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Not charging

tomkk

Well Known Member
My RV-12 system does not appear to be charging at all. It's a 912-ULS with a Silent Hektik VR that has been working fine for almost 4 years, including its last flight about 2 months ago. Now Dynon indicates a constant -7A with the system up and running regardless of RPM.

My first thought was VR so I temporarily replaced the SH VR with a new AM101406 VR I had in the hanger with no change. Fuses all OK.

I don't know what the generator output signal looks like. Should I be able to put a VOM across the two yellow wires from the generator and see something like 14VAC or so? Not sure where else to start, just trying to eliminate possible sources of the problem. I'd welcome any suggestions.
 
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My RV-12 system does not appear to be charging at all. It's a 912-ULS with a Silent Hektik VR that has been working fine for almost 4 years, including its last flight about 2 months ago. Now Dynon indicates a constant -7A with the system up and running regardless of RPM.
Since you aren’t getting a low voltage alarm, let’s cross check the ammeter
What is the indicated battery voltage? Under 13 volts would also indicate no output.
My first thought was VR so I temporarily replaced the SH VR with a new AM101406 VR I had in the hanger with no change. Fuses all OK
How about the soldered in 1 amp fuses
I don't know what the generator output signal looks like. Should I be able to put a VOM across the two yellow wires from the generator and see something like 14VAC or so? Not sure where else to start, just trying to eliminate possible sources of the problem. I'd welcome any suggestions.

Unloaded the two yellow wires from the stator could be as high as 100 VAC.
The first thing I would check is for control power to the regular. This is the thin yellow wire that went to the “C” pin on the original version regulator. You must have battery voltage at this pin when the master switch is on.
 
Since you aren’t getting a low voltage alarm, let’s cross check the ammeter
What is the indicated battery voltage? Under 13 volts would also indicate no output.
Yeah, it's running under 13v. Looking back at the Dynon data of that last flight, I can see a three or four intermittent "cut-outs", where it stopped charging, but the voltage never made it low enough for a low voltage alarm. It is now.

How about the soldered in 1 amp fuses
I get a short with a DVOM between pins 17 & 23 of the switch module. I think that says the two fuses connected to the shunt are OK. I do get an open circuit between pin 16 of the connector and both of the pins in the two pin BAT/GEN connector. I think that might mean that fuse might be gone but I don't think that would affect the charging with the wiring setup where the VR Control is jumped to VR output. I didn't notice whether the Master SW was illuminated.

Unloaded the two yellow wires from the stator could be as high as 100 VAC.
The first thing I would check is for control power to the regular. This is the thin yellow wire that went to the “C” pin on the original version regulator. You must have battery voltage at this pin when the master switch is on.
The first DVOM I used was an "automatic" one that was supposed to figure out whether it was seeing AC or DC. I don't know what the generator signal looks like but that DVOM didn't recognize the AC and basically gave me zero. I got another DVOM that had specific DC & AC switch positions and that read 18VAC - 24VAC depending on RPM so I think the generator and wiring to the VR is OK

So, I'm sort of where I was to start but it seems like I've eliminated most of the likely culprits. Not sure what to try next. Maybe trying to install another VR? Did that once but can't think of anything else to try.
 
I didn't notice whether the Master SW illuminated or not. I suspect not since it looks like that fuse might be blown. I don't think that'll affect charging, though, since that signal is no longer used to control the VR.
 
I didn't notice whether the Master SW illuminated or not. I suspect not since it looks like that fuse might be blown. I don't think that'll affect charging, though, since that signal is no longer used to control the VR.

If Master switch does not illuminate,at least one of your soldered in fuses is blown in the switch panel,they can be replaced but its a pain, I have no idea why Van’s designed soldered in fuses that are not easily accessible, you can send panel to Van’s rebuild, buy new panel or get creative.
Stan
 
And the answer is ... bad connection. The "Gen" pin in two pin connector on the Fuse & Switch module had worked loose and wasn't making a good connection. Charging fine now. Thanks for your suggestions ...
 
And the answer is ... bad connection. The "Gen" pin in two pin connector on the Fuse & Switch module had worked loose and wasn't making a good connection. Charging fine now. Thanks for your suggestions ...

Can’t tell you the number of times that I thought I had a more serious problem, but found in the end it was something simple like a connection or loose wire. Congrats
 
Can’t tell you the number of times that I thought I had a more serious problem, but found in the end it was something simple like a connection or loose wire. Congrats

Wish that were the case for me... I've got the same issue. Low voltage indication, not charging, D180 shows -5 to -7 amps. Our battery was bad, so I installed a new one.

We have the B&C regulator installed, which replaced the Silent Hektik that was still working, but using a charging profile for LiPo batteries that wasn't great for shorter flights. I left the SH regulator in place on the firewall step, and mounted the B&C vertically per instructions with the new cowl scoop directing outside air onto it.

The first thing I tried was moving the plug from the B&C back to the SH regulator, since it was working when we did the swap. Got the exact same indications with the engine running, under 12V with 5-7A drain indicated.

Last night I checked the yellow wire on terminal 6 of the regulator; as soon as I turn on the master switch I get battery voltage there. I do see some AC output on the generator wires when turning the engine over with ignition off -- it was cold and I was there alone, so I didn't check that with the engine running.

So either we have not one but two bad regulators, or there's something else I'm missing.
 
It sounds like your system is charging a bit? Mine didn't charge at all, it was fixed pretty much at -7a as soon as I turned the system on and it didn't vary. The actual value depended on exactly what equipment I had powered up but was fixed at that value.
 
It sounds like your system is charging a bit? Mine didn't charge at all, it was fixed pretty much at -7a as soon as I turned the system on and it didn't vary. The actual value depended on exactly what equipment I had powered up but was fixed at that value.

The amperage would fluctuate some between -5 and -7, but voltage continues to decline. I'm going back to the hangar tomorrow with an O-scope and a JD style regulator I ordered today, just in case. And a second person so I can see what the generator is doing with the engine running.
 
Dale, Check the resistance between the two yellow generator wires. It should be less than one ohm.
Also check to be sure that neither generator yellow wire is grounded.
Have you checked the 30 amp fuse?
 
The vast majority of electrical problems are due to bad connections.
Check each one on the voltage regulator.
 
Alternator coil resistance is 0.5 Ohms. Not grounded. The fuse is fine. All of the connections are fine. Verified continuity on the wires that I knew where both ends go.

The battery that came out of the plane measures 12.9V at rest, but will barely crank the engine so it’s toast. The new one is fine.

I mean, I suppose maybe it’s POSSIBLE that a less than great battery killed two different brands and models of voltage regulators instantly…. I just have trouble believing it. I have a new JD style regulator here that I’d trust for ground runs only, I’d never rely with it. We were debating pulling the wires from the connector and trying it out, but it was 36 degrees, pretty windy, and raining. Decided I was not really that keen on standing in wet cold prop blast getting voltage readings.
 
I am in annual right now. One thing that has bugged me about the plane is the inability to hook up ground power conveniently for a jump start. I am installing a jumper post on my panel with a master relay. I’m setting it up so all the +14V stays forward of the firewall unless the ground power relay (new additional master relay) is energized by a switch to ground.

I’m also swapping out my old 496 GPS to a Aera 660 in an Airgizmo mount.

If you guys don’t have familiarity with electrical circuits I can’t overstate the value of the EAA two day course on electrical and avionics. I’ve been an engineer for 40 years, and I learned more practical field knowledge in that two days than any other course I’ve ever had.
 
Batteries don't kill voltage regulators, but heat does.
Use heat conductive paste between metal mounting surfaces.
My John Deere voltage regulator has many hours on it.
It is afraid to fail because it knows that I have a spare one.
 
I mounted my John Deere VR with heat conductive paste to a subplate on stand-offs that has air circulating beneath. Still located on firewall shelf in original location with no added cooling air. I’d have to look at logbook, but the JD VR must have 500 hours operation...
 
I tried a Deere style regulator a few years back, with thermal paste on a custom made mounting plate. It lasted about 5-6 hours before self destructing in flight. The cheap ones obviously have zero QC; some work and some don't. Rather than see if the expensive ones are any different, I went with the Silent Hektik and eventually the new B&C sold by Van's.

As it turns out Joe was correct, though it took a bit of digging to find the bad connection... and it wasn't mine, nor was it the builder's, nor was it at any of the connections you can check without surgery..

I did some more testing today. The alternator is generating about 19V or so AC at about 2000 RPM, which seemed reasonable. Everywhere I looked I found battery voltage, which today was about 11.7V, except for one place...
the actual output of the regulator. The regulator is fine. I got 15V at the output of the B&C regulator with the engine running. Oddly enough, that was the ONLY place that voltage appeared... not even at the connector on the back of the fuse board. Curioser and curioser; back to the schematics.

The regulator output has two wires that are spliced to a single wire that then goes directly to the plug on the back of the fuse board. The two wires on the regulator had a solid connection to each other, but there was no continuity from that end to the fuse panel. I cut through the heat shrink and encapsulation over the crimp splice near the regulator, and found that the factory crimp was... well, it wasn't. There was a half-hearted attempt at a crimp, sort of, but effectively no crimp on the stripped end of the wire. I put a heavy crimp on the barrel where the end of the wire would be, and it's now rock solid. Charging voltage was right at 14V on the ground, and stayed within the green during a 40 minute test flight after I buttoned everything back up.

The splice as I found it:
IMG_1898-rotated-e1647740759313-221x300.jpg


And after crimping:
IMG_1900-rotated-e1647740273514-245x300.jpg
 
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So you are saying that the regulator assembly from the Van’s kit was not assembled correctly from B&C and was the cause of the problem?
Stan
 
So you are saying that the regulator assembly from the Van’s kit was not assembled correctly from B&C and was the cause of the problem?
Stan

No. This was a cable installed back in 2011 or before, when the plane was built. Supplied by Van’s, as part of the kit at that time.
 
No. This was a cable installed back in 2011 or before, when the plane was built. Supplied by Van’s, as part of the kit at that time.

Just curious... Was airplane previously stationed near costal area with salt air?
 
No, never. The connection in question was quite thoroughly encapsulated in some sort of sealant and heat shrink. Would have been quite impervious to salt air anyway. I’d call the sealant hot-melt adhesive, but I suspect it was something else.
 
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