Do Mercury Free Watch Batteries Leak?

[HK1]

Hi folks, I am looking at buying a watch which has never been used however it's battery needs to be replaced. My concern is if I buy it and find the battery is leaked I will have to buy a new movement for it probably. The watch has a sticker that says mercury free, does this decreases the risk of having a leaked battery? Thanks

[HectorLooi]

There is always a chance that the battery can leak.

If the seller is not willing to open the watch and show the insides or if the seller is not willing to fit in a new battery and test it, walk away. 

Unless the price is significantly less than a new movement and the service charge to replace the movement. 

[HK1]

Thanks HectorLooi

[JohnR725]

2 hours ago, HK1 said:

mercury free, does this decreases the risk of having a leaked battery? Thanks

wishful thinking if you think Mercury free batteries don't leak. In other words typically silver cells although somebody could stick a hearing aid battery in which would not be desirable. Sooner or later if you leave the battery in the watch there is the likelihood that it can leak. It depends on who made the battery when it was made in probably a whole bunch of other factors. But eventually when the battery gets through consuming its internal components if it still has enough whatever it can eat right through the case and then you get corrosion all over everything. Typically the batteries are very alkaline I believe sodium or potassium hydroxide and they really quite destructive. Which is why if you have a battery-powered watch in not using it for an extended period of time it's usually best to remove the battery to prevent damage.

[HectorLooi]

Renata claim that their batteries have a better seal and do not leak. On another forum, members say that Energizer batteries are better than Renata.

But from my personal experience, both these brands leak.

Some claim that the ones that leak are fakes from China.

Renata has a factory in China.

Sooo.... I'll let you make up your mind.

[mikepilk]

I used Renata, but according to the following article, they don't do well for leak resistance. I now use Energiser.

https://www.great-british-watch.co.uk/how-to-spot-and-deal-with-watch-battery-leaks/

"A combined survey was undertaken to assess the issue of watch battery leaks. The outcome of the survey comes from the evaluation of over 3000 watches where the battery had expired. The results derive from a mix of sources from both North America and Europe including independent watch repair centres, official branded workshops and solo enterprises. The variety of watches tested covers the full-range of prices and brands that occupy the majority of the market segments."

Battery Leak Resistance