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[Solved] Inaccurate mah readings Hobbywing 160A


pblack
(@pblack)
Active Member Customer
Joined: 7 months ago
Posts: 6
Topic starter  

Hello everybody!

 

For my new goblin raw i chose the msh brain 2 bt for the first time because of many diferent reasons, one of them was the telemetry integration for spektrum.

Since i run a rc helicopter school for a living it is very important to get the most out of my batteries.

I am also using the same helis for my private flying (2100rpm 3min) and for learning the basics with clients (1200-1400rpm 15-20min).

Thats why it is very important to get an accurate mah reading for me.

 

As i did my set up and first flights i calibrated the mah consumption, at least thats what i thought.

Sometimes it got better, sometimes worse, but with no pattern (calculated the last flight, put in the new values - should be nearly 100% correct - next flight was 1000mah off).

 

After some flights i realized that if i fly only with high rpms and load the system throughout the hole flight i can get a pretty accurate reading with very little correction values.

 

Ok, now i am thinking the esc cant log that low of an amperage (low rpm is in the range of 5-15 amps, high rpm peaks 130 amps).

But when I am reviewing a low rpm flight i can see the amperage data. It is there.

 

I tried one more thing on the workbench with blades off - when the heli is spooling up it gives me a reading, even the low amps are displayed (1-5A - Brain Manual says most ESC do not) but after 2-5 seconds the reading is gone and displays zero the hole time.

 

For me this is no usable telemetry because the biggest benefit, flying high and low rpm - knowing exactly when you have to land, is gone.

 

I also thought it could be the BEC current because Hobbywing does not log them (does not matter on a 3 min flight but maybe on a 20 minutes flight)? But sometimes the mah readings are way to off for that being the reason.

 

My initial plan was to switch to a Hobbywing 130A but first I have to figure out where the problem with the telemetry is. I dont want ending up buying 2 escs just to fix this (try and error). Actually I would love to fix the problem without buying a new esc in the first place.

If you can confirm that the problem is this esc (160A) or maybe HW escs in general, does the YGE auerus 135 have the same problems?

 

There has to be a way to get nearly spot on mah readings, i know so many different systems from working with clients and never experienced problems like this before.

 

 

Set up:

Goblin Raw with stock 690mm Blades

Egodrift Tengu 4525 HT 550kv

Hobbywing 160A

3x MKS 575sl

1x MKS HBL 880

1x Brain 2 BT

1x SLS Xtron 12S 5800mah 30/60C

1x 1st rc buffer 3x 25F

1x Spektrum DSMX sat

1x Spektrum 4651T

 

Logs are with 22T Pinion, will put in 23T tomorrow.

 

Radio:

Spektrum IX12

 

 

I will attache all the files i have.

If you need something else to help my with this problem just reach out to me please.

 

 

Thank you very much for reading my post.

Greetings from vienna (Austria).

 

Patrick


pblack
(@pblack)
Active Member Customer
Joined: 7 months ago
Posts: 6

BrainDev
(@customercare)
Member Admin
Joined: 4 years ago
Posts: 780
 

The problem of low current reading is related to all Hobbywing ESC models (and their rebranded products like Align).
Hobbywing ESCs have in fact a "dead zone" where current values lower than 8A - 6A are not read (it depends on the model but it also changes from product to product due to tolerances of internal components). This is the reason why on the bench without blades and therefore without load, after the initial starting current of the motor the low current absorbed by the running motor is not read anymore.

Consequently, the closer the average current value absorbed during flight is compared to the ESC nominal value, the more accurate the value read by these ESCs is; on the other hand, the lower the average current value absorbed during flight is compared to the ESC nominal value, the more "holes" / "absences" of current will be read while for example removing pitch from the blades and reducing the load.

We do not have the Aureus model of YGE but we have the LVT and HVT models with which we have developed the YGE telemetry protocol management. The YGE ESCs in our possession do not have the "dead zone" problem present in HobbyWing ESCs.
(Same thing is valid for Kontronik ESCs)
We believe that the same current measurement technique is used on all YGE ESCs, but we cannot give any guarantee on this. You should ask YGE.
What we know (but you have already seen it yourself), at the same current rating YGE ESCs cost more than Hobbywing ESCs (Same for Kontronk ESCs).


pblack
(@pblack)
Active Member Customer
Joined: 7 months ago
Posts: 6
Topic starter  

Thanks for your reply!

So the Hobbywing Telemetrie is basically useless.

Just bough an aureus 135.

Looks good so far, its showing 0,8A sitting on the bench and 1,3A while moving the pitch, so its even calculating the bec current. Mah is rising even with no motor.

I will make a test flight today!

 

Now I have another strange Problem - with the Hobbywing the rpm readings where fine but with the yge not.

I have set up rpm 1400 1750 2100, yge on the ix12 is showing 300 380 450?! So basically 4,66 times off?!

I do not know where I made a mistake, poles is set to inh, ratio to 10. That worked for the Hobbywing but not with the yge?! (Brain software is showing the right values!)

I even set up the gear ratio in the yge software, but that should not matter, should it?

 

Thanks again, I will be posting when the test flying is done!

 

Patrick


BrainDev
(@customercare)
Member Admin
Joined: 4 years ago
Posts: 780
 

We never said that HobbyWing ESCs are useless.
They are very good ESCs, they have a very good BEC, they are very reliable and they are sold at very attractive prices compared to the high prices of other ESCs. For these reasons they are among the most used by users.
Regarding the measurement of current draw, if they are used around their nominal value and you always fly using the same or close to the same RPM values, thanks to the correction factor you will get reliable values.
Your case is instead a very special case because with the same model and the same ESC you fly at 2100 RPM but for lessons also at 1200 RPM and in this case you should use two models with two different ESCs (one 160A and one 80A) or even if not so effective use "at least" very different correction factors between them.

Regarding the RPM read from the transmitter, it is not clear if you are looking at the RPM transmitted and read from the ESC telemetry or the RPM read from the GOV port of the flight control unit. On the transmitter, the ESC telemetry page displays the RPM transmitted by the ESC via telemetry; however, in the RPM page, the RPM calculated from the rotation pulses received on the GOV port are displayed.
However, if there are no rotation pulses on the GOV port, then the telemetry RPM page also displays the RPM received via telemetry from the ESC.
If the wrong RPM is the RPM received via telemetry from the ESC, then a divider based on motor pulses or gear ratio may be set in the ESC configuration. You should check the ESC configuration:

immagine

You could also try to select "Basic telmetry" in the flight control panel, which only uses the GOV port signal, and see if the RPM is displayed and correct.


pblack
(@pblack)
Active Member Customer
Joined: 7 months ago
Posts: 6
Topic starter  

Hello,

 

Please dont get me wrong – I said it is useless because in my opinion if I have to fly nearly at the same power level to get good readings, I could also fly with a timer – thats the point of capacity telemetry in my opinion.

Seems like YGE is doing a much better job for my usecase as you said! 😊

 

Regarding the rpm Problem I made another Test :

YGE Telemetrie selected (ix 12 poles inh, ratio 10) -> ix12 30rpm, brain 1400rpm

Basic Telemetry selected (ix12 poles inh, ratio 10) -> ix12 is showing 740rpm when the motor is off?! and 5830 when it is on, brain 1400rpm

 

As I said in my last post I made the yge software set up:

Magnet count (poles): 10

Pinion tooth count: 23

Main tooth count: 212 (Sab manual says when you have to use a calculator with only one transmition to put in 212)

Gear ratio: 1:9,22

 

In the Brain Software:

Sensor count: 5

Gear Ratio: 9,2 (Sab manual says to put in 9,2)

 

In the life logging feature the Brain rpms is showing 1400, the esc rpms ls is showing zero.

 

 

Please let me know if you need more Information, I would love to make this work!

Patrick


pblack
(@pblack)
Active Member Customer
Joined: 7 months ago
Posts: 6
Topic starter  

Just tried this one again:

"Basic Telemetry selected (ix12 poles inh, ratio 10) -> ix12 is showing 740rpm when the motor is off?! and 5830 when it is on, brain 1400rpm"

Now it is showing zero the hole time, I unplugged and plugged in the batterie a few times, always zero rpms in this case now.


BrainDev
(@customercare)
Member Admin
Joined: 4 years ago
Posts: 780
 
Posted by: @pblack

Just tried this one again:

"Basic Telemetry selected (ix12 poles inh, ratio 10) -> ix12 is showing 740rpm when the motor is off?! and 5830 when it is on, brain 1400rpm"

Now it is showing zero the hole time, I unplugged and plugged in the batterie a few times, always zero rpms in this case now.

This means that the GOV port of the flight controller is not receiving the motor rotation pulses and therefore the real-time RPM telemetry cannot work (only the RPM received via telemetry can be used, which has a low sample rate and low update rate) and the governor of the flight controller cannot work either because the real-time feedback of the motor rotation speed is missing.
I guess then that you are using the ESC governor and for this reason you have also set the dividers in the ESC that divide the motor rotation value before sending the RPM value via telemetry. However, the RPM value received via telemetry is assumed to be the motor's rotation value and is therefore further divided by the dividers set on the governor page.
You should check why the motor rotation pulses are not reaching the GOV port of the flight controller.
The connection diagram can be found in the Telemetry manual in the MANUALS section and is as follows:

immagine

pblack
(@pblack)
Active Member Customer
Joined: 7 months ago
Posts: 6
Topic starter  

Hello,

 

Thank you really much for trying to help me! 🙂

 

For all people who may have the same issue in the future:

The solution for me was to set the yge gear settings to "poles: 2 ; pinion:1 ; main gear: 1".

Now with the settings from the brain manual for my spektrum radio (telemetrie settings on the radio) "poles: inh ; gear ratio: 10" everything is working just fine.

 

I fly and always flew with the brain governer and it was working fine, just the rpm readings on the radio was not correct.

I assumed that you have to put in the gear settings in the yge settings but i was wrong, stock settings would have worked 😀

 

Thank you again very much!

 

best regards

Patrick


BrainDev liked
BrainDev
(@customercare)
Member Admin
Joined: 4 years ago
Posts: 780
 

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