Solved Battery Safety

[Wole Oyeyele]

Hi, I'm pretty new to flying. I'm just building my first plane (I so far bought all my other planes rather than building them, and they came with batteries that have safety stuff built into them, so they don't pose a huge risk). I need advice with batteries. I did some research about Lithium polymer batteries, and they can be pretty dangerous if not handled well. I heard so many stories from people on forums who almost burned their house down just from a small mistake in how they stored or charged their batteries.

Nearly every website I visited about the topic advised users to charge their batteries outside, far away from anything flammable. However, this isn't really possible for me. I live in a flat, not a garden house, and I don't have a lot of safety equipment or a huge budget to spend on safety equipment. Therefore, I have some questions:

Are LiPo batteries as dangerous as many people describe, or is the risk slightly over-exaggerated?
Is it too dangerous to store/charge batteries indoors and therefore not worth the risk?
If not, when charging/storing batteries indoors, how do I minimise the risk of one catching fire?
What should I do if one does start to smoke or catch fire?
Is a fire extinguisher absolutely necessary to have?
What are some things I can use (besides an extinguisher) to put out a LiPo fire?
How do I store, use and charge my batteries as safely as possible?
Is there any cheap safety equipment I could buy?
Any other advice regarding LiPo batteries?

Sorry if I seem a little paranoid, but it's better to be safe than sorry.

Thanks in advance.

 

[FDS]

Lipo batteries are not explosive ordnance, they won’t simultaneously combust, devour your town or explode in regular use.
I have never had a battery smoke, catch fire or get close to either of those states. Ignore dumb people stabbing Lipo with sharp objects to make it explode. Some quad pilots smoke packs by crashing into concrete or bandos at 40+mph but that’s not regular use. I have kids in my house and no outside space, I charge Lipo daily at home, sometimes several times per day, usually in my kitchen. I don’t have specialised storage, nor do I own a lipo bag.
A fire extinguisher isn’t necessary for lipo, but every home should have one and a fire blanket for general safety. You cannot extinguish a lipo fire with one anyway, since it’s self oxidising. That’s why you only need to follow the rules to be safe.

The golden rules are simple-

• Never run below 3.3v per cell, ideally stop at 3.5-3.7v per cell. Good fixed wing ESC’s have an auto cutoff at 3.5v that either pulses or cuts the throttle. Quads have a battery warning built into the OSD/FC.
• Never short the + and - of a Lipo Battery (aka “don’t cross the streams.”)
• Never leave them flat between uses- A decent charger has a Storage program to run if you aren’t using them again for a few days or longer, otherwise simply re charge them ready for flying.
• Like any rechargeable battery, never charge unattended
• You can charge in a non flammable container if you like, I use a lasagna dish with a plate over the top for dodgy batteries, but you don’t need to do this if you manage your batteries properly. If it didn’t get below 3,5v it’s going to be pretty stable.
• Check the voltage with a meter after every flight, keep empty packs separate from charged ones so you don’t try and fly a flat pack.
• Store your batteries away from flammable substances, at a moderate temperature in a non sealed container.
• Never feed your lipos after midnight.
• If you puff the pack by running it too low, reduce it to zero volts and dispose of it safely.
• In addition I would recommend a quality charger with a storage setting. Don’t buy the super cheap ones.

 

[RHengelsberg]

Lipo batteries are not typically that dangerous as long as you treat them properly. I personally charge all my lipo batteries indoors, but I watch them for most of the time they are charging. You can use a lipo bag, for charging, or a batt-safe(charging box that is pretty much fireproof, check out the flitetest video). I did some research and it sounds like an ABC or bc fire extinguisher will put out a lithium battery fire. I don't have a fire extinguisher in my home(even though I probably should get one), but it's probably a good idea to have one. On rcgroups it sounds like you could put it out just with sand, like a normal fire. One person said that you could even use water. But, the gas/smoke that is released is extremely toxic. For charging, just make sure that you don't charge lipo batteries above 4.2 volts per cell, and don't discharge them past 3.5 volts per cell. Lipo batteries are best stored at 3.7-3.8 volts per cell.

 

[Hai-Lee]

I have seen LiPos both explode and cause fires. They tend to explode when they either get extremely hot or are physically damaged causing an internal short, or a short from something piercing them. The fires can be started with an explosion but normally from something external shorting out the battery causing massive energy release in a short time.

The secret to safety with LiPos is temperature management. If you never get the LiPo hot it is safe under under any normal handling or storage. Never fast charge a hot battery and generally allow the batteries to cool before attempting any charging.

Never store a hot battery with other batteries and similarly never store a suspect or damaged battery with other batteries. Sand will not extinguish a LiPo fire but it will make it less severe as it denies additional Oxygen to any resultant fire.

It is wise to charge and store LiPos away from other combustible materials and surfaces, and ensure that there are no exposed wires on anything used with the batteries and on the batteries themselves. Plane fires are generally caused by an ESC that fails and shorts the battery output, (not a pretty sight), or a wiring fault!

Treat the batteries with respect and manage their temperature at all times and you will never risk a fire and possibly get long life from your batteries as a result. I have flight batteries with over 1000 flights and that are over 2 years old and yet still providing sterling service!

Just my opinions!

Have fun!

 

[Merv]

I charge and store my Lipo in a box inspired by IBcrazy.

 

[PsyBorg]

Flite Test did a show on this and came up with a battery bunker for charging.

You can boil that down to using a multi hole cinder block. A piece of fire resistant board and a bag of play sand.

Like anything else its proper handling, regular inspection, and common sense.

Never over charge. Never leave unattended. Never keep a damaged battery anywhere near burnable material. Always do post flight checks and put batterirs on a storage charge if drained too close to minimum voltage per cell.

I use plastic containers that sun flower seeds come in to store and transport my batteries in a protected state.