Nuclear Battery Kit (Bring Your Own Tritium)

After we caught sight of some very cool folks online making their very own homemade nuclear batteries, we knew we had to give it a go!

The device in question is actually known as a "Radioisotope Photovoltaic Generator" or "Photobetavoltaic Generator," and it's a pretty clever design: Glowing glass pills filled with Tritium gas and coated in a phosphorescent material are sandwiched between two photovoltaic cells. The beta radiation emitted by the Tritium is blocked by the glass walls of the pill, but they cause the phosphorescent coating to glow. This light has no trouble passing through the glass and lands on the photovoltaic cells where it produces a small amount of electricity! Commercial Tritium batteries — like those produced by City Labs — cut out the middleman by using betavoltaic (as opposed to photovoltaic) cells in direct contact with Tritium gas. Those commercial devices are more rugged and efficient, but come with a very large price tag (thousands of USD per unit). On the other hand, homemade devices constructed using the packing tape sandwich method are as cheap as it gets, but aren't particularly rugged.

This kit provides a good compromise between price and quality of construction. We've designed carrier boards for both of the photovoltaic cells which we supply pre-soldered and fixed to the boards with chipbonder. We've also designed and cast custom silicone rubber grommets which cushion the Tritium vials between the two photovoltaic cells, preventing the cells from getting scratched or chipped and — most importantly — the vials from getting broken. The carrier boards also allow you to choose whether the photovoltaic cells are wired in series or parallel and provide you with breadboard compatible pin spacing for the battery terminals.

So how much power does it make? Not much. The best measurement we were able to make suggests that the maximum power point of this arrangement is 25nW, if you can build a circuit that loads it properly (between 20 and 30nA at about 0.6v). Further experiments show that the battery will — given enough time — charge a capacitor to a voltage of 1.5 volts. Using this battery to do any work will likely involve a clever energy harvesting circuit, but keep in mind that this tiny amount of power will continue to flow for about 20 years — the half life of Tritium being 12 years. It's also worth noting that these measurements were taken using green colored tritium tubes from aliexpress, your mileage may vary with the color and quality of your Tritium glow tubes. Feel free to experiment!

Because the silicone gasket supplied with this kit is not perfectly opaque, you will need to take any measurements in a light-proof enclosure (we made a little box out of copper foil tape) otherwise you will be getting inflated readings from ambient light striking the photovoltaics. You may also fill in the gaps around your gasket using an opaque epoxy resin. In practice, though, it may be beneficial to grab whatever "bonus energy" you can and only rely on the tritium vials when there's nothing else.

This Kit is B.Y.O.T (Bring Your Own Tritium)
Due to fairly predictable shipping and handling restrictions, we are — unfortunately — unable to provide you with the tritium glow vials that you will need to build a functioning battery. We _can_, however, send you in the right direction to acquire the vials on their own. This kit requires 10 pcs of [2x12mm Tritium Glow Vials](, which — as of the time this product was released — should set you back between 90 and 150 USD. You can find them at the link above and also via sites such as []( under the name "Tritium Vial" or "Betalight".
Experimental Product: SparkX products are rapidly produced to bring you the most cutting edge technology as it becomes available. These products are tested but come with no guarantees. Live technical support is not available for SparkX products. Head on over to our forum for support or to ask a question.
  • Top PCB with Amorphous Silicon PV Cell Attached
  • Bottom PCB with Amorphous Silicon PV Cell Attached
  • 2 x Silicone Rubber Gaskets
  • A Strip of Long Breakaway Headers

Nuclear Battery Kit (Bring Your Own Tritium) Product Help and Resources

Nuclear Battery Assembly Guide

June 8, 2018

How to put together your BYOT (Bring Your Own Tritium) Nuclear Battery Kit!


Looking for answers to technical questions?

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  • Member #394180 / about 6 years ago / 3

    Ooh! My very own $1.4 billion per watt radioactive battery!

    Come on, April Fool's was two months ago.

  • Member #1739876 / about a year ago / 1

    Hey sparkfun, could you offer these again?

  • Member #1656311 / about 3 years ago / 1

    Suggest checking radioactive element in smoke detector- Caution! Tampering with these can expose you to hazardous materials. Leave intact! A source of ionizing radiation which could produce small amounts of electricity. Advantage is that these devices are discarded.

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