AGM battery charge voltage

[R-2]

Has anyone seen info that AGM batteries require a higher charge voltage? Apparently most jeeps put out about 13.5 volts and AGMs require 14.5 to charge completely. They will charge but just not all the way. I am getting ready to get rid of the aux battery and want to use an AGM but am wondering if this is an issue?

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[THAW]

• JLs are designed to use, and factory-built with, AGM batteries
• JL alternators/DC-to-DC-converters regularly run at over 14 Volts
• Regardless of peak voltage during vehicle operation, AGM batteries are unlikely to be optimally charged while the vehicle is in use - most automotive electrical systems are designed to quickly replenish minimal start battery energy loss caused by standby systems and brief starter operation, thereby maintaining reasonable but not necessarily 100% SOC

AGM is what you should use in your JL. The best way to maintain your JL's AGM battery/batteries is periodic maintenance charging using an external charger with an AGM setting.

 

[Reinen]

That's why car batteries don't last as long as they used to. Not only do you need to charge them completely (which the JL does) but you also need to keep them fully charged (which every modern vehicle does not). The electronic accessories are always draining the battery slightly, even while parked, so the batteries are hardly ever at 100%

JL OEM batteries are AGM and they must be replaced with AGM batteries.

 

[AndySpill]

I am getting ready to get rid of the aux battery and want to use an AGM but am wondering if this is an issue?

I'm not sure if this means a desire on your part to replace or bypass the Aux battery. On top of other reasons mentioned, if it means replace, it is highly recommended that given the 2 batteries being connected in parallel about 99.99% of the time, but for ESS events and an instant at cold crank, that they match voltage and chemistry, the main battery, as reported being of an AGM variety.

(Then again, it's recommended both batteries be replaced at the same time if keeping an Aux battery connected.)

Some people have reported success with running just a Lithium Iron Phosphate main battery (i.e. Anti-Gravity Brand).




https://antigravitybatteries.com/pr..._9SDEaspIe8tAKZhLW_ag0RCQyMnhsSlTCoHExfdrenhU

But its for places that don't drop below 23 degrees Fahrenheit. It's not for me in the Northeast. (See operational temperature page 6.) I'd also, even if living in Arizona, rather run the battery chemistry my JL was designed for.

https://antigravitybatteries.com/downloads/AG-Automotive-RS-Batteries-User-Manual.pdf

 

[Nvdardx28]

Has anyone seen info that AGM batteries require a higher charge voltage? Apparently most jeeps put out about 13.5 volts and AGMs require 14.5 to charge completely. They will charge but just not all the way. I am getting ready to get rid of the aux battery and want to use an AGM but am wondering if this is an issue?

To settle the debate on charging voltages and chemistry. At the end of the day an AGM is still a lead acid battery, the AGM is only a difference in how the electrolyte is held within the battery cells (glass mats). You can completely charge a battery to 100% by only charging at 13.5-13.8V. Anything above that is to equalize the internal cells since they are in series, also to rebalance the anode and cathode plates in each cell from sulfation. These higher voltages are meant to condition the battery so it can extend its useable life. The JL's battery system will monitor temperature environments to optimize the balance of charge vs. conditioning.

 

[Heimkehr]

Has anyone seen info that AGM batteries require a higher charge voltage? Apparently most jeeps put out about 13.5 volts and AGMs require 14.5 to charge completely. They will charge but just not all the way. I am getting ready to get rid of the aux battery and want to use an AGM but am wondering if this is an issue?

By way of example:

I just replaced the original H6 AGM in my '21 JLU two days ago. It lasted four years, almost to the the day.

I'd periodically have the volt meter displayed on the center TFT screen while driving. The average charge voltage during the original's four year lifespan was 13.9 - 14.2V. That same charging range has been evident for the past 48 hours that the new H7 AGM has been in situ.

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