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Tom Harbin
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Hi,

I've read several hundred pages of this forum and I've decided to attempt to RC a Bachmann Porter On30 0-4-2.
I have it apart already since I was preparing to install DCC but I think I would rather try BPRC with it.

I know there are lots of inexpensive ways to get into BPRC but I also want to support the manufacturers that are trying to create a market.
I've read lots of the pros and cons here and on other forums.
The nay-sayers sound amazing the same as they did when DCC came out.

I have decided that I want to use either Deltang or S-Cab for my test loco.
Hopefully the system will prove good enough to convert my "fleet" so I would rather try to fix on a particular system.

I really like some of the S-Cab features like the ability to charge from the track
(I was thinking of having a track-powered charging station in an engine house).
What I don't like is its reliance on a DCC board.
I think a lot of what DCC offers is not really needed if we go with RC.
I also think the DCC protocol is slow and inefficient if we start thinking beyond pulsed rail power as the communication medium.

I like the size and features of Deltang and that it has a built in ESC. To me that makes sense.
What slows me down on Deltang is that the S-Cab  "seems--I could be very wrong on this"  to have better battery management.

I'm looking for any input that will help me make a more informed choice.

Thanks,

Tom


Rick Dow
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Hi Tom,

The guys usually posting on here will give you excellent advice and are much more experienced than I am.

I am using DelTang equipment. 
The Receiver is a  Rx62-2     
The Transmitter is a  Tx21

With the Rx62-2 Receiver, I can power on and off with my DelTang supplied Pencil Shaped Magnet,
because the Receiver has a built-in reed switch.

I power it with a 2 cell LiPo battery because it is smaller than a three cell LiPo battery.

With the two cell battery I am supplying 7.4 Volts, and that is sufficient for my HO steam power.   

With O gauge you will probably have more space available for installation.

I am able to fit the Receiver and Battery into my HO tenders.

The performance has been exceptional in my view.

DelTang service, communication and delivery to me has also been exceptional.

Good Luck

Rick


Tom Harbin
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Rick,

Thank you.
I really like everything I read about DelTang and DavidT's input in the forums has been very enlightening.

Since I plan to cab mount the gear in the Porter there isn't much room,
but I figure that with the All-Season Banta cab I should be able to fit it all in.
It seems the DelTang equipment is smaller which is also a big plus for it.

I didn't realize it when I wrote my first post but I guess I have a pretty basic question on ESC versus DCC-connected.
With S-Cab, the receiver connects to a small set of standard DCC receivers and operates in 28 speed step mode.
You can also adjust the min/max voltage percentage as a poor-man's speed curve.

One thing I do like about the DCC connected approach, if I understand it correctly,
is that the transmitter talks to all receivers but the command includes a 2-digit DCC address so only the specified engine responds.
That implies that the S-Cab is actually encoding a sub-set of regular DCC commands in its signal.
Not sure if that is a good thing or not as DCC was really developed to solve a different problem
(encoding digital commands on a power signal). 

With a standard proportional ESC I know it is still using PWM,
but is it using something equivalent to speed steps or is it approximating linear control?
I'm pretty sure I've read that, at least with DelTang, you can also adjust starting voltage.

Tom

Rick Dow
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Tom,

I don't have the required technical ability to respond to some of your thoughts.

For instance, I don't know what you mean by PWM.

I also have not been involved in re-programming a DelTang Receiver. (Starting voltage)

I do know however, that the slow speed operation on my HO equipment is right where I like it to be,
and that this occurs on the standard settings from DelTang.
Plus, the top speed I want for my purposes is accomplished with a 2 cell LiPo battery.

I really like the fact that the DelTang Receiver comes to me with the four pig tails already soldered to the four pads on the Receiver,
and I simply connect two of them to the DC motor and the other two to the LiPo battery.  

Rick

Tom Harbin
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Thanks again Rick,

That actually sounds like a very good way for me to get started.
I like what you said about the speeds also.

So you are using a 2S pack?
How do you recharge?

Tom


dan3192
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Hi Tom,

In your first post you mentioned you were concerned about battery management.
Could you elaborate a little more about those concerns?

A typical setup for me includes a DelTang Rx61x receiver and one or two cylindrical Li-Ion cells in series plus a Voltage regulator.

I don't have a need for battery management using a single cell since my "smart" charger has over-Voltage protection,
and the receiver cuts off power at about 3V for under-Voltage protection.

Is your concern about multiple battery use?

Dan  


Tom Harbin
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Dan,

Not so sure it is really a concern but rather a lack of understanding on my part.
I'm pretty comfortable with the idea of charging a 1S
(or 1P although I don't know that there is actually any difference in that case)
but when I read about 2S packs it seems you need a balancing charger more that just the two wire hook up to charge.

What I would like to avoid is fiddling with the loco any more than necessary once I get it built as I am a notorious fumble-fingers.

I kind of planned from the start to put charger leads on rails inside an engine house,
that I could turn on and charge the battery through the rails but leave the rest of the layout un-powered.
The S-Cab supports that out of the box, but I really like the overall approach of DelTang, or converting RC car components.

I think the DCC protocol is very inefficient for a bound transmission.
I also would prefer to be on 2.4GHZ instead of 900MHZ. 

I am also thinking that sticking with 1S would probably be sufficient for my needs,
but I need to figure out whether I need a step-up like a Pololu or not.
That functionality is part of the BPS solution from S-Cab and the reason it uses 1P, 2P or 3P instead of 1S, 2S or 3S packs.

In many ways S-Cab seems to be a perfect fit but something holds me back,
the DCC, the size of the equipment, the price. I don't know.

I think maybe it reminds me of the big fix that finally cemented DCC as "the solution".
"You can still run your DC locos on a DCC system".
Yah, right, as long as you don't mind having it sound like a drunken chipmunk as it sputters down the track.

Tom

Bob R
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On page 3 of this forum there is a thread for the On30 Porter conversion I did with DelTang.  

Tom Harbin
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Thanks Bob,

I thought I remembered a recent thread that was almost exactly what I was going to do but for some reason I couldn't find it.

I will probably do almost the same conversion but probably not as neatly. 

Tom

Tom Harbin
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Just a quick update.

I was at the DelTang site again and found the answer about speed steps, at least for DelTang.

They do use speed steps (which makes sense since it is PWM),
but it is 256 steps in each direction.

So twice as fine a control as the best you can get with DCC,
and about nine times finer than the 28 steps offered with S-Cab.

This is all theoretical as I have never had a problem controlling the speed with DCC.
But it is nice to know that using BPRC with an ESC can give equal or better speed control.

Tom


davecttr
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Tom Harbin wrote: Just a quick update.

I was at the DelTang site again and found the answer about speed steps, at least for DelTang.

They do use speed steps (which makes sense since it is PWM),
but it is 256 steps in each direction.

So twice as fine a control as the best you can get with DCC,
and about nine times finer than the 28 steps offered with S-Cab.

This is all theoretical as I have never had a problem controlling the speed with DCC.
But it is nice to know that using BPRC with an ESC can give equal or better speed control.

Tom


Tom

Some more information about DelTang speed steps, there are 256 but you can't select an individual step.

In effect the throttle approximates a smooth DC throttle.

In addition you can change the low and high voltages expressed as a percentage.

Some programming is needed for this, but straightforward once you master the art!


davecttr
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Tom, you might want to consider some things.

How long is your typical operating session?

How long would a locomotive be moving within that session?

This Porter loco seems to need about 250mAh of battery to run for one hour.
If it is switched on but not moving the RX/Pololu combination will still draw slightly less then 20mA per hour.

For example if the loco ran for 30 minutes it would use 125mAh,
leaving enough power in the battery to leave it switched on for an additional 6 hours!

If you do a few calculations you might be able to use a smaller battery taking up less space. 

Rather than 1 large battery you can connect 2 or more in parallel and they behave as 1 battery even when recharging.
I think the batteries can even be different capacities as LiPo batteries in parallel will automatically equalise their Voltages.


Tom Harbin
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Dave,

Thanks very much for those these two very informative posts.

What I really want is to be able to set the min and max voltage percentage and have a linear (non-notchy) throttle.

One of the things I don't like, is using a 28-step decoder with a 128-step throttle.
While it isn't horrible, I invariably want something like step 8.2 out of 28,
and at lower speeds the notches just make the "momentum" rather jerky.
 
A smooth DC throttle is exactly what I want.

Your information on running time is very helpful.
I can't really afford to make a lot of guesses getting started.

After I'm started, I can sell off DCC components to fund BPRC,
but right now this conversion has to come out of next year's modeling funds.

A one hour run time is about ideal for the Porter.
I actually planned to have run times of about: Porter 0-4-0 - 0.5 hours, Porter 2-4-0 - 1 hour, 4-4-0 - 2 hours, 2-6-0 - 2 hours.
These run times should add some semi-realistic operations opportunities to the layout.
Taking into account idle times, I think this will work out very well. 

If I could be so bold, can you tell me which Pololu you are using for these estimates?

I think I have pretty much locked into DelTang for my conversion as it seems fairly idiot-proof and a purer BPRC solution than the S-Cab.
I really like S-Cab's battery management solution though and will continue to look at where the system goes. 

Tom


davecttr
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I mostly use 9V Pololu regulators with one 12V.

DelTangs Rx are typical 15mA idle, current and the Pololu 2mA.

Here is the 9V version    https://www.pololu.com/product/2116



Bob R
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I also use primarily Pololu 9 volt regulators. 

Most engines are geared to run way to fast at 12 volts. 
You should test run an engine to see how it runs at various voltages. 
I have found on some 5 volts is plenty for prototype operations.
 
Keep in mind that the more you boost the voltage from a battery the less efficient the regulator is. 
Boosting from a single cell lipo (3.7 volts) to 9 volts is not very efficient. 
Boosting from a two cell lipo (7.4 volts) to 9 volts is very efficient. 
If 5 volts will do the trick the Pololu 5 volt with a single cell is very efficient. 

The Porter, as an example, runs one hour using a single cell. 
I have other Bachmann engines with the same motor using a two cell that run in excess of two hours. 

Carefully consider your running needs/desires and the configuration that best suits you and space available for the battery.


davecttr
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Tom, Check out the graph on the Pololu page.

You can see using a 1S battery with a 250mA loco should give 80% efficiency even when the battery is nearly depleted.

Contrast this with a 2S battery and you get over 90% efficiency with a 600mA loco!

I usually install 2 batteries in locos needing more than 250mA.


dan3192
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...and if you take a look at the "Wireless Charging" topic, some guy is trying to do on-board induction charging. 

I think you'll find the way you're heading has many options.

Dan

Last edited on Sun Dec 23rd, 2018 08:14 pm by dan3192

Tom Harbin
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davecttr wrote: Tom, Check out the graph on the Pololu page.

You can see using a 1S battery with a 250mA loco should give 80% efficiency even when the battery is nearly depleted.

Contrast this with a 2S battery and you get over 90% efficiency with a 600mA loco!

I usually install 2 batteries in locos needing more than 250mA.


Dave,

Looks like I'm going to need to buy a new meter and set up some kind of DC supply if I want to do this right.
I bought my multi-meter back when I became a computer tech, 1973, it doesn't know what a milliamp is, well not very accurately.
My last DC train supply blew up eight years ago and gave me the excuse to go to DCC.
I think I have some old battery holders squirrelled away somewhere though.

I like the idea of limiting an engine's capacity based on its type.
A tender loco should have more range than a tank loco.

Tom


Tom Harbin
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dan3192 wrote: ...and if you take a look at the "Wireless Charging" topic, some guy is trying to do on-board induction charging. 

I think you'll find the way you're heading has many options.

Dan


Dan,

I agree.
The more I look at this the more sure I am that this is the way to go.

I like the idea of wireless charging but I also like the S-Cab approach.
It could be set up much like we set up DCC programming tracks,
with charging connected to specific track locations and still not need to "wire" the track...
and any loco you buy today already has track pickup wires installed.

Tom


Rick Dow
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Hi Tom,

One point I would add here, is that I find it extremely easy to charge my LiPo batteries with my "balancing" charger. 

I can't imagine that I'll ever require "On Track Charging",
because I can't envision charging ever becoming an issue for me.
(at least I can't foresee it happening)

I'm still trying to get all my trackwork installed, and so not running my locomotives all that much.

But the experiments I've tried (although rather unscientific),
have seemed to give a little bit over an hour and a half of running time (mostly switching duties),
on a 2 cell LiPo with 250 mAh.
 
Just saying'.

I've taken to recharging my 2 cell LiPos in the kitchen, one battery at a time, while I watch TV in the next room.
Maybe ten minutes each and Safe and Easy.
Charger shuts down when fully charged.

Have a great Christmas season, Tom........... and everyone else too.

CHEERS

Rick


davecttr
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Tom Harbin wrote: davecttr wrote: Tom, Check out the graph on the Pololu page.

You can see using a 1S battery with a 250mA loco should give 80% efficiency even when the battery is nearly depleted.

Contrast this with a 2S battery and you get over 90% efficiency with a 600mA loco!

I usually install 2 batteries in locos needing more than 250mA.


Dave,

Looks like I'm going to need to buy a new meter and set up some kind of DC supply if I want to do this right.
I bought my multi-meter back when I became a computer tech, 1973, it doesn't know what a milliamp is, well not very accurately.
My last DC train supply blew up eight years ago and gave me the excuse to go to DCC.
I think I have some old battery holders squirrelled away somewhere though.

I like the idea of limiting an engine's capacity based on its type.
A tender loco should have more range than a tank loco.

Tom


Tom, I had no DC supply so no way of checking the Amps needed by the loco, so I did it this way.

I set up a DelTang RX/Pololu combination in a wagon of some sort and fed the output to the motor.
Then I installed a 100mAh battery and ran the train until the RX's onboard safety cutout operated at 3 Volts.
You need a wire on the 'L'-Pad to do this.

A 100mAh battery should provide 1 Amp for 6 minutes, so if your loco and train stopped after 24 minutes, the loco is rated at 250mAh.
You can do this with any battery size.
You need a continuous circuit to do this and it is best to isolate the loco pickups because a short circuit on the track will fry the Rx.


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I do enough motor testing that I set up a "dyno" car with an ammeter to check motor current under running conditions.

For this application I prefer an analog meter as they don't jump around as much as digital.





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That's neat, how big is it?

Could the ammeter be mounted vertically?



Tom Harbin
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" Tom, I had no DC supply so no way of checking the Amps needed by the loco, so I did it this way.

I set up a DelTang RX/Pololu combination in a wagon of some sort and fed the output to the motor.
Then I installed a 100mAh battery and ran the train until the RX's onboard safety cutout operated at 3 Volts.
You need a wire on the 'L'-Pad to do this.

A 100mAh battery should provide 1 Amp for 6 minutes, so if your loco and train stopped after 24 minutes, the loco is rated at 250mAh.
You can do this with any battery size.
You need a continuous circuit to do this and it is best to isolate the loco pickups because a short circuit on the track will fry the Rx."


- - - - - - -


Dave,

This is just plain ingenious, imagine using math instead of yet another tool.

Seems like when I play with trains I shut off my thinking cap.

Great solution.

Tom


Tom Harbin
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Bob,

This is a great idea!

What I really like is being able to check the load under actual conditions like grades.
Even though I only have 2% grades they definitely affect the load.
I'm thinking maybe a small flat car with leads to reach the engine.
That way I could even put together a typical lash-up and check it out.

I got leery of grades and loads when many, many years ago I attempted my first Christmas layout.
I slapped a bunch of HO track on half of a Ping Pong table top with like 6% grades,
and put my very favorite train on it, a Rivarossi Old West train.
"On the second day of Christmas my 4-4-0 gave to me, two warning smells, and a totally fried motor."

Tom


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My ammeter is 45 mm square (about $8 on ebay).

It could be mounted vertically, but since I do most of my testing on the floor, it is easier to see when mounted horizontally.

I *really* need a tabletop test track! :)



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Thanks Tom

By the way it is a special day tomorrow, it is Christmas!, no snow or even frost.
Never mind.

I have washed and polished the glasses, the steak is defrosting and there is enough food to last a week.
Perhaps I will sneak off for a couple of beers tonight.

Merry Christmas and a Happy New Year (other greetings of the season are available)


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Dave and Everyone Else Here Too!! -   Merry Christmas from Canada

Rick

Tom Harbin
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All,

Merry Christmas. I hope you all have a wonderful day.

Tom

Bob D
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Tom,

I model in O-scale and have converted about 18 engines from DCS/TMCC to BPRC using the Rx65b and various transmitters from RCS Australia. 
My batteries are 9.6v or 12.0v, 2000mAh, NiMh, or 11.1v 220mAh LiPo packs. 
I get approx 2.5 hours of run time, and it takes about that long to recharge them.

I've attached a diagram I use to wire an engine with a single motor, it incorporates a charging circuit also. 
I generally mount the on/off switch and charging jack under a false coal load made of foam rubber. 

There should be a load of photos in my album on the forum here.





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A typical battery is approx 1"x1"x5" long and fits inside the tenders of my steam engines.
My diesels all have them under the shell usually with the Rx sitting on top.

The ONLY complaint I have is there's no sound.
It's not so much a complaint as it is a side note, I don't like a lot of sounds coming from my engines.
I wouldn't mind having steam chuff or diesel rumble but couldn't care less for horns, bells, whistles.

I do have 2 engines with the BlueRail board installed,
and have 1 with a bluetooth speaker hooked up so the sounds come from the engine instead of my Ipad, pretty cool!


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Hello Bob.

Please remember there MUST be a suitable dropping resistor in one leg of each LED.
470R up to 1KR will be OK.

Not needed with incandescent bulbs but the bulb voltage must match or preferably, exceed the battery supply voltage.

RX65b instructions


Bob D
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Hey Tony!!

You are correct, the LEDs I buy already have the resistor wired in. 
I get them from here:

LEDS

I've been running BPRC for 4+ years now and have had ZERO failures with any of the components from RCS (thanks Tony!) or DelTang. 
If you go to the other train forums you'll see 1/2 of the topics are about problems folks are having with their "systems". 
It was an expensive route I took (replacing 2 systems for 1) but IMO well worth the trip!!!


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Bob,

Thank you for the diagram. It really helps to get it all straight in my head.
I think I'm going to use RX60s or RX61s as they are what the US dealer (On30guy) carries. 

Thank you also for the battery sizes.
Now that Christmas is over and the businesses are starting up again, I am going to order some bits.
I now have eight locos (received two for Christmas) and I will convert one or two to "get my feet wet".

I finally moved to DCC seven years ago when my DC pack decided to retire, and since I have a small layout, the wiring is not a problem.
When I started posting here I started reading many threads here from people using BPRC.
The more I thought about it and the more I thought about the myriad wiring problems of DC-type circuits and the problems of track pickup,
the more convinced I am that BPRC is really the best solution.

Unfortunately, a Bachmann On30 2-6-0 is my largest engine, in fact, it is too big for my layout.
I only have two tender engines, both 4-4-0s.
Getting my head around the sizes of the equipment and the available space inside my locos,
seems to be a challenge that can only be solved by buy-and-try.

I thought about the sound issue, one of my Porter 2-4-0s has sound,
and I decided that while I like it I usually end up muting the engine after a while.
Whole layout sound may be the answer if I find I miss it.
The idea of the Bluetooth speaker is rather intriguing. It sounds like a very cool solution.

My first conversion will be a Porter 2-4-0 since I already have it partially disassembled to install a DCC decoder.

This has not been an easy choice for me as my DCC works fine but I just don't see it as the future.
Things would have been easier and we would probably be further along if we had stayed with 3-rail AC and just added a third rail to the prototypes.

Tom


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Tony,

Thanks for the note to Bob about LEDs, I was a little confused on that point.
My first conversion will have an incandescent light but most of my engines are LED.

Tony, I just followed the link to your web site. Very informative.
I am learning a lot about the various options out there thanks to you. 

Tom


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In a show of support for my decision to pursue a BPRC layout, my wife bought me my first BP (unfortunately, non-RC) train for Christmas.





It actually also has a tender but it has "pins" on both ends instead of the requisite pin on one end and loop on the other.

The little train did serve to bring home several ideas.
The first is that even though this engine has no speed control, in every other way it is totally equal to the same train on DC or DCC.
Good speed control was the differentiator until we started using proportional control with battery power.
The other is that BPRC does not have to be complex.
I have been doing a lot of over-thinking.

Tom


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Hello Tom.

Whilst I specialise in scales of full size 0 and above, the basic principles remain the same.
Just that with the larger scales they draw a lot more power rendering voltage up regulators not really worth the trouble.
They generally do have a lot more room for high capacity batteries.
Consequently I know very little about regulators and their operation.

Bob D has been helpful to me in understanding more about the smaller scales.
I doubt I will ever get involved in BPRC for the smaller scales.
I have my hands full with Large Scale Live Steam and battery power,
but, I can recommend dealing with Micron R/C for anything that is smaller.


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I'll 2nd what Tony says about Micron.

If Tony doesn't have what I need I usually go to Micron for the rest, they deliver quickly to the U.S.


Tom Harbin
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Tony and Bob,

Thanks for the reference to Micron. I will look at their site. I'm not finding exactly what I want locally.

Tom

Rod Hutchinson
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I too use Micron Radio Control in the UK. 

Excellent source of DelTang supplies, and very helpful. 

I live in Australia.


Nice Guy Eddie
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" does not have to be complex. I have been doing a lot of over-thinking "


My psychiatrist has been telling me that for years

And always says have a good think about that

And see you at the same time next week


:f:


Eddie


Tom Harbin
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Back a few weeks ago, I purchased a starter set from On30guy.
I also purchased a 9v and 12v regulator from Pololu.

I figured to start with a "starter set" so that all of the plugs would match up
(still getting a handle on the various types used) and a complete solution for a locomotive.

That way if nothing works, I don't have to wonder if I fouled up the transmitter build, got an incompatible unit, 
or something else if I get no response when I start testing.

Once I have a few working pieces, I'll start to fool around and see what I can fry.
I'll also start ordering from Micron (once I understand the connectors).



While I'm waiting for the starter set to arrive, I have a question:

The On30guy starter set has a 2S battery pack.
If I understand that correctly that is two Li-Pos wired in series with two cable connections.

Two wires from the outside terminals to the load(s),
and three wires from the two outer terminals and one from the series connection to a battery charger plug.

I believe the idea of the three-wire connection is to ensure that the batteries are balance-charged.
That would imply that a 3S would have a 4-wire-connection, etc. 



I believe that you are not supposed to allow a Li-Po cell to go below roughly 3.0v.

I also believe that the DelTang receivers are designed to shut down when the charge decreases to 3.0v.

I know that if I use the Pololu I need to use the L-Pad on the DelTang to monitor battery voltage instead of regulated voltage.



Okay, now the question.
If I have a 2S pack, how do I ensure that neither cell discharges below 3.0v as they are in series?

A related question just occurred to me.
Am I right that the Pololu will maintain the rated output as the input voltage falls but just become less efficient as the voltage drops?



Tom


davecttr
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First question - When the DelTang Rx is switched on it checks the battery voltage and sets the LVC (low voltage cut off).


From the DelTang features page for a Rx.

3V for <4.3V measured at startup
4V for 4.3-6V
6V for 6-9V
9V for >9.1V

As you can see a fully charged 2S Li-Po battery gives 8.4V so the LVC is set to 6V.
These are the default options and can be changed by programming the Rx.


Second question - Yes, the Pololu maintains the rated output and the efficiency falls.
I change from a 1S to 2S battery if the loco power requirements are above about 300mA with a 9V Pololu.


Tom Harbin
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davecttr wrote: First question - When the DelTang Rx is switched on it checks the battery voltage and sets the LVC (low voltage cut off).


From the DelTang features page for a Rx.

3V for <4.3V measured at startup
4V for 4.3-6V
6V for 6-9V
9V for >9.1V

As you can see a fully charged 2S Li-Po battery gives 8.4V so the LVC is set to 6V.
These are the default options and can be changed by programming the Rx.


Second question - Yes, the Pololu maintains the rated output and the efficiency falls.
I change from a 1S to 2S battery if the loco power requirements are above about 300mA with a 9V Pololu.


Thanks Dave,


That makes sense, and some clever programming.

So I guess it is safe to assume that if you have a 2S pack (with the same age and capacity cells)
they will discharge equally, or at least nearly so?

Does that also mean that building a Li-Po pack with different capacity cells is a definite no-no?


It is a little hard to tell on my 5-0-5 ammeter,
but it seems my victim Porter draws somewhere between 250-400mA under light load.
I may end up going with a 1S for simplicity, but the starter set comes with a 2S.

I really need to find an RC shop and get a look at some of this stuff.


Tom


davecttr
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Two different capacity batteries connected in serial is a NO NO.
They should be the same capacity and some say ideally from the same production batch.


I found that cells can have a 0.1V or even more difference at the end of discharge without any problems.
If you are worried you can programme the LVC cut off values to be say 3.2V, 6.4V etc etc.

I used to do this but as my batteries are usually only 75% discharged, I just use the default values.


Hal Pridgen
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bobquincy wrote: I do enough motor testing that I set up a "dyno" car with an ammeter to check motor current under running conditions.

For this application I prefer an analog meter as they don't jump around as much as digital.


Hi Bob (or other EE types)

I found a 3 Amp meter that I’d like to use to make my own DynoCar.

Do I need to use a shunt, and if so, describe please.

THANKS!


Andy R
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Hal

A DynoCar would have a generator driven from the vehicle wheels,
and a variable load so that the pulling loco's motive force can be measured.

I think what Bob was describing is simply a trailing vehicle,
holding an ammeter wired in series with one motor lead.

If your meter really does measure Amps then no shunt is required.

Take care though,
many meters with Amp scales are actually milliamp meters with a shunt,
you need to make sure the shunt is still there.


James Field
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Hi Rick,

Just been reading some of the conversions.

I posted a question elsewhere,
but maybe you or someone can answer this.

I am in the process of converting an old Bachmann Shay to RC.
In tacking the body apart I note that the Shay has a fairly large circuit board.
If I take this out I can get my receiver, charging circuit and battery all in the bunker.

My question.
Is removing the Bachmann board going to be detrimental to the running of the Shay,
or will the DelTang receiver make up for this,
or should I try and retain the Bachmann circuit?

James

Hal Pridgen
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James Field wrote My question.
Is removing the Bachmann board going to be detrimental to the running of the Shay,
or will the DelTang receiver make up for this,
or should I try and retain the Bachmann circuit?


Hi James,

I’ve only done three of these,
but I don’t see how you could piggy-back the DelTang chip, on the Bachmann board.

Doesn’t the Bachman board provide for sound. as well as motor control?

The DelTang clip will do fine for controlling the motor/loco,
just no DCC type of sound.

This stuff is fun!


James Field
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Thanks Hal,

The Shay was a DC model so no sound.

Just wanted to make sure that the Bachmann board had nothing on it,
that would be detrimental to it's running should I dispense with it.

Since writing this query, have found a link to someone who has converted a Shay,
and clearly shows that you can dispense with this circuit board.

James



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