RV12 Shows battery discharge

mxhossai · #1 01-21-2023, 01:39 PM

Hello fellow RV'ers:

So when I turn on the master swith, the two ignitions and run the engine/props, the battery does not show charging. The main battery is almost new, and have no issues starting the engine. After which, would assume alternator takes over and should be charging the battery. But its not, and the volts subsequently drops below 11.5v.

Any thoughts?

I pulled then pushed back back in the generator master fuse with no noticeable effect.

Think its regulartor or some other issue?

Regards,
Monir

Jcurry · #2 01-21-2023, 02:19 PM

Check all the usual stuff like wiring and connectors.
Voltage regulator may have failed. Common item to go bad. I put in a $20 John Deere VR. 100+ hours no problem. And for the price, I ordered 2 extra for spares.

mxhossai · #3 01-21-2023, 03:31 PM

Jack,

Sounds good. I will order one, any particular instruction on installation of it? Do I need to order any compound to be put on or does it come with all needed?

Thanks,
Monir

Mich48041 · #4 01-21-2023, 05:02 PM

A new voltage regulator is unlikely to come with any heat sink compound.

mxhossai · #5 01-22-2023, 07:42 PM

Joe,

Thanks for your reply. It (https://www.amazon.com/dp/B08SJ4D4X5...roduct_details) will arrive this week, any suggestions on wiring or needed compound etc.?

Regards,
Monir

Piper J3 · #6 01-22-2023, 08:19 PM

Here is wiring for.John Deere VR...
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Mich48041 · #7 01-23-2023, 08:54 PM

Correct me if wrong, but I think that Rotax calls for heat sink compound on spark plug threads.
That same compound can be used between metal parts when mounting the voltage regulator.

mxhossai · #8 Yesterday, 04:16 PM

So, the John Deer wasn't a help (it was only $20, so not a big damage), since I have a Silent Hektik F4120 installed. So any idea how to install it (mine was not built by me). Does it have a compound that it is holding to the firewall side? Also, where to order it?

DHeal · #9 Yesterday, 06:38 PM

The Rotax 912 ULS is equipped with what is really a "generator" not an "alternator" -- see:

https://www.rotaxowner.com/pdf/IM_912_Series_Ed3_R0.pdf

As such the generator does not generate very many amps when the engine is operating at relatively low RPMs -- say 1,800-2,200 RPMs. At such low RPMs the generator will not charge the battery and you may see yellow warning indications and low readings on your Voltage and Amperes gauges. Do your low voltage and amperes indications increase if the engine is operated at typical cruise RPMs? If so, your electrical system may be operating normally. In cruise flight (@ 5,250 RPM) I typically see @ 13.9-14.0 Bat Volts and 1 Bat Amp with all electrical loads operating.