Replacement Battery for Philips Sonicare Elite HX7500 Toothbrush, FDK NiMH, 2150 mAh

The battery arrived quickly and was well packaged and I'm sure it was a fine replacement, however it didn't work for me, to fix my Sonicare Elite. Follow the YouTube tutorials. Opening the housing wasn't nearly as difficult as I feared. I would strongly suggest desoldering braid to help remove the old battery's solder. A skillful and delicate touch with the soldering iron on the new battery's leads (and carefully trimming the leads to just above the surface of the circuit board) probably would've increased my chances of success. I was a residential electrician in a past life, and have soldered lots of low voltage project wires together in my day, but nothing as fine as what was required for this job. I suspect my lack of skill was the reason this didn't work for me. If you're confident with the soldering iron, it'll probably be a worthwhile endeavor.

Caveat: I'm a retired/still active electronics professional+hobbyist, with good tools for replacing parts in electronics. - - I have an old Sonicare "quad pacer" brush that I always liked. It died, wouldn't hold a charge, and based on Philips' claim that there wasn't any way to service it, I put it aside and bought an inexpensive replacement that wasn't as good. When I found instructions for opening the Sonicare, I got the replacement battery. The instructions are good, but I'll offer some additional hints. First off, mine, left unused and uncharged for, um, maybe a couple years, had some battery leakage on the circuit board that I needed to clean up. So instead of just trying to replace the battery without doing anything else, I unsoldered the whole board: from the charging coil pins on the bottom end and from the vibrating 'motor' on the top end, and from the battery. That let me take the whole board assembly out and thoroughly clean it with water and a brush. Once it was cleaned up, it was easy to put back in. I was able to put the battery into its plastic holder and then put the board over the battery's pins and the other pins all at once and solder everything back in. As I was doing it, I was thinking it was perhaps easier than trying to replace the battery without taking the board loose from the other pins. So if you're competent working with soldering on electronics boards, you have an option to the on-line instructions.Since replacing the battery a couple months ago, the brush has been working like it used to before the original battery died, and I'm glad to have it back "among the living."

UPDATE 4/16/15: Battery continues to charge normally and deliver 10-12 days of normal use. Still recommend this for anyone handy enough to disassemble and solder.UPDATE 6/14/14: after three recharge cycles, the LED indicator is in sync with the battery charge. Original battery lasted 4-5 days between charges. This battery lasts twice as long in my use of 2-3 times daily brushing with the Phillips Elite.ORIGINAL REVIEW:Battery shipped the same day as I ordered and arrived when promised. Battery fits perfectly in my Phillips Elite HX7500 handle.This is the Nickel Metal-Hydride (NiMH) version of the original Nickel Cadmium (NiCd) battery, which has higher storage capacity.The instructions on the seller's site are brief and complete: be sure to read them carefully. Their brevity may lead you to overlook key items.A few notes that may help you replace the old battery.The instructions tell you to pull and rock the threaded portion of the handle to slowly loosen it from the body. They also suggest you use a threaded collar piece from a used/old toothbrush assemble to help with grip and loosening. This makes removal of the electronics easier. Tighten the collar down as you loosen the center piece: this pulls the inner part out a small fraction of an inch at a time. Make small adjustments or you run the risk of breaking the collar.Note...it is NOT easy to remove the inner piece: it requires a strong grip...and patience. Resting between pulls helps removal since the seal has a chance to adjust to the pressure it is under as you remove the inner tube.When it is time to de-solder the battery connections, I suggest you have a second person available to pull lightly on the old battery . It is quicker to let someone pull the battery lead out when the solder is hot after an initial de-soldering. You can then take time to clean out the hole on the circuit board without the battery in the way with a wick or de-solder tool.The long leads on the battery make it easy to line up the holes on the circuit board and install it. Solder the leads, then trim off the excess. Pay attention to polarity: the positive pole is towards the center of the board.Use a grounded (3-prong plug) thin tip soldering iron which will reduce the possibility of damaging the integrated circuit on the board.The battery arrived with a note about some problems with the L.E.D. charge indicator on the handle after installing the new battery. They use the term "hysteresis" to explain, which basically means the charge indicator will slowly adjust over time with multiple discharge/charge cycles to be in sync with the actual charged state of the new battery. (The L.E.D. circuit has its own "memory")My unit demonstrated this behavior. Even though the L.E.D. display only lights to the middle, the battery is fully charged. After running it a few times, the L.E.D. goes dark, but the toothbrush continues to run.A new handle is $100 or more: this saves you a little over 80%....

This is the second time I've replaced the battery in my Sonicare electric toothbrush. The old battery wasn't holding much of a charge. The new battery lasts for at least 1 week and the brush is more powerful.Instructions on how to do it are on YouTube and you'll need to be handy with a soldering iron.

Too difficult for the average end user to swap out. I have extensive experience with soldering and the like and I couldn't get this battery in correctly much less get the old one out without trashing the unit. Wasted money.

Thwarts Sonicare's carefully planned product obsolesence!. Makes my electric toothbrush work like new. I'd forgetten what a vigorous brushing it could provide. The biggest challenge is getting the old battery out. You need to use a flat screwdriver to carefully pry on the battery while simultaneously melting the solder. Like many things, it's easy to after you've done it once. Look online for more instructions.Phillips could have made this a trivial thing to do, like replacing a battery in a flashlight; they chose not to.

Saved a ton of money by using this to replace the battery in my sonicare 7500 toothbrush. Well worth the money

Really difficult to replace the old battery and still have a working unit. Battery is probably fine but didn't work after installing it on the circuit board.