It has 1 current shunt resistor for total current. The signal is on the CRT pin of the header. You will not have current on ESC telemetry. That requires a shunt resistor for each of the 4 channels. Some 4-in1’s have those, most don’t only total.
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It might be worth putting that in the wiki with the esc telemetry since its clearly been a common issue.
Here is an example of a 4in1 with 4 shunt resistors (Ori32 I have one).
This gives Current via ESC telemetry. Current calibration is done in firmware with blheli suite.
I think the problem is a lot of people assume blheli telemetry means you’re getting everything from each esc and don’t realize it might have analog current measurements or none at all depending on the esc.
True, that has been a topic of discussion before. But when you realize that 4in1’s are just 4 individual ESC’s on1 board it becomes a bit clearer. There are a few, maybe 1, exception to that. Matek’s Serial Shot is one exception but those seem to be vaporware still.
yes i am aware of how they are made, im just suggesting a note something along the lines of “Not all BLheli32 escs have a current sensor supported by blheli telemetry.”
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im just looking on aliexpress and there are a few that are configured like this with the analogue common shunt or no current at all
This is just what I could find in 10 minutes, Blheli_32 escs without current sensors on the blheli telemetry are far more common than I thought, so a note about the current sensor telemetry abilities would be a good idea.
Guys, “T-Motor P50A 3-6S BLHeli_32 4-in-1” has current Pin, and it was working perfectly, it was giving me exact current value with iNav.
I just switched from iNav to Ardupilot and this problem raised.
I only see 1 shunt right where it should be… What value is iNav giving you total current divided by 4??
As I am in the market for a 4-in-1 ESC with telemetry, any suggestions?
Sorry trolling for part recommendations so I can support folks better. 
- One for: 6s, 15A max. no safety factor so say 20A max load)
- another with 40A max. doesn’t have to be 4-in-1…
Are you able to submit a PR to the Wiki if you think there needs to be a change? It is pretty easy by hitting the edit button on the correct page.
If you write the sentences I can add it if you can’t figure it out the edit process… It helps us a lot when these things comes up to add them to he wiki directly or by creating an issue.
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Yes, in iNav it was giving me correct value of total current drawn by 4 motors.
I am sorry I dont know details what you explained, i am just comparing same setup between iNav and Ardupilot.
If it works in Inav why not in Ardupilot?
It can be made to work. You will just get total current rather than per esc. Connect the current pad to one of the analog inputs and set it as an analog power module. But it doesn’t give per motor current measurements. What flight controller are you using?.
Thats ok, i am not interested to check for each esc current, if it give correct total current thats totally fine.
I am using Matek H743-Slim
I did below parameter settings
BATT_MONITOR=4//Analog Voltage and Current
Then reboot.
BATT_VOLT_PIN=10 //on board battery voltag
BATT_CURR_PIN=11 //on board current sensor
BATT_VOLT_MULT=11.0 //Used to convert the voltage of the voltage sensing pin (BATT_VOLT_PIN) to the actual battery’s voltage (pin_voltage * VOLT_MULT)
BATT_AMP_PERVLT=40.0 //Number of amps that a 1V reading on the current sensor corresponds to
The current sensor is on 4in1 ESC whose current sensor range is 50A then calculate BATT_AMP_PERVLT as below.
Total Amp=200A(50A*4), n = 200A/3.3V = 60.6
Wiring as shown below
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that should work just like a regular analogue power module.
But not giving correct current values, I am not expecting very accurate but should give me within tolerance, now it shows 100A at start and some random current value
you will need to calibrate the current and voltage readings, when the analogue power module is first set up I think it defaults to values for a 3dr power module.
Are your voltage readings accurate?
to calibrate current, put a power monitor between your battery and quad, put the props on backwards so its pushing itsself into the floor and throttle it up to put a load on it.
then type those values onto measured voltage and current and it should calculate the ratios by itself.
Yes, it shows voltage correct
do the current readings move with the motors, ie are they just inaccurate or is the current totally erratic unrelated to the motors.
if its just inaccurate then it’s just calibrations, if they are totally erratic then it’s another issue.
Thanks, i think its because of incorrect value of BATT_AMP_PERVLT, initially i tested with BATT_AMP_PERVLT=40.0 which is given by Matek, now when i contacted matek they told me to use
BATT_AMP_PERVLT=60.6, I have to test it with this value, and will update.
Many many thanks for your prompt reply.
I am also facing one more issue ( there were when i switched from iNav to Ardupilot many got resolved)
The shunt is on the esc not the matek board so may not be accurate.