Engine voltage operating requirements?

[angleiron]

I know these 4-stroke engines need a 31 series AGM, but what is the minimum voltage that these engines need to run? I ask because for some reason the AGM I have will not charge over 12.8 volts now, and I know I have seen it in the 13.2V range in the past. It is only 4 months old, and I am using a Minn Kota precision charger. When I plug the charger in it goes to the AGM setting for a few seconds and then starts flashing red. Want to get out one more time before the snow comes.

I did a search and could not find anything using the search words that I used.

[Buck456]

I would first check both the inline fuses from your charger to that battery. Also check connections and polarity.

If all of that looks fine then try to charge the battery on a different bank. Just make sure you program the charger to charge an AGM battery. If you try a different bank on your charger and it still flashes red your battery maybe the issue. If it continues to charge the battery fully you more than likely have a bank out of your charger.

May not have directly answered you question, but these steps will help you troubleshoot your problem.

[CatFan]

Many if not most AGMs are fully charged at 12.8V. A few go higher than that, but nothing I know of is as high as 13.2V so you were likely seeing surface charge. Which particular battery do you have?

[EuropeanAM]

Many if not most AGMs are fully charged at 12.8V. A few go higher than that, but nothing I know of is as high as 13.2V so you were likely seeing surface charge. Which particular battery do you have?

+1

Still a good idea to check your connections, fuses, and make sure that it's not a bad bank on the charger.

For your "Minimum voltage required to run" question, that's a bit tricky. The engine MIGHT start with voltage as low as 11 Volts (IF there is adequate amperage capacity to keep the voltage high enough to retain the closed-contacts on relays, drive fuel pumps and ignition, PCM, injectors, sensors, etc). The engine will not, however, run RIGHT at that voltage (and will likely go into Engine Guardian).

Just a courtesy reminder: Be sure to take a few moments to review the Announcements at the top of the Forum, and provide the Required Info (serial number) when posting. Thanks!

[angleiron]

It is the charger. Switched leads and the problem stayed with the same leads on the charger.

[EuropeanAM]