So today I experienced what I believe may have been the BMS hard cut, but I’m not totally sure because it doesn’t match glyderfreaks description of the event from an earlier post… Here is the details on what happened to me today.
On Monday I flew the machine for 25 min, and ended the flight with no load battery level of 44%.
The machine sat until today, wednesday, when I decided conditions were good to fly and at about 3 pm I charged it up for 90 minutes to 97v displayed on the charger. Just shy of a full charge.
I set up to launch and the throttle display read 92% @ 96.0 .
Outside temp is about 50 degrees and the battery temp is similar.
I launched and saw a hole in the cloud layer at about 3500 ft agl and decided to try and get to it before it passed over me. In 11 min I reached the hole at 3300 agl and had consumed 2.0 kw.
Reviewing my video footage I see between 11 and 13kw on the monitor. This seems to check out because 2.0kw over 11 min comes out to about 10.8kw average consumption.
This is the hardest I have worked the motor to date. Usually I cruise around 6-8kw.
The last video clip I have at 11min 32 sec shows that I was on cruise at 10.1kw and reading 79.9v under load. 2.0kw consumed power indicated.
@12.0min into the flight the motor cuts out, the controller is beeping erratically like it does when it boots.
After about 2 min the controller comes back on and stills shows 38% @ 84.7v no load. The controller re-ams successfully and motor spins up.
I opt to take a landing in a random field vs risk returning to lz which would take me over a river. Granted I had 2800ft elevation when the controller came back on. I just didn’t want to risk crossing the river at any elevation at all if the battery could possibly disarm again.
I land in the field ( very muddy) and out of nowhere a lady comes to see if I’m ok in her van and offers me some KFC chicken.
I accept the KFC chicken because I was hungry and use the extra napkins to clean some mud off my wing.
40 min later my friend comes to pick me up in his van ( he lives in his van ) and I return home without injury or damage to any gear. I offer him some left over KFC chicken in exchange the ride.
3 hr post flight I measure the battery voltage with a fluke meter, showing 85.8v. I open up the pack and measure 3.570 to 3.578v across all cells.
Other notes of possible relevance :
Recently spliced a screw together connection into the cable for the controller. Relocated controller to right hand.
Running an extended battery cable, 8" longer than normal.
Relocated my battery behind seat ( not behind back ) and turned it sideways because there was no other way I could accomplish a safe hang point on the gooseneck bars. ( I weight 155lb ).
Mondays flight had these same mods and I flew for 25 min with no issues.
I will update this post with the video link once it uploads to YouTube ( the neighbors wifi is really slow)…