Rolling-stock lighting - Track Charged Rechargeable Battery

[Trains and More]

I am with Greg. He is rightfully upset about the comments he received. His point about Li-Ion batteries is extremely important. Overcharging them is dangerous. If you have ever seen one catch fire, you will know what I mean. They are the only battery I know, that actually carries highly flammable material inside.
An intelligent charger typically tests the battery's charging state when first connected with a small bust of power. That presents no danger to the battery. However, if this connection is repeated in rapid succession hundreds of times the effect accumulates and the resulting overcharging can become injurious and even dangerous to the battery. If there is any question about what a charger will do under intermittent voltage conditions, it is a good idea to stay away from charging a Li-Ion battery via the rails. That goes even when stationary, because the wheel-rail contact is inherently not very reliable.
Does my opinion carry any weight, I suppose, I am an electrical engineer. And Garden railroading for me is not just a hobby, it a way of life. I do it since LGB came up with the Stainz.

 

[dunnyrail]

I am with Greg. He is rightfully upset about the comments he received. His point about Li-Ion batteries is extremely important. Overcharging them is dangerous. If you have ever seen one catch fire, you will know what I mean. They are the only battery I know, that actually carries highly flammable material inside.
An intelligent charger typically tests the battery's charging state when first connected with a small bust of power. That presents no danger to the battery. However, if this connection is repeated in rapid succession hundreds of times the effect accumulates and the resulting overcharging can become injurious and even dangerous to the battery. If there is any question about what a charger will do under intermittent voltage conditions, it is a good idea to stay away from charging a Li-Ion battery via the rails. That goes even when stationary, because the wheel-rail contact is inherently not very reliable.
Does my opinion carry any weight, I suppose, I am an electrical engineer. And Garden railroading for me is not just a hobby, it a way of life. I do it since LGB came up with the Stainz.

Excellent warnings re Li-Ion, I have had concerns about these batteries for a long time. Now can we please have a similar bit of education about LiPo’s?

 

[Greg Elmassian]

even more concern, the battery is easily damaged in it's thin flexible pouch... otherwise same as liion

 

[JimmyB]

even more concern, the battery is easily damaged in it's thin flexible pouch... otherwise same as liion

Greg, things are often lost in "translation", I assumption to your above comment is about LiPo batteries, and if so, then I am confused, I have three LiPo in three RC sets, and none have a "thin flexible pouch", they have a solid case very much like most other batteries.
I have no doubt it is dangerous product, but as long as the safety precautions provided (and there are a lot) with the batteries are followed there should not be an issue, and for ME, I would only charge them using a recommended smart charger, it has already prevented, what could have been a disaster from incorrect wiring.

 

[PhilP]

This is a little simplistic, but a basic overview..

Lithium-Ion batteries:
These look like a conventional battery. They (normally) have a metal-tube-type outer case, and an internal structure not unlike a conventional battery.
Due to the inherent robustness (is that a word) of a 'metal-tube', although they can vent, and get hot, it is unusual (though not impossible) these will 'burst into flame'. - As the masses of nay-sayers would have it.

Lithium-Polymer batteries:
These can take many forms.. Many of the 'packs' you see for model-aircraft/drones (the larger ones) a packaged in an outer 'hard-case' - a plastic box, basically.

The cells themselves are constructed as a flat 'sandwich', using a polymer-layer between the 'plates' (for want of a better-term).
The outer package is a rugged plastic bag. - Hence they can be folded into different size packages. The smallest of these you see, probably only have a manufacturers 'wrapper' around them (used in the smallest models and drones). Those from China (other sources too) may not have any outer, other than the 'bag' the cell is made with.

This is why they are less robust.
The act of folding, produces stresses in the original package and also stresses the internal construction, so an area more likely to fail.
The cell itself (not having a metal outer) is more easily damaged.
Many of you might have had a chemistry Teacher drop a small piece of Sodium into a water-bath to show how reactive is was? Lithium is in the same 'family' of metals, and is also very reactive. NEVER try to put out a battery-fire with water! Especially a Lithium battery. Dry Sand is probably the best thing you could use in the home environment? The red bucket (metal) with a lid, half-full of sand would not look out of place around a railway-themed garden shed..

Back to Li-po's..
If mistreated, physically damaged, over-charged, etc. they will gas, and the package expand. - They *should* be designed to vent, but in an extreme case the package will burst. once this happens, the polymer layer may be compromised, causing a short between the 'plates'. This will cause rapid heating, probably a fire, definitely melting / deforming of the plastics/polymers involved.

This is why you here the horror stories about these batteries. - You do not tend to here of the times (now history) of all the lead-acid batteries that blew-up (they produce hydrogen, only needs a spark) and the injuries from the acid..
Many advocate charging externally to the model/device, in a 'special charging bag', or on a metal tray. - The tray is possibly a good idea, as you could move a failing battery (early stages) to outside fairly safely? Perhaps a thin silicone-mat would be a good idea??

You are now thinking these things are way-too dangerous, and you will have nothing to do with them!
Truth is, you probably have one, in your pocket, if you have a modern 'smart-phone'. If you have a 'Power-Bank' to recharge it, then there is another.
Taken to an extreme: The most popular Tesla powerwall contains 7,104 18650 cells! - 85kWh of energy.

Understand the technology.
Treat it with respect, but do not fear it.
Charge at a sensible rate, and preferably do not leave unattended. - Which really hold's-true for any battery technology.
Personally, I do not think they are any more dangerous, than hot-steam and volatile-spirits, in our hobby? YMMV, of course.

 

[Dan]

With leds and large supercaps, I find I can run lights for a good amount of time. I installed a bank of 10 farad supercaps in a stainz loco and found it will run in mid air for 15 seconds with smoke, motor and regular lights on. Leds alone would last well over 1 minute. So, I would ask how long does one want something work for them when power is removed.

 

[Paul M]

With leds and large supercaps, I find I can run lights for a good amount of time. I installed a bank of 10 farad supercaps in a stainz loco and found it will run in mid air for 15 seconds with smoke, motor and regular lights on. Leds alone would last well over 1 minute. So, I would ask how long does one want something work for them when power is removed.

Interesting, but I'm sure Stainz are really meant for flying!
Presumably if you had track power and enough capacitance, LEDs could stay lit for excess of a minute, thus there is no need for batteries, unless you want them permanently on rather than just waiting in a station

 

[Greg Elmassian]

Jimmy, my response was indeed to the previous post by Jon.

Phil did a great job of explaining the packaging, so nothing to add except you can still buy LiPo's in the plastic bag without a protective case, and as he says, even in the case they are less rugged.

Remember the great Samsung problem with the phones catching on fire? The battery subcontractor made the batteries a bit longer than the space in the phone. This crimped up one corner and caused the plates to short internally and the phones often burned up.

Greg

 

[PhilP]

I could link various YouTube clips of batteries being made / taken apart, but am loath to promote some of the practices therein..

Especially the guy who has a (luckily, very dead) one, and is unwinding the plates from the polymer, and handling them with bare hands! - There is still some electrolyte present, I think, but not a recommended practice.

 

[Riograndad]

I am but a simple Rio and use a simple use of 3v systems with rechargeable AA`s when using peanut bulbs or hearing aid batteries that last for ages with strip LEDs in some of my passenger stock, I rarely run at night so works fine for me,,,,,,a little old fashioned way of doing things but each to their own,as an example on my long caboose bash AA`s will last about 4 hours,so will do for an evening run without problem.