Brushless ESC with a brushed motor - RC Groups
Thread Tools
May 03, 2012, 04:24 PM
RES flyer
Discussion

Brushless ESC with a brushed motor


I have an old Speed 480 sailplane that I originally flew on Nmih. It has an old Jeti brushed ESC. I want to switch to Lipos to save the weight. I plugged in a Lipo pack to the old ESC and it worked fine - until the next day when I went to charge the Lipo pack and discovered 2 dead cells. I have a new brushless ESC. I would rather use it now that than replace the old 480. Will the old 480 work with the brushless ESC if I just connect the + and - and leave the white lead from the ESC unconnected?
Sign up now
to remove ads between posts
May 03, 2012, 05:57 PM
Marion
No. It doesn't work that way at all. Do not try it, please.
May 03, 2012, 05:58 PM
Registered User
No. There is no + and - output from a brushless ESC,. All 3 wires do the same thing and it doesn't include driving a brushed motor....the way the ESC works is completely different.

Steve
May 03, 2012, 06:00 PM
We want... Information!
Bruce Abbott's Avatar
No, it won't work.

If you are worried that your Jeti might be over-discharging the Lipo, limit your motor run time to 2 or 3 minutes, then check that the battery hasn't gone below 11.1V. If your radio doesn't have a timer then just count off the seconds for each motor run (eg. 30 seconds x 4 runs = 2 minutes).
May 03, 2012, 06:04 PM
Wake up, feel pulse, be happy!
Piece's Avatar
You could also get a brushed ESC with a lipo cutoff function. They're pretty inexpensive these days.
May 03, 2012, 07:01 PM
RES flyer
Thanks for the input folks! I think my brushed ESC may have killed my Lipo pack. I'll use my Nmih until I get the motor replaced.
May 04, 2012, 03:25 AM
Registered User
Quote:
Originally Posted by soprano1
Thanks for the input folks! I think my brushed ESC may have killed my Lipo pack. I'll use my Nmih until I get the motor replaced.
You didn't leave the pack plugged in until you went to charge it next day, did you? That could drain any battery.

The older Jeti ESCs are programmed to shut down (lvc) when the battery voltage reaches 68% (I think) of what it was when the battery was plugged in. For a fully charged LiPo at 4.20v that'll be 2.86v for lvc, which is far too low. It's even worse if the battery wasn't fully charged when it was plugged in.

Other than that, there's nothing about the ESC that makes it unusable with a LiPo. If you want to use LiPo you simply need to time your flights so that you stop flying before 80% of the battery capacity has been used. In fact, that's true even for "LiPo friendly" ESCs, for lvc should only be regarded as a safety feature, not as your regular indicator to stop flying.
May 05, 2012, 02:10 PM
RES flyer
Thanks abenn. Very valuable info. I think I may have left the batteries plugged it


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Brushed motors, Brushed ESCs darmar Aircraft - Electric - Power Systems (FS/W) 0 Jan 30, 2012 12:00 PM
Found WTT: My Pro Boat Brushless ESC for your Pro Boat Brushed ESC Diegoboy Boats (FS/W) 12 Dec 23, 2011 10:48 PM
Sold Zagi XT Twin NIB complete with zagi brushed motors, esc, & battery $45 phoneguy Aircraft - Electric - Airplanes (FS/W) 5 Oct 19, 2011 09:16 PM
Sold Zagi XT Twin NIB complete with zagi brushed motors, esc, & battery (LPU) $50 phoneguy Aircraft - Electric - Airplanes (FS/W) 1 Oct 16, 2011 04:33 PM