My Personal Experience with DIY Lithium Ion Battery Packs 2006 to 2012

[Loco Bill Canelos]

The following represents my personal experience.  I am not an expert, but do like to experiment with things.  Please keep this in mind as you go through this. It is long.

Over the last 6 or so years I have been working with Lithium-Ion Batteries.  Early on the big scare was on about them blowing up, catching on fire, and all sorts of other dire warnings.  I studied up on them at Battery University.com, with guy's who were using them on R/C cars and aircraft, and in correspondence with some of GRR friends in Germany who back then were having great success making their own battery packs.  I also studied manufacturer's info and engineering sheets and found that some of them even had instructions on making battery packs.   I decided to jump in and try it.  Back then I made them using 18650 3.7 volt 1800 Mah or 1.8 Amp batteries from Hong Kong.    There were printed circuit board (PCB) protection circuits which prevented the batteries from overcharging getting hot and rupturing or exploding. This board also protected the batteries from over discharging which would ruin the battery and prevent recharging.  The boards also offered short circuit protection, which essentially shuts down the battery if the condition exists.  Here is a link to one of these add on PCB's from all-battery.com

http://www.all-battery.com/ProtectionCircuitModulePCBfor4Cells14.8VLi-ionBattery-32118.aspx

Following the instructions with the PCB I built my first 14.8 Volt 1800 Mah battery pack using four cells. I used Tamiya connectors, but any connector will do.  I always charge each cell individually up to full charge before building the pack.  I learned that it took a very hot Iron to solder the connections to the batteries especially to the positive end.  I hooked up my Tenergy Smart Charger, set it to the 14.8 volt position and waited for the batteries to blow up, or otherwise burn down my barn.  To my joy it worked perfectly and during the charging period the battery pack remained cool to the touch.  I made another one and used them in my Annies and Connies with great success. They are both still serviceable as I write this, proving to be far superior to my NMIH or NiCad batteries.  The major (to me) pain of all this was all the soldering to the PCB and batteries.  I mentioned my success on one of the major GRR forums and was promptly flamed to death about how it was impossible to do safely, and how NMIH technology was far superior!  blah blah Etc. Etc.  I was not discouraged and loved the low cost and good runtime using the home made packs.

Next All-battery.com  came out with the 18650 Tenergy 3.7 volt 2200 Mah battery with a built in PCB in the negative end of each cell.  I thought WOW! this would really reduce the amount of soldering necessary and greatly reduce the possibility of an error so I built two more packs using them.  Here is a link to show a battery with the built in PCB.  Care is necessary when soldering to avoid getting the negative end too hot and destroying the PCB.

http://www.all-battery.com/4pcsTenergyLi-Ion18650Cylindrical3.7V2200mAhRechargeableBatteriesWithTabs.aspx

These packs were such a success and so much better, that I got rid of my NMIH and NiCad packs altogether.  I had so many inquiries I ended up doing a few clinics on making the packs, and got great raves from others who also had success. I was also flamed, beat up on, blah blah etc.etc. for doing these clinics and "endangering others".  Things have changed since then and Lithium technology has become mainstream.  To me the only real disadvantage of the lithium Ion batteries was that when the packs get down to the 2.5 volt threshold the undercharge circuit kicks in and shuts the battery down abruptly to prevent over discharge.  This occurs without warning since the batteries perform so well there is no subtle slowing down noticeable like you get using NIMH or NiCad batteries.   This would be bad news if it occurred in a long tunnel and you had to fish your loco out of it.   This led to a desire for longer run time.  When Tenergy came out with the 18650 2600 Mah cells I used them as well and loved the improved run time, especially noticeable over the older 1800 Mah cells.  I have had one Tenergy 2600 mah pack fail due to one bad cell.  It is a pain to troubleshoot because all the cells have to be disconnected to find the bad one.  I do not know the cause, but it is possible I damaged it by dropping it, or had a PCB board fail.  
A good friend who likes to run 4 F7's and an Alco PB (ABBBA)  Pulling 13 heavy passenger cars was getting about an hour and 45 minutes run time using home made packs of  12 2600mah 3.7 volt cells connected in series to make a 14.8 volt 7800 Mah battery pack.  He has grades of 3.5%  He saw the GTL 3.7 volt 5300 Mah cells on Ebay and we bought some, thinking they did not have the internal PCB protection circuit.  We were pleasantly surprised to find that they did have the built in PCB protection, and that they were the latest type with the PCB protection circuit enclosed within the case rather than added on the end like the Tenergy example above.   At a price of $39 for twelve cells and no shipping I was amazed.  You can make three 14.8 volt 5300 Mah packs for about $13 each including a connector.  The Tenergy smart charger works fine with them.  The run time is so good that I never run them down to a shut down using my Connies and Annies.  

Here are the pictures of the printing on the side of the 5300 mah cells showing the information on the internal protection:  Sorry about the poor quality, had to borrow a camera.




Here is a home made "Square"5300 mah pack soldered and wrapped with electrical tape. It is made to go into a U25B from a top hatch on the loco.  I'm too cheap to use expensive large shrink wrap when color electrical tape is cheap at Harbor Freight.  I have also built them into the fuel tanks of a couple of GP-7's using an external charging jack.  The second pic shows a "flat" one to fit under the coal load on Connies & Annies.


Our testing so far indicates that the 5300 mah batteries are good quality and the protection circuits work like they are supposed to.   We have only been using them for two months so time will tell if they hold up.  Compared to the Tenergy Batteries the GTL's are more difficult to solder to the positive end.   While I personally dislike trail cars with receivers & batteries these home made battery packs are just fine in trail cars as well.

These batteries are 18650 size and fit in commercially available battery holders (or boxes) which hold one to four cells.  If you have room in your locos using these would totally eliminate the need to solder to the batteries.  You would only need to solder on the connector of your choice pop the batteries in and go.  This would be of great advantage if a cell failed.  All you would need to do is take them out test them individually, replace the bad one and you are ready to go again. Here is the link for the battery boxes:
  http://www.ledsupermall.com/diy-battery-box-for-4-18650-battery.html

I have not yet received mine and will post later about my experience with them.  

Remember You MUST follow all safety rules and measures.  I use a clear mask when soldering, wear a long sleeve shirt, and place the batteries in a ceramic bowl when charging.  I also make sure ventilation is good.  There are other rules I probably haven't mentioned.  When engaging in these activities it is your responsibility to learn and follow all safety rules, procedures and instructions.  I do not guarantee your results will be similar to mine or your safety.  Soldering to the batteries will void any warranty.
Most of all have fun!!!
Bill

[R and K RR Products]

  Hey Bill
Great write up on your experience with the batteries.
Can you give the link to the 5300 ma batteries as I can not find them

Thanks
Rodney

[Loco Bill Canelos]

Thanks Rod,

Here is the latest link.  Definitely a hard to beat price with free shipping.

http://www.ebay.com/itm/12x-18650-GTL-Li-ion-5300mAh-3-7V-Rechargeable-Battery-LED-Torch-/160717846089?pt=US_Batteries&hash=item256b87b649

Be aware that some say they are not 5300 Mah, I have no way of proving if they are or not.  I do know that I am getting great runtime out of them so far.   If problems occur I will report them.   

Bill

[Young one]

Bill,
Thanks for all the info!  I have a few questions.
   What size wire do you use to build the packs?
   What amperage do you charge them at?
   Do you run four cells alone, or multiple packs of four cells wired in parallel?

Thanks again very very informative!


Rick

[R and K RR Products]

Thanks Bill
I would guess that you are charging them as a pack as that is what I want to do.
I ordered 48 cells to try them cause that is a heck of a good price
Rodney

[NarrowMinded]

Hi Bill,

Nice of you to post all this, it's funny what you say about getting flammed and all the "Danger Will Robinson" screamers. when the steam engine was invented the ancestors of those anti progress mongers were screaming just as loud.

I use these in a boat which have the issue of stopping out in the water, to avoid going swimming I installed a small relay and small Ni-cad pack, when the Li-po's are providing power the relay is energized and the Ni-cad is isolated when the relay drops out the Li-po's are isolated and the small ni-cad pack gives me power to get back to shore, the relay draw is so small I don't notice a loss in run time.

NM-Jeff

[R and K RR Products]

Bill,
Thanks for all the info!  I have a few questions.
   What size wire do you use to build the packs?
   What amperage do you charge them at?
   Do you run four cells alone, or multiple packs of four cells wired in parallel?

Thanks again very very informative!


Rick

  Rick
I use either 18 or 20 gauge wire on mine and make sure you add a FUSE in the battery side.
I charge my Li-Ion batteries at about 1.6 to 1.8 amps. this seems to work good
The batteries are wired in series to get the proper voltage. With 4 cells in series you get
14.8 volts. I use 5 cells for 18.5 volts for all my Bachmann locos and 6 cells for 22.2 volts
in my Accucraft and Berlyn locos.
The battery amps are what the battery are rated at and these batteries are rated at 5.3 amp hours.
Hope this helps

Rodney

[Dave]

Had a peruse on the Web site Bill, but they wont ship to New Zealand. They must be classed as Dangerous Goods .

               Dave

[Loco Bill Canelos]

Rick,

Rodney's answers are right on the money!  I run only four cell packs, but my friend uses 3 four cell packs in parallel to get a 14.8 volt 15900 Mah pack to run his five unit diesel set. seems to work fine. I would never have believed he could get any decent speed at only 14.8 volts, but it will go faster than I am comfortable with, even pulling all the heavy passenger cars up the 3.5 % grade he has. 

Rodney, when I first build a pack, I charge the individual cells to equalize them,  after they are built I charge them as a pack.

Dave, sorry to hear the bad news about New Zeland, hopefully you will find another source.

Jeff that is a slick way to solve the shutdown problem.

Question for Rodney:  What do you use to charge the higher voltage packs??  My smart charger is good for a max of 14.8 volts at 1.8 amps.

Bill

[Young one]

Thanks guys!  I swear, this forum is more helpful and more informative than any forum I have taken interest in.

I run 14.8 Volts and am thinking of using multiple packs in parallel to extend run time.  Like Bill, I do not like trail cars.  I have the receiver in the locomotive and the batteries in the tender.  I have a whopping 36 feet of track (yes, that's thirty six) and it's all tight turns and steep grades.  One tender is shortened and 'bashed' to model a partial coal load and therefore has little room for batteries.  These 18650's look like the answer for me.

With packs made up of Li-po cells one must consider "balancing the cells" during charging.  I assume that with each cell having a cut off circuit, this issue goes away.

Having fun,
Rick

[Loco Bill Canelos]

Rick,

Glad you are enjoying the forum, we have a lot of great guys here who are very helpful, and a friendly Code of Conduct!!

I have never yet had a balancing problem with my lithium -ion packs.  Li-po technology does look very interesting, especially the bendable ones. They are too expensive for me right now.  I do drool about a bendable Li-po battery which could easily be hidden under the cab roof of a porter or a 2-4-2T or any cab roof for that matter.

Bill

[R and K RR Products]

  Bill
I use 2 different ones for the Li-Ion batteries
I have a Electifly Triton 2 that is about 10 years old and will charge Li-Ion up to 18.5 volts
The other is one I bought last spring from All Battery. Its a Tenergy TB6AC and will charge
about anything that we use with out trains.

http://www.all-battery.com/Tenergytb6ac-charger-01322.aspx

I have never used it as a balancing charger yet and might try it on one of the new packs that I'll build with the new batteries

Rodney

[Loco Bill Canelos]

Hi Rodney,

Thanks for the link.  I just had one of my older more simplistic Tenergy smart chargers die on me.  The TB6AC is out of stock and I am wondering if you think it is so much better than the other two on the page that I should wait till it is back in stock?   Looks like they need an add on power supply, or did one come with it?? 

I hate not having two chargers.  If the other goes out I will be out of business!! 

Bill

[R and K RR Products]

   Bill
If you have a good 5 amp 12 volt power source go ahead and get the TB6B
It looks like the TB6s would be OK also as it has a power supply and is a little different
but will do the same as either one of the others.

Yes I know that it is nice to have both chargers for Li-Ion batteries. I wire all my locomotives
with a switch so I can also run them with a trail car with a battery.  All the Ni-Mh batteries that
I replace with Li-Ion I use in the trail cars and never have to charge the onboard batteries till
I'm done for the day.  At my open house last summer, I ran one of the K-27's for about 10 hours
nonstop other than to replace the trail car battery.

For Ni-cad (tool batteries) and Ni-Mh batteries I have a Black and Decker charger that I modified with leads
and a plug to charge them.

Rodney

[Loco Bill Canelos]

Thanks Rodney,

I appreciate your advice they did look a lot alike , I will go a head and get an order out!

Your way of using trail cars and onboard batteries is a pretty nice for continuous running.  I got rid of trail cars and make my loco coal loads removable so I can pop them up, put in a new battery and go. 

Bill