# Roll Your Own Battery Replacement using Super Capacitors



## gunrunnerjohn (Nov 10, 2010)

A popular option nowadays is to replace the rechargeable batteries in MTH locomotives with a super capacitor replacement. I've compiled a short post on how to do your own. I hope this will be of some use to folks considering this option.

Also included is a circuit that will allow you to put a supercap into your Lionel train to support the RailSounds during track power interrupts or when running in conventional mode. This circuit is powered from track power and keeps the supercap charged to be ready for when it's called on.

* 9V Battery Replacement*

9V battery replacement component list (from Digikey).

1N5223B 2.7 Volt Zener Diode

JUMT1335MPD 3.3F 2.7 Volt SuperCap

9V, Snap Connector with Leads

Here's the component reference pictures for the 9V battery replacement.

























Wire capacitors in series and placed a 1N5223B across each one, band end towards capacitor +. Connect the 9V snap connector red wire to negative and black wire to capacitor positive. The reversal is necessary because we are reversing the role of the battery connection cable from the equipment to the battery, thus the male and female contacts reverse their role. Cover with 1.0" heat shrink tubing and done.

Here's the finished 9V battery replacement before covering with heatshrink.











*2.4 (3V) Battery Replacement*

The 2.4 (3V) version is much simpler, it consists of an off-the-shelf SuperCap and the matching connector for the MTH board.

2.4 (3V) battery replacement component list (from Digikey).

EMHSR-0002C5-005R0 2.5F 5.4V SuperCap

CONN SOCKET 24-30AWG TIN 1735801-1

CONN RCPT HOUSING 2POS 2.0MM 440129-2

















Here's the finished 2.4v (3.0V) battery replacement.










*Charging Circuit for Lionel Use*

Here's an optional circuit for the 9V battery replacement that can be added to use the 9V unit in Lionel locomotives for RailSounds battery backup. This circuit will keep the supercap array charged whenever there is sufficient track voltage, typically around 8-9 volts.


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## WildcatRR (Jul 28, 2013)

*9v replacement*

Way to go John. I've been wanting to replace the MTH batteries in my fleet for years. Thanks for your hard work and time to help make it possible.


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## gunrunnerjohn (Nov 10, 2010)

No problem, I'll send you the bill later.


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## Lee Willis (Jan 1, 2014)

These are very useful. They are easy to make and substitute nicely.


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## Patrick1544 (Apr 27, 2013)

John,
Great stuff. Thanks for sharing. Can the 9v cap pack be used in K Line engines, equipped with Lionel rail sounds and the 9v battery clip in their engines?


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## gunrunnerjohn (Nov 10, 2010)

Sure, the 9V battery substitute with the power supply will work for any 9V battery system. The K-Line, Atlas, Weaver, 3rd Rail, etc. all use Lionel RailSounds, so it's the same electronics.

I build one of those power modules on a breadboard for testing, I may lay out a little board at some point for it.


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## sjm9911 (Dec 20, 2012)

I think you posted something similar before? Anyways, cool stuff even though I don't have a use for it now hell, I don't even understand it good job regardless, it will help someone!


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## teledoc (Oct 22, 2014)

When I saw "roll yor own", I waited to see a reference to ZIGZAG paper, then realized wrong rolling!!!! ROFL.....

Really it is a great tip, and will most likely be used by a few Who could use it. 
Way to go GRJ, with another great tip.


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## Patrick1544 (Apr 27, 2013)

John?
What is the part number and value for the Bridge Rect, and end of line Diode (+ side), as well as the component across the output lines for the charging circuit above?


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## gunrunnerjohn (Nov 10, 2010)

The bridge is a standard 1A bridge rectifier. I have a bunch of them I bought on eBay, so I don't have a usable part number.

The two capacitors are a 100uf at 50V and a 0.1uf at 50V, and the diode is a standard silicon diode, like a 1N4003.


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## Patrick1544 (Apr 27, 2013)

Thanks so much, John.


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## Lynn D Bennett (Jul 27, 2013)

Gunrunnerjohn:

1.5, 5, 7 *FARADS*? At that small size and even at 2.7 volts? What are these beauties made of? MicroFarad capacitors (1 x 10 to the minus 6) are huge by comparison????

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

The large capacitors are the so-called supercap or ultracapacitor. They used to be called electric double-layer capacitor.

Here's a page on the Supercapacitor, take a look.


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