# Which battery pack do I need?



## MaineCentral (Feb 10, 2015)

Hello Everyone

I am looking for information I can't seem to find or maybe I have overlooked it. I have a USAT GP38 and a USAT S4 and wish to eventually install battery packs on board each loco. I see suppliers offering battery packs of everywhere shape, size and power rating but can't seem to find info on which ones will fit these locomotives.

I will install a charging jack at the fuel tank though I don't necessarily have to install the battery pack there, do I? I'm guessing it will depend on the loco type?


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## Dick413 (Jan 7, 2008)

what are you using the battery for? if for RC what voltage are you going to use. i am airwire and use 14.8 volts 4800 to 5800 mah batterys these will fit in 38 and s4 i can get up to 4 hrs with them. i get them from http://www.all-battery.com/


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## Bill Swindell (Jan 2, 2008)

The GP-38 will hold 2 14.8V 5200MAH packs wired in parallel. They would be in a 2 x 4 cell configuration. The S-4 would use one of the same capacity pack but would be configured as 2 x 2 sticks of 2 cells. I have done this on several locomotives.


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## chuck n (Jan 2, 2008)

I am very cautious when it comes to where I place my batteries. NiCd, NiMH can go anywhere, but I will not put any type of lithium battery In an engine. If something goes wrong, I'd prefer to have the sacrificial vehicle to be a car rather than an engine. I know that a problem is unlikely, but that is my choice. I can easily remove the battery from the car for charging and replace it with a fresh one. The nice thing about a battery car is that it can service several engines. 

I have a battery car that I run behind an Aristo mallet or a USAT Hudson. I'm using REVO receivers in the engines.

A box car or reefer can often be seen as a head end car on many passenger trains. 

My battery car is a USAT boxcar.

I also use an Accucraft 1:20.3 D&RGW boxcar as a battery car behind a Bachmann K-27, for freight or passenger service.

Chuck


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## Bill Swindell (Jan 2, 2008)

Chuck, I understand. The batteries that I am talking about have internal circuit boards to protect undue stress on the batteries, II also use chargers recommended & sold byu the battery vendor. If one were to use unprotected model airplane/car batteries, I wouldcompletely agree with your concearns since these packs are totally unprotected. The battery car is certainly a reasonable choice.


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## chuck n (Jan 2, 2008)

Bill, I am using the protected batteries and recommended chargers, I am just over careful.

Chuck


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## East Broad Top (Dec 29, 2007)

Is there perhaps a way to modify the fuel tank so it's easily removable? I'm working on an NW-2 kitbash right now, and am turning the fuel tank into a battery drawer. I'm not familiar enough with the fuel tanks on the Geep or S-4 to know if it's possible to do something like that with those locos.

I prefer removable batteries simply because I can swap them out with new ones and keep running the same loco. Steamer are easy--the tender is a de facto battery car, so I can make the shell or coal load removable. Diesels aren't so simple. Where I can't, I put as high capacity battery as I can in the diesel for maximum run time. I've got a 5200 mAh pack in my 40-ton center cab (Bachmann kitbash), and get 6+ hours run time on a charge. (It's also in the fuel tank, but I didn't have the brainstorm to turn it into a drawer when I was building that one.) 

Later,

K


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## MaineCentral (Feb 10, 2015)

Dick413 said:


> what are you using the battery for? if for RC what voltage are you going to use. i am airwire and use 14.8 volts 4800 to 5800 mah batterys these will fit in 38 and s4 i can get up to 4 hrs with them. i get them from http://www.all-battery.com/


Thank you. Yes, for RC, AirWire/Phoenix Sound. Will 14.8 volts be enough? Or should I go with 18 volts?


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## East Broad Top (Dec 29, 2007)

What voltage you need depends on how fast you want the loco to go. Run your loco on track power at what you would say is your "typical" speed with a train in tow. Measure the voltage. If it's over 14 volts, go with an 18 volt pack. If not, you can stick with the 14 volt pack. 

I doubt you'll need more than a 14 volt pack unless you're running your trains really fast. I can't speak specifically to the two locos you have, but the NW-2 I'm working on definitely doesn't need more than 14 volts; neither have the FAs, PAs, or Genesis locos that I've put R/C in for folks. But it's your loco, your operating environment, so you're the one who will have to make the "how fast is fast enough" determination.

Later,

K


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## BigRedOne (Dec 13, 2012)

Another factor to consider is weight. By placing batteries in the locomotive, you add weight over the driven wheels. By using a trailing battery car (or steam locomotive's tender), you've added weight and drag to the train you're pulling. This might make a difference to the length of train you can pull, especially if your railway has grades or tight turns.


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## Treeman (Jan 6, 2008)

The CR-1605 would be our best seller.


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## East Broad Top (Dec 29, 2007)

Weight in trailing cars or tenders isn't the issue it used to be with older battery chemistries. The 2600mAh packs I typically use in my tenders weigh about 7 ounces, which is less than a set of metal wheels (4 axles). Even if you use an ultra-high-capacity pack (on the order of 10 - 12 AmpHours), you're still only looking at about 2 pounds. You're likely not going to fit a pack of such capacity inside a locomotive tender, but that will easily fit in a trailing box car. The battery and the weight of the box car is still likely going to be less than 5 pounds, which is on par with a passenger car or something of that nature. 

I've found when installing Li-Ion batteries inside locomotives themselves (especially steamers without tenders where space is critical) that I have to sometimes get a bit creative in terms of adding weight back to the loco when I remove the factory weight to make room for batteries. 

Later,

K


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## Totalwrecker (Feb 26, 2009)

BigRedOne said:


> Another factor to consider is weight. By placing batteries in the locomotive, you add weight over the driven wheels. By using a trailing battery car (or steam locomotive's tender), you've added weight and drag to the train you're pulling. This might make a difference to the length of train you can pull, especially if your railway has grades or tight turns.


The NiCads were half of the weight I removed, lead shot filled domes and other spaces over the wheels to try to make up the diff.
John


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## MaineCentral (Feb 10, 2015)

I'm not into running high speed trains. Slow freights and excursion type passenger trains is what I plan to run. I also do not plan to have any grades over 2 degrees or tight curves (20 foot minimum) except at a few turnouts/sidings but nothing tight at extended lengths so it sounds like 14.8 volts should do nicely with 3 mah and 6 mah batteries for the S4 and GP38 respectively. Each will have Airwire decoders and Phoenix sound. You guys are very helpful!


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## Dan Pierce (Jan 2, 2008)

I think you mean 3000 mah which is 3ah. same for the 6mah needs to be 6000mah.
3mah is 3 milliamps, 3ah is 3 amps.
Most likely a type but if ordering, this typo could result in getting a battery that would hardly light up a led.


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## MaineCentral (Feb 10, 2015)

Dan Pierce said:


> I think you mean 3000 mah which is 3ah. same for the 6mah needs to be 6000mah.
> 3mah is 3 milliamps, 3ah is 3 amps.
> Most likely a type but if ordering, this typo could result in getting a battery that would hardly light up a led.


LOL.. Yup..a typo! 3000 and 6000 mah.


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## IPTRAIN (Jun 1, 2012)

Speaking on price/performance and performance/volume definitely this brand is a very good choice http://trustfire.en.alibaba.com/pro...able_PCB_Protected_26650_battery_Battery.html

You will find many serious laboratory tests in the Internet which confirm best measures by diagram evidence compared to other LiIon batteries. Overload protection is built in.

As this (chinese) brand is well recognized worldwide many chinese clones are offered! Be carefull! All genuine Trustfire products are hologram protected!

Nevertheless a good price is 5 Dollar per cell! 

I have already ordered 50+ cells of them!

Best regards

Karl


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## Vinny D (Jan 25, 2013)

MaineCentral said:


> Thank you. Yes, for RC, AirWire/Phoenix Sound. Will 14.8 volts be enough? Or should I go with 18 volts?


If you are using AirWire they don't want you to use over 14.8v with there electronics.
I just installed a AirWire system in my GP38 with Phoenix sound and I used this battery:
http://www.reindeerpass.com/Railroad-Remote-Control-CR-1605-14-8V-5200mah-Lithium.aspx
It fits perfect where AirWire recommends to install it (over the rear trucks, after removing the lead weight)
I bought the recommended smart charger for it so I don't screw up charging the battery.
Reindeer Pass was very helpful when I purchased from them for this install.


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## Michael Glavin (Jan 2, 2009)

AirWire equipment is designed to work with up-to 28VDC and/or @ 120 Watt MAXIMUM current draw.

So in most circumstances you would simply find the speed/voltage range you desire and chose a battery that will provide same while working within the 120 Watt limit.

Something to keep in mind; batteries typically come off charge at elevated voltage numbers, a 4-cell Lithium-Ion 14.4V battery comes off charge at 16.8V static and will hold this elevated voltage for a brief period of time under load, this maybe a concern if your broaching the current demand limit.

120W/12VDC=10 Amps current
120W/14.4VDC=8.3 Amps current
120W/18.5VDC=6.49 Amps current
120W/22.2VDC=5.41 Amps current
120W/25.9VDC=4.6 Amps current
120W/28VDC=4.29 Amps current

Another noteworthy consideration is how much current/amperage will the battery in play deliver under load? The typical 18650 Li-Ions will provide its mAh capacity under load to voltage depletion specification. This means a 2600mAh capacity battery should deliver 2.6 Amps for an hour or thereabouts. FWIW: I've realized on average 4.6 Amps for 20 minutes at rated voltage.

Increased battery capacity is realized by using cells in multiples or series-parallel configurations. 2600mAh + 2600mAh = 5200mAh capacity battery. 

Michael


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## Beddhist (Dec 17, 2013)

According to my Airwire G3 manual 24V must not be exceeded.


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## Michael Glavin (Jan 2, 2009)

Below is data copied from the AirWire website:

In any event, its not likely anyone is going to run 28V, its simply capable of same according to CVP/AirWire. 

Many will find 14.8V anemic for specific engines and or desires.

*What is the output power of the motor driver?* 

The AirWire decoder can provide 120 Watts of continuous power. For example, a 12 volt battery means the decoder can supply 10 Amps of motor drive. If using a 24 volt battery, the decoder can provide 5 amps of motor drive. 

*What is the highest battery voltage that can be used?* 

All AirWire decoders can tolerate up to 28 volts. Naturally, the motor must be capable of safely handling the battery voltage used. Most motors are rated at 12 to 22 volts. However, higher voltages cause the motor to generator more electrical noise which will cause a reduction in the radio reception range. We recommend the 14.8V lithium battery pack. It is a perfect compromise between radio range and pulling power. It is also one of the more economical packs and one that we offer for sale. 

Michael


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## Beddhist (Dec 17, 2013)

Great, CVP are contradicting themselves. In the FAQ they say the above, in the G3 manual:

Never exceed 24 volts input voltage or you will damge the G3 decoder.
Always measure the battery voltage when fully charged and confirm
that it is below 24 volts.

So, which is correct? In any case, they recommend not to exceed 18V to minimise radio interference with the receiver.


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## Bill Swindell (Jan 2, 2008)

The G-3 does not accept as much voltage as the G-2 does. According to the manual, 24 volts is the correct number for the G-3. That means that with Lithium batteries, the most that you can use is 18.5 volts. The 22.2 volt battery has too high a voltage whe freshly charged.


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## Michael Glavin (Jan 2, 2009)

Garnering information from each individual AirWire models manual, I noted the following MAXIMUM voltage specifications.

Original AWD10SS -- 28V
All Drop-Ins ----------- 18V 
G2 ----------------------- 28V
G3 ----------------------- 24V

Learned something today... 

Michael


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## Beddhist (Dec 17, 2013)

Convrtr -------- 28V


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