LiPo battery may have caused RC shop fire

RC pilot Jim Bonnardel has been flying Radio Control aircraft since he was seven-years-old. He’s president of the Silent Electric Flyers of San Diego and owner of Radio Control Specialties.

And on Jan. 16, he watched the shop burn down.

Bonnardel says he suspects it was a LiPo fire,  noting that he was charging a bank of batteries and was on the last one when he stepped away for about 10 minutes.

For years, lithium polymer batteries (LiPos) have gotten a bad rap for being dangerous and unpredictable. Dropping, denting or crushing can shorten the life of the battery and even cause an internal short — a recipe for fire. There are a myriad of guidelines for storing, charging and transporting them.

But for even a highly experienced pilot like Bonnardel, the slightest misstep can cause extreme danger.

So why don’t we just use alkaline batteries — your standard Duracell or Energizer?

“An alkaline battery has much more power than a lithium ion, but it cannot deliver heavy loads,” said Isidor Buchmann, founder and CEO of Cadex Electronics.  “Something like an AA battery is an energy cell, not a power cell. It simply cannot deliver the power needed.”

A drone needs a battery that can handle higher currents. LiPos are power cell batteries, mean they can deliver a lot of energy in a short amount of time. Your standard kitchen clock battery delivers a small amount of power over a long period of time.

“It’s like how a bottle with a bigger mouth can pour out a lot of water more quickly than water with a smaller mouth,” Buchmann said.

John Salt, creator of RC Helicopter Fun, put that amount of energy into perspective.

“Some of my big LiPo packs that I use in some of my largest RC helicopters have as much energy potential stored in them as a couple cups or so of gasoline,” he said. “Get a dozen or so LiPo’s on your work bench and you essentially have a jerry can of gas sitting there from a potential energy standpoint.”

That’s not to say Lithium-ion batteries are not safe.

“Lithium-ion is safe under the right circumstances, but they need to be properly designed and approved,” Buchmann said.

Salt chalks it up to an educational problem.

“LiPo power is just as safe or dangerous as any other high energy fuel source and has to be treated that way,” Salt said.

By that, he recommends storying them in fire safe containers and in safe locations just like fuel.

“Is this “LiPo education” up to the battery manufactures, RC aircraft manufactures, or the individuals flying and using them? I would say all three,” he said.

But there’s one more solution, and DJI, creator of the popular DJI Phantom series of quadcopters, holds the patent to it.

Shortly after the launch of the original Phantom, developers with DJI wanted to ensure that consumers with less experience with soft pack batteries would be able to use them.

“We knew it would be a game changer because it further lowered the barrier for first time pilots interested in quads,” said DJI spokesperson Michael Perry.

Development on the Smart Battery for the Phantom II line of drones began in April 2013.

The Smart Battery’s are also LiPo batteries, with a capacity of 5200 mAh and voltage of 11.1 V. Power management is handled internally, meaning no balance connector is required to charge.

The one major criticism Phantom II users have? The price.

DJI smart batteries cost about $130, in comparison to the $20 LiPo batteries sold on DJI’s site (and often found cheaper on hobby sites).

“We cannot say for now if the price will drop. Part of the reason that the batteries are priced higher than normal LiPos is that all the smart features requires additional hardware (not just the LEDs, but circuitry), software and testing costs,” Perry said. “We feel that the intelligent features that people get out of these batteries corresponds fairly to the price differential with typical batteries.”

And that’s not to say that the DJI Smart Batteries are 100% foolproof.

“Heat is a big enemy of all Lithium battery chemistries, so even a DJI smart pack could be damaged by letting it sit inside a closed vehicle on a hot sunny day for instance,” Salt said. “Chances are it would never start on fire, but there is still some risk there – especially if it’s fully charged.”

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