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So far, I have built 5 Nimh 2.4V battery packs using AA rechargeable batteries. It takes a lot of heat to solder wires to a battery, especially to the negative ends. Moreover, soldering wires to the batteries makes them too big for the battery holder, so I have had to modify those as well. Then I discovered that some of the MTH 2.V Nicd batteries have tabs that eliminate soldering to the battery case. So I just ordered a pack of ten of these Nimh batteries via Amazon. Also, these batteries should eliminate reworking the battery holder. I am not skilled in electronics, so I learn the hard way by trial and error, and by getting good advice from Gunnerjohn and GGG.           .1.2V Nimh AA w Tabs

DCS 3V Battery Arrangement

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  • 1.2V Nimh AA w Tabs
  • DCS 3V Battery Arrangement
Last edited by Bobby Ogage
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@Bobby Ogage posted:

Hi John,

What's even stranger, I have a draw full of caps:

50V 470umf; 35V 1000umf; 35V 22oumf; 35V 100uF; 2.5V 3.3F.

Will two 2.5V 3.3F connected in parallel work?

NO!  You need the 5V rating for the caps, that's why I use the flat 5V caps.

In order to use two caps like that, they have to be in series.  As long as they're from the same lot, you don't need any charging equalization, just connect them in series.

My limited understanding is that a battery is for a long term storage of a DC charge for a relatively long term discharge. In contrast, a capacitor is for a short term storage of a DC charge for a rapid discharge. If this notion is correct, then technologically, how does a capacitor replace a battery in a PS2 circuit?

The Kastar and Kruta AA and AAA packs work very well and hold their charge for a long time. They are available from Amazon singularly or in quantity.  I usually cut the end off the old battery and solder it to the new pack, observing the correct polarity. That, and the Tenergy low self discharge nimh 9v are installed in hundreds of locos I've serviced.

I buy in bulk as I use them in a couple of my electronic products.  I like the AVX and NESSCAP brands, they're real quality product with full datasheets available, something that many bargain supercaps lack.   I've used many of the "off" brand ones in the past, but I had some failures that soured me on bargain supercaps.  I've never had a bad AVX or NESSCAP supercap out of hundreds I've used, so I trust them more.

Bruce, I have over 30 Rail King steam engines, a few diesels and several trolley cars that have Nicd batteries. BCRs would cost me north of $700, so my least cost option is to make my own replacements using supercaps. I am now doing locomotives per hour.

Gunnerjohn, thanks again. Your help and expertise are very much appreciated on my railroad.

Gunnerjohn,

I am envious of your skills. It would take me many hours, perhaps a day or two, to make the amount of battery replacements you made. My drawful of 2.5V 3.3F Caps is dwindling, so I need to buy a bunch of the 5V 1.5F Caps to keep my battery replacement project going. I am finding that my motive power fleet has more 3V PS2 than 9V PS2 which is a good thing. So far, I found one 9V Nicd with corroded terminals.

I occasionally find corroded terminals on the 9V NiCad batteries, a couple times I had to replace the battery cable.

As for making the assemblies, I just line up all the parts and don them assembly line style.  Trim all the leads the same, then do one soldering step, and the next, etc.

Since I have pre-made cable assemblies, the 3V replacements go really quickly, just trim the cap leads, slide the heatshrink on the cable, solder them, and hit them with the heat gun.

The 9V ones take a little more time, but not bad.

Here is my score card to date. 95% of my motive power now has supercap battery replacements, BCRs, BCR2s, Nimh 9v rechargeable batteries and 2.4V rechargeable Nimh batteries. I made one flub-up so far by connecting the (+) of  a battery replacement pack of two 2.5V 3F caps to the (+)  of the circuit boards. So my Rail King GG1 makes sounds, it lights up, but it does not obey the DCS handheld controller. I changed the polarity so the cap (-) goes to the board (+). Is my GG1 fatally damaged?

5V board about 12V.  3V board about 5V.  That's for the charging circuit and would be what is technically called the open-circuit charging voltage.

If rechargeable batteries are connected the battery "technology" limits the voltage to ~8.4V or ~2.4V.  The 8.4V rechargeable battery is effectively 7x generic 1.2V batteries.  The 2.4V battery pack is 2x generic 1.2V batteries.

For caps, 5V versions based on four (4) stacked (in-series) 2.5V supercaps usually have some kind of voltage clamping technology (e.g., Zener diodes) to limit the voltage across the individual 2.5V caps...so in round numbers the voltage should not exceed 10V.  For the 3V versions based on one (1) 5V supercap, the voltage charges up to 5V.

" I made one flub-up so far by connecting the (+) of  a battery replacement pack of two 2.5V 3F caps to the (+)  of the circuit boards. So my Rail King GG1 makes sounds, it lights up, but it does not obey the DCS handheld controller. I changed the polarity so the cap (-) goes to the board (+). Is my GG1 fatally damaged? "





Since nobody else has answered ( I know zip about DCS )  I would try to attach a properly charged battery or supercap and do a reset to factory defaults ( 1 horn, 5 bells )   If it doesn't work with your DCS controller you may want to try it in standard AC.

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