Using state of the art devices and PCB design we've made a reasonably small and lightweight isolation switch capable of switching high current batteries directly. Advantages we think this offers:
- Isolation of all electronics on the ground for safety
- No connection pitting compared with using large switch based isolation solutions
- Minimization of EMC radiation as connectors are plugged in and out
- External electronics can be used to switch the power system on / off
- Auto Off in case of aircraft incident. A pull out cable can switch power off automatically
- Simple very low current toggle switch can be mounted more or less anywhere for easy power isolation
Isolation (switching) normally happens when very low current is drawn, however the switch still needs to pass the full current when ON. This switch will happily pass through the heavy currents required by many large multi-copters and electric aircraft. (70A continuous. Much higher for few seconds bursts).
Some testing at 140A:
We think this is a unique solution on the market today, please do tell us if this is not the case.
Please come to see more details on our site:
Bluelight Technologies
Comments
I used a Mosfet to accomplish this several years ago to eliminate parasitic losses while perching.
What are the heat sink requirements?
I always found that using a solid state switch is much safer than a plug, or mechanical toggle. The beauty is that you arm the motor remotely.
Good point about the inrush current.
A mechanical switch for such high currents would be very big indeed. To use a smaller mechanical switch would be very dangerous.
Your main load is already controlled by an electronic switch: the ESC. This technology has become quite reliable enough that we don't go back to mechanical speed controllers. I see this as similar technology (VERY similar, actually); once we have enough of them in the field, the technology will develop to the point that we don't even think about not using it.
I can see this circuit being integrated into the ESC in very short order.
As far as "no arcing of the contacts", you evidently don't understand just how much inrush current a discharged capacitor (like those commonly found in modern ESCs)can draw; it is in many cases 10x (or more) as much as the actual intended load. This manifests in arcing at the battery connector, and is VERY common in multirotor craft with 3-12 ESCs connected to power in parallel.
I would NEVER install a common mechanical cutoff switch as you suggest on a multirotor craft; the potential for imbalanced current draw due to contact resistance and likelihood of a fire make it a truly dangerous suggestion. There ARE a few designs for switches I might consider; however the required weight of said switches make them a poor candidate for a craft which hoists itself into the air by brute force.
Paul
Hi Chris, yes anything above 3.3 v will shut it off, anything below about 2v will switch it on
Hi Chris, the electrical input only takes a fixed DC level to do the switching. If you want to switch from the RC Rx then you'll need to get an RC to DC switch such as from here, or use the pico switch, eg from here. Our unit weighs around 0.9 Oz
Thanks for that, could it be controlled using Arduino/APM, i.e. a 3.3 or 5v logic?
Thanks BacklashRC :-)
This is a fantastic product. It really has the capability of enhancing the safety of our hobby and your efforts in creating it are very appreciated. This switch will be in all of my builds from now on, and I will retrofit several of my older builds as well. Great work!
Hi Quadzimodo, this takes a bit of getting one's head around! I can see how to do with 3 switches but not 2. Let me give it further thought.
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