Replacing nicd AA batteries in Sonicare e5300 tooth brush (NiCd to NiMH?)

901-Memphis

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So i have a Sonicare e5300 toothbrush, and the manual states it has 2x NiCd AA batteries which are non replaceable but easily removed for recycling. I am wondering if its possible to replace them since it would be much cheaper than buying a new one.

The manual shows pictures of prying the device apart and it appears to destroy it by doing so. Maybe just wondering if anyone has done it before?

Also would the charger know the difference between NiCd or NiMH if i replace it with a higher capacity cell?
 

Steve K

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I've got a Rotadent brand electric toothbrush thing, equipped with a nicad battery. The battery eventually died, so I took a shot at replacing it.

Opening up the housing was more difficult than I expected, but I did get it accomplished with the use of a Dremel and cut-off wheel. The battery was soldered in. It was a bit smaller than a AA, but I was able to stick in a AA nimh by soldering to the terminals (not a nice thing to do to a cell, but....). Some JB Weld epoxy was sufficient to put the housing back together, and it worked!

The charger was designed to trickle charge nicads, and nimh cells aren't as tolerant of trickle charging. Limiting the charge time can help compensate for this. The battery has lasted for a few years, and is starting to fail.

At the same time that I replaced the nicad, I also ordered a new Rotadent. About the same time that the nimh in the old Rotadent started dying, the nicad in the new Rotadent was fading away. I replaced it with a proper tabbed nicad, and feel much better about it.

So..... I would suggest replacing the original nicads with new nicads, if only to make the recharging process less harmfull. Tabbed nicads are available, but will probably require going to a dedicated electronics or battery business. The charger is probably a simple transformer that has no regulation or charge termination. It won't care if you use a higher capacity cell.
 

Steve K

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That's a great Indestructables article! It has me wondering why there is a 100v cap in there... something to do with the coil at the top that actuates the toothbrush?? Can't imagine that any other part of the circuit could be above 3v or so.

It's surprising that so much desoldering is required to get the batteries out too. Not a huge problem, but certainly a nuisance.
 

JazJon

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Aug 12, 2013
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I've got a Rotadent brand electric toothbrush thing, equipped with a nicad battery. The battery eventually died, so I took a shot at replacing it.

Opening up the housing was more difficult than I expected, but I did get it accomplished with the use of a Dremel and cut-off wheel. The battery was soldered in. It was a bit smaller than a AA, but I was able to stick in a AA nimh by soldering to the terminals (not a nice thing to do to a cell, but....). Some JB Weld epoxy was sufficient to put the housing back together, and it worked!

The charger was designed to trickle charge nicads, and nimh cells aren't as tolerant of trickle charging. Limiting the charge time can help compensate for this. The battery has lasted for a few years, and is starting to fail.

At the same time that I replaced the nicad, I also ordered a new Rotadent. About the same time that the nimh in the old Rotadent started dying, the nicad in the new Rotadent was fading away. I replaced it with a proper tabbed nicad, and feel much better about it.

So..... I would suggest replacing the original nicads with new nicads, if only to make the recharging process less harmfull. Tabbed nicads are available, but will probably require going to a dedicated electronics or battery business. The charger is probably a simple transformer that has no regulation or charge termination. It won't care if you use a higher capacity cell.

Hey thanks for the details on your rota-dent adventures. I just opened mine up tonight and made a youtube video.

How to open & replace a Rotadent Electric Toothbrush battery. (Finally!) Part 1.
http://youtu.be/4LbrTO2rUFU

I'll follow up with Part 2 on which battery I ordered, and how easy/hard it was to de-solder/re-solder the wires. If you Google for 1.2v 1500mAh NiCd battery tabs sub-c you'll see a few for $5 that look like a match. I'll make sure it's a tabbed nicad as you said. I'll save $100 and make my electric tooth brush last another 10 years. (and actually hold a charge for a week again) I was recharging it every day for the 6 months just to get enough power to brush my teeth once. It finally died all together so I thought it couldn't hurt to bust it open. (and I did)
 
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Steve K

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Seeing the opening shot of the video showing a Rotadent, a chisel, and a hammer did raise my eyebrows a bit. :)
Once you know how they come apart, though, it really isn't too hard.

I hadn't considered finding a proper sub-C cell, and have been making do with a plain AA nicad. Seems to function okay, although I do limit the charging time.
All in all, replacing the cell is a fairly cost effective use of one's time, and it does reduce the amount of plastic going to the landfill.
 

JazJon

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Joined
Aug 12, 2013
Messages
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Seeing the opening shot of the video showing a Rotadent, a chisel, and a hammer did raise my eyebrows a bit. :)
Once you know how they come apart, though, it really isn't too hard.

I hadn't considered finding a proper sub-C cell, and have been making do with a plain AA nicad. Seems to function okay, although I do limit the charging time.
All in all, replacing the cell is a fairly cost effective use of one's time, and it does reduce the amount of plastic going to the landfill.

My new sub-c battery(s) arrived today from eBay (seller name = radioshack)

I made another video. It's the complete process of opening and replacing the battery. (desolder/solder etc)



Hopefully this helps someone else save $100
 
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