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 change 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 show you step by step how to do it, what pitfalls there are, and how to get the light meter running reliably again.

Why an adapter and why Type 675?

The Rollei 35 models were originally designed for PX625 mercury batteries. These had a very constant voltage over their lifetime – an advantage for analog light meters. Today, mercury cells are banned. Hearing aid batteries of type 675 (mostly zinc-air) offer a similar voltage and discharge curve and are therefore 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 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) to unscrew the battery cap

• Q-tip / cotton swab and contact cleaner

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

Step-by-step: change battery

1. Open 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, screwed-in battery chamber.

1. Remove battery cap

The small cap of the battery chamber capsule is unscrewed counterclockwise. You can use a 10-cent coin or a small tool. The cap falls out, then the chamber is open.

1. Remove old battery & check contacts

Take out the old cell. Look at the two contacts: one fixed, one spring-loaded. For used cameras, it is advisable to clean the contacts.

1. Contact cleaning

If the contacts are oxidized or dirty, clean them carefully: gently scrape with a screwdriver, some contact cleaner on a cotton swab. Slightly spread the spring contacts so they later apply firm pressure on the battery.

1. Adjust spring contact

Modern replacement batteries are often a bit thinner. Slightly bend the small spring outward so it securely contacts the battery later.

1. Prepare 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: on the Rollei, the plus side of the battery points down (toward the camera bottom). Insert the battery with the rubber ring into the chamber, put the cap on, and screw it back tight.

1. Test

Close the camera and check the light meter. If necessary, check the contacts again or that 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 react immediately? Not always. They need air contact, so it can take a few minutes until they deliver full voltage. Some cells only provide full measurement after a short time.

• Can I cause damage? With the low voltage and capacity of the batteries, damage to the camera is very unlikely. Still: leaking old batteries can cause corrosion – remove old cells and clean the chamber.

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

• How long do the batteries last? Usually several months to years, depending on usage and model. Rollei light meters can discharge faster if the meter is constantly activated – covering or removing the battery during longer 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 contacts, slightly bend the spring, observe polarity (plus side down).

• Zinc-air batteries sometimes need air contact, so a few minutes until full power.

If you have questions or are unsure which battery or adapter fits your model best: write to us or search the shop for Rollei products. With that said — good light and lots of fun with your Rollei! Your team from Ausgeknipst