Are EUC Batteries Safer than Hoverboards?

[Rehab1]

Following up on a @John Eucist's  topic concerning the recall of over 500,000 hoverboards due to the lithium-ion batteries catching fire.

Question: What makes the EUC lithium-ion batteries less susceptible to explosion or fires?  Would EUC manufacturers honor such a recall?  Have battery safety standards been established by the EUC industry?

[Hunka Hunka Burning Love]

http://www.dailymail.co.uk/news/article-3358357/Now-electric-unicycle-sparks-fire-guts-house-fire-brigade-warns-against-using-cheap-batteries.html

There's not as many EUCs being ridden so I think we're seeing fewer problems with them, plus maybe they have less trauma to the cells due to the larger air filled tires?

[dmethvin]

Even a good battery can cause a fire if it's used with a poorly designed control board, wiring layout, or charger. I get the feeling that hoverboard buyers are less technical than EUC buyers and that may affect the level of care and caution to reduce the chances of fire.

[Rehab1]

@HunkaHunkaBurningLove Great Research! I have not seen that story. 

I have a tendency to open Pandora's Box only to have it implode on me. @dmethvin are you talking about me??

[dmethvin]

19 minutes ago, Rehab1 said:

I have a tendency to open Pandora's Box only to have it implode on me. @dmethvin are you talking about me??

Only if you're an exploding battery. 

[Keith]

2 hours ago, Rehab1 said:

Question: What makes the EUC lithium-ion batteries less susceptible to explosion or fires?

Have battery safety standards been established by the EUC industry?

They should be  exactly the same cells and balance boards so the short answer is:" nothing at all makes hoverboards more susceptible" except unscrupulous manufacturers and/or resellers dumped crap on the Hoverboard market because that was where the money was. Unfortunately good quality cells are a major part of the manufacturing cost. From the reports I read it looks like poorly and cheaply made chargers, crap cells, sometimes even sourced second hand out of old laptops, etc. Were the main causes.

Lithium Ion is safe enough if good chargers, good BMS and good cells are used. They store a lot of energy so do need treating with respect, it is really not a lot different to treating petrol (Gasoline) with respect you wouldn't walk down the street smoking with a tatty rusty leaking can of petrol in your hand. 

[HEC]

@Keith and @HunkaHunkaBurningLove are both spot on. Combination of sub par cells and chargers with unprotected battery packs getting bounced around inside sharpedged plastic casings while ridden on tiny wheels and getting thrown around by kids is a recipe for a dissaster ...

[The Fat Unicyclist]

31 minutes ago, HEC said:

@Keith and @HunkaHunkaBurningLove are both spot on. Combination of sub par cells and chargers with unprotected battery packs getting bounced around inside sharpedged plastic casings while ridden on tiny wheels and getting thrown around by kids is a recipe for a dissaster ...

But I throw my IPS191 around (being an EUCExtreme wannabe)... so does that mean I am relying solely on battery and charger quality?

[HEC]

1 hour ago, The Fat Unicyclist said:

But I throw my IPS191 around (being an EUCExtreme wannabe)... so does that mean I am relying solely on battery and charger quality?

The biggest risk is from getting the cell punctured by inner sharp edge or corner of the shell as wheel bumps around during rides or drops. Battey packs shall be realy mounted in shock absorbing foam or rubber patches to avoid direct contact and abrasions against body shell. If you've already opened your wheel you should be familiar with exact fitting of your battey pack(s) and if not it might be good time for inspection and if needed adidng of some protective elements. Sooner the beter. But don't overdoit be wrapping the packs completely in the foam as it might negativelly influence the heat dispersion from the packs.

[Hunka Hunka Burning Love]

You're relying on the grace of God that nothing explodes.  Face it you're basically a rolling time bomb of lithium ion chemical energy waiting to be catastrophically released.  Sleep with one eye open .

Hopefully IPS uses quality cells in its wheels.  Thankfully most EUC casings are made of plastic around the battery housing rather than pot metal like in a hoverboard. I've also seen pinched wiring housings screwed down under plastic battery cages so who knows what some added vibrations and crashes would damage over time.

It would be good to know what is exactly going wrong with these hoverboards so maybe they can be modified or the battery packs replaced with better ones if that's what the problem is.  I haven't seen anyone pinpoint what the issues are conclusively so there's bound to be a lot of guesswork. 

It looks like UL is doing some tests, but there's isn't a whole lot to go on.

http://www.cnet.com/news/why-are-hoverboards-exploding-and-catching-fire/

[dmethvin]

Double-sticky tape is definitely a good way to keep the battery packs from banging around. The first time I rebuilt my Firewheel I did it on 3 sides, which is super tricky to do because you have to pull out the protective tape while keeping the battery in the exact right position. The second time I just did two sides and that was easier. The batteries are solidly in place, no clunking. It also helps that the battery compartments don't have any sharp edges.

 

[mhpr262]

My guess is that the manufacturers used only the most rudimentary BMS (maybe even without individual cell monitoring) and the cheapest cells with unsafe chemistries. I fly RC aircraft where only very vulnerable pouch format LiPo cells with just some plastic and aluminium foil walls are used (and often severely damaged in crashes) and those fires are very uncommon in the sport. I guess technology has advanced in the last couple of years.

 

This is a video I shot myself of what happens when you intentionally overcharge an old, cheap LiPo pouch cell:

https://www.youtube.com/watch?v=tuoZB8Y3IOg

 

[Keith]

Bottom line is if you want a much safer technology for powering electric vehicles use LiFePO4 (a.k.a. LiFe) cells. Funnily enough the very next video after the one linked by @mhpr262 above is this one:  

 The downside is they are slightly lower voltage (they sit at 3.3 volts per cell for most of the discharge cycle) and thus also somewhat lower watt hour capacity, so, relatively, more expensive than Li Ion or LiPoly but they do have a very low internal impedance, hold their voltage very well so give more consistent power way deeper into discharge than LiIon. Those properties are why, I believe, Uniwheel chose them, and why their battery isn't as low capacity as people think it is (because it gives very good power way  deeper into the discharge.)

By the way, I've been using LiFe cells as model receiver batteries for several years, this week I dug out a plane that hasn't been used, or charged since August 2014 and its 2 cell 6.6V LiFe battery was down to a total of 2 volts. I charged it, putting 2300mAh back into a 2100mAh pack left it for a day and then discharged it down to 6V (3 volts per cell) at 0.5Amp I took 2050mAh out of it. Had that been a Li Ion or LiPo it would have been landfill.

P.S., like @mhpr262, I've seen (much less rugged than 18650 cell) LiPo's concertined in high speed aircraft crashes and not heat or burn. To get rid of packs where one cell has failed I often (very carefully) bang a nail through them to discharge them they get very hot, boil and bubble but, so far have never caught alight.

[mhpr262]

I agree, LiFePo4 cells would be an answer. They are FAR more robust regarding their ability to handle non-mechanical "abuse" - extreme quickcharging (sub 20 minute), extremely high discharge currents, huge cycle numbers (2000+), much better to able to withstand high temps (they actually work best at temps above ~ 100°F/40C°). All that is not an issue with LiFePo cells.

 

Like Keith Said, the downside is lower voltage and less capacity per volume and weight, so you'd need a bigger battery pack for the same range.

 

[edwin_rm]

I have a fire extinguisher suitable for electric fires that I keep accessible nearby, just in case if something goes wrong with the battery while charging.

However, I believe I won't ever need to use it, as brand-name unicycles use high quality, legitimate batteries.

 

[Rehab1]

@edwin_rm Suppose I could stick one under my pillow at night and sleep with one eye open

[esaj]

Just now, Rehab1 said:

@edwin_rm Suppose I could stick one under my pillow at night and sleep with one eye open

If you have a cell phone, and keep it near you while sleeping, you're already sleeping next to a lithium-battery... Hard-cased (but still just plastic) lithium-polymer (LiPo), to be exact   

[Rehab1]

@esaj What time is it there buddy?

No I was referring to a fire extinguisher under my pillow not a hoverboard My cell phone is tucked far away at night. I can't afford to diminish my cortex any furthe%  th%n it alread$% is

[steve454]

10 minutes ago, esaj said:

If you have a cell phone, and keep it near you while sleeping, you're already sleeping next to a lithium-battery... Hard-cased (but still just plastic) lithium-polymer (LiPo), to be exact   

Yes and after reading a lot of these posts, it got me thinking about having so many batteries of all types most people have in their homes.  In mine I have two EUC's, a laptop, cell phone, 5 vape 18650's, a smoke and monoxide alarm with 9 volt alkalines, electric shaver, 5 or 6 quadcopter batteries.  I have a lot of batteries.  

@Rehab1 I do have a fire extinguisher in the hall near me.

[esaj]

29 minutes ago, Rehab1 said:

@esaj What time is it there buddy?

Around 2AM.

Quote

No I was referring to a fire extinguisher under my pillow not a hoverboard My cell phone is tucked far away at night. I can't afford to diminish my cortex any furthe%  th%n it alread$% is

Oh, sorry, mixed things up x)  I blame the sleep-deprivation, I went to bed at 6AM yesterday (as it's already Wednesday here now), and got woken up at 11AM by my mother coming to visit unannounced (like she usually does)...

18 minutes ago, steve454 said:

Yes and after reading a lot of these posts, it got me thinking about having so many batteries of all types most people have in their homes.  In mine I have two EUC's, a laptop, cell phone, 5 vape 18650's, a smoke and monoxide alarm with 9 volt alkalines, electric shaver, 5 or 6 quadcopter batteries.  I have a lot of batteries.  

@Rehab1 I do have a fire extinguisher in the hall near me.

Yeah, there are batteries everywhere, wallclocks, phones, tablets, laptops, digital thermometers, remote controls, pocket calculators, toys... 

In this room alone that I'm sitting in right now, off the top of my head, I can say that there's at least 4 x AAA rechargeable NiMH-cells on the TI-89 graphing calculator, a (probably) low-quality LiPo in the cell-phone I use personally (a cheap Chinese non-smart phone), some LiPo in a tablet, another couple of LiPos in the iPhone 5 + Lumia I use for work stuff, a couple of rechargeable NiMHs in the digital thermometer and 12V 1.3Ah rechargeable cadmium-battery in a cordless drill. Those are just the "more ordinary" things, then comes: probably around 20 rechargeable 1.5V AA-NiMHs, 25 or so alkaline primary AA-cells, some primary alkaline 9V-cells, 5 x 9V (8S) rechargeable NiMHs in multimeters, surface temperature meter, LC-meter and some projects, and the icings on the cake: 11.1V 5500mAh 3S hard-case LiPo, 7.2V 3600mAh 6S NiMH, 16S2P Firewheel-battery (NMC-lithium, the wrapping is cut open and all the wiring is exposed). Now the 4 x 16S1P -packs (NCA-lithium) are in the next room, waiting in the Firewheel-shells (during storage, they're in a closet in this room). Probably I'm still forgetting something   

[steve454]

54 minutes ago, edwin_rm said:

brand-name unicycles use high quality, legitimate batteries

Something strange has happened recently.  Twice I recharged the batteries after draining them down to about 50%.  The next day I rode a mile, to drain off some charge, because reading about lithium batteries 

 

13 minutes ago, esaj said:

Around 2AM.

Oh, sorry, mixed things up x)  I blame the sleep-deprivation, I went to bed at 6AM yesterday (as it's already Wednesday here now), and got woken up at 11AM by my mother coming to visit unannounced (like she usually does)...

Yeah, there are batteries everywhere, wallclocks, phones, tablets, laptops, digital thermometers, remote controls, pocket calculators, toys... 

In this room alone that I'm sitting in right now, off the top of my head, I can say that there's at least 4 x AAA rechargeable NiMH-cells on the TI-89 graphing calculator, a (probably) low-quality LiPo in the cell-phone I use personally (a cheap Chinese non-smart phone), some LiPo in a tablet, another couple of LiPos in the iPhone 5 + Lumia I use for work stuff, a couple of rechargeable NiMHs in the digital thermometer and 12V 1.3Ah rechargeable cadmium-battery in a cordless drill. Those are just the "more ordinary" things, then comes: probably around 20 rechargeable 1.5V AA-NiMHs, 25 or so alkaline primary AA-cells, some primary alkaline 9V-cells, 5 x 9V (8S) rechargeable NiMHs in multimeters, surface temperature meter, LC-meter and some projects, and the icings on the cake: 5500mAh 3S hard-case LiPo, 7.2V 3600mAh 6S NiMH, 16S2P Firewheel-battery (NMC-lithium). Now the 4 x 16S1P -packs (NCA-lithium) are in the next room, waiting in the Firewheel-shells (during storage, they're in a closet in this room). Probably I'm still forgetting something   

Put them in the oven if they will all fit, then turn off the main breaker so you cannot use the oven for cooking!

That's what I did.  I use the stove for extra space.

[esaj]

3 minutes ago, steve454 said:

Put them in the oven if they will all fit, then turn off the main breaker so you cannot use the oven for cooking!

I'm not that worried about the packs. Besides, not only are smoke alarms required by law here, we've also got 3 fireplaces (a cooking oven in the kitchen, stove in the sauna and a fireplace), so there's also fire extinguishers, extinguishing mat and a carbon monoxide alarm, so I if things go south, we should be able to hear the alarms, and if the fire's already out of control, escape through the front door or nearest window (single-story house)

[steve454]

28 minutes ago, esaj said:

I'm not that worried about the packs.

I am not worried about the packs, they are safe, just worried about my ability to use them safely.

[Rehab1]

@esaj omg hyper fingers...well you covered most but I would have to add the battery in my dog's invisible fence collar. Hopefully your mother cooked a nice breakfast/lunch. Get some rest?

[Keith]

I keep my rather excessive collection of model flight LiPos (I must have more than 50 packs from 3.7V 150mAh to 44.4V 6000mAh) in ex army ammo boxes lined with foam.

It did, quite quickly, occur to me that should a cell fail inside one of these very well sealed containers it could chain react with the others in the box and build up potentially very explosive levels of pressure. I then drilled a 3mm hole in the lids of each one, under the handle so rain cannot get in, as a pressure relief valve. 

In the many years I've been crashing, hard landing and dropping LiPo packs accidentally onto concrete they have never heated up except when banging a nail through them deliberately. (Although I've seen some impressive YouTube footage, my favourite being this one if only because there is a field full of lawn sprinklers just beyond where he crashed (and I have the same heli!): 

However, 18650 cells are much tougher and I think it extremely unlikely that puncturing 18650 cells against sharp objects is a significant cause of fires. What will be a serious problem though is wearing through the insulation and short circuiting adjacent cells against metal parts in badly thought out (I.e. especially Hoverboard) installations. That would be more than capable of generating very high temperatures, enough for the cells to burn and then chain react with the whole pack.