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Waterproof charging input? Answered

Hello everyone,

I'm new to electronics and while I can usually find what I need by asking good ole' Google, I decided to try asking a forum of people more knowledgeable on the subject. My question relates to the charger input on devices with internal batteries. I have a Braun razor that can be used in the shower, and I was curious how it can go in water with the two charging prongs exposed?

Thanks in advance! 


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9 years ago

There are two problems with the exposed prongs:

1) Water might creep in the device between the prongs and the housing. This is most probably addressed by a kind of rubber/silicone/whatever seal

2) Electrolysis at the prongs when they are shorted by water. This can easily be addressed by not exposing any voltage at the prongs. The prongs are not connected directly to the battery but the will be a diode (or - as I know the Braun engineers from my job - a sophisticated charger circuit) that allows current to flow into the device but not out. No current flowing - no electrolysis.

Do those under-the-shower razors really have prongs? I expected them to be charged inductively.


Reply 9 years ago

Thanks for the response Verence. For some reason the instructables web pages take forever to load on my computer and when I tried to reply 3 days ago, it didn't post. Hopefully it will this time.

That makes sense. I guess many charger inputs have diodes, which is why we don't get shocked by them if we touch them.

So basically if I have a rechargeble battery that I wanted to put in a waterproof container, I'd just have to ensure that the container is completely sealed especially around the charger input? I was thinking of canabalizing the Braun razor (and yes there are two prongs) and using its charger input since it's designed to be watertight around the prongs, and then using silicone sealent around the gap between the container hole and the input assembly.