Rollei 35 / 35S / 35T: Changing the Battery (PX625 → Type 675 with Adapter)

Many Rollei 35 owners eventually face the same question: Which battery belongs in the small camera, and how do you replace it correctly? The original PX625 mercury cells are no longer available. Fortunately, the old batteries can be reliably replaced with Type 675 (hearing aid batteries) combined with a small rubber ring adapter. In this guide, I'll show you step by step how to do it, what pitfalls to watch out for, and how to get the light meter working reliably again.

Still not sure which model you have or which Rollei 35 is the best? Our Rollei 35 model comparison categorizes all models (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 for PX625 mercury batteries. These provided a very constant voltage throughout their service life, which was an advantage for analogue light meters. Mercury cells are now banned. Type 675 hearing aid batteries (usually zinc-air) offer a similar voltage and discharge curve, making them the best modern alternative. Problem: Type 675 cells are slightly smaller than the old cells. Therefore, you need either a simple rubber ring adapter (ideal for the Rollei 35) or a specially designed adapter for other camera models.

What you need

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

• Rubber ring adapter for PX625/Type 675 (small O-ring)

• 10-cent coin (or a suitable tool) for unscrewing the battery cap

• Q-tip / cotton swab and contact cleaner

• Small screwdriver (for carefully roughening / straightening the contacts)

Step by step: Changing the battery

1. Open the camera

Open the back of the Rollei 35 and slide out the film holder. The battery is not in the film area itself but in a separate, screw-in battery compartment.

1. Remove the battery cap

The small cap of the battery compartment is unscrewed counterclockwise. You can use a 10-cent coin or a small tool. The cap comes off, leaving the compartment open.

1. Remove the old battery & check the contacts

Remove the old cell. Look at the two contacts: one fixed and one spring-loaded. With used cameras, it is advisable to clean the contacts.

1. Clean the contacts

If the contacts are oxidized or dirty, clean them carefully: lightly scrape them with a screwdriver and apply a little contact cleaner with a cotton swab. Pull the spring contacts apart very slightly so they will exert firm pressure on the battery later.

1. Adjust the spring contact

Modern replacement batteries are often slightly thinner. Bend the small spring slightly outward so it will make secure contact with the battery later.

1. Prepare the battery

Insert the Type 675 battery into the rubber ring adapter. Note: zinc-air batteries react with air; they have small openings and sometimes need a few minutes to deliver their full power.

1. Insert correctly

Polarity is important: in the Rollei, the positive side of the battery faces downward (toward the camera base). Insert the battery with the rubber ring into the compartment, put the cap on, and screw it back on tightly.

1. Testing

Close the camera and check the light meter. If necessary, check the contacts again or make sure the rubber ring is seated correctly. In my test, the light meter works immediately after insertion.

Useful tips & frequently asked questions

• Do zinc-air batteries respond immediately? Not always. They need exposure to air, so it may take a few minutes before they deliver their full voltage. Some cells only provide full metering after a short time.

• Can I cause damage? With the low voltage and capacity of these batteries, damage to the camera is very unlikely. Nevertheless, leaking old batteries can cause corrosion, so remove old cells and clean the compartment.

• Why not silver oxide or alkaline? Silver oxide has a different discharge curve; some camera light meters may therefore measure incorrectly. Zinc-air (Type 675) comes closest to the old mercury curve.

• How long do the batteries last? Usually several months to years, depending on use and model. Rollei light meters can discharge faster when the meter is constantly activated; covering the meter or removing the battery during extended storage is advisable.

In brief

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

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

• Check and clean the contacts, gently bend the spring back into shape, and observe the polarity (positive side facing down).

• Zinc-air batteries sometimes need exposure to air, so it may take a few minutes to reach full performance.

If you have questions or are unsure which battery or adapter is best for your model: write to us or search the shop for Rollei products. With that in mind, happy shooting and enjoy your Rollei! Your team at Ausgeknipst