Large Scale Central

Making NiMH battery packs

Electronics Power and Sound
#1

So I have an idea that is cruising through my head for a winter project once I come inside. I am already building the very small logging loco out of a B-Mann Lil Hauler.

This is how it sits at the moment. I also have two more Lil Haulers that I want battery power R/C. One is the saddle tank loco with no tender. The problem with these guys is the very limited amount of space to work with. Del Tony has a Viper ESC which is tiny and is advertised to run on 6-14.8V. I am excited about this. After seeing how long 14.8v 2600 mA batteries last in my GP9 I am thinking I can get away with lower voltage and way less mA hours on these smaller locos. Its just the motor and head light and small light loads being pulled.

So this brings up the idea of custom making battery packs for these locos so that I can split cells and shove them where I need them. Such as in the saddle tank loco making the tanks into battery packs. I know they make tabbed batteries for soldering too. So what is involved in making battery packs out of say NiMH cells. Is this worth even exploring or am I better off trying to shoe horn in an existing product? I would make the batteries more or less permanent and use on board charging jacks.

Thoughts on how to get R/C equipment and batteries into tiny locomotives? Minimum voltage required to run a Lil Hauler reliably? What about good old fashion 9v batteries?

#2

Tenergy makes a 9v NiMH 250 mAh battery with standard connectors. Now if these little Haulers will run off 9v ( I will test this) is there any reason not to use two of these to get me 400 mAh of run time?

#3

Talk to Dave Goodson. He’s good at stuffing batteries into small locos (remember the two porters at his layout). I believe he made some custom fit batteries in the past.

#4

My suggestion is to get a pack like this one. With that, you can connect in a DC-DC boost circuit. They are available for a couple of dollard from sellers on eBay. With that, you can have whatever output voltage that you want.

7.4V 2200mAh Li-ion

AT: Tenergy Li-Ion 7.4V 2600mAh Rechargeable Battery Pack w/ PCB (2S1P, 19.24Wh, 5A Rate)

Sale Price: $19.99

#5

Bill,

Forgive my ignorance but how does that work exactly and at what cost. I am assuming this is some sort of step up transformer? In order to take 7.4 and have it procedure say 9V or 10v is there a cost in mAh output?

That is a small battery pack and if it still has a decent mAh output may be intriguing.

I have been taking with Tony and he gave me the idea of using the AA size NiMH batteries with tabs and making my own pack. I have options.

#6

Bill Swindell said:

My suggestion is to get a pack like this one. With that, you can connect in a DC-DC boost circuit. They are available for a couple of dollard from sellers on eBay. With that, you can have whatever output voltage that you want.

7.4V 2200mAh Li-ion

AT: Tenergy Li-Ion 7.4V 2600mAh Rechargeable Battery Pack w/ PCB (2S1P, 19.24Wh, 5A Rate)

Sale Price: $19.99

Most of those units I am seeing are rather large. This has to go inside a tiny loco.

#7

Hey Devon,

How much room do you have. dimensions? NiMh would require at a minimum of 9 cells I’d suggest, yes they make small cells, problem is will they provide say 1 AMP and for how long?

Are you opposed to Li-Ion?

Michael

#8

I don’t have any actual dimension As I am working with three different locos. So most of this is theoretical at this point. But if you familiar with the lil Haulers then you know what kinda of space I am dealing with. Probably the worst will be the tank version because there is no tender. The loco above has the tank and the boiler so I have a bit to play with. And the third of the bunch is the yellow one with the tender so that’s the least of my worries as I will probably leave it just the way it is.

The only reason I am opposed to Li-Ion is the ESC I am getting from Tony says it is not Li-Ion safe. Not sure why. The other reason I am thinking NiMH is that I can buy the ones with the tabs and form my own packs and basically shove batteries everywhere. I just got the tank loco in the mail. One thing I would like to do is see what space I have. I would be nice to shove some in the tanks.

Anyways thats kinda what I am up against. If push comes to shove I can add a small fuel bin to the tank loco and give myself some room. It needs one anyway since it carries no fuel with it.

Edited: I just pulled the tank loco out of its package. The tanks on it look as if they will hold AA size batteries. At least three per tank plus wiring. If I could figure out how to do it I could get six batteries inside the tanks. The rest of the batteries and electronics should fit in the boiler. I also figure these should run on 9v pretty well.

#9

So Tenergy makes a AA size NiMH with tabs. 1.2v 2000 mAh. * of them gives me 9.6 V. I think with some creative placement I can make an on board pack that will fit in the tank and boiler along with the rest of the electronics.

One thing I will say is that I am getting a real hoot out of these tiny locos. I find them to be a fun challenge trying to work with such tight constants.

#10

Devon, if worse come to worse, you could make a trailing car. Maybe a tool car or something, to hold the batteries and such.

#11

Devon

I believe the 1600 mAh cells below would work great for you needs. Plenty of power for the lil engines your toying with.

Small too; Dimensions: 16.8 x 28.5mm (D x H), these cells need the CORRECT NiMH charger and require forming, at least three charge/discharge cycles to come to life. I suspect Tony’s concerned is based on the voltage of battery, more so than technology. Lithium cells typically provide elevated voltage levels for short periods of time, static. That being said Tony knows best! If it were me I’d use Li-Poly battery, MANY-MANY-MANY choices for size and capacity and there inexpensive and utilize balance charge technologies… There a few considerations herein, if your akin to the idea we can discuss same.

http://www.tenergy.com/10710

Michael

#12

Devon is going to be using an MTRONIKS VIPER ESC.

I think Devon is referring to the note in the VIPER instructions that these do not have Li-Po battery low voltage detection.

Therefore, whatever Li-Ion battery pack is being used should have a low voltage pcb fitted to the pack. All the Li-Ion packs I sell do have such a pcb fitted. I know of no Li-Po packs that have such a protection pcb built in, so I do not sell them.

Not needed with NiMh of course.

#13

David Maynard said:

Devon, if worse come to worse, you could make a trailing car. Maybe a tool car or something, to hold the batteries and such.

That is always an option. But I am really hoping to avoid it. The main reason is two of these little guys (the tank engine for sure) will be for running on the shunting puzzles and as such need to be small for my layout. I want to keep the locos as short as humanly possible and no extra baggage. For this purpose if I have to have a trailing car it will be a tender and that should be enough to get it all to fit.

#14

A small 2 axle coal tender for the tank engine, yea, I can see that. Heartland makes short 2 axle cars. You could use a flat and build your own fuel bunker, or use the gondola and just put coal boards on the locomotive end.

#15

Tony Walsham said:

Devon is going to be using an MTRONIKS VIPER ESC.

I think Devon is referring to the note in the VIPER instructions that these do not have Li-Po battery low voltage detection.

Therefore, whatever Li-Ion battery pack is being used should have a low voltage pcb fitted to the pack. All the Li-Ion packs I sell do have such a pcb fitted. I know of no Li-Po packs that have such a protection pcb built in, so I do not sell them.

Not needed with NiMh of course.

That is where I got the info. I do know some of the Li-Ion packs have it, my 14.8v 2600 mAh does, I believe. Since I can’t use LiPO which does come in so many different shapes and sizes and a regular pre-assembled Li-Ion pack is just not the right shape no matter what shape I get, I am going to go the route of NiMH. If I buy individual cells with the tabs this will allow me to stick them where ever I can with wires running everywhere to connect them. This will give me tons of flexibility. The loco become the battery pack. This will require on board charging but that is no big deal and I have a programmable smart charger so I can get it done. Tony’s equipment package is very small. That viper is down right tiny, if I remember right its only 26mm X26mmX9mm. The RX is also very small. A few switches and a couple polyswtches and I will be in business. If I measured right I might even be able to get all 8 cells in the tanks of the tank loco. Leaving the whole boiler for electronics and if lucky some added weight. Worse case scenario 6 of the 8 cells will fit in the tanks. Two more in the boiler and then the electronics and no added weight.

We will see where this goes. The tank loco will be the worst. If I can get it in there the rest will be a breeze.

#16

David Maynard said:

A small 2 axle coal tender for the tank engine, yea, I can see that. Heartland makes short 2 axle cars. You could use a flat and build your own fuel bunker, or use the gondola and just put coal boards on the locomotive end.

If I have to build the tender a two axle one is a great idea. Since its a tank loco it doesn’t need a water tank just a fuel bin. So really a scratch built stake side gondola would be perfect. We will see if I need it. Of course I could make it an 0-4-2 with a very small fuel bin. There are tons of options. I won’t be doing to much of any bashing to it until much later. I want to get it running and pretty much leave it as is. To many other projects need finished, like an entire layout. But I need two locos running by the grand opening next year so people can work the puzzles. I have the tank and another yellow lil hauler with the tender. These two will get the nod if the logger doesn’t get finished on time.

#17

Devon

You CAN use Li-Po batteries. PCB low voltage is simply a gadget used to help ruin your battery pack and or provide you with a false sense of security. I use Li-Po’s on trains, plains and copters.

And yes there are Li-Po batteries available with PCB’s (slim pickings though) or you can simply use a PCB as an ancillary device or maintain/utilize your batteries correctly and there is no need for a PCB. And there are gadgets available for a couple bucks that plug into the balance pigtail and make noise, flash lights or display voltage telling you when the battery has discharged to the appropriate voltage level, which is long before a battery with a PCB low voltage cut-out takes hold.

That said NiMH will work fine IME, yet you can run these batteries down below safe voltage numbers too, which like other technologies; will eventually contribute to short life cycles. So best case is to monitor your batteries voltage while your running your trains (I alluded to several options above).

Michael

#18

Devon Sinsley said:

So I have an idea that is cruising through my head for a winter project once I come inside. I am already building the very small logging loco out of a B-Mann Lil Hauler.

This is how it sits at the moment. I also have two more Lil Haulers that I want battery power R/C. One is the saddle tank loco with no tender. The problem with these guys is the very limited amount of space to work with. Del has a Viper ESC which is tiny and is advertised to run on 6-14.8V. I am excited about this. After seeing how long 14.8v 2600 mA batteries last in my GP9 I am thinking I can get away with lower voltage and way less mA hours on these smaller locos. Its just the motor and head light and small light loads being pulled.

So this brings up the idea of custom making battery packs for these locos so that I can split cells and shove them where I need them. Such as in the saddle tank loco making the tanks into battery packs. I know they make tabbed batteries for soldering too. So what is involved in making battery packs out of say NiMH cells. Is this worth even exploring or am I better off trying to shoe horn in an existing product? I would make the batteries more or less permanent and use on board charging jacks.

Thoughts on how to get R/C equipment and batteries into tiny locomotives? Minimum voltage required to run a Lil Hauler reliably? What about good old fashion 9v batteries?

#19

Devon Sinsley said:

So I have an idea that is cruising through my head for a winter project once I come inside. I am already building the very small logging loco out of a B-Mann Lil Hauler.

This is how it sits at the moment. I also have two more Lil Haulers that I want battery power R/C. One is the saddle tank loco with no tender. The problem with these guys is the very limited amount of space to work with. Del has a Viper ESC which is tiny and is advertised to run on 6-14.8V. I am excited about this. After seeing how long 14.8v 2600 mA batteries last in my GP9 I am thinking I can get away with lower voltage and way less mA hours on these smaller locos. Its just the motor and head light and small light loads being pulled.

So this brings up the idea of custom making battery packs for these locos so that I can split cells and shove them where I need them. Such as in the saddle tank loco making the tanks into battery packs. I know they make tabbed batteries for soldering too. So what is involved in making battery packs out of say NiMH cells. Is this worth even exploring or am I better off trying to shoe horn in an existing product? I would make the batteries more or less permanent and use on board charging jacks.

Thoughts on how to get R/C equipment and batteries into tiny locomotives? Minimum voltage required to run a Lil Hauler reliably? What about good old fashion 9v batteries?

#20

Yes you can but tagged AA cells and make your own battery packs.

I do it all the time,I stuff them into any nook and cranny I can fit them into then just wire them together

Guess being an aviation maintainer and seeing the engineers do this stuff has rubbed off.

I hope I have attached 2 pics of a battery install in an old MDC Big Hustler (not much room in there) admittedly at the time of the pics it was just manual running but with a few accessories eg tool boxes, electrical racks it can be R/Cd

You just have to use a bit of imagination and think outside of the box.