Fading ESC

Ededge2002 · December 23, 2012, 06:09:52 AM

Quote" Bench testing has shown the ESC fades at 3.0 volts/cell under load (abouot 5/8 throttle), and shuts off motor power completely if the fade is allowed to continue for 10-15 seconds."

Isn't this just low voltage cut off?? Possibly the packs are not up to the task.

Michael · December 23, 2012, 11:31:59 AM

How old are the battery packs being used?

Andy Hoffer · December 23, 2012, 12:13:17 PM

Quote from: Ededge2002 on December 23, 2012, 06:09:52 AM
Quote" Bench testing has shown the ESC fades at 3.0 volts/cell under load (abouot 5/8 throttle), and shuts off motor power completely if the fade is allowed to continue for 10-15 seconds."

Isn't this just low voltage cut off?? Possibly the packs are not up to the task.

Quote from: Michael on December 23, 2012, 11:31:59 AM
How old are the battery packs being used?

Packs (each with 2x 4S 2150 mAh 20C Rhino in parallel) are 14 months old and have only been used a few times each; winter stored at 50% charge.

Today's tests looked decent: started at 16.76 volts resting, 13.33 volts (3.33 volts/cell) under load after 3 min at full throttle; 13.20 volts (3.3 volts/cell) under load after 5 minutes. One minute at 1/2 throttle then 1 minute at full throttle gave 12.86 volts (3.21 volts/cell). Fade did not occur until 12.6 volts uinder load (3.13 volts/cell). Total run time = 10 minutes. Peak power = 576 watts.

Second test, more aggressive (almost all at full throttle), sustained good power until fade started at 12.5 volts (3.12 volts/cell) ater 6.5 minutes run time.

So, I just have to use my best packs and monitor throttle management carefully.

Thanks all for your input.

best regards,

Andy

Ededge2002 · December 23, 2012, 02:39:04 PM

I must say that prolonged static tests are normally unrecommended. And running long at full power seems a bit punishing to the packs ect

pmackenzie · December 23, 2012, 04:34:44 PM

I agree, no more than 30 seconds static should tell you everything you need to know.

Pat MacKenzie

Andy Hoffer · December 23, 2012, 06:41:17 PM

Quote from: Ededge2002 on December 23, 2012, 02:39:04 PM
I must say that prolonged static tests are normally unrecommended. And running long at full power seems a bit punishing to the packs ect

Even at only 10C on a 20C continuous rated pack? Normally I never test power systems like this, but I am trying to monitor the dynamics of the pack/ESC combination through a simulated run to ensure I am not missing anything.

Andy

Gregor77 · January 04, 2013, 10:39:30 AM

Has this been resolved yet?

Andy Hoffer · January 04, 2013, 11:38:50 AM

Quote from: Gregor77 on January 04, 2013, 10:39:30 AM
Has this been resolved yet?

Hi Greg:

My path forward is in my December 23, 2012, 12:13:17 p.m. post. In a nutshell, I just have to manage my power carefully to stay above 3.3 volts per cell under load. This will involve frequent brief throttle reductions to zero. Eventually I will replace the ESC, but for now I really want to see if I can successfully use my planned workaround.

Andy