by Matt Doernhoefer, Product Director
This article made me recollect the simple greatness of engineering that is the character of Montgomery Scott, chief engineer of the USS Enterprise. Kirk would eternally be demanding more power and that is an issue I sympathize with. Our current LiPoly batteries top out at a hefty 650 grams and our drone itself will hit nearly 3 kilos dry weight. This is due to the nature of the extensive measures we go to build a rugged drone. Structural choices aside we need to utilize the most weight-efficient power supply we can find. We also elected to set a hard limit of 99.9 watt hours for the onboard battery capacity. This is to comply with FAA regulations as many our customers are travelling inspectors and we want to be able to serve their travel needs.
That said, I’m all about options, so I’m trying to find the way to get the most watt hours for the least weight. Energy density is the biggest value we’re looking for and so I’m always looking for new chemistries that can make our batteries go further for less weight. Fortunately, we can benefit from not only the drone revolution, but also the electric vehicle revolution. The formulations and developments for electric vehicles tend to trickle down to the drone world quickly so keeping an eye on what Tesla is up to with their batteries is always a good sign.
I have seen some interesting formulations come out with our favorite material to never make it out of the lab – graphene! I located and sourced a set of batteries that advertise using a Lithium Graphene matrix for their batteries (Whether they do or not – we’ll see). What I noticed was that the “graphene” formulation would offer us either a 20% decrease in weight, or a 20% increase in capacity. I am skeptical of these claims but would definitely appreciate a chance to put them to the test. Both are always welcome developments as I would love to fly 5200 mAh to feed my hungry hungry hippo that is our UVC array payload.
The most interesting development that looks real is the Lithium-metal battery. Several startups are coming out of the SF Bay area that are specializing in lithium metal. One of these companies posted a video of a DJI Phantom rocking one of their batteries and flying for an additional 7 minutes. Color me impressed. I’ve had a discussion with a couple of these lithium metal battery providers and would like to learn more. If anything, I’d kill to get a test cell onto the drone just to see how it does (subtle hint to any lithium battery startups – call me!)
This new-found energy density will play havoc with our 99.9 watt hour requirement but that would be a good problem to have. Honestly, I would prefer the higher capacity rather than the smaller weight. Energy capacity = flight time and/or payload operational time, and flight time/service time is always good. The other thing I look for is that any capacity left on the ground is value lost. Think of it as flying a half-full airplane. There’s always more room for activities unless your specific requirements need lengthy flight time. So raise a glass to Montgomery Scott, bringer of power, ‘cause I need more of it.