Sonicare Elite 7300 - Battery Replacement

Step 5 Battery In

Get your 4/5A cell the OEM was NiCd but I used NiMH which should have longer life.
Scratch up the positive and negative terminals of the battery with a hobby knife so that way solder will stick to it. Use a low watt soldering iron (you do not want to apply too much heat to the battery) to solder the correct wires to the positive and negative terminals. Stuff the battery back in the compartment and tuck the wires in so we can reassemble.

Comments

[rakudrama]

 Batteries are available with circuit board pins - check out the Terminal Style drop-down at
http://store.batteryspecialists.com/kr1500aul.html

Does anyone here find it outrageous how close this design is to one that lets you easily change the battery?

The only reason I am looking at this is that I just bought a 4-pack of heads.  My dentist says the newer (FlexCare?) brush does a noticably better job.  (I trust my dentist - all the latest gadgets to support but one filling in 10 years.)
There is a review here: http://gadgets.boingboing.net/2007/11/08/sonicare-flexcare-re.html
The review says it is 77% more efficient. Has anyone does an analysis (e.g. Kill-a-watt) to see what it costs to run a toothbrush?

[tgone]

My board was a little different from the one in the pictures.
I picked up a 4/5A from batteries plus and it was too long to fit into the orig slot. had to modify the plastic and relocate the crystal. its a good thing I've got a talented EE to help me out when i get into trouble, this wasn't something I would have been capable of on my own.
Also, he warned about soldering on the battery terminals and seemed convinced that the battery with pre"welded" posts would be available online. from his info, welding is much hotter, but also much quicker and soldering changes the battery so the outcome is not gauranteed. So, make sure you take a look around to find the right one dimensionally (it'll save you A LOT of time and effort).

[chuckk]

My wife's Sonicare finally reached the point where it had to be charged every day and she allowed me to crack it open for the battery replacement described above. Finding the correct battery was a little tricky. The description of 4/5A cell was enough to find a cell online. However I wanted to do the project in a single day and went to a local "Batteries+" store in the Chicago area. I expected the worst with a name like Batteries+, but was surprised to find them knowledgeable and able to find a match. I bought a 1200mAh NiCad as it was all they had in a matching size in 1.2V. The store tech also spot-soldered a couple of prongs onto the battery. The de-soldering is difficult if you're new to it. Just be patient. The connection on the outside end, the negative, is easier to de-solder. If you use some pressure on the soldering tip to push the pin through the board it is easier than trying to pull all the solder out. The positive connection,up by the LEDs is more difficult. I puled the battery halfway out and intentionally broke the leads off the battery in oder to get the battery removed before trying to de-solder this point. Once the battery was out I just used pressure on the tip to push the pin through the board. Once the battery leads are out of the board it is much easier to clean up the remaining solder on the board with copper braid.

[fewolf]

How do I find he replacement battery.. I looked at Tenergy and couldn't find a match is it "sub C" ? thanks

[appsman]

I disagree with using a low watt iron. A low heat iron means you have to stay on the battery terminals longer and will cause more damage. It's better to get a fairly high heat iron (like 40W or more) and make the solder connection quickly. That will do the least damage.

[jayfriday]

Has this battery continued to work and take a charge? I replaced my Nicd with a Nimh and it's behaving strangely...not charging fully, discharging quickly etc.