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Old Jan 19, 2013, 09:02 AM
Lou
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United States, VA, Waynesboro
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I suspect that more fires have been caused by tossed cigarettes, unattended camp fires and sparks from car exhaust than LiPo batteries.

I can tell you first hand what a section of carpet and the sub-floor look like when a kid charges a NiMh race pack incorrectly. Replace the sub-floor, replace the carpet, paint the room. Retrain the little junior commando on proper battery handeling.

Of my worries in life, LiPo usage in a sailplane is not one of them.
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Old Jan 19, 2013, 09:54 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
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^^ my attitude too...

Chris
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Old Jan 19, 2013, 10:08 AM
sKrude up, Rejected!
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United States, CA, Santa Barbara
Joined Jun 2008
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I read a story where Japanese engineers stated the batteries were being charged at too high of a voltage.
That will cause problems with any battery pack.
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Old Jan 19, 2013, 10:42 AM
weisenflymanheimer
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http://www.9news.com/money/311173/34...g-787-mishaps-
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Old Jan 19, 2013, 10:51 AM
Gravity gives sinking feeling
Joined Jun 2011
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It's really sad to read this thread. We're i.e. model flying pilots are supposed to be more techno savvy than a guy on the the street and yet revealing our lack of knowledge.... and allowing tabloid papers to tell us about science... outrageous.

Lipos are well known to be susceptible to rapid temperature changes and in extreme cases can even explode. This is an established fact with Lipos. I'd not go into technical details why this happens.

This temperature change can happen if you rapidly cool it - as in the case of an aircraft which can reach a height of 36,000 feet in matter of few minutes. Temperature there is sub zero.

Second scenario, when you discharge a lipo at a rapid rate than it's specification states.(hence, 25, 30, 40 etc C on a Lipo pack).

We've no facts yet why Boeing Dreamliner's battery exploded. Let's not be hasty and let some fact emerge.

Let's face it, millions of people are using Lipos in their laptops, tablets and phones. So technology is well proven in these areas. But a few laptops did catch fire in the early days of lipos. That has been taken care of now and thanks for that. So we can now charge our laptops in 2-3 hours and not in 10-12 hours.

NiCd or NMH are pretty ancient technology - we don't want to go there. again. How any of you would like to use brick size mobile phones????


EDIT : As I was writing this post, the above thread appeared..... what a coincidence ..
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Old Jan 19, 2013, 11:02 AM
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USA, NV, Reno
Joined May 2003
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Wow! Did you even read this thread?
Now we have the electric guys coming to school us on Li-Ion tech.
Come back when you've drilled your LiPo powered Stryker into a brush covered slope at 400MPH.
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Old Jan 19, 2013, 11:10 AM
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United States, CA, Bear Valley Springs
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Quote:
Originally Posted by Trisquire View Post
I'd be less concerned about Boeing's lithiums, and more concerned with all the lithium equipped wireless devices that passengers bring on board. Boeing will find a solution. I can't say the same for Joe Schmoe who just dropped his smartphone before coming on board.
That is being addressed as we speak...particularly for flight crews.

mw
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Old Jan 19, 2013, 11:12 AM
Where's the wind?
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United States, CO, Denver
Joined Jun 2004
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If they were using 3ph Japanese power for their charger it might have something to do with Japan's affinity for corner grounded delta configuration. Always causes lots of weirdness with 3 phase circuits. I have no idea why they use it but its a pain for electric equipment.

Andrew
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Old Jan 19, 2013, 11:14 AM
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Mark Wood's Avatar
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I doubt they're using a Japanese electrical system. The 787 is built in South Carolina, isn't it?

mw
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Old Jan 19, 2013, 11:18 AM
Where's the wind?
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United States, CO, Denver
Joined Jun 2004
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Ya, but if they plug the plane in while on the ground you get Japanese power on the plane.

I can see a design engineer designing the charger for balanced 3ph power and then not consider the Japanese who are one of the only countries in the world that ground one corner of a delta 3ph power. It causes all kinds of issues with 3ph power supplies. It's hard to tell what it would do to a battery charger.

Andrew
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Old Jan 19, 2013, 11:28 AM
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United States, SC, Greer
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I figured it had to be a overcharge issue, nobody would be dumb enough to undersize a battery!

Come back when you've drilled your LiPo powered Stryker into a brush covered slope at 400MPH. So that's who's starting all those fires! Haha!
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Old Jan 19, 2013, 12:07 PM
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Austin TEXAS area
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I was a working a&p then later an Inspector. Thermal runaway was/is as big an issue on Nicad battery packs in aircraft as li based batteries can be. Training is the answer for crews/mechs on the new batts just as it was when nicads first were introduced. The problems will be fleshed out, fixed and new proceedures will be put into practice.
Quote:
Originally Posted by glasairIII View Post
Years ago I saw the after effects of a nickel-cadmium battery thermal runaway. This was on a Cessna Citation. We found the battery remnants on the ground. We also found a square hole were in burnt it's way out the bottom of the plane At the time, this style of battery was fairly new to the industry. Now, it's used in all the commercial jets. Airbus, Boeing etc..... And I've haven't seen any issues, except dead battery's from being left on


Bottom line, Boeing will find the cause. And, I'd hazard a guess that they will temporarily go back to the tried and true nickel-cadmium. I'd also hazard a guess they went to the new technology for the same reason we do. Weight and capacity.
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Old Jan 19, 2013, 02:26 PM
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United States, TN, Blountville
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Quote:
Originally Posted by JetPlaneFlyer View Post
I wonder how many cars have been incinerated due to gas (petrol) fires? ... an answer to the nearest 100,000 will do
Is that statistic to exclude those used by criminals to destroy a body after being murdered, destroy evidence of crimes in the vehicle, or dispose of a stolen car, etc
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Old Jan 19, 2013, 03:28 PM
Dean
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USA, CO, Littleton
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Hmmmmm.....I guess I had better pay closer attention when I charge my lipos.......and when I put gas in my car.
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Old Jan 19, 2013, 03:53 PM
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Quote:
Originally Posted by chris s View Post
Boeing has Lithium iron batteries ( LiFe) in the B787. I think it has a set at the front for the cockpit etc and another set down the back for the APU.

I'm not a battery expert by any means but I am surprised such technology is being used in an aircraft if there is a risk of it catching fire and thus having to be contained. Normally in an aircraft the only thing you expect to burn is the fuel, not the battery.

I think most people who use Lipo`s know about the risks, and that the risk is real. It's hard to believe Boeing would risk their product just for the supposed benefit of a new battery type.

Anyway, hope Boeing get this plane ( not just the batteries ) sorted out asap. It doesn't look good for the moment, thats for sure.

C
The risk of thermal runaway has been known and taught for years, it first showed up when the transition was being made from lead-acid to ni-cad and resulted in a requirement for overtemp warning systems on all "exotic" batteries. Battery fires are nothing new.......
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