Throttle and BMS switch behaviors

I’ve got two questions/concerns about the behaviors I’ve noticed while practicing ground handling with my SP140. (I haven’t flown it yet).

I’ve been turning the power on, just in case I have a good inflation I can arm and apply a little throttle to ease myself into some take offs since its been a year and a half since I had my training.

One thing that happened was the system “armed itself”, which was basically me fumbling with getting the As and brakes in my hand while holding the throttle. That in and of itself isn’t concerning, what was concerning was that I had pressure on the throttle when it armed and before I knew it the paramotor was starting to spin up and thankfully none of my lines got caught. I remember early stories about the throttle being difficult to arm, and the tolerance was changed on the button presses. It appears its now easily to do accidentally with the risers bumping up against it at the right random interval. A few thoughts on improvements:

  1. it would be wise to not allow arming of the throttle if an input is detected on the throttle itself.
  2. I would recommend changing the shape of the throttle body to protrude past the button, and have an indentation around the button, so a button press is much more likely to be intentional and less likely caused by a flat surface like a riser or the ground bumping it.

The second issue I noticed last night was I after having it powered on, I flipped the red switch on the battery pack to off and the throttle stayed on. I was able to re-arm and activate the motor while the battery pack showed it was physically off. I verified correct behavior later after unplugging the pack, plugging it back in and toggling the switch. I don’t know if I have a bad switch that sometimes doesn’t change contacts, or if its the BMS (as I’ve heard its actually a soft-switch). Either way, its an extra layer of safety that my unit appears to selectively ignore.

This is certainly the case with every controller we have shipped. The controller is programmed not to allow arming (it will even make an error tone if you attempt to) when there’s more than a few percent (to allow for hardware discrepancies) of throttle input.

This is likely due to extra capacitors still being charged in the ESC, which provides the low voltage for the controller. After a few seconds, all of the low voltage components should also turn off.

Interesting…I know I didn’t intentionally arm the throttle, I’m pretty sure it wasn’t armed moments earlier when I picked it up, I was just fiddling with my grip on the brake when all of a sudden it spun up and surprised me, so I figured my lack of hearing the arming tone was that it was simultaneous with it spinning up. I’ve been meaning to manually test that without being tied in to my lines. Maybe it was armed for longer than I even knew :grimacing:

@zjwhitehead Alright, I verified you are correct, I can’t arm while the throttle is pressed.

But I also verified (accidentally) twice, that the A’s brushing up against the button is enough to arm the throttle. As a new flyer who shuffles things around and keeps stumbling with the grip, and suffers with wing collapses during launch with lines falling down on my controls and around my prop. I don’t need an accidental arming with how sensitive the throttle is.

Do you have the files available for the 3D printed throttle? I want to try making it harder to unintentionally double press the arming button.

On a different BMS switch topic I had brought up a month and a half ago when I first got the unit, I’m still having the original BMS issue.

Three times today I got my lines sorted out, the motor up on my back, reached over my shoulder to flip the BMS switch on the battery pack, and got no power. Everytime this happens I have to take everything off, unplug the battery, and plug it back in. And then everything works. Is there a solution for this?

@zjwhitehead per the couple questions I last raised 2 weeks ago:

  1. Are the 3D print files available for the throttle controller?
  2. Is there a solution for the battery pack BMS not powering the SP140? This is a repeat issue for me, I can’t reproduce it on demand, but it keeps happening. I put the whole unit on my back and then reach over the shoulder to turn the power on (I feel this is safer than potentially arming by accident while lifting it up), but once i flip the battery switch, maybe 15-20% of the time the SP140 doesn’t power up. The only fix has been to disconnect and reconnect the battery connector, which requires me taking everything off and putting it back on. Its time consuming, tiring, and frustrating.