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This will show you how to replace the internal battery on your Sonicare Elite 7300. After having my 2nd one die on me within 3 yrs I figured out how to rip it apart and fix it.
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Signing UpStep 1Disassembly
The first part of disassembling the elite 7300 is removing the small trapezoidal rubber bumper at the top back of the unit. This piece has two small clips which holds the internal components inside of the casing. Next, slide the main screw ring (upper left) off of a brush head. Twist the screw ring down onto the handle all the way and pull the internal components straight out.
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I used the wire clipper in the image below to extract the battery (leaving the battery tabs soldered in for possible use with the new battery)...
Vibrations may cause brief disconnection from these tabs if the new battery isn't soldered to these tabs...
1) The bottom of the charger stand has a three-part illustration of how to disassemble the unit. It was difficult to remove the side key. It broke, but it's not an essential part. Discard it. I used an OLD brush head collar, in case I cracked it (I didn't). I found that by tightening it down, and then rocking it slightly from side to side, using some leverage action would extract the core about a half millimeter. Then tighten again and repeat the rocking action until you've pulled the core.
2) For safety reasons, locate the solder bridge labeled "JP1" near the charging coil at the battery "-" end and remove it. Use solder wick or a solder sucker. This now isolates the battery from the circuit in case you short something out. (On reassembly remember to re-solder this jumper as your LAST connection.)
3) I chose to remove the entire printed circuit board. I show the pictures here for those interested. When desoldering the Battery "+" it was helpful to remove the plastic LED lens so I didn't melt it. There is a three part plastic chassis inside. One for the drive coil, one for the charge coil, and one for the circuit board and battery. However, it appears that Philips has glued these together during assembly.
4) I located a replacement battery online for only $1.50, however, like everything on the Internet, the Shipping and Handling was too expensive ($8). Online, Batteries Plus had the battery for $4 (and an extra 25-cents for solder tabs). However, in the actual store they wanted $7.50 and $1 extra for EACH solder tab. Sorry, that's a rip-off.
5) In the end I realized that the cavity for the 4/5 A-cell would easily accommodate a single AAA-cell NiMH rechargeable. I choose a 900 mAH battery. (Others are in the range of 800 ~ 1000 mAH.) Scrap or sand the terminal ends, and solder a spare lead to each end. Use a hot iron and do it quickly to avoid damaging the cell or forcing it to internally vent. Be careful inserting the leads to the circuit board as the battery could damage the circuit if you touch the wrong contacts. It helps to have extra long leads to guide them in, then trim them off after you've soldered them.
6) So far the AAA-cell is working well. If I later see problems I will replace it with a AA-cell (AAA -> AA), as the AA-cell is closer in capacity to the original 4/5 A-Cell. However to accommodate the longer AA-cell I'd need to remove some of the plastic chassis. For the time being I'm sticking with the AAA-cell. The charging characteristics of the NiMH are nearly identical to NiCd.
7) I had also considered using a battery holder inside, however, I suspect the contacts would be more trouble than they are worth. There is nice AA-cell holder available from Radio Shack for $1. That would be useful for those that don't have access to a soldering iron a year or two from now, in case the battery needs replacement again.
8) To reassemble, I used a small amount of KY-gel to lubricate the rubber O-ring and seat. I had some Teflon gel available, but decided the KY-gel being water based would be more compatible with the rubber O-ring since Philips obviously expected this to be a water environment. The KY-gel makes it a lot easier to pull the core again should the need arise.
9) I was surprised how clean the inside was. The tube and o-ring design is much better than the split shell design used in other Sonicare brushes. I only wish that Philips had used a AA-cell.
Yes, you have to remove the little rubber clip at the top that keeps it from rolling around on the table before attempting to 'pull' the innards out.
Secondly, just pull the innards straight out. You don't need to twist it or anything, but you do have to really pull hard.
Thirdly - Get a solder sucker or something to really remove the solder from the joints....makes it sooo much easier. If not, you just get globs of solder everywhere and it really makes a mess and could damage the board with stray solder
Note - Do not remove the pcb board from the unit unless you really have to. If you do, try to clean out all of the solder holes and "post" very good before putting it back together. The board is sitting low on the post so it gives room for the power button to clear the sides. When you put it back together, make sure the on/off switch doesn't get press all the time. If you don't get that board low enough on the post it will. So if you do remove it, make sure you re-solder it way down on the post so it fits back in cleanly.
Fourthly - I have always replaced the battery with the same kind..NiCad…never any problems with charging and such.
Fifthly - I always have the battery tabs spot welded when I get the battery.
Note - The tabs that I get attached are almost needle like. This makes the insertion into the battery holes on the pcb very easy. You can see this in the picture.
Also, you can see that in one of my pics, you do not have to have that jp1 jumper 'jumped' with the negative terminal to make it work.
Also, i have had the battery out of mine for about a week now. No ill effects with having the battery out that long
Now that is done - I have thought of something. The pictures at the start of this show to the board as having 2 buttons. I only have one BUT do have a spot on the board to solder another button to. It is named 'SW2'. I might try that to see if I can regulate the timer and such as you can with the one that is posted here.
I meant to say SW1 -- not SW2. My fault
I just did two of these Elite 7300 (HX7300) battery replacements. The first one took about 2 hours; the 2nd took about 20 minutes. Things I did differently the 2nd time around:
(1) To remove the rubberized bumper, try slipping a thin knife blade under it from the long edge of the trapezoid. This little plastic piece isn't critical, but it's nice to keep it intact, to keep the brush from rolling around on the counter.
(2) Don't bother desoldering the battery pins. I wasted a ton of time trying to get that done, and it just isn't necessary. Instead, ...
(3) You'll see a couple of plastic tabs that hook over the top (+) end of the battery. Use a diag cutter and/or utility knife to remove those. Also use a utility knife to remove much of the soft plastic blades that hold the sides of the battery. Try to leave the wide black rubber band around the battery intact.
(4) Melt the solder on the top (+) battery pin, and lift the battery until the pin is all the way out of the circuit board. (If the black band is still intact, you can slide a paperclip or tiny jeweler's screwdriver under it and use it as a handle to lift the battery.)
(5) Repeat for the bottom (-) battery pin, and lift the battery clear. If you feel the need, now you can easily desolder the holes. :-)
For one tootbrush, I replaced the battery with a regular old AAA Energizer NiMH rechargeable (850 mAh). It constantly complains that it wants to be charged, but it goes a good sixteen 2-minute brush cycles between charges.
For the other toothbrush, I bought a real "4/5A" from BatterySpecialists.com (NiMH 2200 mAh, $6.50 w/ free shipping). I haven't managed to run that one all the way down yet, but I suspect it'll do just fine. :-)
Just did two too. 15 minutes for the second one, as the experience from the first was useful. :-)
As an experiment, i purchased both NiCad (1300ma) and NiMH (2000ma)batteries.
I have a few more of these to do in the house, so I am hoping to conclude which is better based on evaluation over then next several weeks. Specifically hoping to shed more light on the questions on charge and display behavior, as they pertain to the different battery types. Stay tuned, or write claudio@patriot.net if there is no followup post by October.
A quick hint on battery insertion that worked for me:
buy batteries with tabs.
Trim these to ensure a small enough stint that will fit through the reasonably cleaned hole in the circuit board after desoldering. (metal or even kitchen sheers should work fine to do the trimming)
If the tab is long enough, bend the last millimeter back onto itself. Next, loop some thread over these tab ends and feed this back through the original circuit board holes. Now you should be able to pull the new tabs directly through the original circuit board (presuming a reasonably clean hole) For me, the battery alignment and insertion and soldering took about 2 minutes with this approach.
Thanks.
Mine says HX7500 on the bottom but from the picture it looks the same as the 7300. Except mine has only 1 button, and the one in the picture looks like it may have 2..
Anyway, a year later and things are still the same- 2 uses then recharge. After overnight charge, bar graph indicates successful full charge. Interestingly, after first use, charge indicator still says fully charged. But at the end of second use, I get the "recharge now" vibration signal, and the charge indicatior is has only the bottom led lit and it is flashing amber, just as it normally would do, but after a week or 2 of uses not the second use. If the battery were marginal I think it would have failed by now.
Not this part is pure speculation... but It is as if the electronics which manage the battery looses it's settings, possibly due to being without any battery "keep alive" voltage at all for too long (even after the battery won't power the device anymore, it still may be keeping some memory alive or something like that). You may have noticed this with other electronic devices, if you swap out the batteries fairly quickly, you don't have to reprogram all the settings, but if you take a few minutes to complete the swap, you end up having to reprogram it. So if you do as I did and remove the old battery and then wait a day or 2 before finding and installing the new one, the electronics has lost it's settings, and the default it powers up with doesn't work so well. Something like this could enplane why one of your toothbrushes responded well to the battery replacement and the other did not (one spent more time with no battery voltage at all, and lost it's memory, while the other had it's battery replaced in time. Then when you swapped the batteries (probably fairly quickly, all in one sitting), the problem remained with the brush which lost it's settings, instead of the problem following the battery to the other brush.
Also, I just want to mention that substituting between a NiCad with a NIMH is not 100% proper, the different chemistry have different optimal charging profiles / charge termination processes. You may get away with it most times / sometimes / in a pinch, but you won't get top performance from the battery.
I will continue to use my sonicare until it drops dead or gets to the point where it won't get through even one complete brushing cycle after charging. Then I will be forced to evaluate sonicare versus their competition. All in all, I have to admit that it has been a good toothbrush and has lasted a long time. It just rubs me the wrong way that after all the work to get the case open and the search for the replacement battery, and delicate surgery to replace the battery that I did not get my just reward of a few more years of proper function out of it.
Please let me know if you think my speculation about loosing the memory fits with the timing of how you did your replacing and swapping.
Kelvin
I had some trouble getting the inside part out of the tube but then I used a 1mm sheet metal, made a suitable hole in it and seized it tight at the body with the brush head screw.
Then I drilled another slightly larger hole in a wooden board pulled the toothbrush assembly through the hole and rapped the metal against the board.
This way the inner part came out without any fuss.
For a replacement battery I got a NiMH battery with solder taps for 3,5 € (http://www.elv.de/output/controller.aspx?cid=74&detail=10&detail2=6660).
I used a side cutter to bring the solder taps into shape and soldered the battery into place.
The new battery is smaller than the old one so putting it in place without breaking anything was not too difficult. Yet the capacity of the NiMH cell is larger than that of the original NiCd cell.
I used some hot glue to fill the gap and to keep vibrations forces off the solder joints.
Finally I applied some silicon grease from my underwater equipment to the O-ring and reassembled the device.
It now works again like a charm.
It may not have mattered, because I think the one on my model worked differently than the one on this example model. At any rate, it did not come off or even budge under any circumstances. But I'm not one to let the Man win, so I had to do whatever it took to get into the thing anyway, just to see what was going on. As you can see from photo, "whatever it took" involved pulling and tearing and scraping all of the plastic off around the top, until finally the "instructions" on "how to" "remove the battery" that are printed on the charger base could be "followed". For those who have never interpreted ancient Egyptian before, let me put it into simple language for you: screw the cap thing back on sans toothbrush head, and then simply rock the cap back and forth in there until the innards slide out. Mine didn't begin to slide out until it was torn up, but I was never sure if I was doing it right as I was doing it anyway, making it all the more difficult. Turns out I was doing it right, it was just very hard.
(I recently replaced the battery and hard drive in my iPod following instructions from a video, so while I'm not a regular handyman I'm also not entirely clueless : )
In the end, it would have likely been an academic exercise for me anyway, as I don't have a soldering iron and may not have been willing to get one for this project. Now though, I think that even if I did replace the battery the toothbrush would be useless because there is no longer any seal preventing water and toothpaste from getting into the works. I did muck about a little with removing the battery anyway, but then it hissed at me and spit out some smoke, so I figured I was in over my head. Word of warning.
I post this here so that, if anyone else has the same troubles as I did, you don't have to feel (too) stupid and alone. Just calmly admit that Philips corporation has won this round, and make peace with yourself and the universe.
Incidentally, the death of my Sonicare came 2-3 years after I bought it. It worked perfectly for all that time, with no indication that it was dying. When I got back from a 2 1/2 week vacation in which workmen had been in my apartment mucking about with things, the toothbrush was in its charger with the bars green all the way to the top, but pushing the power button had no effect. It wouldn't turn on, and has been thus ever since. I don't know if the problem was that it sat in the charger all that time, that it didn't sit in the charger all that time, that someone dropped it, or what. Could be anything. At any rate, I find it ecologically reprehensible and a personal affront that this battery is essentially irreplaceable for all but the handiest of people. The more things get better...
If you have read all this, you are probably demoralized - you do the work, and the new battery won't charge any better than the old one.
NOT TRUE! Everyone, except Eurojojo, has missed a critical point. Just because the battery indicator says it is dead (one blinking amber light), is the battery is really dead? The answer is no. For NiCD and NiMH batteries, unlike alkaline batteries, the voltage remains essentially constant from fully charged to almost completely empty, so you can't use voltage to determine how full the battery is. That means the software has to keep track of how much charge is currently stored vs. the software's notion of the capacity of the battery, and report out the ratio (the fractional charge) as the level on the LED indicators. I switched my battery to a new 2200 mAh NiMH, charged it for 24 hours, and started using it. After 3 days, the indicator said the battery was dead (same behavior as with the old battery). However, with the old battery, at that point it would have really died and stopped working in the middle of a brushing cycle. With the new battery, two weeks later the indicator is still blinking yellow, and the toothbrush is still working just fine and feeling peppy.
The software must manage a dying battery by reporting lower and lower capacities (mAh) as "full" or 5 green bars (just like it does on a Prius!). It remains to be seen whether the software can revise its estimation of battery capacity upwards as well as downwards. If so, my charge indicator will become more accurate over time. We'll see. Most chargers will "trickle charge" full batteries, so if I leave it charging long enough, it should fully charge even this larger capacity battery.
Oh, and a few more tidbits: the plastic clip that holds the plastic casing over the electronics is shaped like a staple (l_l), with teeth on the inside surface of the vertical legs that hold it in place. To remove it, squeeze it from the sides with a plier, slip a thin screwdriver underneath it, release the plier, and pry it off while pushing outward against the legs to free the teeth so they don't break off. Also, getting the new battery terminals through the holes in the board is a pain and takes longer than anything else. Solder wick is your friend here. Have fun!
I just replaced my battery per your instructions.
I just want to start doing this for everyone to keep the waste down!
I got a Sonicare Elite HX7551 in September 2004, and it worked until October 2009. 5 Great years for our teeth! We use the same base with two persons, each with their own brush heads. We needed to charge the toothbrush every week, and left it off the charger until it was blinking orange. In October 2009 it stopped charging.
So I turned to these pages. First I got a NiMH replacement. In Europe probably cheapest at RS-Online. I got a Sanyo Tagged 4/5A NiMH cell,2150mAh, RS-stocknumber 400-7178 for 8,45 Euros, incl. VAT, incl. postage. Quite reasonable, I think, and they even delivered by courier.
But, it did not charge fully, discharged in a couple of days, and, most important, it charged less and less. Sometimes it would suddenly start charging, but when you used the toothbrush and put it back in the charger, it would not continue to charge.
So, I got at the end of January 2010 the same NiCd that was in the toothbrush when I started the project. A Sanyo Tagged 4/5A NiCd cell,1.2V 1250mAh, RS-stocknumber 377-7753 for 6,71 Euros incl. VAT, incl. postage (courier again).
This cell displayed the same problem! So, I started analysing. People here at the blog suggested there might be timers in the electronics. Philips writes in the manual that the battery does not suffer from the memory problem , which is quite an overstatement if you use NiCd cells, but we had 5 years of good operation with the thing, which hints at extra electronic measures.
So I thought: I will get the battery from the brush, charge it, and put it back in. Indeed we could brush for a week, but funny enough the light blinked orange all the time! With a guaranteed fully charged battery! Proof of electronics. And it did not charge properly. Same erratic behaviour: sometimes it would suddenly charge, and stop after being used.
Conclusions: 1. Apparently the green/orange blink light has no real relation to the power in the cell. 2. Charging is not provoked by the real charge level left in the battery. 3. The level of success of the people responding to this instruction is dependent on the level in the timers built-in the electronics when they started soldering the replacement battery.
But then I experimented, to try to align/reset the timers. I noticed that after soldering the brush would always start charging. I took the charger from the light socket for 15 minutes. Then put it back in: charging started! Time after time I could provoke the charging this way (yes, it would not overcharge, and display normal behaviour when full: stable green lights which go off once and a while). So, I put a timer between the charger and the light socket. Twice a day it disrupts power for 15 minutes. And what do you know: it now charges my brush every time to the maximum, and when taking the charger off power it will last for a week without charging. Finally it is as good as new. And I do not have more noise than before. It is nothing more or less than as good as new .
I guess this trick would not have needed me to buy the NiCd, and should have worked with the NiMH as well. For now I keep the NiCd in, since it works perfectly (as new). I hope in a couple of months the timers are all aligned again, and I can remove the timer.
One trick I learned in this instruction: use a bit of grease (apply with a match stick) to easily open and close the brush when experimenting.
Thank you all for your contributions, it helped me a lot.
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?
1) I did not do the trick for soldering wires onto the new battery proposed in this instructable b/c I did not read the instructions carefully. After reading some of the bad luck people were having in the posts below, I wonder if the extra wire may be picking up some current from the charging field. So, how much wire you use and which way you wrap it around to the battery may interfere with the charging of the battery. I'm an EE, but one with no "practical" skills. So it's possible that a few turns of wire would not pick up anything that could interfere with the circuit. Maybe someone else can do a back of the envelope calc?
2) Desoldering trick: solder sucker and de-soldering braid were not working for me. A friend told me to "flick" the solder off, and it worked like a charm. Mix some new solder in with the old solder to get a nice glob, turn the board over while still applying heat, and flick the board at the table, hitting the edge of the toothbrush against the table. Voila, the solder comes flying out! After 2 or 3 flicks, it's gone. Put some newspaper down, or you'll burn your table.
3) I replaced the old battery and tabs with a new battery and tabs. It is IMPOSSIBLE to get the new tabs into the holes on the board b/c of the tight fit of the battery. I had to cut away all the plastic that holds the battery down, so I could just drop the new one in. Then, I taped the battery snuggly into it's spot. Not ideal, but it seams to have worked.
4) Disassembly: it was not clear to me, but screwing down the brush head only lifts the body away from the internals about 1mm. After that, you need to pull straight out. I used a small screwdriver to work the internals away from the body a bit more. At first, I kept trying to twist the body off, but there is a guide that keeps the internals from rotating with respect to the body.
5) The next time I do this, I will try what one other poster did - pry the tabs off the old battery, and solder the old tabs onto the new battery. I think this would be easier than what I did.
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).
Here is the whole ball of wax in one go:
I followed these instructions to get my Sonicare HX7800 Elite Pro when it died recently. Be prepared - It is very difficult to get the brush apart and I destroyed the toothbrush head doing so but I have three replacement brushes so I didn't care too much. I should have just pushed the toothbrush part itself up through the rubber hood. For some reason it wouldn't work though so I resorted to tin snips...brute force sometimes works well, but it's not pretty.
I did succeed in removing the battery itself only after breaking the solder bond attached to the contacts on the battery while it was still attached to the toothbrush board (I did this by sliding a thin flat screw driver behind the contacts and prying them off). I saved the metal tabs soldered on to the battery and reused them later on the replacement battery.
This is the information written on the outside of the battery:
KR-1200AUL
Ni-Cd
When I looked this information up using Google I found it was a 1200 mAH battery in a PS-4/5A size (style). If you see one written as PS-4/5A-T it just means it has SOLDER TABS already attached to the battery. If you look at the screenshot I have attached it will give you more specifications on the battery if you are curious.
I found a video on YouTube that helps the disassembly of the unit (the video is just still camera shots - NOT actual motion video!) http://www.youtube.com/watch?v=pO-ugfWmn10
That video is for a 9000 series but it is the same as the 7800 as I have. That guy is selling batteries for $18.95 which is a rip off though. Buyer beware...they are available in a price range of between $2.50 - 8.50 US each depending on who you buy it from. I found mine for $7.35 CAD here locally.
For those interested here is were I bought my battery from in Calgary, AB, Canada (They constantly stock thistype of battery):
Battery World
#103, 6036 - 3rd Street SW
Calgary, AB
T2H 0H9
(403) 252-0074
chinook@batteryworld.net
www.batteryworld.net
The cost was $5.00 for the battery & $2.00 to have my old tabs soldered on to the battery. They did not have PS-4/5A-T style batteries. The total price, including sales tax was $7.35 CAD.
I noticed that in order to get the battery to work at all I had to make sure the 2 soldered points labeled JP1 needed to be bridged together ALONG with the - (negative) battery tab. ALL 3 needed to be connected together in one large horizontal solder. If these were not connected (all the solder sucked off) nothing worked at all. Once I completed all three solder points the battery worked once more.
Putting things back together was pretty hard. It required a lot of force to be able to get the retainer clip in once more. I decided to use a piece of plumbers tape (teflon tape) around the top of the components when putting things back together to help keep out moisture. You could even use silicon sealant but that's more permanent.
I charged the battery for 24 hours and then reset the battery by holding down the green button while the toothbrush is on the charger. I then let it sit on the charger for another 24 hours. This didn't really help me out in the end.
One thing I noticed about the toothbrush once I replaced the battery is that the unit is much louder than before and I attribute this to breaking the initial sealed connection of the unit when taking it apart. Though great care was taken to put things back together, I still feel there is a bit of a gap in the seals. They most likely use some type of sonic welding to snug things up. As such, I have used a piece of surgical tape (its see through plastic type) used on large bandages and such to provide the seal around where the parts come together. It keeps out the moisture. When I am holding the unit in my mouth the sound is reduced (the vibration is probably being transferred through my hand & arm).
In the end, I too have only managed to get four days use off the charger once the new battery was installed. No where close to the original two weeks off the charger. I thought I had this solved but it turns out I was wrong. There must indeed be some type of logic on the board (or maybe in the battery) that prevents these OEM batteries from being seen as new. For now at least I will be able to put up with this for I don't take this toothbrush with me when travelling. Unless someone else can figure this out I think I will have to just bite the bullet and buy a new toothbrush.
http://www.usbcell.com/product/1
This is a 1300mah NiMH. .The battery has solder tabs once you remove the usb head. It is physically a bit shorter than the original, so lead extensions must be soldered on. A little electrical tape or shrink wrap for insulation and a few dabs of hot melt glue to keep it in place and eliminate vibration. Still testing charge life.
Tried Digikey for a true Sanyo replacement SY110T-ND but they said 8 weeks. Too long! In fact, this battery is cheaper once the shipping and taxes for Canada are thrown in.