# Lithium ion battery packs - building your own



## FlagstaffLGB (Jul 15, 2012)

Working several issues with some local hobbyists, but thought I would ask the question that I don't seem to find an answer to as a browse this forum site. Does anyone have a series of "photos" or links or useful information on how to build your own lithium-ion battery packs? I know that you can string (in series) four 3.7 volt batteries for 14.8 volts, five for 18.5 volts, etc. and obtain what most battery operators consider the best configuration for G-scale operation. Since I notice that similar voltage packs have varying mAh ratings (2800, 5600, 8400), I assume that to increase the amps that either the individual batteries are rated higher or you must put the cells wired in series together in parallel for more amps? May not have the right, but I'm sure one of the local electrical wizards has the answer.

If anyone has a good supplier for just the individual 3.7 volt Lithium-ion batteries and/or larger scale shrink wrap for holding the packs together...that would also be nice. I've read lots of the great discussions on which types of engines do better with different size battery packs, so I think I have that one figured out.

Also (don't you love it when there are multiple questions), has anyone had any experience in using dual battery packs with smoke units. I know that they can draw a lot of power (anything with a heat resistive coil has to) and therefore not using the same power pack might be a good option. I'm not sure how it would be wired to an Airwire G2 encoder card since they aren't designed for multiple power sources...maybe it just has to be an on-off switch or a separate card?

Thanks for any help that you have....Ed


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## East Broad Top (Dec 29, 2007)

Head over to the Bachmann forum and ask Loco Bill Canelos. He's done a lot of research into building your own Li-Ion packs, and can point you in the right direction. 

In terms of powering a smoke unit with a separate battery pack, depends on how you're going to be running it. If you're just running it by itself (no chuff-synchronized fan/motor control a la some DCC decoders) then you'd just use a separate battery pack and wire it directly via its own on/off switch. It might get a bit more complicated if you're using a decoder to sync the smoke unit to the exhaust. But I'm also thinking that shouldn't be too difficult, either. I don't have those circuits in front of me, but if they're built to pass current through the decoder to the motor using the traction batteries as a power source, you may be able to build some kind of interface circuit that interrupts that, and uses a separate battery for the power instead. (The Aristo somke unit interface board may even work.) I'm 99% positive it's been done, but haven't looked into the specifics as yet. 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

First tip, only use the voltage you need for adequate speed, more than that is really not going to help your run times. 

Smoke units with a switching power supply (like the Aristo unit) will work efficiently from any voltage over about 8 volts. 

You did not indicate the type of remote control system you are going to use, that will help answer other questions you had. 

Making a LOT of smoke takes close to an amp, making the normal wimpy smoke (stock setups) will take about 1/2 amp. You can see this is a significant addition to the load of the loco. 

Another thing about building your own packs, I would recommend adding the control circuit board that monitors individual cells and prevents over or under charge. 

Yes, there will be people who tell you not to worry and you can make your own pack, but those people probably know batteries and electronics much better than you do. (I'm not insulting you, but if you don't know the answers to the series and parallel questions and how to construct a pack, then you are a beginner). 

Based on your level of expertise, my recommendation is to NOT build your own pack, but purchase packs and chargers from someone in the business if you are going lithium ion. 

Regards, Greg


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## Michael Glavin (Jan 2, 2009)

Ed,

Li-Ion battery packs are expensive, deliver low current/amperage numbers and have a short life expectancy as compared to other battery technologies. That said they are popular, offer lower weight numbers than others and are packaged with safety circuits.

You have to parallel multiple cells to garner higher capacity ratings; the atypical 2800mAh 18650 cells are capable of delivering about 4 amps for twenty minutes at rated voltage. 

2800+2800=5600mAh and so on……

An 18V/5600mAh Li-Ion battery is comprised of (10) 3.6V cells connected in a series-parallel configuration. While it is plausible to purchase loose cells (approximately $8.00 each) and assemble your own battery packs, it’s NOT recommended due to the fragile nature of these cells. Additionally you’d want to employ an ancillary device commonly known as or referred to as protection circuit. These are generally small PCB and or button type devices and are inexpensive too.

I personally believe Lithium-Ion cells are a poor choice for our needs. I have been playing with these cells since they were introduced to the Radio Control industry nearly 10 years ago. My assertion is based on many factors predominately cost and the life cycles realized of the hundreds of batteries I have used, tested and graded.

I’ve been using Lithium-Poly (Li-Po) batteries for some time now; these are inexpensive come in various capacities and voltages; a 5-cell 18.5V, 5000mAh 15C battery sales for about $25.00 online (hobbyking.com) and can deliver 20 amps effortlessly. No need for ganging batteries in this circumstance.

Li-Po batteries like Li-Ion require safe handling practices peculiar to many Lithium cell chemistries. Additionally Li-Po batteries are available with balance pigtails for state of the art battery maintenance and increased life cycles. 

I’ve discussed the Li-Ion and Li-Po battery conundrum a few times at detail, I’ll see if I can find the previous threads and post a link herein.

Michael


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## Greg Elmassian (Jan 3, 2008)

Michael, I don't get where you see a difference between the two chemistries.

You can design a lithium cell for high discharge current or low current.

The chemistry is virtually identical.

I feel you are making this distinction because of what you have found for sale for the various hobbies.

Read this and tell me if you dispute the claims that they are virtually identical in electrical characteristics PER CHEMISTRY. Read the last paragraph in the first section:

*"Charge and discharge characteristics of Li-polymer are identical to other Li-ion systems " *

*http://batteryuniversity.com/learn/...ce_or_hype*

Regards, Greg


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## Michael Glavin (Jan 2, 2009)

Greg,

I was aiming my thoughts at the atypical 18650 Li-Ion cells used in trains, Laptops and RC products. That said while the chemistry is essentially the same with some caveats, the construction method is distinctively different and I suspect the results garnered with Li-Po’s is a factor of same.

And you know I don’t recall ever seeing high discharge numbers for Li-Ion cells, in all the testing I performed the Li-Ion fell flat on their face instantaneously when asked to deliver high discharge numbers, not so with Li-Po…..

Michael


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## Michael Glavin (Jan 2, 2009)

Greg,

I did a little web searching and something I read on a Wiki page refreshed my memory, Li-Po’s are of “secondary cell” construction, i.e., multiple like cells laminated in parallel. Same chemistry for the most part as discussed, but inherently designed/assembled for higher performance.

Michael


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## TonyWalsham (Jan 2, 2008)

I am still a neophyte when it comes to Li-Ion chemistry and will only use them when it is physically impossible to fit other batteries in very small locos. I have had a small capacity Li-Ion pack in a demo loco for a couple of years now with complete reliability. 
I limit selling them to customers who I can trust not to over discharge them. Yes, I know they can be made with low voltage cut off pcb's, but not by my battery pack maker here in Australia. The maker does have a protection circuit fitted in the packs but that is only to protect against overload drain and overcharge rate. 

Li-Po's would probably be OK but they do require proper balancing during charging, but, that means an extra multi pin connection mounted in a loco which really does complicate the installations. Unless of course you make the battery pack removable which can be a pain.
BTW Li-Po manufacturers require all packs to be be removed from a model and charged in ceramic containers to guard against accidental spontaneous combustion. 

I don't like NiMh batteries because except for some AA and AAA size hybrid Alkaline - NiMh cells, the self discharge rate of NiMh means they have to be kept regularly charged otherwise, they are always flat when you go to use them after a short period of time, usually after weeks, but sometimes after just days. 

I still use and recommend NiCd chemistry. Good quality SubC cells will last twice as long, in terms of the number of recharges, as NiMh batteries. Plus, unlike NiMh, they can be left on low trickle charge without any ill effects. 

No matter which chemistry you choose *NEVER* solder wires to cells unless they have solder tags fitted. The heat generated in the cells when doing so will shorten the life span of cells. Professionally built packs are spot welded together.


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## FlagstaffLGB (Jul 15, 2012)

Well, interesting....I have garnered some good thoughts and directions. I have several friends that build their own, both Lithium Ion and NiMh packs...but like many, each has their own preference and why. Sorry if I mislead Greg, I fully understand the difference between parallel and series, but probably didn't put the question properly. {I used to build my own Heathkit RC controllers in the 70/80s and then moved on to electronic organs} The battery packs advertised (commercially built) offer a fairly standard range of voltages....14.8, 18.5 and 22.2 volts. Likewise, they offer the same voltages, but with different mAh ratings (2800, 5600, 8400), looking at Mike and Renee's Reindeer Pass website. So the question was whether they are using different Lithium Ion batteries, such as 3.7v but with different mAh ratings or configuring the packs built in series and then doubling them to increase the mAh (arranging the series packs in parallel, I think that Michael was hinting at that). Guess a good diagram would be helpful. 

I have also read (not sure how much you can trust research sites on the web) that soldering wires to batteries without a heat sink or lugs is a bad idea (thanks for that reminder Tony). 

I see that a lot of "smart" chargers seem to address the issue of balancing the charges in the various cells (some come with LCD screens that provide the capability of toggling between cells so you can see if they are balanced or not). These charges are often more than the $35-50 models and seem to start around $135 each. 

Appreciate Greg's observation on the smoke units. I know my LGB engines come with a 5 volt generator, but some of the larger units (like the Uintah #51) have a 17 volt smoke unit. My real issue is how much using the smoke unit is going to reduce run time on an engine. Lights and sound doesn't seem to have a great affect overall. I have also heard that one of the best methods for deciding on the voltage for a battery pack is to run the engine with a load (rolling stock) on track power and measure the draw....my disadvantage with current layout is that it is mostly level, so the measurement would probably be low...and I know that I can fudge that. This may be an area that I end up just testing and experimenting with to see what works best. 

Also like Michael's comments and observations between the Lithium-Ion and Poly batteries....didn't notice the pricing difference; I know...more research on my part. 

I have found many individuals have posts that show step-by-step a variety of portions of this hobby. For example, several showing the installation of Airwire, G2, Phoenix P8 sound in a Bachmann Climax was extremely helpful (I'm very graphic and can often visualize faster than most people can write or orally communicate), so that was really part of my question; whether there are any good links to sites showing the building these packs. I do appreciate all the helpful hints on chemistry and performance... 

So, if any of you re-read this. I have a collection of LGBs, one Aristo craft and one Bachman "connie"....all are currently track power. I am building my second layout and going to be converting using an Airwire T5000 wireless remote, with G2 decoders. Mainly because I am moving outside for the second layout. Both Stan Cederleaf and Stan Cornforth have highly recommended the Phoenix P8 sound boards and I'm still working on the speakers/plugs/etc. Stan C. has pointed out that commercial battery packs often have size restrictions (unless you just want to house everything in a trailing box car)...hence my desire to get more information on building my own. Lots of good stuff, if anyone or those of you who have weighed in have more thoughts...I do appreciate them. 

Thanks in advance, Ed


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## izzy0855 (Sep 30, 2008)

I'd like to add a couple of things that I don't believe were discussed. 

1st - Lithium cells have to be welded at a very low voltage and not soldered. 
2nd - The PCB needs to wired in the correct order that the cells will be charged in, if not; the cells will go out of balance. 
3rd - If the cells are not balanced within .03 volts of one another prior to manufacturing, the pack will go out of balance within the first three months of usage. 
4th - Make sure you have a good Home Owners Insurance Policy, if not and you wire the PCB in the reverse order; 10 minutes after you finished building the pack and you charge it for the first time it will catch on fire! 

Not to scare anyone, but please be careful if your going to adventure into this relm!

Rick Isard 
Cordless Renovations, LLC 
RCS America


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## K27_463 (Jan 2, 2008)

This has been an interesting thread on a number of levels. My comments are from a background where in I have installed Lithium -ion (and nicad and NIMH) in literally hundreds of garden scale locos over the last 22 years. Accept or reject my comments, your choice. Using almost exclusively lithium for the last 5 years or more. 
There is no need to reinvent the wheel here. Many folks have been successfully running trains for YEARS with basic smart chargers, Lithium -ion protected packs, commercially built and warranted , at an economical price. 
There is no reason to build your own pack. It is true that they are available in certain sizes and configurations, however, this is in no way a limiting factor for installations. In fact there is no need whatsoever for a trailing car , unless you so choose, battery size or shape limit is simply not the reason. Lithium -ion are available in enough sizes and configurations to meet our needs. Furthermore, buying a protect pcb in small or single numbers may be pricey. 
Packs must be welded, not soldered. Difficult to do at home. 
Lithium -ion include the protection pcb. This pcb makes not only for reliable operation, but makes them economical for reasons discussed below. 
Mr. Glavins comments , while accurate, are misleading. Running trains is inherently a low draw application, when compared to other typical uses. High amperage is simply not required. We operate completely differently than a r/c race car, or airplane. Current draw in these apps can be in the hundreds of amps, for generally a very short time. We run trains at draws of 1, 2, or maybe 3- or 4 amps, for a few hours at a time. The comment of 20 minutes is ridiculous. I routinely see run times in excess of 4 hours. Balanced charge operations are helpful in these applications because the race car guy needs and wants every last electron from that battery pack to discharge evenly and fast, hopefully fully depleting as his car crosses the finish line. 
In low current draw environments, having matched cells is not nearly so important, and performing balanced charge applications is simply not a must. Maybe nice to have, but the added complexity adds no real benefit. Look at your laptop battery, it is not a balanced charge connection, and neither are most of the other lithium devices you already use. you will find three connections, generally, plus and minus, plus a third for temp sensor. Balanced charging requires a pair of connections for each individual cell in the pack. 
Lithium poly or lipo packs do not generally include a protection pcb. As such, unless you are an expert like Mr. Glavin, and unless you very closely monitor your LIPO pack for runtime, it is possible to draw your pack down to the zero point. If this happens, as the cells fall below their rated value and reach a zero voltage level, they usually will not recover and you will need to get a new pack. Lithium -ion with pcb will shut off at the energy depletion point that is within specification, will allow full recharge,, a nd allow maximum performance over many repoeated cycles. LIPO also lack overcharge protection, for the same reason of a lack of internal protect pcb. This pcb is missing because of a desire to save weight and space, again for electric flyer and race car applications. A smart charger can do a fine job of charging a lipo without a pcb. However using the same smart charger with protection pcb on a lithium -ion, gives you a second complete layer of protection and performance assurance. 
Lastly, lipo are often constructed in a soft exterior casing, much easier to damage and negatively impact with handling mishaps. 
The low budget lipo racing packs espoused by Mr. Glavin will indeed work, they are not first quality however(the same companies making those 25.00 packs also make ones selling for 4 times as much), and do represent some operational tradeoffs compared to commercial grade Lithium -ion pcb packs. if you accept the need for careful monitoring, and other factors of over discharge and over charge, then go for it, still better than building your own. 
Lastly, I have indeed built many of my own packs . I have enough experience to do it quickly, effectively and supposedly at low cost, and I still think it is a waste of time and effort. 
The locos mentioned by ED are all very standard conversions, with no need for custom size or configurations. All can have battery pack ON BOARD, with no need for trail car complexity, and will run for many hours on internal power, or even endlessly on a quick change pack setup. 

Jonathan/Electric modelworks 
www.rctrains.com 
Cost of lithium -ion is now very close to parity with other older chemsitries.


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## FlagstaffLGB (Jul 15, 2012)

Good stuff. After considering the costs of doing it myself versus commercially purchased ones and the fact that I'm not really fighting a lot of space inside the engines, I do appreciate all the thoughts and suggestions. NOW, seeing that some of you represent various website suppliers, I guess I am just going to have to search for who has the best price for Lithium Ion or Poly battery packs. It has been a good discussion. 

Thanks, Ed


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## Del Tapparo (Jan 4, 2008)

Very well said Jonathan. This should be made a sticky note in this forum!


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## Michael Glavin (Jan 2, 2009)

FWIW:

Battery protection circuit modules or PCB’s are inexpensive, $5.00 or so will provide a unit that exceeds most OEM battery assembler offerings. 

I did not suggest high amperage discharge batteries were required for trains I merely suggested that Li-Po’s can provide same. The O.P. asked about smoke, multiple batteries and paralleling Li-Ions. What is “ridiculous” about knowing the capabilities of your batteries, this info has merit, is documented and garnered from a PC docked programmable Electronic Load. And I spoke in error the Li-Ions cells I tested provided 4 amps for about twenty minutes at 3.0V not rated voltage! 

Electronic devices that utilize balance charge regimens are more common than suggested, take a look at your laptop battery, note the pin or conductor count, only two is required to charge a battery. 

Cell “balance charge” regimens have proven and it’s well documented to further the life span of the cells in play as compared to the atypical “smart charger”.

Li-Po’s do not require cell balancing chargers any more than the Li-Ions; the technology simply provides sate of the art battery management, which garners greater cycle life. You can safely use the same smart charger for either cell type. Two pigtail/plugs are required for cell balancing, the first pigtail is the same as any other battery with a positive & negative conductor, and the second is a small JST type connector that is pre-wired into the battery by the OEM. It is NOT[/b] necessary to utilize the balance charge pigtail to charge a so equipped battery, you can charge cell balance pigtailed batteries exactly like a Li-Ion battery if you so desire.

If you’re concerned about discharging any[/b] battery below the recommended voltage threshold you can add a simple diminutive ancillary device that makes an audible noise or activates a warning light when the battery reaches a pre-determined voltage. These gadgets sale for about $3.00….. PCB/PCM or cell protection circuits can easily be added to a Li-Po battery via the existing cell balance pigtails if you prefer this approach. These devices typically preclude a battery from over charging, deep discharge and limit discharge current, many offer even more features. 
Yes, Li-Po’s are constructed of a soft shell envelope; this does not present a problem in my mind. Proper installation, care and protection of the battery is required in any battery circumstance. I have seen numerous Li-Po’s removed from crash damaged aircraft with a nary scratch, in some cases serious compression and the envelope is still intact. 

While I agree the inexpensive battery packs I suggested are not of the highest quality, but they are certainly no worse than the Li-Ion cells in the marketplace ( I’m basing this assertion on documented life cycles ) . And yes, there are more expensive batteries offered; the prices increase as the discharge current climbs. We don’t need high discharge batteries for trains, thus the 15C rated cells I suggested work fine. If you need high discharge cells, offerings from 10C through 45C are typical, and you pay much more for the 45C batteries.

Whom offers a commercial grade Li-Ion battery pack? They all use the same OEM cell suppliers? Batteries are assembled by resellers, not OEM’s. And yes there are low quality Li-Ion cells out there too. 

I don’t consider the typical $150.00 price tag inexpensive for an 18V, 5S2P, 5600mAh Li-Ion battery. That said the $25.00, 18.5V, 5000mAh Li-Po battery offers greater life cycles, greater discharge current and superior battery management in my opinion is inexpensive. Even if you desire the benefits of voltage depression monitors and or PCB/PCM’s (which become integral to the installation not the battery) Li-Po’s represent a great battery power value for our trains.

Michael


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## Greg Elmassian (Jan 3, 2008)

I have to agree with one thing Michael said in the last post: lithium multi cell packs do not REQUIRE the "balancing" charging adapter. It's a nice gadget, prolongs the life of the cells, provides safety, but this product came about because of the "extreme" types of use by the R/C crowd, super high charge and discharge rates, and trying to get the last bit of life from the batteries. 

Our model train applications are much more "gentle".... lithium batteries were used in packs for years in laptops without such devices. If you have a "good" smart charger, it will determine if a cell is weak in a pack long before you burn down the garage in MOST cases. You want more protection? Then spend the extra money. 

Also, I'd like to echo the comment from Jonathan, basically there's very little to be gained by making the pack yourself, look around and you can buy them built up for a reasonable price AND with nicely welded tabs, ensuring that you did not damage the cell even a little bit by soldering. 

I've use rechargeable cells for quite a long time, and rechargeable lithium metal cells even 20 years ago (remember the Molicell AA?). Again, you can take or leave my experience too ha ha. 

Greg


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## Jethro J. (Apr 4, 2012)

Just another reason I chose to stay with track power, If this stuff is done wrong, could be dire consequences.

Jethro


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## Stan Cedarleaf (Jan 2, 2008)

Well said, Jonathan. I have using Li-ions for a number of years and been very happy with them. Not trying to build my own but rely on the folks who assemble and distribute them as their business. 

Been very happy with that arrangement and the quality supplied.


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## rmcintir (Apr 24, 2009)

A note on PCB protection. I've recently installed 5 cell packs with PCB protection (4 amp max draw). One loco had the ability to use battery or track power therefore, I had installed a 3300 uf cap to maintain operation on dirty spots. In battery mode, when first turned on, it would trip the PCB protection. Turns out the charge current of the cap briefly exceeded the 4 amp rating and shut it down. Since I very rarely use battery power, I removed the cap and all is well. Just thought I would point out that although our locos don't require high current (LiPos) they can have brief but high inrush currents. Perhaps all PCBs are not created equal.

BTW, the loco described above is a Bachmann 4-4-0 that required a small battery due to tender size. All electronics including sound and speaker reside in the tender. It runs for ~4 hours using a 2600 mAh Li-ion pack (cheap one at that). 

russ


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## Greg Elmassian (Jan 3, 2008)

Put a low ohm resistor in series with your cap and your problem will be over... probably even a 1 ohm will do it. 

Greg


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## FlagstaffLGB (Jul 15, 2012)

Well, guys....I guess you just have to wait if you want some other views on this subject. Just got my Garden Railways December 2012 magazine in the mail and in the middle is a six page spread by Willaim Canelos, Missouri on how to build your own lithium-ion battery packs for under $30 (14.8 v, 2600 mAh) and some very interesting discussion and tips on his multi-year journey on how to do this safely....even without welding if you want to wire up your packs versus using battery holders. So, I guess I may continue to explore doing some of this myself to see what I can come up with. Good discussion. Ed


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## Dansgscale (Jan 9, 2010)

I built one of the battery Packs as described in the article using LI-ION unprotected 16850 3000mah Batteries from ebay, and Battery Holder I got from Digikey and a PCB that I purchased off Ebay months ago with the Batteries. It went together easily and only took about 15 minutes. I have one of the Tenergy Smart Chargers and set it for 14.4 volts and charged up the cells with no issues. No Smoke, No Fire and No Explosions. After the charge light changed to green, I checked the voltage and the pack read 16.9 Volts. Awesome I thought, WOW I just built a battery pack for about $14.00, so I dropped it into one of my Bachmann 4-6-0's and hooked it up the the Aristro Train Engineer and truned it on and, and Nothing. The power light didn't even come on. I pulled the pack out and checked it again. Humm it still reads 16.9 Volts. So I pull out the Aristo TE manual. Wouldn't you know it. The Aristo TE operates on voltage from 16 to 24 Volts. I guess that the 16.9 volts that the pack puts out is at the very edge of TE operating voltage, so it won't power it. I guess I should have got the 6 Cell PCB back when I ordered them. 

So I have a question for those of you that built your own packs and use 14.4 volts. What R/C train controller do you use? The Article said that he tested the 4 Cell Battery packs with the Aristo Revolution and it worked fine. I am guessing that it has a wider voltage range than the TE does. I have been using the Aristo battery packs that are 21.5 volts 2amp. 

Any info would be helpful. 

Dan S. 
Colorado & Rio Grande Southern 
http://danshobbies.webstarts.com/index.html


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## East Broad Top (Dec 29, 2007)

Something's wrong with your TE if it's not powering up at 16 volts. I run 14.8v Li-Ion batteries almost exclusively, and have never had issues with the Revolutions not powering up down to voltages as low as 12 volts. 

Later, 

K


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## Dansgscale (Jan 9, 2010)

Keith: I am using the old 10 Channel Train Engineer system and it says that the receiver voltage is 16 to 24 volts. I am not using the New 2.4Ghz revolution system. Thr receivers work fine when I hook up the Aristocraft 21.5 volt batteries, but won't power up when I try using the 14.8 Volt battery pack I assembled. I will check it again to see if I did something wrong, but it was pretty straight forward on how to wire it and it did charge up correctly and has 16.8 vots out when I connect it to the volt ohm meter and whe I hook a pitman motor directly to it, the motor runs fine. 

Dan S. 
Colorado & Rio Grande Southern 
http://danshobbies.webstarts.com/index.html


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## Dansgscale (Jan 9, 2010)

Update on my Home Built LI-Ion packs. I have built and assembled 4 Packs now with no problems what so ever. I am using 4 cell Battery Holders like shown in the Article in garden railways. The Cells I am using are from S.S. battery and are the 3.7V 3000mah 16850 Cells. I double sided taped the PCB to the back of the battery Holder and the wired the contacts for each battey position to the pads listed in the instructions that came with the PCB. It was simple as pie. Anyone that can use a soldering Iron could easily do this. After all the wires were soldered in place I added the two wires that are used to charge the pack and the two wires that will connect to the motor controller. I used black a red wire, so I could make sure that all the wires were in to correct places. Once all the wires were in place I covered the back of the battery holder with a piece of .020 styrene to cover the wires and protect the PCB. I used Electrical tape to attached this piece of styrene to the batter holder. Next I inserted the Batteries into the holder and wrapped a couple of pieces of electrical tape around the battery holder to make sure the batterys stay in place. My LI-Ion Pack was complete. Time to asseemble was 15 Minutes. 

I pluged the pack into my Tenergy Smart Charger that had been set to 1.4 volt packs and the red light came on showing it was charging. 4 hours later I checked it and the green light was on, so I removed the pack from the charger and check the voltage. it read 16.9 volts, which is a full peak charge. 

I did not find anything complicated at all or hazardous about building my LI-Ion packs and as long as you pay atttention to what your doing and wire the PCB according to the instructions that come with them, then I see no reason why anyone can not build your own pack. I had purchased the Cells, PCB and Holders months ago, but never got around to building the packs, but since I wanted to operate my Egglinners for Xmas, I decided it was time to put them together. 

I initially was going to use the packs in my bachmann 4-6-0 engines wired to my 10 Channel Aristo Train Engineer Controllers, but the 14.8 volt packs will not power them as these receivers require 16V min to operate. the manual and email sent to Crest states that the operate on 16 - 24 volts. The New 2.4 Ghz Revolution receivers will operate at a lower voltage of 12 volts, so the packs I built would have worked with the revolution just like the article said, but I don't have this system. So I used the battery packs in my eggliners and wired them straight to the motors through the battery/track switch. I ran them that way on my outdoor layout in the front yard and then ran for about 2 1/2 hours before needing charging. I would say that was pretty good for no being able to control the speed of the motor plus powering all the lights in the eggliners. 

I will be installing a 12V 3amp speed controller in the egglineers in next next few weeks and then I will be able to change the direction and speed using a keyfob controller. I also just ordered one of G Scale Graphics Rail Boss Plus Speed controllers that I will be using with one of my 75MHz transmitter / receiver R/C systems I have laying around which has a wider operation voltage. I will install it in to one of my Bachmann Spectrum 1:20.3 engines with the 14.8 Volt LI-Ion pack I built and see how it works and what run times I get with it. The battery pack will also operate the Modeltronic Sound system already installed in the tender. judging from the size of the Rail Boss plus speed controller. I should be able to get the Speed controller, RC receiver, Battery pack and sound system with speaker all inside the tender. 

Depending on how well the Rail Boss Plus works out, I might convert over to them and stop using the Train Engineer all together, that way I can continue building my own LI-Ion battery packs. 

I will take some photos of how I built my Battery packs and do a short write up and put it on my web site in the coming week. 

Dan S. 
Colorado & Rio Grande Southern 
http://danshobbies.webstarts.com/index.html


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## Dansgscale (Jan 9, 2010)

Here is the update on the Home made Li-Ion battery packs I built after reading the article in Garden railways. I had already purchased the Protection boards, Battery Holders and Cells before the article came out, but never got around to assembling them until I read the article. Here are a few photos of the battery pack . It is a 4cell pack the produces 14.8V at 3000ma that I am using with Del's G-Scale Graphics Rail Boss Plus controller and a 75MHz Ground Frequecny R/C system. 

http://www.flickr.com/photos/[email protected]/8442556094/in/photostream/ 
http://www.flickr.com/photos/[email protected]/8442556158/in/photostream/ 
http://www.flickr.com/photos/[email protected]/8442556062/in/photostream/ 
http://www.flickr.com/photos/[email protected]/8442556022/in/photostream/ 

After I assembled the battery pack I placed a piece of styrene over the circuit board and wires and taped it in place with electrical tape and then wrapped three strips of electrical tape around the holder and batterys to hold them in place. 

The cell were already charged when I got them, but when you put them in the holder with the PCB wired, the output is not activated. You have to connect the battery pack to the smart chrger to activate the PCB. After that the pack worked as it was intended. I am using the Tenergy smart charger that is set up to chance 1 to 4 cells by moving a selector switch. I leave it on the 4 cell setting. I have built 4 of these packs now and they works great. At a cost of about $14.00 is very hard to beat which was the cost of the PCB, battey Holder and Cells. I got 8 cells for $9.00 off Ebay, the battery Holder was $4.00 from Digikey and the PCB was $9.00 from All battery.com

Dan S. 
Colorado & Rio Grande Southern 
http://danshobbies.webstarts.com/index.html


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