MUI 150 sensor?

[Seasick78]

Does anyone have any photos of one if these sensors installed? Any feedback on how accurate they are?

[Kiba]

I've got a MUI200, MUI150, and MUI30 on hand but haven't installed them yet (waiting for the receivers to make the changeover from Spektrum to Jeti.)

You wire the heavy wires in line with the positive wire of your ESC for amperage, for voltage there are two small wires that you connect across the flight pack positive & negative, and then there is the wire with standard servo connector to the receiver telemetry port. The units themselves are only about the size of a quarter.

I used bullet connectors in line on the positive wire of the ESC so I can run my YGE with or without the MUI installed. I also used the Jeti anti-spark bullets-- very nice! I may eventually change to a Mezon 130 for wiring simplification.

I would guess the MUI itself is quite accurate, at least comparable an Eagletree. The limiting factor for pack consumption accuracy displayed on the TX will probably be the telemetry link update frequency rather than the accuracy of the MUI itself; I'm not sure what the refresh rate is of the Jeti telemetry. That's also assuming all the calculations are done on the TX from instantaneous voltage/amperage data from the MUI. If the refresh rate of the telemetry is low (say 1hz) then the mah consumed wouldn't be very accurate as flight pack voltage/amperage is a very dynamic parameter. However, if the MUI monitors the pack consumption calculations on-board at a higher refresh rate, buffers it, and then sends that data to the TX at the lower telemetry refresh rate that would be far more accurate than the first scenario.

I'm not sure how Jeti handles the MUI telemetry so it's hard to say. I guess I'll find out once I have my receivers and I'm flying with it!

[Seasick78]

Any pictures you can take of the uninstalled MUI 150?

[Jotto]

As far as I have understood, the mAh calculation is done on the MUI itself. The cumulative mAh consumed is sent to the transmitter. The capacity alarm threshold is also defined on the MUI, and an alarm code is sent to the transmitter when the defined capacity is exceeded. At least that's the way it works with the JetiBox.

I forgot to turn on the JetiBox the other day. I turned it on mid-flight, expecting the mAh counter to start at zero. But no, the counter started at some 1000 mAh, which was the amperage consumed since I connected the battery on the model!

[Kiba]

Originally Posted by Jotto

As far as I have understood, the mAh calculation is done on the MUI itself. The cumulative mAh consumed is sent to the transmitter. The capacity alarm threshold is also defined on the MUI, and an alarm code is sent to the transmitter when the defined capacity is exceeded. At least that's the way it works with the JetiBox.

That was my assumption as well; as much thought as Jeti puts into things it would make the most sense for accuracy and packet size reasons to do all the calculations/buffering on the MUI itself and then periodically send that data via telemetry. If the TX or JetiBox did all the calculations the refresh rate between the MUI and the TX would have to be very high to maintain a reasonable level of accuracy.

Your impromptu test of forgetting to turn the JetiBox on and then finding it at 1000mah during the middle of the flight is enough evidence that the MUI does all the storage/calculations on-board and then sends out periodic telemetry updates.

[Seasick78]

Very nice!

[tribe3]

So the MUI replaces the positive wire on the ESC to say? Can I cut the MUI wires shorter? I want to avoid cutting the ESC pos as much as possible

[desertstalker]

Originally Posted by tribe3

So the MUI replaces the positive wire on the ESC to say? Can I cut the MUI wires shorter? I want to avoid cutting the ESC pos as much as possible

You can cut them as short as you like.

[Sanction]

Here is a picture

[rchelijc]

Just out of curiosity, why positive and not negative? Would it work if connected in-line with the negative?

[desertstalker]

Originally Posted by rchelijc

Just out of curiosity, why positive and not negative? Would it work if connected in-line with the negative?

It is designed to work on the +ve lead, since it has voltage measurement as well it may not work correctly on the -ve lead.

[cbdane]

Originally Posted by desertstalker

It is designed to work on the +ve lead, since it has voltage measurement as well it may not work correctly on the -ve lead.

I believe it should work in either lead. Of course the current is the same in both. The current sensor is most likely a Hall effect style (Allegro, etc.) with no electrical connection between the high current path and the rest of the circuit. That's why there are completely separate voltage measurement + and - wires.

[desertstalker]

Originally Posted by cbdane

I believe it should work in either lead. Of course the current is the same in both. The current sensor is most likely a Hall effect style (Allegro, etc.) with no electrical connection between the high current path and the rest of the circuit. That's why there are completely separate voltage measurement + and - wires.

theoretically, but since the instructions show it hooked up to the +ve I was not game to risk cooking the electronics if it turns out the main lead and red wire are actually connected.

[ArguZ]

Honestly...dont bother with the MUis
Get yourself some UNISENS-E from SM Modelbau and you get Capa, Voltage, Amps plus RPM and Altitude all in one sensor.
I only have a MUI on the Hexa because this one also has the GPS.
But for the Helis and planes I am all SM now.
http://translate.google.com/translat...16e656&act=url

[Puttputt maru]

Originally Posted by ArguZ

Honestly...dont bother with the MUis
Get yourself some UNISENS-E from SM Modelbau and you get Capa, Voltage, Amps plus RPM and Altitude all in one sensor.
I only have a MUI on the Hexa because this one also has the GPS.
But for the Helis and planes I am all SM now.
http://translate.google.com/translat...16e656&act=url

Does it measure capacity used ?
Are the displayed values names in English ?
Not sure if they have changed that.

[johnjonfenomenon]

how do you install an MUI on a multirotor with 4 esc? I have a qav 500 and I use 2 packs in parallel to make a 8,000 mah pack? how do I wire it? I was told that to get the proper MUI i should add up all the amps and go to the nearest MUI, so I have 4 30 amp esc's. Hence I went with an MUI 150. But can I just simply solder this to the board and replace one of my red leads for my battery connection? Also I have 2 power leads one for each battery that taps direct from my board. how should I wire this?

[Seasick78]

I have several of these installed now. Setup is no different than any other system. Just wire it between the pre-existing power lead and the battery. I'd take pics for you but I would have to disassemble my Phantom.

[psylence519]

Originally Posted by johnjonfenomenon

I have 2 power leads one for each battery that taps direct from my board. how should I wire this?

With 2 power leads you have a problem. The MUI needs all power from the batteries to run through it to be able to monitor it.

I would remove the dual power leads, replace with a single negative wire and a single positive wire with the MUI spliced in. Then just use a parallel adapter close to the batteries. Kind of a pain but there's no other way for the MUI to see all the current.

[Seasick78]

Originally Posted by psylence519

With 2 power leads you have a problem. The MUI needs all power from the batteries to run through it to be able to monitor it.

I would remove the dual power leads, replace with a single negative wire and a single positive wire with the MUI spliced in. Then just use a parallel adapter close to the batteries. Kind of a pain but there's no other way for the MUI to see all the current.

+1

I missed the comment about two power leads.

[Mr.Gobler]

OH this looks neat! Should give this a try..