# Lithium ion battery packs - demystified - good stuff



## FlagstaffLGB (Jul 15, 2012)

I had written a query (thread) under RC/battery operation and realized that maybe with the introduction of some "new news" that it might be good to share this in the beginners forum as well. Like many people getting started or transitioning from a smaller scale of model railroading to a larger one, the hobbyist has its growing pains. For G-scale, a lot of that is surrounding the costs of the hobby. I don't mind spending money on the items that get a lot of curb appeal, but the guts of trains seems to always make me cringe a little. Anyway, I asked some questions about building your own lithium ion battery packs. Seemed like a good question since they often cost between $60-140 depending upon the voltage, milli-amps and who produces them. I got lots of tips, advice and warningz about trying to do this yourself. Everything from exploding battery packs to need expensive welding equipment to a complete understanding of battery chemistry. None of the information was wrong and it all pointed to having these packs purchased from a company that makes them or an expert with experience doing it. I therefore went ahead and purchased a 14.8 volt, 5600 mAh battery for around $90 plus shipping.

Then yesterday, in the mail, comes my December edition of *Garden Railways*. In the middle of the magazine and also highlighted on the cover, is a detailed article by William Camelos on how to build your own battery packs. Some of the latest attempts doesn't take soldering or welding and answered a lot of my questions. The article has its warnings, but I found it to be very informative and easy to understand how the author managed through the tasks...still has all his fingers and toes.

Anyway, if you haven't looked this over, I highly recommend it. Good reading and I suspect more folks will try to make there own in the future. Ed


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## Torby (Jan 2, 2008)

Cool. Mine hasn't come yet. I'll watch for it. 

I bought some "5300mAh 18650" cells for a rediculously low price from a far east source, but I'm having trouble with them going dead. I guess I know why I got them so cheap. The chargers I bought are only 350mA, so they take centuries to charge these. Also, the spring clips seem to be made of silly putty and I have to bend them back into shape to make them work.


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## izzy0855 (Sep 30, 2008)

There is a revision coming to the article that was not covered about safety that implores you to be careful! Also, you can not solder directly to a lithium battery. 

Rick Isard 
Cordless Renovations, LLC 
RCS America


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## Del Tapparo (Jan 4, 2008)

William Canelos' article, "Battery Packs Demystified", points out one of the downfalls of Lithium battery packs. To protect the battery pack from full discharge, the protection PCB cuts off the voltage completely and the train just stops dead in its tracks, most likely on a hill or in a tunnel, making it difficult to get the train back to storage. This forces the operator to guess when the pack might be ready to quit, and therefore never get the full run-time from the battery pack.


This problem is resolved with the G-Scale Graphics RailBoss Plus controls, which feature built-in low battery warning systems for Lithium batteries. A user programmable setting warns you when you have only a few minutes remaining on the battery pack by slowing the train to get your attention. Then you run it home before the PCB cuts it off. This feature takes out all the guess work and the need for monitoring run-times. 


There is also a "hard cut-off" for use with Lithium Polymer battery packs not having a protection PCB, or to act as a backup to the Lithium-Ion battery packs' protection PCB. For more information go to www.GScaleGraphics.net.


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## Greg Elmassian (Jan 3, 2008)

I'm at the show and did not have time to read the article myself yet. 

Ed, did the article talk about soldering to the lithium cells yourself? 

Greg


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## eheading (Jan 5, 2008)

Actually he did talk about soldering the individual batteries, Greg, and recommended being careful. However it seemed to me that his preferred way was using little battery holders that eliminated the soldering issue. My only personal problem with the battery holders is that he said they are much like the Radio Shack AA and AAA holders, and they did indeed look like those to me. I personally have had a lot of problems with the reliability of those Radio Shack holders.

The other Ed


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## Greg Elmassian (Jan 3, 2008)

Agreed, the quality and thus the electrical reliability of the RS holders is poor in my opinion. I'll have to look at the holders he talks about, but most of the surplus lithium cells I come across are 4/3 AA .... 

Greg


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## FlagstaffLGB (Jul 15, 2012)

Tried to add another comment the other day...but it disappeared (timed out I suspect), sigh. I know that Rick says you can't solder lithium ion; so I'm not sure how Bill's clinics went, but maybe they were doing some sort of welding instead? No idea. I know that his battery holders are specific to the size of batteries he is using. The real issue for me is one of costs. If these battery packs are roughly 25-75% less than the commercial ones and can last the 3-4 year life expectancy of the higher priced units, then unless you run your trains 4-5 hours a day....I'd say that this is a boon for those needed some relief from the higher cost batteries. I'm sure as battery life expectancy increases and methods of allowing the sudden drain of lithium-ion is more readily known, that better stuff will become available. I was just happy to read that someone had in fact been able to build their own without investing large amounts of money. Good article, I want to try it for my own knowledge. Ed


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## Greg Elmassian (Jan 3, 2008)

Bill DOES solder directly to lithium cells. 

Wisdom says inexperienced people should not. 

I've done it. 

Problem is do you recommend people to do it? I don't. Why? Because when I give advice in a public forum, especially in a beginners forum, I try to give SAFE advice, and something that will work for 99% or more people. 

Soldering to lithium batteries is NOT in that SAFE range. 

It's like going 100 miles per hour on the freeway. Can you do it? Yes. Is it safe for everyone? NO. Are there people who should NOT go that fast doing it? YES. 

Being able to do something that is risky is gambling. I'm not giving advice to beginners to gamble with starting a fire or worse, loss of life. To me even ONE problem is too many in this area. 

Greg


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## Torby (Jan 2, 2008)

Hmm. Those 5300mAh "GTL" cells are the same that I have. Have 4 dead ones, and 2 live ones. 

I see battery-space.com now will add solder tabs for 25 cents / cell.


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## Greg Elmassian (Jan 3, 2008)

I read the article. 

I think there was plenty of disclaimer information, that nice grey box was sufficient I think. 

Interesting on the misrepresented amp hours... I have test setups to actually measure this, and have a good charger that discharges batteries and measures the amps and time. 

Speaking of chargers, I was surprised that it was sort of glossed over. Chargers can be very different, and I really prefer one that has some feedback on charge level, and what current is being used. 

I have a favorite charger, a Maha, that autosenses the number of cells, shows you the charging voltage, the current "put into" the cell(s) and the time. 

It also has a discharge cycle that basically will give you the REAL amp hour capacity of the battery, it discharges it over a few hours and records the total amps "taken out of" the cell(s). 

Having this kind of information allows you to tell how a pack is aging... another topic that is interesting, although probably a bit out of the scope of the article. 

A short explanation is as a cell "ages" or wears out, it's terminal voltage at full charge goes down... basically it will eventually become fully charged at a voltage insufficient to operate your equipment. 

I have a charging technique that uses this situation to track the aging of cells and predict failure, but it involves some techniques and equipment beyond the beginner stage. 

Overall a good article. 

Greg


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