Rollei 35 / 35S / 35T: How to Change the Battery (PX625 → 675 with Adapter)

Sooner or later, many Rollei 35 owners run into the same question: which battery does this little camera take, and how do you change it properly? The original PX625 mercury cells are no longer available. Fortunately, there’s a reliable replacement: 675 hearing aid batteries combined with a small rubber O-ring adapter. In this guide I’ll walk you through it step by step, point out the pitfalls, and show you how to get the light meter working reliably again.

Not sure which model you have, or which Rollei 35 is best? Our Rollei 35 model comparison breaks down every version (35, 35S, 35T, SE, TE, B) by lens, light meter and price.

Why an adapter, and why type 675?

The Rollei 35 models were originally designed to run on PX625 mercury batteries. These held a very steady voltage throughout their life, which was a real advantage for analogue light meters. Mercury cells are banned today. Type 675 hearing aid batteries (usually zinc-air) offer a similar voltage and discharge curve, which makes them the best modern alternative. The catch: 675 cells are slightly smaller than the old ones. So you’ll need either a simple rubber O-ring adapter (ideal for the Rollei 35) or a purpose-built adapter for other camera models. Our PX625 guide compares the other options, such as an MR9 adapter with a silver oxide cell or the rechargeable Varta V80H, and what each of them costs over three years.

What you’ll need

• Type 675 hearing aid battery (zinc-air is ideal)

• Rubber ring adapter for PX625/type 675: an 11 × 15 × 2 mm O-ring (11 mm inside, 15 mm outside diameter) from the hardware store

• A 10-cent coin (or a suitable tool) to unscrew the battery cap

• Cotton bud (Q-tip) and contact cleaner

• Small screwdriver (for gently roughening up or straightening the contacts)

Our solution for the Rollei 35, 35S and 35T: Instead of a hardware-store O-ring, you can use our PX625 adapter, which brings a 675 cell up to the size of the old PX625. The set costs €22.95 and includes two adapters and six cells, so there’s nothing else to buy. Place the cell with its flat positive side on the cross in the base of the adapter, then insert it as described in step 7.

Disclaimer: We sell some of the products mentioned here. Even so, this article is meant first and foremost as a helpful guide, not as a sales pitch.

Step by step: changing the battery

1. Open the camera

Open the back of the Rollei 35 and slide out the film carrier. The battery isn’t in the film compartment itself but in a separate, screw-in battery chamber.

2. Remove the battery cap

The small cap on the battery chamber unscrews anticlockwise. You can use a 10-cent coin or a small tool. Once the cap drops out, the chamber is open.

3. Remove the old battery & check the contacts

Take out the old cell. Have a look at the two contacts: one fixed, one sprung. On a used camera, it’s a good idea to clean the contacts.

4. Cleaning the contacts

If the contacts are oxidised or dirty, clean them carefully: scrape them lightly with a screwdriver, then apply a little contact cleaner with a cotton bud. Gently pull the spring contacts apart just a touch so they’ll press firmly against the battery later.

5. Adjust the spring contact

Modern replacement batteries are often slightly thinner. Bend the small spring outwards a little so it makes reliable contact with the battery.

6. Prepare the battery

First, peel the sticker off the 675 cell. Only then can air reach the cell; with the sticker on, it won’t deliver any power. Then fit the cell into the rubber ring adapter. Once the sticker is off, zinc-air cells sometimes need a few minutes to reach full power.

7. Insert it the right way round

Polarity matters: on the Rollei, the plus side of the battery faces down (towards the bottom of the camera). Drop the battery with its rubber ring into the compartment, put the cap back on and screw it down tight.

8. Test it

Close the camera and check the light meter. If needed, check the contacts again or whether the rubber ring is seated properly. In my test, the meter worked as soon as the battery was in.

Useful tips & FAQs

• Do zinc-air batteries work straight away? Not always. They need contact with air, so it can take a few minutes before they deliver their full voltage. Some cells only give a full meter reading after a short while.

• Can I damage anything? Given the low voltage and capacity of these batteries, damage to the camera is very unlikely. That said, old batteries can leak and cause corrosion, so take out old cells and clean the compartment.

• Why not silver oxide or alkaline? Silver oxide has a different discharge curve, which can cause some camera light meters to read incorrectly. Zinc-air (type 675) comes closest to the old mercury curve.

• How long do the batteries last? A type 675 zinc-air cell usually lasts 2 to 3 months in the camera, counted from the moment you peel off the sticker, even if you’re not shooting. Heat and very dry or very humid air cut that down to a few weeks. If the camera is going to sit unused for a while, take the cell out.

Quick summary

• Rollei 35 / 35S / 35T: the PX625 (mercury) is obsolete and no longer available.

• Use 675 hearing aid batteries with a small rubber ring adapter as a replacement.

• Check and clean the contacts, give the spring a slight bend, and mind the polarity (plus side down).

• Zinc-air batteries sometimes need contact with air, so allow a few minutes for them to reach full power.

Further reading

If you’d like to check for yourself, here’s the original manual and a repair shop that takes a different view of zinc-air than we do.

• Rollei 35, 35 T and 35 S instruction manual (butkus.org), the original instructions for changing the battery, also available in German
• Classic Fototechnik, Braunschweig, a Rollei repair shop that recalibrates cameras for 1.5 V batteries and considers zinc-air unsuitable

If you have any questions or aren’t sure which battery or adapter suits your model best, just drop us a line or search the shop for Rollei products. Until then, good light and lots of fun with your Rollei! Your Ausgeknipst team

You’ll find accessories and spare parts for the Rollei 35 gathered together on a single page. Go to Rollei 35 accessories.