[STYLO LT1]

Let me begin by apologizing for posting this here on the general section and not in the Camaro issues section. In my opinion it’s hard to get a quick answer when posting there. Unfortunately, batteries are not my expertise.

So I’ve noticed for the last 4-5 months that the battery voltage reading in the dash has been lingering in the 12.25-12.4V range when idling and driving. I’ve come to notice now that when I put the headlights on, the volt gauge reading goes up 14-14.5V and the battery will gradually charge up near 100%. Turn the headlights off and the voltage drops back down 12.3V range and battery % lowers. I have a Antigravity Batteries Battery Tracker device installed on the battery with the app on my phone. I’ll drive for an hour and the voltage gauge in the car will never go past 12.5V and the battery app says the battery is at 70% after said trip. It will only get to 100% when I flick the headlights on and drive the car for a while.

I bought a brand new AGM battery a couple days ago as it was losing its ability to maintain a charge. It could be at 100% one day, then 2 days later be at 75% just sitting. So even with the new battery, the gauge is always at @ 12.3 driving or idling. Is this a normal occurrence on these cars? Is a voltage reading of 12.3 at idle most of the time normal? Should the car bring the alternator up to 14V more often? Is the battery supposed to charge up to 100% with every drive? Could my alternator be the culprit? Any help and suggestions will be greatly appreciated. Thanks in advance.

[raptor5244]

Originally Posted by STYLO LT1

Let me begin by apologizing for posting this here on the general section and not in the Camaro issues section. In my opinion it’s hard to get a quick answer when posting there. Unfortunately, batteries are not my expertise.

So I’ve noticed for the last 4-5 months that the battery voltage reading in the dash has been lingering in the 12.25-12.4V range when idling and driving. I’ve come to notice now that when I put the headlights on, the volt gauge reading goes up 14-14.5V and the battery will gradually charge up near 100%. Turn the headlights off and the voltage drops back down 12.3V range and battery % lowers. I have a Antigravity Batteries Battery Tracker device installed on the battery with the app on my phone. I’ll drive for an hour and the voltage gauge in the car will never go past 12.5V and the battery app says the battery is at 70% after said trip. It will only get to 100% when I flick the headlights on and drive the car for a while.

I bought a brand new AGM battery a couple days ago as it was losing its ability to maintain a charge. It could be at 100% one day, then 2 days later be at 75% just sitting. So even with the new battery, the gauge is always at @ 12.3 driving or idling. Is this a normal occurrence on these cars? Is a voltage reading of 12.3 at idle most of the time normal? Should the car bring the alternator up to 14V more often? Is the battery supposed to charge up to 100% with every drive? Could my alternator be the culprit? Any help and suggestions will be greatly appreciated. Thanks in advance.

Yeah, it is normal, these cars use an on demand charging system. It will only charge the battery if it needs to. You see the voltage increase with the when you put a higher load on the system, otherwise the battery management system determines if it needs to add voltage or not. These systems help extend the life of the batteries.

[keep_hope_alive]

This kind of system has been in place in Hondas since the 1990's. In a Honda the load sensing device that is used to tell the PCM to turn on the alternator field current is the ELD or Electronic Load Detector. The ELD monitors the ignition circuit and things like lighting or A/C can result in the alternator being "on". Originally, the alternator would be either on or off, and users found it annoying that their headlights would dim. Since 2013 they started regulating the "off" output to 12.5V which prevents battery voltage from dropping below that (they could get to 11.9V on the old system).

I'm intrigued. I developed a bypass for the old Honda system. I'll look at the charging schematics and see what the PCM is looking at to make the determination to turn the alt field current on or off.