Inaccurate Voltage with IOSD -

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ProPilotWannaBe

Member
Guys, let me see if I can clarify the problem Tim(R6media) has as I understand it, and you can correct me.

The problem seems to have nothing to do with voltage sag and/or internal resistance. We all know the voltage is going to sag once a load is placed on the motor which is what all the data is showing. But the problem seems to be when reading the voltage. The voltage sag occurs at the source (I.e. batteries), as such, the voltmeter that Tim has connected to the battery should reflect that sag every bit as much as the voltage alarms and the iOSD. In other words, if at rest the voltmeter reads 24v, the alarms should read 24v as well as the iOSD. Then under load all of them should drop the same amount of voltage (theoretically). I know that is the case for me. When at rest my voltage alarms read the same voltage that is reported by the iOSD (or within a .1V). Likewise when loaded, they both drop the same amount.
 

R

R6Media

Member
Tim (Pro), yeah that's exactly it. Thanks for chiming in.
The Wattmeter that I'm using in this equation is within .1V of the balance port voltage alarms but neither are close to the iOSD.
There's definitely room to troubleshoot which I'll be doing more of today.
I'll take the Zen off the load and see if that makes any difference too but considering your iOSD reads correct with your other indicators I doubt it will matter at all.
I'll clear out my iOSD Data too and take another look at fresh data from 2 flights, as well as double check the voltage protection calibration.
I could use another iOSD to compare against for sure.
 
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R

R6Media

Member
Just found this on xaircraft website about the PMU:

V-SEN Port
This port has two functions:
1) It collects the power input of the PMU for MC to monitor the battery voltage. The white wire from this port is the signal wire, and its maximum output voltage is 3.3V, so it will not damage your receiver if you connect this port to it.
2) It provides a 3A@5V power on red wire for the receiver and other electronic device through X1 port on MC.

With the voltage discrepancy issue I've been asking about in these posts, what do you guys think of the possibilty of having an issue with the PMU OR the Wookong MC and not the iOSD after all since it really acts as just a display?

I'm also still running firmware 5.22 on my MC because it works. Any thoughts on if upgrading to 5.26 would resolve my issue?
 
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R6Media

Member
Let me ask all readers this question instead to help me in my quest for an answer because 526 views and not a lot of possible answers leaves me less than optimistic of figuring it out here.

Those of you who use iOSD and also Voltage alarms on your battery balance ports as an additional warning..... Do your voltages match in flight (more or less)? Check for me.
Tim I know you said yours do. I need more responses like that to try and narrow down my issue.

Thanks
 

C

Captain Kangaroo

Member
Sorry to bring up and old thread but.........

I'm also looking for some ideas on this too.

Normally i get a very comfortable 7-8 mins with about 25% left in the packs on my S800 (landing at 21.6ish). The other day the iOSD was reporting 21.6 after about 4 mins of flight. When i put a battery checker on it was reading 60% left in the packs!

I flew again and this time hit 21.3 on the iOSD after about 5 mins; however by this time the 1st level protection should have been flashing yellow but it wasn't. Again the packs were at about 50%.

Really odd and don't know what to trust!
 

T

Tahoe Ed

Active Member
I was getting inaccurate reporting on my A2 and installed a lipo sensor and then calibrated the battery via the A2 App. I did a manual calibration and I have not had an issue since then. You may want to try it.
 


B

BATCAMuk

New Member
Tahoe Ed said:
I was getting inaccurate reporting on my A2 and installed a lipo sensor and then calibrated the battery via the A2 App. I did a manual calibration and I have not had an issue since then. You may want to try it.
Click to expand...
Hi Tahoe.

Having this issue and about ready to ditch the reading from the a2. what lipo sensor did you use?
 

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