Large Scale Central

Yet another Lithium-Poly warning

Electronics Power and Sound
#1

I received this from a friend today:

“As you all know, I fly a lot of R/C, and use LiPo batteries in most everything I fly. I have been charging them for years without incident, up until today.
I was charging a 3 cell 2000 pack on my AstroFlight LiPo charger. Something I have done hundreds of times…
I started the charge and went back to work in my garage. I wandered in to the house after 15 minutes to get something to a really bad smell. I knew right away it was a battery. I have a charging station in my living room, away from things like appliances, gas lines, etc.
The battery being charged was smoking and the charger read “FAULT - 4C”, so the charger thought it was a 4 cell pack (it read 3 cell when I plugged it in).
I grabbed the battery by the long leads and ran outside to my driveway. I dropped the battery and turned went back inside to check if anything else was damaged. As soon as I went inside, the battery exploded. I mean really exploded. KaBOOM!
My son Steven and Bob H. were watching it and said it was better than a 98mm M grain [rocket propellent] fire. It burned for several seconds, and my quick thinking son grabbed an extinguisher and put it out. We keep a lot of fire extinguishers around. Very impressive burn marks on my driveway.”

#2

I guess you won’t be using them in your locos then?

#3

Thanks for the info , I try to be very careful with the lipos for my planes also …and your problem is really bad that the charger failed .I will be even more careful now with lipos . And no , I would not use them in my trains . The RC trucks and planes , yep , sure do .

#4

I am pretty sure most of the problems with Li-Polys is that they have to be charged very carefully.

When the battery packs have the electronic control circuits built in they seem to be pretty reliable although I have heard of one or two spontaeous combustions just on their own.

I deal with a large R/C model plane & car importer here in Australia because I use Hi-Tec servo connectors with my R/C stuff. That importer imports and sells Li-xxx batteries in all shapes and sizes. The packs are primarily for the electric R/C plane market. They do not have the electronics built in. When I asked about trying them inside a loco the gentleman helping dissuaded me by stating that they must ONLY ever be charged out of the plane etc, inside a fireproof container. Hardly practical for our use anyway.

The above is by no means meant to criticise the Crest Li-Ion packs. They have electronic circuity built in.
I just don’t like them because the voltage at 21 volts is unnecessarily high. If they were 18 volts I would be glad to try them.

#5

LiPo packs really aren’t needed in model RR’ing. Their major advantage for RC flying is energy density where we are concerned with weight. They offer hogh voltage in a lighter weight package than NiMh’s or Nicads. In model RR’ing added weigh is usually an asset.
They indeed need a specialized charger and most modern LiPo packs worth spending money on have balancing taps that you charge through. You indeed get into trouble if you charge improperly and also if you discharge the pack below 3.1V per cell. They take a long time to charge when compared with other chemistries.
I’ve been flying for 15 yrs and flying electric power exclusively for 5 yrs. I made the jump to Lipos last season and fly exclusively with LiPo’s now. They opened a lot of doors by virtue of their light weight. I am very careful charging them, using a balancing charger from FMA, and monitor them carefully. I’m experimenting with RC for
RR’ing and will use those NiMh’s I no longer use for flying I have sitting in a box.
Hope this info helps. If you want to get more info on battery technologies go to the Batteries & Chargers forum on RCGroups- http://www.rcgroups.com/forums/index.php
Dave

#6
TonyWalsham said:
I guess you won't be using them in your locos then?
Hehehehe

How about using them in a “very realistic Dynamite Car”? :lol: :lol:

#7
Hans-Joerg Mueller said:
TonyWalsham said:
I guess you won't be using them in your locos then?
Hehehehe

How about using them in a “very realistic Dynamite Car”? :lol: :lol:


Oooooooh!!! You are awful. :wink:

#8

As long as there is a smoke-detector in the car that, when sensing smoke, activates the “chicken dance” sound routine…

Some day, probably long after I am gone, folks will remember what I’ve been posting about those batteries.

I don’t want them in my shop.
Out on the RR, okay, but not in my shop.

#9

I want to build a “destroyed” dynamite factory for the layout. Maybe I could use one of those instead of setting it on fire! I also have an old M80 that might work!

#10

An electrican on the job site last night had a 24Vold Li powered drill. He said it ran full RPM’s till the battery was discharged then it would just stop, not slow down like my DeWalt.
Are we talking about the same batteries??? Nick Jr

#11

Nick- Yes.
Doug- a completely destroyed dynamite factory is very easy to model.
Just find a bare spot on your railroad, with nothing there, and put up a sign “destroyed dynamite factory”.

Run a spur to it, take about 6-8 ties off the end, and bend the rails up and away from each other just short of the “site”.

A small crater wouldn’t hurt.

#12

Yes Nick. There is electronics, probably in the drill itself, that do not allow the drill to run if the battery pack voltage is dangerously low. Avoids dangerous deep discharge. Often, over-discharged batteries will reverse polarity. When this happens and you charge them, that cell is basically a short circuit, and you get lots of heat for free, right away. Boom.

Regards, Greg

#13

Greg, maybe your explaination is why one of my DeWalt battery packs is showing an error when charging. So, do the battery packs for the Li drills have circuits to protect them from over heating and over charging??? Nick Jr

#14

They are supposed to, at least commercial packs.
Whether they work or not is a crap shoot.

To Wit:
Early NiMH technology had heat sensors in the packs that connected with one (or two) extra wires to the charger.
The charger sensed the heat from these batteries and shut down charge oh heat rise.

Okay. Fine. Except the sensors did not always work, the sensor plug could get corroded, the battery pack could have been dropped, etc, etc, etc.

Finally we had Smart Chargers that externally sensed current and voltage peaks.

On Li based batteries, at least one manufacturer has a protection circuit that shuts them down, except SOME folks seem to be reporting they shut down WAY too early.
Go back and read the part about heat sensors on early NiMH.

Remember the writeup on the one site with garage, shed, workbench, locos burned and melted?

Finally we get some odd type of corrective response, that while all batteries were Li based, the new claim was the one that blew was NOT from the particular manufacturer in question.

So, now the question arises:
Do we have batteries custom made to one exact charger, all HAVE to be purchased from the same maanufactuer?

So, if you use the same voltage Li pack from someone else, on the specific manufacturers charger, will you get the same results as the photo?

Li-based technology is NOT ready for prime time.

When we go one year without cell phones, laptops, model aircraft and model trains blowing up or smoking or catching fire, we’ll be close.

But not yet.

#15

Nick, virtually every li-ion pack made has SOME provision for protecting itself. I normally see at least a thermal cutout in series with the cells, and some kind of overcurrent protection, like a fuse, or fuseable link.

But you can get excessive heat and excessive current even when these circuits are functioning. The thermal sensor cannot read the temp of EVERY cell, normally it is touching one or 2 cells.

There are sensor failures like TOC says.

In consumer devices like drills, where it is assumed your batteries will wear out much faster than the appliance, they tend to put the smarts in the drill and the charger, and basic protective devices in the packs.

I suspect your charger is sensing the problem, like the pack voltage is not right, possibly indicated a shorted cell. Also, if the battery charge characteristics do not match what is expected, that can cause an error. Everyone does things a little differently.

Regards, Greg

#16

Greg, Dave, thank you for your explainations. I looked around for the Milwaukee 24V Li drill and couldn’t find any. Hoping as you said the ones for commercial use are built a little better. My other DeWalt battery is barely holding on. I can’t complain as I got a new set of batteries about 4 years ago, they are in use almost constantly and are kept in the back of a truck that is subject to the temp changes here in Jersey. I was told the Li batteries aren’t effected by the temp changes, is that right??? Nick Jr

#17

Nick, go to home depot, you might be able to find the Rigid brand of lithium drill batteries. They make 18v and 24v lithium packs. I’ve never seend the 18v ones, but I was drooling over the 24v set yesterday, and read all the info on the chargers. Some of their tools will accept the 18v nicad, 18v lithium and 24v lithium. Was trying to see which chargers, if any, were likewise universal.

The cool thing about Rigid, is they have a lifetime warranty on their batteries. So, could be one heck of a deal, just be sure to register them. (And don’t say you are using them in trains!).

So far, the local stores do not carry the batteries by themselves, just the sets and chargers, but you could probably order them.

Regards, Greg

oh, have never researched temp performance of lithium, usually the temp is only a factor in 2 areas, where the performance suffers, would imagine that the range of temps you run your trains at is way within this range; and temperature that causes actual damage to the electrolyte. Usually this is when you actually freeze the electrolyte in the cells, it crystallizes, grows in size, and damages the “separator” between plates, (which might be physical distance, thin paper, or a chemical layer).

I would never leave batteries out in freezing temperatures, but I do not know the danger points for lithiums.

#18

Greg, the salesman @ HD did try to sell me the Rigid set, and it was almost half the price the electrican said he paid for the Milwakee set. I have no experience with Rigid electrical tools, only their manual plumbing stuff. BUT the lifetime battery replacement seems more than worth the price if Rigid battery tools are commercial grade. I know DeWalt has Home and Commercial grade tools. Nick Jr

#19

Perhaps you should charge those out in the driveway :o

“Visit our beautiful sunken gardens on the site of our former Atomic Research facillity.”

#20

I wonder what kind of batteries they’re using in these new electric and hybrid cars. A car-sized Lithium battery would probably make a pretty good crater if it decided to blow. On the plus side, it might take out a tree-hugger or two. :wink: