LiPo Battery Charging and Storage

The Charming Mrs. EastBay RC puts up with a lot in the service of her husband's various hobbies, but one place where I'm pretty sure she would draw the line is burning down EastBay RC's international headquarters.  I've experienced first hand the rather unpleasant experience of having a LiPo battery short out and burst into flames, so I'm a stickler for careful battery charging, handling, and storage.

 Here's my main charging station.  That's a HobbyKing 4 port charger powered by an old PC power supply.  The charging bunker consists of a standard sized concrete block sandwiched between two flat blocks.  I painted everything white to look a little better and to keep dust, etc from coming off the concrete.  I've notched the block so that battery leads can fit in with the top closed.  There's a smoke detector on top, and a fire extinguisher next to my workbench.

 Here's my battery storage bunker.  It's a fireproof safe that I salvaged out of recycling.  It weighs a ton.  The unit was open with the door bolts set in the locked position.  I tried (unsuccessfully) to figure out how to set a new combination, but it works perfectly as a battery storage bunker.  The door is heavy, so I just need to be careful not to drop it on my fingers.

Here's a view showing some batteries.  One day when I have some time to kill I'll put some shelves in to make the storage a bit more tidy, but for now I'm really pleased with it.

Prior, I stored everything in an old ammo box, which was a bit more restrictive in space.  The Internet seems to think that it would be fine for containing the open flame of a burning LiPo.  Prior to that, I kept everything stored in a concrete block similar to my charging bunker.  I've also got some LiPo bags for use on the go.





Bottom line:

• Take LiPo charging and storage safety issues seriously.  Watch some youtube videos on "lipo battery fire" to ensure that you do.
• Get something to put your batteries in while charging.  I think a LiPo is actually a good solution, but it's a bit more convenient to have a larger bunker if you've got the space.
• Always stick around while your batteries are charging.  I typically charge while I'm at my workbench so it's not a problem for me.
• Keep a fire extinguisher nearby.  This applies to your workshop or hobby table as well.
• Be careful, but not anxious.  I've never (thank God) been in a car accident, but I still wear a safety belt when I drive.  Same here... it's a bit overkill until the one time it isn't!
• If this save you from burning down your place and getting in big trouble with the family, you owe me a verrrry nice dinner!

update: here's my bag of sand that I was using to cover the hole in the concrete block before I switched to the flat concrete block.  The reasons I switched were:

• I wanted to move the charging station from the garage to my workshop so it would be a bit easier to attend to.
• I was in deathly fear every time I handled the bag, afraid it would split open and I would be vacuuming sand for hours.
• After watching a couple of youtube videos I think the concrete topper will contain any open flames.

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Pool Noodle Blade Guards

It's summertime, and that means cheap pool noodles at the store! In honor of the terrible, horrific, scary posting at diydrones about prop injuries, here's a method a lot of people use when working on their quads.

Slice out a section, and it will fit nicely over your props.  If you accidentally power them up, they'll shake and shudder alarmingly in the noodle, giving you plenty of time to pull the plug.







See it shimmy and shake in the most shocking manner!

New Phantom Blade Guards

Snapped from a video interview with DJI CEO Colin Guinn at NAB 2013.  Most of the talk was about their new brushless gimbal, but what caught my eye was the blade guard on one of their upcoming models.  I might try making something like this for the Arcticopter!




Here's the full video:

New Battery Bunker

 Here's my new battery charging bunker.  It's a concrete block, with flats on top and bottom.  I chiseled out a slot for the wiring.  I'm going to try the "sand in bag" technique for the top.  The idea is that you put the sand in a plastic bag, and a fire will melt the plastic, smothering the battery.  I might keep the concrete flat on top of the bag, so it will totally seal.  There's a smoke detector on top.

Here's the reason for the new battery bunker.  It was a 3S 500, relatively small.  I'm pretty paranoid about watching over charging, so I was there when one of the cells popped.  I took it off the charger and examined it; within a couple of minutes smoke started coming out, so I tossed it out the door and it burst into flames a few seconds later.  I wasn't concerned with the leaves, because it was a rainy night and everything was soaked.  I've also got a fire extinguisher next to my bench; you should too!

Update: with the recent dry weather, I have a sand-filled bucket sitting outside the door.

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Please Be Careful!

A Public Service Safety Announcement from EastBay RC!

Usually when I talk about RC, quads, etc, the emphasis is on how enjoyable it is and what interesting people are involved. If it looks like they're serious about learning more, or if they're going to come out fling with me, the first thing I do now is show them this picture, to let them know they're dealing with something that, if care is not taken, can hurt them very badly.


I grabbed these pics from an RCGroups thread... you can go there for lots more of the same.  In almost every case it was somebody doing the first thing they're warned against:  Testing and building with live props.

I don't want you to be scared off by these pics, but I do hope they scare you enough to follow the basic rule:  If you're fiddling with your quad, disconnect your ESCs or remove your blades.  And if you don't, be sure and post the results as a warning to others!

My own experiences that have make me very fanatical about this:

• While measuring the power on a small (blue wonder powered, 8x6 props) quad, I reached across the blades to adjust the wattmeter, and grazed against the edge of the blades.  This resulted in more of a scratch -- no real bleeding -- but it made me not want to get any closer ever again.
• When at a conference, I was helping another very experienced quad builder; one of the designers of the Ardupilot Mega, in fact.  I was somewhat uneasy, because he had the blades attached, but disarmed.  Since he was so experienced, I rationalized to myself that it was OK.  When he reset his unit, one of the ESCs provided full power for a brief instant, flipping the quad in my direction.  It grazed my cheek (yikes!) and gave me three relatively small cuts (nothing like those above!) on my hand.

So, I kicked myself for having ignored what I knew was best, and promised myself to never make an exception in the future -- safe working, or I'll be happy to stand back and watch.

Another thing that's worrisome:  With the advent of little helis such as the Syma 107, people are much more likely to have been in close proximity to a small flying craft.  Getting hit by one of these will sting and perhaps leave a scratch, but definitely won't do the damage depicted above.  In addition, people will pay you the awesome compliment of assuming you're in complete control of your aircraft with millimeter precision and millisecond timing.

So, to summarize:

• There's a reason they're called Blades.
• Unplug or remove your props when working on your unit.
• Make a habit of disarming your unit.
• Don't fly close to people, especially those who don't know the potential hazards.

BTW, this picture is from my recent drone presentation, filled with lots of interesting technical bits and more cheerful shots like these!

Quad EPS blade protection

The website is down now, but here's a quad with an eps blade guard.  The guard is sold separately as well.  It's four circular pieces with straight edged that attach together.

It would be great to be able to provision a homemade quad with something like this.

An Idea for a Safe Lipo Charger

I heard somebody describing this idea, but I can't remember who.  He had seen a much larger system like this while working on a military project.

• take two flowerpots.  flowerpot 1 is the base, flowerpot 2 is the top.
• cut a notch out out of the rim of flowerpot 1.  this is for lipo charging wires.
• fill flowerpot 2 with sand.
• cover flowerpot 2 with a sheet of thin plastic, something like grocery bags.
• secure the plastic around the rim.
• attach a piece of chickenwire to flowerpot 2.
• put the batteries in flowerpot 1.
• place flowerpot 2 upside down over flowerpot 1.
• if the batteries catch fire, the plastic will burn and the sand will flood the batteries in flowerpot 1.

This works best if you have nice long charging cables.  I intend to try this some day, but for now I'm just using a lipo sack since I usually am charging small batteries one or two at a time.

It would be nice to have this setup sitting on the porch and just run the charging cables outside.

Safety First: Props and Fingers

As the package says, these are not toys.

• Don't hold flying wings by the prop cutout.
• Be careful while hand launching.
• Don't hold a prop in your hand while you're testing it.
• Related: don't tuck your remote under your arm where you will bump the throttle.

For the gas guys:

• Be careful while starting.
• And don't reach around a running prop.

Ordered LIPO bags

From ebay, being shipped from Hong Kong. Bought 4 bags, I'm going to try and set one on fire just to make sure they work. Price for 4, $18.36.