Battery power -- Accucreat Bigboy

[thebl1]

I am considering converting my accucraft bigboy to batteyy power and have a few questoins. I plan to have a dedicated boxcar for the bateries, and was thinking of using the cordless renovations 22.2 Vdc Lithium ION batteries @ 5600mah. First is this sufficent for the bigboy. I have heard of others converting to battery but never got any specifications.  2. Should I get a separate battery for the smoke unit. Third, given a draw bar weight of 50 pounds how long on a leve track can I expect the train to run?

[cacole]

First question that pops into my mind is, what control system are you going to use with the battery ?

I use AirWire900 decoders for all of my battery conversions.  The runtime is going to depend on how heavy a train you intend to pull -- more cars equals shorter battery life.

I have ran a Bachmann 2-8-0 Consolidation with an AirWire decoder and Phoenix sound system for several hours at an open house without having to recharge a Cordless Renovations 14.8 Volt 5600 MaH lithium battery, pulling six assorted cars on a layout that includes several grades.  I never use smoke, which draws considerable amperage from the battery.

Theoretically a 5600 MaH battery should be good for at least 5 hours of operation at 1 Amp current draw, provided you're not pulling a heavy load, but there are too many variables for this to be a cut and dried answer.

[thebl1]

For the bigboy I am planning on using the NCE wireless cab with Gwire with the D808 decoder. I am looking at the airwire boards for my USA  locos.  The bigboy is my test case, If I can get it to operate successfully Ill convert to battery. The issue I am having is that on my aristo locomotives I am destroying the wheels because of the amount of current I am driving through the track and eventhough the track is clean it is pitting the wheels.

[kstrong]

First, get rid of the thought of a trailing box car. There's simply no need for it anymore--especially when converting a Big Boy (whose tender is larger than most box cars of that era), but also simply because the electronics--including the batteries--have gotten so small now where trailing battery cars are simply obsolete.There's no reason you can't fit all the necessary electronics in the tender of all but the tiniest of steam locomotives. The tenders have become de facto battery cars in their own right, and since most already have a number of wires running between the loco and tender, it's easy to tap into them to get power where it needs to go.

I'm not familiar with the Accucraft Big Boy tender, but if there's a way to make the coal load removable, then you've just given yourself access to the batteries to easily swap them out when they run flat. I've got removable coal loads or removable tender shells on most of my battery-powered steamers, and it makes it very convenient. I don't have to worry about installing the highest-capacity batteries for the space, since I can just change them out when needed. On my locos where I can't get to the batteries, sure--put in the highest capacity battery you can for the space--which on a Big Boy, even with a LARGE speaker, should be no trouble.

As for gauging what you're going to need in terms of batteries, test things with your power supply and a volt/ammeter (assuming your power supply doesn't have one built in.) Set your loco to run as you normally run it--complete with train, lights, and smoke--then measure the volts and amps its drawing. Then figure out how long you intend to run the locomotive each operating session and plan your batteries accordingly. For the sake of illustration, let's say the loco draws 2 amps fully loaded. If your average operating session is 2 hours, then you'd need a 4 amp/hour battery (4000mAh) to get you through. The 5600 mAh battery you're looking at would be perfect. If the loco draws less (or more) current, then your run times will be extended (or shortened) proportionally.

I like the idea of a separate battery pack for the smoke unit. I don't know that it's mandatory, but if you've got the real estate in the tender and can isolate the smoke unit to connect to its dedicated battery, why not? You may also consider wiring two packs in parallel. That way when you want to run the smoke, you've got the added capacity that won't affect your run time, but when you don't want to run smoke, you can use that battery to also run the loco, giving you even longer run times.

Good luck!

Later,

K

[St Francis Consolidated RR]

thebl1

The issue I am having is that on my aristo locomotives I am destroying the wheels because of the amount of current I am driving through the track and eventhough the track is clean it is pitting the wheels.

     oh, boy (no pun intended), I have a question: I see little whitish/blue sparks between the wheels and the rails of my Bachman three-truck and my brass and stainless steel track...is this a symptom of the pitting phenomenon you are talking about?

     I'm definitely converting to battery power, it's just a question of how and when and how much$. I think my test engine will be an Aristo PA, then the Shay.

    

[cacole]

kstrong,

Cordless Renovations and CVP Products have both recommended that you NEVER wire two Lithium batteries in parallel or series due to the nature of their electronics protection circuitry.

Have you actually wired them in parallel without adverse effects?   I have considered doing so but was advised otherwise.

Just curious.

[thebl1]

So based on your descreption I would say yess, but I will caution that the wheels on you Bachmann may not be the same material as my dash 9’s. I have not heard of any other issues from other manufactures except for the Aristos. I have several USA locomotives that I have been running the same amount of time as my Dash 9 and am not seing the same issue.

[thebl1]

Understood, and I would not plan on connecting the two together, I have found several other batteries that will work, one is 7800mAh.

 

Capacity	7800mAh
Voltage	22.2V  (Peak at 23.4V)
Dimensions	110mmx54mmx73mm
Weight	866g
Max. charge current	2Amps
Max. discharge current	7.8Amps

 

Should provide enough power to run the Bigboy for 3 to 4 hours with 50+ cars on a 2% grade.

[kstrong]

cacole

Cordless Renovations and CVP Products have both recommended that you NEVER wire two Lithium batteries in parallel or series due to the nature of their electronics protection circuitry.

Have you actually wired them in parallel without adverse effects?   I have considered doing so but was advised otherwise.

That's a good question. There's definitely agreement that the packs cannot be charged in series or parallel. Each individual pack must be charged by itself, completely independent from any other packs. As for connecting them in series or parallel for use, different manufacturers seem to have different positions. Some say it's okay, some say don't do it.

The reality is that there's really very little need to wire multiple Li-Ion packs in series or parallel for our purposes, so it's largely a moot point. We can get packs in voltages up to 25 volts, and capacities upwards of 12 amp-hours! If you've got the space, you can find the battery pack to fill it. Really, the installations where you'd need to "split" a pack would be installations where you're trying to shoe-horn things into small locomotives or critters. But they seldom need lots of speed, nor do they draw much current, so you can usually find small packs that will fit those installations, too. And if space is that tight, you're probably not going to be able to remove the packs to charge them individually anyway. So for practical purposes--whether the experts say it "can" be done or not--it's just not something that's worth bothering with.

Later,

K

[piercedan]

Since single cell batteries are wired in series to get to 14, 18 etc. volts in a battery pack, then how can anyone state they can not be hooked in series as they are in series inside the battery packs.........

 

[kstrong]

It has to do with how the batteries are wired within the pack. The cells are wired in series to give you the desired voltage, but each individual cell is also wired to a PC board that monitors the individual cell's performance during charging and use. If something goes awry with any one of the cells, the PC board shuts the pack down. Li-Ion packs need that PC board to operate safely, since the cells don't react well to over-charging or over-discharging.

The "danger" comes in hooking the packs themselves in series or parallel, for instance two 11.1 volt packs to give you 22.2 volts (series). You definitely don't want to charge two packs in series or parallel, since the PC board that protects the cells doesn't know about the other pack. That can lead to over-voltages and higher current which can adversely affect the pack. Typically the PC board is designed to catch these things and shut things down, but often the "shut things down" part means the PC board sacrifices itself, and you've now got a dead pack. You also run the risk of things not shutting down as they should, and the cells going out "in a blaze of glory."  

In terms of wiring two packs in series or parallel for use, that's where things get a bit murkier. As I stated earlier, I've read some manufacturer reps saying it's okay to hook them in series to discharge them, but not to charge them, and I've read others saying don't even hook them in series to discharge them. I've yet to read an easily-understandable explanation as to why discharging them in series (or parallel) is a bad idea. The lack of consistency in this regard (as opposed to charging them) leads me to wonder if some manufacturers are just "covering their..." just in case. Again, though, there's little reason you'd need to given the variety of packs available on the market, so it's largely a moot point. If you must use two packs in series or parallel for your installation, e-mail the specific battery manufacturer for their recommendations.

Later,

K

[captain perry]

Lithium batteries have the potential to explode and burn, so care MUST be taken with them. 

wiring batteries in parallel can be problematic ... if one battery is more charged than the other and/or has a higher voltage, it will discharge through the other at least until they reach the same voltage.  if the voltage/charge curves vary between the two one battery may always be discharging though the other to some extent.  in NiCd  and NiMH batteries this is not dangerous but it can be in lithium batteries. there will be wasted energy at the least and damaged batteries at the worst.

There can be issues when using batteries in series as well.  all this has been taken into account when manufacturing battery packs.  the cells that make up the pack are carefully matched the are monitored by the internal electronics and charger.

Note that modern lithium re-chargeable battery packs have more than two contacts which connect to the charger and the device.  the extra contacts are to control the charger.  some NiMH batteries had a simple heat sensor, I think that the new Lithium packs have other electronics to monitor the battery voltage, current, state of charge, and  temperature.

Lithium batteries of the older type have been known to have spectacular failures causing injury and death, I think the newer re-chargeable batteries are safer -- emphasis on the "er". problems result from improper use and handling.  do not puncture the case, do not short them out, do not incorrectly charge them use only the approved charger that works with the battery's electronics.

Lithium Batteries are very powerful and will do great things for us if we respect them.

[kstrong]

If the Li-Ion (or Li-Polymer) packs have built-in PC board circuit protection, then you'll find them with only two leads coming out of the pack. When they do not, the charger must do the balancing during charging for them, hence the need for additional wires. That also requires a charger that can do the balancing for the pack, which tend to be a bit pricier. The good news is that a quick check on all-battery.com's web site show all of the packs we're likely to use for our trains--both Li-Ion and Li-Po--have built-in PC board protection.

One word of caution about the Li-Po batteries--they're not as "robust" as the Li-Ion cells. The R/C car and plane guys love 'em because they pack a ton of power into a very small, light space, but if the pack is dropped (or the car or plane crashes), they will almost always toss the pack. The risk of the cells being damaged by the impact, and the risks of charging those damaged cells is too great. For our purposes, the Li-Ion packs, with their more physically stable construction, are adequate for our needs.

Of course, now I'm waiting for hydrogen fuel cells... :)

Later,

K

[TJ Lee]

K,

> Of course, now I'm waiting for hydrogen fuel cells... :)

How cool would that be? Awesome!

Best,

TJ

 

[St Francis Consolidated RR]

TJ Lee

K,

> Of course, now I'm waiting for hydrogen fuel cells... :)

How cool would that be? Awesome!

Best,

TJ

    ....and who needs it?  All I need is a boxcar big enough to hold this little 18 AMP (eighteen) pack.....get Kevin to hook it up for me, just a couple of leads, right??