Freerails Home 
Home Search search Menu menu Not logged in - Login | Register
Freerails > Model Railroad Forums > R.C. The Future Now If You Desire > Pros & Cons - 'DelTang' & 'S-Cab' Radio Control ?

Freerails IS ACCEPTING new Members ... To join Freerails ... See how to Register as a Member in the 'Joining Freerails' Forum

Pros & Cons - 'DelTang' & 'S-Cab' Radio Control ?
 Moderated by: . Page:  First Page Previous Page  1  2  3  4  5   
New Topic Reply Printer Friendly
 Rating:  Rating
AuthorPost
 Posted: Sun Dec 30th, 2018 02:03 am
  PMQuoteReply
41st Post
Nice Guy Eddie
Administrator


Joined: Mon Sep 5th, 2016
Location: Long Beach CA
Posts: 202
Status: 
Offline
" 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




____________________

" We Got Places All Over The Place "

Back To Top

 Posted: Wed Jan 30th, 2019 05:57 pm
  PMQuoteReply
42nd Post
Tom Harbin
Registered
 

Joined: Sat Sep 1st, 2018
Location: Arizona USA
Posts: 112
Status: 
Offline
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


Back To Top

 Posted: Wed Jan 30th, 2019 06:31 pm
  PMQuoteReply
43rd Post
davecttr
Registered
 

Joined: Sat Nov 9th, 2013
Location: United Kingdom
Posts: 491
Status: 
Offline
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.




____________________
Dave
Back To Top

 Posted: Wed Jan 30th, 2019 07:24 pm
  PMQuoteReply
44th Post
Tom Harbin
Registered
 

Joined: Sat Sep 1st, 2018
Location: Arizona USA
Posts: 112
Status: 
Offline
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


Back To Top

 Posted: Wed Jan 30th, 2019 11:14 pm
  PMQuoteReply
45th Post
davecttr
Registered
 

Joined: Sat Nov 9th, 2013
Location: United Kingdom
Posts: 491
Status: 
Offline
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.




____________________
Dave
Back To Top

 Posted: Mon Jul 1st, 2019 02:46 am
  PMQuoteReply
46th Post
Hal Pridgen
Registered


Joined: Mon Jun 10th, 2019
Location: Aiken, South Carolina USA
Posts: 15
Status: 
Offline
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!




____________________
—-Hal

Superintendent
Crepe Myrtle Garden Railroad
Back To Top

 Posted: Mon Jul 1st, 2019 06:19 pm
  PMQuoteReply
47th Post
Andy R
Registered
 

Joined: Thu Apr 4th, 2019
Location: Malton, United Kingdom
Posts: 4
Status: 
Offline
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.




____________________
AndyR
Back To Top


 Current time is 04:42 am
Page:  First Page Previous Page  1  2  3  4  5   

Freerails > Model Railroad Forums > R.C. The Future Now If You Desire > Pros & Cons - 'DelTang' & 'S-Cab' Radio Control ?
Top



UltraBB 1.172 Copyright © 2007-2016 Data 1 Systems