FDK OEM NiMH Replacement Battery Compatible with Selected Oral-b Type 3731 or 3745 Toothbrush, with Narrow tabs (48L x 17D mm, 2700 mAh)

I bought two of these for our Braun electric toothbrushes, and so far I am happy with the results. It is no easy task to replace these, believe me, but there are some pretty good YouTube videos out there that got me through it. The batteries were the correct size, and the leads on the battery are the right width and in the correct spot for installation and attachment to the circuit board. This was also my first time soldering and de-soldering anything, but again, YouTube videos showed me the way. I recommend using a "solder sucker" rather than a de-soldering wick, as the former is much more effective when trying to remove the leads of the old battery. The batteries charged up and have been going strong and holding their charge for a good while now. The batteries are a good value for the money as they saved me from replacing 2 $150 toothbrushes that I like very much and have worked well.

8 month update: still going strong! Original Review: This battery is working perfectly for my Braun 4736, 2-speed toothbrush. After finding an online video of a guy showing how to remove the old and solder on a new battery, I was really pleased to find this available at Amazon. It turned out that the narrow tab on the negative side was skewed right of center and my model toothbrush needed it left of center. I simply put a z-fold into the tab, getting it to arrive skewed to the other side, also being careful not to break the spot welds. It's good that the supplier sends them with long tabs for trimming by the user. If one is able to make this repair (pretty delicate operation), then a small adjustment like this is not a big deal. The battery charged well and has been going strong for at least 6 weeks now. Ironically, my actual problem turned out to be my charger! So I ended up getting that too. Paying for something I didn't need was a little frustrating, but the repair was a good teaching moment for my son and me, and we felt some satisfaction when the toothbrush actually worked after the "operation".

After installing this new battery and charging it I found the motor would barely work. I found I had installed the spring backward. The spring end should contact the battery. After correcting this, everything worked fine.

I looked online for instructions on how to replace the battery in my five-year-old Braun Oral-B pro toothbrush. I bought this battery in hopes I could successfully take mine apart and replace the aging battery. The pre-shaped leads on this battery make it MUCH simpler to position the battery and solder it back into the circuit board. Everything works great, the toothbrush works like new, and my teeth are finally clean again. ;-) Way nice!

After installing this battery it went dead overnight and now it wont recharge. I think its better to just buy a new unit instead of trying to change the battery.

Other reviewers got it right--this is not a particularly easy job to execute. It is doable, but you may well find yourself better off by having someone who does the job routinely do it for you. Update: Only a couple months old and this battery doesn't hold a charge like it did when first replaced. Not sure why as it has not been "sitting on the charger" when not in use. In other words I'd let it "run down" before re-charging, and now the charge just doesn't last very well.

I received one of these batteries about a week ago and installed it and it seems to be working well. After 5 days I've only lost one "bar" of charge. But I'm giving this 4 stars because of the value. The battery was $20 with shipping. At this point, you have to wonder whether it's worth it from an economic standpoint to replace the battery (at least when paying $20). I happened to have a soldering iron and solder so the cost for me was really $20 but it would have been more if I had to buy an iron. Also, you can now buy a brand new Oral B "black" toothbrush for $40 from Amazon and this includes a new brush head. I will probably continue to try to replace the battery in the future from a "green" standpoint, but I will likely shop around for a less expensive battery.

My wife told me that her Oral-b Triumph toothbrush runs even stronger than new after I replaced its battery with the Sanyo Ni-MH 2150 battery, The hardest part of the repair was removing the upper blue, plastic retaining ring, which will then allow you to slide the internal workings out from the handle encasement. I recommend using a piece of plastic as a pry tool (I used a heavy gauge guitar pick), as a metal screwdriver can easily damage this retainer ring. Caution: keeping this retainer ring free from damage is crucial during reassembly in order to have the top of the toothbrush remain watertight. Good luck with your repair...