System voltage

[Dorsal]

What system voltage should you get with a 912 at ~2000 rpm?

[DesertFox4]

Mine shows between 12.7 and 12.9 volts.

[wildlandjon]

If your battery has a good charge you should see between 13-14 volts, if the battery is low you should see 1-2 volts above the battery. It is much easier to see that your charging system is putting out amps rather than the voltage. This is done by turning on a load, the voltage will drop slightly then start to climb again as long as the load doesn't exceed your charging system rating. I'll look and see if the manual says the amps @2000 rpm and let you know.

Blue Skys

Jon

[RobS]

I agree with Jon – the important thing is the amperage rating of the alternator. I am not familiar with a Kitfox so my comment may not apply, but an electrical system with a 12 volt battery can be slightly misleading. The charging system in most 12 volt alternator systems will generally produce a voltage between 13.5 and 14.4 volts while an engine is running. The charging system has to generate more voltage than the battery's rated voltage to overcome the internal resistance of the battery. The current needed to recharge the battery would not flow at all if the charging system's output voltage was the same as the battery voltage.

As long as the engine is running, all of the power for any electronics/lights/etc is delivered by the alternator and in effect the battery is actually a load on the charging system. The only time the battery would supply power (amps) when the engine is running is when the current capacity (amperage rating) of the alternator is exceeded or possibly when the engine is at a very low idle.

[CDE2FLY]

I see 14-14.5 running the external Rotax alternator.

[Dorsal]

Thanks for the replies, works fine now.