I think we are pushing the limit of wire length between the batteries and ESCs. Remember that long wires cause voltage spikes because of induction and that’s the reason why ESCs have capacitors in them. But those capacitors aren’t enough to support extra long wires. I’ve tried to keep my wires as short as possible including the leads of the batteries (this also keeps them out of the props). After I added added wire to connect two more batteries (total of 6) I had an ESC go bad on my first flight with that setup. I think the extra wire pushed it over the edge in combination of one year worth of previous wear from voltage spikes.
I replaced the bad ESC and added two more capacitors in parallel as close as possible to each ESC. The capacitors are identical to the ones inside the ESC. I covered the solder connection with liquid electrical tape and then used some 3D printed parts to secure them.
I think the same and commented about this in the forum. If you use more than 4 Lipo’s, the wire
length is just too long. I bought these 63 v 5000uF (5x1000uF) Capacitors and will solder them to my ESC’s just to be on the safe side.
Those alarms are a separate off the shelf item that have no way of being connected to the system controller. A custom monitoring system could feed a signal to the controller and make it vibrate. My plan is to have a display on the gooseneck bar that will flash to get your attention.
Is the low voltage alarm on your drone a separate system that could be purchased and adapted to OpenPPG or is it part of your drone?
That concept is really good but it doesn’t help us that it’s integrated into your drone and can’t be purchased separately. Did you order the BMS with your batch 4? That will communicate individual cell voltage to your controller.
Just to be clear… OpenPPG shows system voltage on the controller. The thing it has been lacking is individual cell voltage which will be part of the batch 4 BMS. I added the alarms for now to let me know if I have a low cell.
I soldered a 1/4”-20 brass bolt to an Xt 150 connector. I ran a tap into the connector first because the bolt was slightly too big. After soldering I cut it to the right length. Now the wires bolt directly to the connector with brass nuts (zinc plated nuts shown in the picture but I used brass). Now the connector cover is part of the surface mount holder.
2 x 330uF Capacitors = 660uF / 220uF for every 4 inch extension of battery cable!
I searched for 7 x 63V 330uF capacitor packs (2310uF) and they are not available, but the
63V 5000uF packs were available and so I bought them. Are they overkill - maybe, but I am on the
safe side.
When I build my batch4 I will use 100A ESC’s and thinking about putting the ESC’s inside with
fan blowers…
I ordered the parts in PLA / 100% infill / Layer height 200 in black.
Here are the prices I paid in $ - I will report back how the quality is when I receive them…
The battery incidents I am familiar with were the result of poor manufacturing quality and quality control systems. In general, Lipo are considered fairly safe from what I’ve read. (more safe than Li-on)
I believe the reason they are so heavily used in EPPG is because they have a very high discharge rate, which is needed to deliver the power PPGs need, and there aren’t many other options out there. Most of the other electric options are far too heavy which would result in increased wing size/drag requiring bigger motors and more batteries.
Someone just posted about the new Aerostak H2 power cells which are designed for aviation… I’m really interested to learn more about that. Previous power cell designs have been far too heavy to be viable… this one’s just going to be really expensive I suspect (Entire power cell weighs less than 2lbs… fuel would be another 15lbs or so)
Paul,
I’ve been trying to locate these on Amazon, but can’t find the same size as you used. Do you have an item number? They only have 35 mm that I can find. Thanks.
(Entire power cell weighs less than 2lbs… fuel would be another 15lbs or so)