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- New Battery Technologies - What Do We Need ? -
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 Posted: Sat Feb 28th, 2015 01:53 am
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dan3192
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Lithium cells work fine for LED lighting. Many probably know this, but for those that don't, the closer your battery voltage is to the voltage drop across the LED you're using, the better.

Example: Using a 9V battery for say an LED headlight (3.2V voltage drop) requires a 330 ohm resistor, which consumes 0.116 watts. But using a 3.7V Li-ion/LiPo requires a 27 ohm resistor which uses only 0.01 watts. That's a ratio of 11.6:1, a big difference when trying to conserve milliamps.

A good LED resistance calculator can be found here:

http://www.quickar.com/noqbestledcalc.htm


And when trying to sort out battery power and balance wiring for all my BPRC components, I found an excellent interactive website that made it very easy to understand. Just plug in what you are planning to do and the results are immediately calculated for you. It's a great learning tool for how multiple batteries should be arranged to provide power and to get balance charged. Here's the link:

http://scriptasylum.com/rc_speed/lipo.html

Let's build some trains!

Dan

Last edited on Sat Feb 28th, 2015 03:26 am by dan3192

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 Posted: Sat Feb 28th, 2015 08:04 pm
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dan3192
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Two more tidbits from the experts:

1. Never use protected cells together to make a battery pack. This defeats the purpose of the battery's PCB. Protected cells are meant to be used individually.

2. NiMH cells can be arranged and wired like Li-ion/LiPo cells for multi-cell powering, charging and monitoring, if you don't want to remove them from your train.

Dan

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 Posted: Sat Feb 28th, 2015 09:52 pm
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Pete Steinmetz
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dan3192 wrote:
Two more tidbits from the experts:

1. Never use protected cells together to make a battery pack. This defeats the purpose of the battery's PCB. Protected cells are meant to be used individually.

2. NiMH cells can be arranged and wired like Li-ion/LiPo cells for multi-cell powering, charging and monitoring, if you don't want to remove them from your train.

Dan


Dan:

I must ask where you got this information? What experts? Are these RC guys?

1. Completely untrue. I can't even imagine anyone would say that. Maybe for RC with high discharge rates. They can't use PCM's because most PCMs will trip at around 3 amps. For train guys, protected cells are much preferred to non protected cells in a 2 or 3 cell pack.
The huge advantage they have is preventing the cells from discharging to low. Most cut off at 3V per cell.

2. True, but there is the challenge of connecting the cells together in a pack. soldering on the top and bottom of the cells can damage the cells internally due to excessive heat. If a person can buy Ni-MH cells with solder tabs, then solder to the tabs, that is the preferred method of building packs.

Pete



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 Posted: Sat Feb 28th, 2015 10:08 pm
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Pete Steinmetz
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dan3192 wrote:
Two more tidbits from the experts:

1. Never use protected cells together to make a battery pack. This defeats the purpose of the battery's PCB. Protected cells are meant to be used individually.

2. NiMH cells can be arranged and wired like Li-ion/LiPo cells for multi-cell powering, charging and monitoring, if you don't want to remove them from your train.

Dan


Dan:

You keep giving us facts from the RC car/airplane/heli side of the hobby. Their use of batteries is pretty different from the train guy use of batteries.

They have high discharge rates and have to deal with many elements that don't concern train guys.

There is some info we can use. The link to the wiring of the packs is a good one. If you want to balance your cells, it will show you how to wire the packs.

They use series parallel battery configurations. I don't recommend this for train guys. It makes everything much more complicated. It is not really needed by train guys.

I look at some of their links. Some info is true, some is absolute BS, some is humorous. I had to laugh at the buy on one of their forums that decided to drive a nail through a lithium polymer cell, just to see what would happen. Don't do this. Only bad things will happen.

They may be experts in the RC side, but much of what we do is more on the commercial side than the RC side.

Pete Steinmetz



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 Posted: Sun Mar 1st, 2015 02:25 am
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dan3192
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Pete:

You've put a lot on my plate, and I need to 'hit the sack" now because I'm being picked up early tomorrow by the guys in my train club for a train show.

I'll be happy to cite references with verbatim explanations. Some of your assertions are inaccurate or misleading based on my five years of research and three years of running BPRC locomotives. I think we have a misunderstanding based on how each of us is attempting to implement battery power for operating our trains.

That's fine, diversity is good, but please allow me 24 hours or so to get back to you to discuss all this in detail.

Dan

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 Posted: Sun Mar 1st, 2015 05:12 pm
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Pete Steinmetz
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Dan:

Please don't quote a bunch of info from the RC airplane/car/heli guys. What they do and what we do are different.

I do NOT recommend RC cells (High rate cells) for train operation. The quality of RC cells isn't as good as commercial cells.

I have no problem with your views on Li -Ion or Ni-MH cells. Enloop and Panasonic are quality suppliers of "commercial" grade cells.

It's the Li-PO info that has some errors. You are getting a lot of information from the RC guys. Much of their information is not pertinent to our Model Train application.

Enjoy your train show.



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 Posted: Mon Mar 2nd, 2015 01:13 am
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dan3192
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Pete:

I'd like to respond. If I run out of time this evening, I will continue to respond until the subjects you brought up are addressed.

1. Re using protected cells to make a battery pack, I've purchased many of my 18650 batteries from a seller and assembler of commercial cells in Texas. I consider him an expert in what he does. He also sells on eBay under the user name sqtruong and answers an FAQ as follows:

Q:  Is there a Protection Circuit Board (PCB) in this battery pack?
A:  No.  The battery pack is intentionally built without a PCB.  Contrary to popular belief, a PCB does more harm than good to a battery pack.  A PCB prevents the battery pack to be balanced.  All lithium battery goes out of balance as the batteries age, there is no exception.
 
You can read more about this on one of his auctions at the link below. Be sure to note his ability to customize battery packs as well as his large inventory of commercial cells. If you dispute his opinion, please contact him.    
 
http://www.ebay.com/itm/USA-8-4V-7-4V-battery-pack-for-CREE-XML-T6-SSC-P7-18-6Ah-capacity-GUARANTEED-/321630762306?pt=LH_DefaultDomain_0&hash=item4ae2aff542
 
 
Another source of information is the international seller batteryjunction.com. They comment on the use of protected batteries as follows:
 



Home > Batteries > Rechargeable Batteries > 18650/18500/18350 Lithium-Ion Rechargeable Batteries

18650/18500/18350 Lithium-Ion Rechargeable Batteries




"Lithium batteries are a great option for today’s high end electronics as these cells typically have higher capacities than their alkaline counterparts. Although rechargeable batteries tend to cost a little more than standard alkaline batteries up front, over the long haul, these costs are reigned in because you won’t need to replace rechargeable batteries nearly as much as alkaline cells. Of course these upfront costs are lower when you purchase your rechargeable batteries at Battery Junction. Our selection of 18650, 18500 and 18350 series rechargeable batteries from the Ultrafire, Titanium Innovations, TerraLUX and Tenergy brands are typically priced well below retail and in many cases, you can buy these batteries in bulk which lowers the prices further. We have just about every size of rechargeable battery that you need, with products including protected and non-protected cells. The protected cells feature a patented Internal PCB protection against under voltage and over voltage. These protected cells are best used in single cell applications because the protection is based on the correct voltage of a single cell.

If you attempt to bundle protected cells as a battery pack, this defeats the purpose of the protection. Battery Junction also has rechargeable batteries in stock that do not have PCB protection and these batteries are perfect for pack building. The bottom line is that if you are a remote control car or airplane enthusiast in need of batteries to build battery packs for these devices, or if you have a high-quality Nitecore or Fenix flashlight that you need to power, Battery Junction is your best source for very high-quality rechargeable batteries available at very reasonable prices with fast shipping on most items."

Again, if you dispute their opinion, please contact them. I'm comfortable with my decision to not use protected cells in a pack, however, you are free to do what you think is best. Please allow me the same freedom.

On another point you raised, I monitor cell voltage when in use and know how long it will be before I need to recharge. Also, the newer, high capacity batteries I use have sufficient capacity remaining after an operating session so that overdischarge is highly unlikely. Finally, the receivers I use have the ability to shut down when voltage gets low. Therefore my use of protected cells (I only have 2) will be limited to single cell applications.

More tomorrow.  

Dan

Last edited on Mon Mar 2nd, 2015 02:53 am by dan3192

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 Posted: Mon Mar 2nd, 2015 05:11 am
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Pete Steinmetz
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Dan:

This is so off the wall as to not even be reasonable. You are not comparing apples to apples. Far from it.

You are grabbing a little info from one market (Bicycle lights). Then grabbing a little from another market (Flashlights)..

So far, none of this has anything to do with what we are doing which is model trains.

All applications are different. You can't compare battery usage in bicycle lights and flashlights to model trains. It doesn't work that way.

First, the guy in Texas is using a series parallel configuration. A PCM on these cells will affect the balance. We are using a straight series configuration. You can't compare the two. They re completely different.

The pack you referenced must be shipped as Class 9 Hazardous goods or the seller is in violation of federal law. Special packaging is required and it must be marked and registered. They are not allowed to be shipped by USPS under any circumstances. They can only be shipped by ground transportation as Class 9.

He knows a lot about batteries. However he must be buying Panasonic Cells on the Grey Market as authorized Panasonic Distributors are required to sell Panasonic Lithium Ion cells with a protection circuit.
Here is the data sheet from one of the cells he is selling.

http://tinyurl.com/mlczc8p
Read the Panasonic requirement.
I believe this cell is used in E cigarettes.

Here is another Panasonic cell he i referencing.
http://tinyurl.com/k3dvzna
Read the Panasonic requirement.
This is for a bicycle light.
No comparison to what we are doing.

The Ultrafire are flashlight batteries designed to be used in single cell applications. Some have protection, some don't.
Nothing to do with model trains. Once again, you are comparing apples to oranges.

Battery Junction is a fine supplier, but they are not a Panasonic Industrial Authorized Assembler. Their rechargeable Lithium products are from secondary suppliers.

You are free to use protection or not. It's entirely up to you.

The thing I resent is you are trying to act like you know something about batteries and you clearly know just enough to be dangerous.

You show this by grabbing some technical info from the flashlight industry, the bicycle industry, and the E Cigarette industry and applying that information to model trains. Apples and oranges.

Someone who was well versed in batteries would not do that.

I hope that the model train guys that read your posts, don't use your information in their model trains.

If they have bicycle lights, E Cigarettes, and flashlights, this info is mostly correct, but it doesn't apply to model trains.

All applications are different.

I currently have a project going with a high end flashlight manufacturer. I researched a lot of cells and chose a Panasonic cell with protection.

I was asked by an E Cigarette manufacturer to design a battery for their product. I declined.

Mostly I work on design of battery powered hand held medical devices using Lithium Ion and Lithium Polymer batteries from major suppliers.

My RC credentials include matching cells and supplying packs that won National Championships in RC Cars, RC Airplanes, and RC Boats. These were with Ni-Cd packs.
I'm not involved with current LiPo cars, or flight. Way to many mad scientists.

Pete Steinmetz



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 Posted: Mon Mar 2nd, 2015 08:31 am
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Helmut
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Here's something to support Pete's point.

Addendum:
Maybe you both are talking of  different 'cell protection'
IMHO Pete is talking about the built-in CID and PTC that every cell above a certain capacity sold retail must have, and Dan is talking about the external protection circuits that are found e. g. in every cellphone Li battery.

Last edited on Mon Mar 2nd, 2015 12:16 pm by Helmut



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 Posted: Mon Mar 2nd, 2015 02:44 pm
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Pete Steinmetz
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Helmut wrote:
Here's something to support Pete's point.

Addendum:
Maybe you both are talking of  different 'cell protection'
IMHO Pete is talking about the built-in CID and PTC that every cell above a certain capacity sold retail must have, and Dan is talking about the external protection circuits that are found e. g. in every cellphone Li battery.


There are two types of protection circuits. Many cylindrical Lithium Ion cells such as 18650 size have internal protection on each cell. This can make the cell a little longer. Flashlight guys are famous for this.

Lithium Polymer packs and Lithium Ion packs have external protection either on each cell or one that protects the whole pack.

RC packs usually have no protection because the current draws are to high. they would trip the safety circuit. Safety circuit usually trips at 3 amps.

Dan was drawing his information from multiple battery applications. As I said, all applications are different.
We need to concentrate on model train applications and forget the rest of the applications.

Even in model trains, there are different requirements. G Scale draws more amps than On30 scale for instance.



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