the battery must be closely monitored since it can get over-charged.

    That is why even though you technically don’t have to have an AGM tender for an AGM battery, it is a good idea to have one.

    For more details, see this website:

    https://autofthings.com/agm-vs-standard-battery-charging/
     
    Last edited: Dec 20, 2019
  5. synoptic12

    synoptic12 Full Access Member

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    *In fact, you do need a specific charger for "AGM" batteries.
     
  6. synoptic12

    synoptic12 Full Access Member

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    A brief synopsis of the Deltran Battery Chargers/ Maintainers:
    022-0185G DL-WH : Deland- Western Hemisphere- 'Good for outdoor use'.
    For Cars: Up to Year 2018
    For cars 2019 UP: 3amp, 4amp, or 5amp.
    This Battery Charger has a five year warranty.
    021-0128 - The original version (oldest model). Not viable for outdoor use. The 022-0185G-DL-WH is acceptable for outdoor use; not waterproof.
    This battery charger has a 10 year warranty.
    Both chargers are 12V and 1.25 amp respectively. Both chargers charge, and maintain a battery. The product icons are not accurate, relating to charging and maintaining. They are listed on the box and in specs which are incorrect. Again, both ‘charge’ and ‘maintain’ a battery. One must charge a battery before “maintaining”, irrespective of a fully charged battery. Both are microprocessor controlled and are suitable for all (AGM) - Absorbed Glass Mat batteries.
    The Junior Version (Junior 12V, 750mA Battery)-(021-0123) is for older cars that employ far less electronics than newer vehicles. Newer cars use an abundance of electronics with many more sensors than older vehicles. In this respect, Deltran is constantly moving forward to improve and upgrade in accordance with the latest electronics.

    Older vehicles do not employ the amount of electronics as on newer vehicles, therefore the 'Junior' can be used. On newer vehicles (up to year 2018) one must use at least a 1.25 Amp Deltran charger. This is for the upgraded electronics in newer cars. In years 2019 up, a 3 amp, 4 amp, or 5 amp is strongly suggested.
     
  7. synoptic12

    synoptic12 Full Access Member

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    * Don't ever apologize when you're right.
    Read Here: https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm
     
    Last edited: Nov 14, 2020
  8. synoptic12

    synoptic12 Full Access Member

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