Battery safety

Hi everyone, I'm new to the community and am in the process of building my first quad. I'm almost ready to get this thing in the air, but I'm alarmed at the apparent safety record for lipos. At RC groups, there are well over a hundred threads documenting lipo fires, some with obvious causes and some that are completely inexplicable. So, I have two main questions: are these things really dangerous, and if they are, why?

Given that these are incredibly volatile bundles of chemicals, it's not surprising that they're dangerous when punctured, crushed, or subject to charging abuse. But barring obvious physical stress, it seems unreasonable to have to charge these things in an ammo box. These things aren't (supposed to be) bombs--lipo technology is used quite safely in many other applications. So why all the fires?

The evidence I've read is anecdotal, so I'm wondering if the danger has been exaggerated, or if the cause of failure may be something the poster failed to notice or mention. I know that some people can be particularly rough with their devices, so perhaps some of these are cases of mechanical stress that weren't noticed in time.

If these reports aren't exaggerated and user error isn't so much a factor, then are these things poorly engineered? Are shoddy chargers to blame? Because seriously, it strikes me as wrong that a piece of technology should be so dangerous under normal usage conditions. Spontaneous house fires are nothing I want a part of.

What is your guys' experience with lipos, and what are your opinions on this issue?

Apologies if this is in the wrong category; none of the others seemed appropriate.

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Replies

  • "Spontaneous house fires are nothing I want a part of."

    Well, most of those you read about - laptop batteries, was due to a manufacturing problem at Sony. - sharp/bent edges on the foil inside.

    When it comes to iphones, it's due to (very) poor quality product. (after all , without option to replace battery (for most users), they are expected to drop capacity and make you buy a new device)

    Remember that our cells are much better (at internal resistance and C-rating) than those used in phones/laptops.

    Still manufacturing errors can occur - but Sony and their loss was a good warning to the industry.

    - Wrong handling and physical damage are the real threats. - store in proper bags, and you'll be safe.

  • Moderator

    The first flight-intended LiPo's that came out (I got my first ones in 2004) were very sensitive to the slightest short circuit (caught alight in my hand), damage (caught alight in my crashed plane) or abuse (overcharged at wrong setting) resulting in the phenomonen known as "venting with smoke and flame", there were no balancing taps then, one had to assemble them yourself and capable chargers were limited. Also being so new people's knowledge of them was initially limited so there were many early reports of of damage or catastrophic fires, etc due to misuse, ignorance and plain stupidity (check the dates of many of the reports in the RCGroups thread).

    Today's LiPo's are much hardier but will still "vent with smoke and flame" if abused or damaged. I've safely "abused' a few tired ones and they take a lot of punishment before...:)


    If charged, stored, protected and discharged correctly they pose very little threat, after all we all have LiPo's or Lithium Ion batteries in our phones and laptops.


    Electricity, x-acto blades and petroleum (gasoline) are all dangerous too, so one just has to take care with LiPo's.


    A greater concern for me is the disposal of my many dead LiPo's (containing lithium) as I don't know of any recyclers can deal with lithium in my city.

  • Lipos are plenty safe, but the dangers aren't exaggerated.

    You know the warnings on regular batteries?  Those are stupid lawyer BS.  On lipos there are a lot more of those type of warnings and they are for real.

    Understand the tech, follow the rules and you'll be fine.

    Physical damage is one area where they are more dangerous.  But that's like saying a 25 gallon gas tank is more dangerous than a 5 gallon tank... Duh!

  • Jennifer, I'm not sure how you read that same safety info and didn't get the facts:

    I'm wondering if the danger has been exaggerated, or if the cause of failure may be something the poster failed to notice or mention.

    Basically, no the danger isn't exagerated, but the reports are to be taken with a grain of salt. In other words, a person in general is dumb, groups of people are stupid and thus looking at a group of results, you see how stupid people really are.

    LiPo batteries are very simple high density storage devices. Because of the extreme energy density, there are a few well known gotchas. I mean come on, if you had a cup of gasoline, you would follow certain rules, the same is true with any battery, it's just energy storage. That article was written a long time ago, when LiPos first came out, NiCad and NiMh were king, and a crapload of people ignored the warnings. So in other words, the info you are looking at is very old, not well documented and even the hardware back then wasn't great.

    FACTS:

    Never ever do the following

    Charge a single cell in a pack above 4.2 volts

    Never discharge a cell below 3 volts

    Never charge with anything other than a balancing LiPo charger (They ensure rule 1 )

    Never short a pack

    Never trust a damaged pack (crash, dropped on the floor, etc)

    Never charge inside a vehicle

    Never store in a hot vehicle

    Never exceed the packs discharge current rating (Understand the C ratings)

    To recap, the danger is real. The difference is, the cause in well known even if the idiot that had the accident didn't post it. Lot's of people are in denial they caused it. They don't just burst into flames for no reason. They either overcharged, shorted, damaged physically causing short, or over dishcarged those packs.

    Funny part is, the same accidents happen with NiCads and NiMh packs too. They don't have the same energy density and that's why LiPos are pretty much the requirement that makes multi-rotor helis even possible. The older batteries didn't cause as many major fires because they simply run out of energy. I garantee, if you short you car battery, bad things will happen. Further, Lead Acid batteries emit hydrogen gas an are known to explode but we still use them.

    Please read this article http://diydrones.com/profiles/blogs/complete-guide-on-lipo-batteries

    Your concerns are pretty well addressed.

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