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My 2024 Cayenne is using an AGM battery. I have been using the OEM Charge-O-Mat Pro charger to top up my AGM battery every couple months.
I need to use the Cayenne during the days, so I have the charger plugged in from 9pm til 7am, and it usually takes 2 nights for the charger indicator to show fully charged (4 LED bars). But yesterday, I charged for 2 consecutive nights, but the charger indicator still shows 2 LED bars.
Then I study the Charge-O-Mat Pro in more details, and notice that the charger is only for Lead-acid batteries and Lithium batteries. There isn't a AGM battery mode as like other aftermarket AGM chargers. Does it mean the Charge-O-Mat Pro is not suitable to charge up AGM batteries ?
The main difference in charging profiles is the charging rate during bulk charging. AGM can sustain much higher charging current than flooded batteries. Since your charger outputs only 5 amperes, it doesn’t really matter. Also, AGM charging voltage is about a half-volt higher than flooded.
Here’s the Charge-O-Mat Pro’s charging profile for lead-acid batteries: https://tequipment-finder.porsche.co...t_Pro_EU_1.pdf
Bottom line: I think Porsche uses the generic “Lead-Acid” to describe your AGM battery. Your Charge-O-Mat Pro should work just fine.
I need to use the Cayenne during the days, so I have the charger plugged in from 9pm til 7am, and it usually takes 2 nights for the charger indicator to show fully charged (4 LED bars). But yesterday, I charged for 2 consecutive nights, but the charger indicator still shows 2 LED bars.
The Charge-O-Mat Pro continuously cycles through the charging stages represented by the LED's, i.e. it starts over after reaching the 4th LED. Maybe you didn't happen to look at it when the 4th LED was lit.
Edit: Maybe I should have said that this is how my Charge-O-Mat Pro is operating. Maybe it's not always the same.
I have come to the conclusion that the OEM Porsche Charge-O-Mat Pro (COM Pro) isn't compatible with AGM batteries.
The lack of an AGM charging mode on the COM Pro is the first sign. The second sign is that sometimes after 2 days of charging (just to top up the charge), the charging status indicator still shows slow flashing red bars, meaning charging is still in progress. A slow flashing green bar means battery is fully charged.
I ended up purchasing the NOCO Genius 5 (with an AGM select mode) which supplies a 5A charging current that is similar to the COM Pro. Now my Cayenne AGM battery is always completely topped up after 4-8 hrs of charge time.
I have come to the conclusion that the OEM Porsche Charge-O-Mat Pro (COM Pro) isn't compatible with AGM batteries.
It seems to work fine on my AGM repeatedly cycling through the four status LED's ad nauseam after the battery reaches its maximum charge. A potential issue I've identified is that it would not resume charging after power outages which are extraordinarily rare here. When power to the Charge-O-Mat is interrupted it is necessary to again toggle it to the lead acid charging mode. This could be a problem for those who are away from home more than a few weeks at a time.
Can your NOCO Genius 5 automatically resume charging your AGM after a power outage?
Last edited by Woofman; 08-10-2024 at 11:16 AM.
Reason: gwammer correction
No. It will go to standby mode, which doesn't do anything until the user selects the battery type again.
Correction !!
Today, I pull out my Noco Genius 5 to top up my Cayenne's AGM battery once more, and I can confirm that the charger will remember the last battery mode setting. I hook up the AGM battery, then plug in the Genius 5. After the charger initializes with a bunch of LED light show, the "12V AGM" icon lights up and charging starts.
06-24-2024, 02:47 AM
Porsche Charge-O-Mat Pro & AGM batteries
