V74PX Battery: Compatible Cameras

The V74PX is a 15-volt alkaline stack battery in a slim cylindrical format (roughly 34.9 × 15.1 mm), made by Varta from the 1960s onwards. The “V” stands for Varta, while the “PX” suffix was adopted by Varta as a generic photo designation. Common equivalents are the 504, MN154, BLR154 and 10LR54. Unlike the mercury-based PX625, the V74PX never contained mercury: it was alkaline from the start, which was perfectly adequate for its typical uses (flash units, trigger electronics).

The V74PX mainly powered flash units and the odd light meter from the 1960s and 70s. Typical examples from the compatibility list above:

• Flash units: Nikon BC-7 flash, Minox BC flash ‘A’ and ‘B’, Minox flash for AG-1, Rollei 16S flash, Yashica Flash-O-Set (I/II), Fuji/Fujica Rapid SF Flash
• Light meters: Gossen Sixtron
• Compact cameras: Voigtländer Vitoret F, Yashica E

Outside the photo world, the V74PX also turns up in the Feinwerkbau LP90 air pistol. That’s why you’ll often see people searching online for an “LP90 battery”, even though LP90 is strictly speaking a pistol model, not a battery name.

Varta stopped making the V74PX years ago. Original Varta cells only surface as pricey leftover stock on eBay or at specialist dealers, and that stock has often sat on the shelf far too long. Fresh cells in this format are practically no longer produced industrially. A few third-party makers such as Exell still offer a functionally equivalent cell, the 504A, but it’s awkward to get hold of in Germany. For most collectors, an adapter using standard button cells is therefore the more practical route.

Because the V74PX is made up internally of ten stacked 1.5 V cells, it can be recreated cleanly with an adapter:

• Ausgeknipst V74PX adapter with 10× AG10 (LR54): An engineering-plastic housing with the exact dimensions of the original V74PX, filled with ten standard AG10 button cells, delivering exactly 15 V. AG10 cells (also sold as LR54, 189, 389A) are cheap and available everywhere: no Wein cell hassle, no zinc-air expiry clock. Available from us as the V74PX adapter incl. 10× AG10.
• Exell 504A or NOS Varta V74PX: A 1:1 drop-in, no adapter needed. Pro: pop it in and you’re done. Con: high price per cell, availability varies wildly, and old stock may already be half drained when you pick it up.
• DIY with heat-shrink tubing + 10× LR54: Works in principle, but it’s fiddly and mechanically unreliable. The stack shifts around in the battery compartment and the contacts oxidise faster. Only worth it as a tinkerer’s solution.

No, and that’s the key difference from the PX625 debate. With the PX625, the meter reading depends directly on the voltage, which is why the steady 1.35 V output of the mercury cell mattered so much. V74PX devices are different: flash units only need the 15 V to charge a capacitor. Whether the battery delivers 15.5 V when fresh or 13 V towards the end of its life only changes the recycle time, not whether the flash works. The trigger electronics of the Feinwerkbau LP90 also tolerate a wide voltage range.

The one exception is the Gossen Sixtron, a true light meter where a voltage drop could in theory affect the reading. In practice, though, the effect is small, because the Sixtron was built around a simple galvanometer circuit rather than a mercury-cell reference. A fresh alkaline V74PX is all you need here; if you want more precision, calibrate the meter against a modern spot meter.