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Discussion Starter · #1 ·
Does anyone use constant track power to charge the batteries?



Could someone connect USAT sliders to a reverse loop detector (to insure consistent polarity) that would feed a battery charger that would charge an on board battery to the decoder/motor in the engine?

Seems a better way to run trains than to (a) worry about feeding track power throughout a large layout and (b) charging batteries without an external charger on or off the layout.

You could just pull into a station track or service track and the batteries would be charged while you wait.

Dave
 

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Discussion Starter · #4 ·
Right!

As I'm going to be doing further experiments with AirWire down the road I had to ask myself why would I need to remove engines to charge when there is sufficient charge current already on my 'track power' layout?

The advantages of AirWire and but with no recharging unit. The reverse loop detector will always assure that the charger gets the same polarity even when that track polarity changes. I think anyway. :rolleyes:

Dave
 

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Discussion Starter · #7 ·
Posted By craigcoffman on 06/05/2008 4:33 PM
I did this at one point. I was already running fixed polarity fixed voltage on the track (24.5) volts. This made it easy to trickle charge a 19.2V battery pack with a 1 ohm resistor figuring in losses for the needed bridge rectifier between the track & the batter pack. But you also need a diode in parallell with the resistor for the electrons to flow thru when running off of battery power (as opposed to the resistor), so that drops your effective voltage from the pack enough so that you do notice when dirty track causes the failover to battery power.



Very good points. I printed it off and stuck it in my 'notes' for sometime in the fall/winter. I appreciate your experience with this idea.



Also, at a trickle charge, the batteries rarely get a chance to fully re-charge, unless you leave the loco on a powered siding overnight, meaning they will eventually run down & require taking out, or taking the loco inside to charge, depending on how you have it setup.



Being inside already it may actually be of some use. We'll see what develops with this..


So in the end, it ends up being more work for less satisfaction that just going battery, IMHO.




You could be right.
 

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Discussion Starter · #8 ·
Posted By TonyWalsham on 06/05/2008 4:34 PM
Good luck in your quest.

If and when when you can get a system working that will cater for all types of battery chemistry, all voltages and is reasonably priced, please let us know.






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I can see that happening.

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Discussion Starter · #11 ·
Posted By K27_463 on 06/05/2008 11:18 PM
AS Greg alluded to , there is a problem with charging while rolling. When a battery goes on a charger, the charge cycle does not start instantly. There is a reaction delay(chemical/molecular) that takes place first. Charging commences at some finite point after voltage is applied to the cells. The interval is small but present none the less. Charging while rolling would present enough intermittent contact -unless you had PERFECTLY CLEAN rails- that the actual charge cycle would always lag the input such that it is unlikely any significant charge could result. Rolling wheel contacts are really very poor contacts. Direct dc motor drive works because the motors have inertia and the available power levels are high to drive the armature easily. (why track power locos stall at slow speed often) but the actual contact is very inconsistent.
Now, charging from rails while stationary is certainly commonly done , but rolling will really never get much charge into the battery pack., plus you will never know the actual state of charge in your packs, since charging is intermittent, and as Greg said, any processor based charge will constantly reset.
Jonathan/EMW




Very interesting points and most informative. You have probably pointed out the only real reason we don't see more of this.

Thanks.

Dave
 
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