View single post by davecttr
 Posted: Mon Dec 24th, 2018 10:15 am
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davecttr

 

Joined: Sat Nov 9th, 2013
Location: United Kingdom
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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.




____________________
Dave
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