This is crucial information. I think it should be standard practice to use a minimum of 4 bonkas (or equivalent) to give ample leeway in the temperature range.
This goes beyond just protecting batteries from degradation, it’s a safety issue. This electric system can be significantly safer and more reliable than a gas powered motor, but only if we don’t overload the batteries.
Paul, thanks to Kealyb and his printer I installed the hinge stoppers you designed. I found I had an approx. 1/2" gap between them when the hoop was aligned. Yours look as though they are touching, and I assume your hoop was aligned, is that correct? One other item: when these are installed you can no longer fold the legs up for transportation. Do you keep your Openppg unit set up and ready to go while stored? Bill
If you can’t fold them up then you must have installed them on the wrong side which would also explain the gap.
I also picked up a Dudek Powerseat and I see how you connected it but I figured a standoff is supposed to go there. Can somebody confirm if I’m right that the red highlighted bolts are where the standoffs for the backplate are supposed to go?
Yup, that’s where I put em, except the one by the arm pivot on each side.
I also have a powerseat and put the top harness point through both slots and all the way around the standoff
Thanks! @davek79 I went by this pic from their store page:
Easy to see as their standoff bolts are silver not black. You can see they don’t have standoffs where the top of the harness straps in, but I figured those holes were for standoffs. Just wanted to confirm, thanks again!
Where you put the standoffs aren’t all that critical as long as they are spaced fairly evenly. The way I routed my harness makes it more like a hinge so the straps don’t slide through the carbon slots as you fold it up. Therefore, I moved the standoff’s to the next closest holes. Plenty strong and folds up smooth.
Oh geez… you are right. I had them on the wrong side. Ha ha! Thanks for the clarification, Paul. That teaches me to not be in such a hurry! I thought you must be just keeping your frame assembled and not folded.
The strap wrapped twice around the frame base, supporting the machine and keeping it really tight against the frame. Once properly adjusted and purposely a bit short in length, I pull hard on the two halves to clip them together - no excess webbing floating around - just have to remember to fasten the straps during the pre-flight routine.
@GliderPilot I live in Orem and would love to come see your OpenPPG and watch you fly sometime. Perhaps you could let me know when and where you’re flying next and hopefully I can come up.
I saw Glider Pilot’s paramotor today and it is awesome with a lot of modifications mostly geared toward safety and more to come. Very worthwhile to see paramotor in flight as well.
Today I practiced a no wind launch technique using the thrust from the motor to pop the wing up. I love how short the takeoff distance is with this technique.
I’m just over the weight range when motoring on this Tequila 4 wing and my climb rate is close to 300 fpm with the OpenPPG.
Met @GliderPilot to see his OpenPPG rig and watch him fly. Very impressed with OpenPPG.
Took a few videos. Had a very nice sunset for a backdrop. Sorry about the video glitches, ironically I believe having image stabilization on my camera caused it. Note that there is also a gas PPG flying around that you’ll hear in the first video.
Thanks @GliderPilot
That first video is great for a rough sound comparison between gas and electric!
After about 100 flights my switch melted. I found arcing marks on the contacts inside the switch (they were hard to find with all the melted plastic). The switch can handle the current fine if the contacts aren’t damaged. Several people are looking for a bigger switch to prevent this issue but that doesn’t fix the arcing and even a bigger switch will arc and degrade.
The arcing happens when the switch is turned on because there is a rush of current to charge the capacitors inside the ESC. Several people have talked about using a precharge circuit where the current flows through a resistor to slow down the rush of current. Once the capacitors have the same voltage as the batteries the main switch can be turned on without arcing occurring inside the switch. This is the route I decided to take. I tested several resistors and found 22 ohms to work well. With anything higher than that I could hear arcing inside the switch. This is because the higher the resistance the lower the voltage gets inside the capacitors so when the switch is flipped there is still a rush of current.
Paul is supplying two switches with the kits now so we can use both switches at the same time with half the amps running through each one. He sent me two switches and another bracket. But then the question of how to wire two switches. There are several ways to do it. One way is to have one set of batteries run two motors and the other set run the other two with a switch between each. The method I came up with is to have a switch between each battery set but either set would run all four motors. If one switch goes out I will still have power to all four motors but that power would all be coming from one battery set. This is preferable, in my opinion, over having two motors not running.
Having two switches is a good thing but the first switch flipped will still arc so one switch needs to be connected to a precharge system. Here’s what I came up with: I designed a replacement knob for the switch that has a precharge switch built into it. All I have to do is twist the switch about 10 degrees to precharge the system, hold it for less than two seconds until the motors beep, then turn the switch 90 degrees to fully power up with no arcing. There is a spring inside the knob that disconnects the precharge circuit when I let go of it. It’s nice because it can be done with one hand as opposed to using a separate button.
All the knob does is press two wires together to run the current through the resistor. The resistor is covered in heat shrink on the orange wire:
Here is how I wired the two switches… the battery leads come in on both sides and run to the nearest switch and to the nearest motors. This makes the wires as short as possible. The two wires running left and right join the two circuits (I ran out of red so both are black). Power won’t really even run through these wires other than to discharge the batteries evenly. But if a switch goes out they will feed the other side:
While I was rewiring my whole machine I 3D printed covers for my electrical junctions:
Here are the files for anyone who wants to use them:
Pre-Charge Knob - Part 1.stl (255.3 KB)
Pre-Charge Knob - Part 2.stl (383.1 KB)
Pre-Charge Knob - Part 3.stl (1.9 MB)
Connector Cover - Top.stl (582.7 KB)
Connector Cover - Bottom.stl (582.7 KB)
Hi Paul , is your pre-charge switch momentary push to make or toggle , I only ask because im sure I read somewhere that the Pre charge should only be via a momentary switch I think nasty things happen if its accidently left on when full battery load is going through ESC …But don’t quote me on that just a thought but then again I may have missed something in the vid …Cheers for posting …by way Dontcha just luv 3d Printers 
the flexibility they give regarding custom made items is abs Brill ,Nice work that man …
Yes, it is momentary. Twist 10 degrees to close the circuit. A spring opens the circuit when I let go of it. It’s nice because it can be done with one hand as opposed to using a separate button.
I do love having a 3D printed for stuff like this!
Whoa awesome design!
Cheers my man , as mentioned loving the work you guys are doing here and a nice active forum for people to learn more and contribute what they can to moving E flight forward. Thanks again its all great info soaking into the ol grey matter (With emphasis on the ol LOL )
Aha I just realised your 3d Printed pre-charge addon is retrofitted to the main ON /Off Switch hence my mistaking it for a Toggle action … the penny just dropped ( I did mention ol grey matter LOL with emphasis on the Old ) I must say nice lateral thinking and as you pointed out 2 action in one…JOB Done … even more impressed now
