View single post by Tom Harbin
 Posted: Wed Jan 30th, 2019 05:57 pm
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Tom Harbin

 

Joined: Sat Sep 1st, 2018
Location: Arizona USA
Posts: 152
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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


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