DYNON D120 - AMP Fluctuation -Nothing Running

[lrfrey]

The AMP Meter on my D120 fluctuates constantly from -10 to plus 15 Amps or so, nothing powered up except the D100, D120 and GPS 296 (Does it without the 296 as well). I have continuity from both of the dSub pins to the shunt, continuity from between the dSub pins thru the shunt and can see no problem with the pins in the dSub mounted on the D120. I "shorted" the two wires at the shunt end with no notable changes. Voltage is steady at 13.4 V. Everything else seems to be working normally.

I noticed the problem others have reported with engines running, noise etc but could find no reference to this problem with everything stable.

Any suggestions? Thanks

Larry

 

[dynonsupport]

Have you checked that both of the wires that you have going to the shunt terminals are going to the amps+ and amps- pins on the connector?

 

[lrfrey]

Yes, this is correct. From pin 24 (Amp +) of the female harness plug thru the shunt and back to Pin 25 (Amp -) of the female harness plug I measure .5 Ohms. These are the Orange/Green and Orange Purple wires supplied in the Dynon Harness.

All the pins on the male plug are visably intact, I obviously don't know about internally.

Larry

 

[dynonsupport]

Larry,
One thing to try is hooking both wires together at the shunt (I mean hook them both to the same side of the terminal). This should read 0 all the time. If it doesn't, that tells us something, and if it does it also tells us something.

Just to check, you do have the shunt on the (+) side of the system, right? We don't support the shunt on the ground side.

 

[lrfrey]

Yes, I tried both wires on the same shunt post, no difference. And yes, the shunt is between the battery + and the load.

I have not updated to 5.1 yet but saw no mention of a fix in that Version.

Larry

 

[dynonsupport]

Give technical support a call at 425-402-0433 for further help.

 

[lrfrey]

Just a quick update FYI.  The problem is resolved, we have met the enemy and it is me.  

This panel has an E-Bus, and it is fed directly from the battery.  The  AMP meter was floating when I was testing using the E-Bus as the power source - of course - current was not flowing thru the shunt! Duh.  Perfectly normal indication when the Master switch was used as the source of power.  Thanks to Mike and DYNON support for pointing out the error of my ways. :-[

Larry

 

[robertc]

I think I've got the same problem, but I don't understand what's going on. The shunt is connected between the alternator output and the bus. The engine is not yet installed;however I've connected a battery charger to the alterntor output wire. The amps read 0 then after a few seconds jump up to a mid range (25-35amp) then back to 0 after a few seconds. This repeats with increasing measured amps until it cycles at a high level. (50-80amp). This happens whether or not the charger is connected. The same behavior happens when both amps high & amps low wires are connected to the same terminal. If both are disconnected then the amps reading is a steady 99amps. Do I have a problem that needs corrected now or do I just build on. My goal is to have all othe electrical working before I take the fuselage for my RV7 out of the rotator. The charger does charge the battery through the alternator output and the voltage increases when the charger is on.

Bob

 

[robertc]

Well, I updated the software on the whole system today and the problem went away. Not sure if thats it, but it's working. I've had this equipment around for a while and yesterday was the first I had power on it. The version was 1.X something or other.(real old) Sorry for stirring the mix.

Bob

 

[dodsond]

I see this too, but I do have a set up that may be the culprit.  I have two busses also and have a shunt on each one. I have a DPDT switch that selects which shut goes to the D120.  The #2 buss is fed with its own battery and master switch, and also with the #1 buss  through a diode.    The D120 is on the #2 buss.

With everything powered up, it works fine.  If I switch off the #2 battery and power the #2 buss with the #1 buss, it works fine.  If I switch off the #1 buss and switch on the #2 buss, the amps on #1 buss read erratically as described earlier in this thread.

I presumed there was some issue reading a shunt on a circuit not powering the D120.  Is this correct?

FWIW, I don't much care since if I set the switches that way, then I have no interest in the #1 buss amps.  The switch is off and the load is 0.  It works in all configurations I want to see.

Doug Dodson
Glasair II-S FT

 

[dynonsupport]

Doug,
It is true that the shunt must be in the circuit that powers the D120 or the readings will just be random.

(We require a common mode voltage of at least 6V on the shunt wires for you EE's out there)

 

[dodsond]

Just a minor clarification please.  Recall, my D-120 gets power from the #2 buss which gets its power from either the #1 buss through a diode, or its own battery/alternator.

Is the current on the #1 buss is read accurately so long as it (the #1 buss) is powered?

 

[dynonsupport]

As long as the Shunt has at least 6V on it compared to the D120's ground, then it will read properly. So as long as you have a common ground between Buss 1 and Buss 2, then it will work as long as the buss being measured has power on it.