First Level Voltage Protection

[gtranquilla]

When I accelerate my MR motors hard, the red led begins to blink indicating 1st level voltage protection but only momentarily (until I return to a lower throttle speed).
Once the red led blinks consistently I land asap.
I assume the intermittent red led blinking is because the motors, during acceleration are suddenly drawing the battery voltage down
So I am wondering if the intermittent red blinking during acceleration will be reduced or eliminated if I use higher C rating batteries or install two in parallel, e.g., 2 x 4S 5000 maH.
I have in the past chosen the lower 25C rated batteries.:dread:

 

[Benchmark]

What are you current voltage protection settings? This has nothing to do with your battery C rating.

 

[gtranquilla]

My voltage protection settings are as follows: (these are fairly new Hyperion 4S batteries c/w battery calibration via NAZA and multimeter).
View attachment 9432

 

[Bradatech]

If you fly in the cold (like -10 C) you will get this. The BEC/Voltage monitor circuit is off in this temp range. We have found reducing the first level protection to 14.2 - 0.7 = 13.5 and second to 13.5 - 0.7 = 12.8 will work just fine.

Once temp starts to warm up, then start increasing these values again.

To confirm it was off, we would recharge the LiPo and noticed that only half of the capacity was being used when the first level was hit (using of a good charger which monitors the amount of mAh required to top off the battery).

Hope this helps.

Yves

 

[gtranquilla]

Bradatech......
Thank you for the excellent information. I realized that battery, i.e., electrochemistry is greatly affected by temperature but did not realize that the DJI voltage monitor would be off at that temperature. In any case I will need to make these adjustments using NAZA Assitant on a daily basis due to frequent chinooks here or only fly when the temperature aligns with my low voltage protection settings. Chinooks create severe and sudden temperature changes in this area, i.e., from -25 to +10 in 8 hours or even less....

 

[gtranquilla]

Yves....
Can I then assume from your information that voltage protection for a 3S battery supply would be as follows?
3.55 x 3 = 10.65 so for - 10 deg C this works out as follows:

1st level protection: 10.65 - 0.7 = 9.95 volts (under load)
2nd level protection: 9.95 - 0.7 = 9.25 volts (under load)

If you fly in the cold (like -10 C) you will get this. The BEC/Voltage monitor circuit is off in this temp range. We have found reducing the first level protection to 14.2 - 0.7 = 13.5 and second to 13.5 - 0.7 = 12.8 will work just fine.

Once temp starts to warm up, then start increasing these values again.

To confirm it was off, we would recharge the LiPo and noticed that only half of the capacity was being used when the first level was hit (using of a good charger which monitors the amount of mAh required to top off the battery).

Hope this helps.

Yves

 

[Bradatech]

Yves....
Can I then assume from your information that voltage protection for a 3S battery supply would be as follows?
3.55 x 3 = 10.65 so for - 10 deg C this works out as follows:

1st level protection: 10.65 - 0.7 = 9.95 volts (under load)
2nd level protection: 9.95 - 0.7 = 9.25 volts (under load)

Yes, those numbers are about right for 3S. We've confirmed this to be a Naza BEC issue in the cold since we leave the gear outside at -10C (without battery) for about 10 minutes to let the electronics condition. We then fly and once we get to the first level, the Lipo's at about 20% left according to what the charger needs to put in.

The wookong's PMU on the other hand corrects for temperature but at $100, it's expected to. We dial in the same voltage monitoring numbers regardless of temp.

 

[mbsteed]

Yes, those Chinooks are brutal - I am just south of you - down here in Lethbridge and struggle with the the weather, the wind is always stronger here.