Calling all AGM battery experts

[Harold&Cat]

Where are you getting that information?




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I believe what Chad is referring to is that the charging voltage is higher than the " State of Charge " voltage .
To charge a battery fully the charging voltage must be higher than the battery voltage trying to be achieved .
My 36 volt smart charge golf cart charger goes to 45 volts at 5 amps before switching to a trickle type maintenance charge .

 

[Steel City 06]

Where are you getting that information?




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Preferred alternator charging voltage for AGMs is usually between 14.2 to 14.8V, with the ideal being around 14.4V, slightly higher in very cold conditions or under shorter cycles; slightly lower in very hot conditions or very long drive cycles.

The standard alternator charging point of TJs without a battery temperature sensor (or with a malfunctioning one) is typically too low to get the max lifespan out of an AGM battery.

Simply put, the charging voltage needs to be well above battery resting voltage as there needs to be a significant imbalance in potential to get current to flow into the battery at an appreciable rate. In addition, the higher voltage helps break up sulfation (which can indeed occur in AGM batteries, though the properties are different compared to flooded cell), and also serves as a super crude form of cell balancing.

 

[alittleoff]

I got a question related to this post. I have a HF charger and it has a 'recondition' setting.
What does that do and can it be done to an AGM battery and a flooded cell battery?
My instruction pamphlet went missing a few years ago too.
Thanks.

 

[Steel City 06]

I got a question related to this post. I have a HF charger and it has a 'recondition' setting.
What does that do and can it be done to an AGM battery and a flooded cell battery?
My instruction pamphlet went missing a few years ago too.
Thanks.

Probably charges to 15-16V for a short period to disrupt sulfation and crudely balance the cells. Works way faster than what the TJ's alternator can do under normal programming.

Modern cars actually do this automatically and bump up the charging voltage to 15V+ for short periods of time, usually during deceleration (which simultaneously serves as a crude form of regenerative braking).

 

[alittleoff]

Thank You Sir.
I've got a Premier Power Welder alternator rated at 190 Amps and a 6 year old Sears Platinum AGM.
I drive it a couple of times a month but, it does seem to crank slow at first start up on these cold mornings.
And it's hooked up to the HF charger at 2 amps when parked. But the lights are bright and charges at 14+ while driving.

 

[Harold&Cat]

I got a question related to this post. I have a HF charger and it has a 'recondition' setting.
What does that do and can it be done to an AGM battery and a flooded cell battery?
My instruction pamphlet went missing a few years ago too.
Thanks.

I don't know much about the reconditioning process , but I ran across this in a search . I don't know about the HF charger , you might can google the model for specs .

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://kickassproducts.com/blogs/article/use-the-recondition-mode-on-kickass-12v-acdc-chargers-to-restore-your-agm-batteries?srsltid=AfmBOor2fdrPi5zVzW0tEGdkfRPBNwx9O4Fk4V9Zw6hWZ_qEuE02xgnY&ved=2ahUKEwjE1Y3q5aeKAxWYLtAFHQ3TCosQFnoECD8QAQ&sqi=2&usg=AOvVaw3WJA91jnG7ESY7UYVzdjGN

 

[alittleoff]

Jajaja, watt a rippa

 

[TJ Jim]

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I believe this is the answer to when to look at replacing an agm.

 

[ChadH]

Preferred alternator charging voltage for AGMs is usually between 14.2 to 14.8V, with the ideal being around 14.4V, slightly higher in very cold conditions or under shorter cycles; slightly lower in very hot conditions or very long drive cycles.

The standard alternator charging point of TJs without a battery temperature sensor (or with a malfunctioning one) is typically too low to get the max lifespan out of an AGM battery.

Simply put, the charging voltage needs to be well above battery resting voltage as there needs to be a significant imbalance in potential to get current to flow into the battery at an appreciable rate. In addition, the higher voltage helps break up sulfation (which can indeed occur in AGM batteries, though the properties are different compared to flooded cell), and also serves as a super crude form of cell balancing.

That is dependent on the battery design and manufacturer though, it is not a catch-all. Though 14.2-14.8 will work. For example, my batteries are designed for a 14.7 preference.

 

[TJ Jim]

Got the Audi battery replaced yesterday. Now after a long rest period it reads 12.5 volts when the old battery read 11.5. On the way to the dealership it started doing all kind of weird stuff. Imaginary seat belt alarms. Headlights out of aim. Really weird. Now on to getting the jeep battery charging higher. It’s 11.9 today.

 

[B1Toad]

To update this thread, the Superstart AGM in the Infiniti croaked shortly after this thread and it was just over 2 years old. They actually gave me a free replacement but this time I installed a NOCO maintainer right away with the new battery and it is plugged in the majority of the time. The same battery in the motorhome is now over 5 years old and still going strong, it has been on a maintainer at all times when not in use.