- Jul 11, 2001
- 40,426
- 9,941
- 136
I know this is long but I wrote it very carefully and checked it for accuracy. I think this is a very interesting question. What really happened? Please post a reply if you have a theory or any ideas.
Most of my rechargeable batteries are Eneloops. I have dozens. AAAs and AAs. I also have maybe a dozen Ikea rechargeables (AA and AAA) that are higher capacity. I'd have bought more but IIRC they stopped selling them.
Back in 2011 I bought a fancy electric toothbrush, German made Oral-B Professional Triumph, 9000 Series, I believe. AFAIK, still the best electric toothbrush ever made, but what do I know? Anyway, it's pretty fancy, has a separate clock gizmo that when you turn on the toothbrush counts up from 0 to 120 seconds, letting you know when you reach 30, 60, 90 and 120 seconds, the idea being that you've fully brushed your teeth at 120 seconds. It keeps going until you turn it off. The toothbrush has an LCD that shows the charge on the battery. Full, 3/4, 1/2, 1/4 or virtually none.
A charger is included that works by induction.
in 2015 I replaced the battery with one I bought off ebay. I did this again in 2019. So, it appears the NMH batteries for these worked for around 4 years and then wouldn't hold much of a charge.
I decided to try using an Eneloop AA instead, because they are long-slow discharge and are marketed as being able to maintain good functionality over thousands of charges. Only problems might be fitting in the toothbrush and my ability to connect the battery. The replacement batteries I'd bought had tabs that could be soldered to the circuit board of the toothbrush, which the Eneloops lacked.
A few years back I encountered a video that showed how to swap out the battery in an Oral-B toothbrush (different model from mine) with an Eneloop battery:
I managed to solder flexible solder removal wick to the Eneloop AA, and that to the circuit board. This was maybe a year or two ago. It worked. Recently it hasn't held a charge super long but has been good for maybe a dozen uses or more between charges.
So, about a week ago I inadvertently drop the toothbrush. The LCD display went blank, suggesting to me that probably a solder joint to the Eneloop AA battery had broken off. I opened up the toothbrush and saw that this was the case. Now, touching the braid to the battery end (negative), the LCD lit up. However, I would have expect it to show at least a 1/2 charge like it was showing before the mishap. Instead it showed the pattern that indicates that it is virtually discharged and wants to be charged. I didn't think too much about that but proceeded to resolder the braid to the negative end of the battery. Once that was accomplished I reassembled the toothbrush insides to the body. The instructions I used said to fully charge the toothbrush after replacing the battery, "12 hours." It's a real good video:
<---------- 12+ minutes, it's thorough
I put the reassembled toothbrush on the charger. When the LCD indicated that it was almost fully charged (3/4 plus), I took it off the charging stand and turned it on, just to make sure that the toothbrush still worked after having sustained the fall a couple days before. It turned on fine but damn, after about 14 seconds it turned off and showed the flashing icon indicating it was virtually discharged and needed a full charge!!! WTF! Oh, oh, I figured, something's really wrong here. The battery appears to be fully charged, I turn on the toothbrush and it only works for 14 seconds and is discharged. Maybe the circuit board is damaged or there's a short. I put it back on the charger and this time allow the LCD to get to where it indicated the battery is fully charged, over 12 hours. Once there, I turn it on and begin brushing my teeth. Full cycle is 120 seconds, I usually turn it off at that point. However it went to about 110 second this time (more than the ~14 seconds the first time) and then turned off and showed the battery was depleted and needed to be charged. Hmm. I put it back on the charging stand. I let it charge to where the LCD indicates it's fully charged.
At this point in the goings-on, I'm thinking the battery's gone bad, will only hold a minimal charge and I probably have to swap out that Eneloop AA with another (I have a lot of them, could even use an Ikea, which is rated at something like 2300mah, I think), but decide since I don't have a lot of Ikeas I'll stick to Eneloop AA.
I try the "fully charged" toothbrush again to see what will happen. It actually works for a full 120 seconds! The LCD indicates it still has a full charge. After turning it off I put the TB on the charging stand again. Next time I use it (today) it works for the full 120 seconds, LCD still shows full charge.
Well, I'm wondering why it appeared that the battery couldn't hold a charge after I resoldered the braid to its negative terminal. I'd thought that maybe the battery was damaged due to the heat from the solder iron (a 25 watt solder iron, IIRC), but now the battery appears to maybe be capable of holding a charge. I don't typically keep the toothbrush on the charging stand, or if I do, I unplug the charger unless the toothbrush shows the charge is low or I sense that the toothbrush doesn't have the oomph it does when fully charged.
What do you make of this?
Most of my rechargeable batteries are Eneloops. I have dozens. AAAs and AAs. I also have maybe a dozen Ikea rechargeables (AA and AAA) that are higher capacity. I'd have bought more but IIRC they stopped selling them.
Back in 2011 I bought a fancy electric toothbrush, German made Oral-B Professional Triumph, 9000 Series, I believe. AFAIK, still the best electric toothbrush ever made, but what do I know? Anyway, it's pretty fancy, has a separate clock gizmo that when you turn on the toothbrush counts up from 0 to 120 seconds, letting you know when you reach 30, 60, 90 and 120 seconds, the idea being that you've fully brushed your teeth at 120 seconds. It keeps going until you turn it off. The toothbrush has an LCD that shows the charge on the battery. Full, 3/4, 1/2, 1/4 or virtually none.
A charger is included that works by induction.
in 2015 I replaced the battery with one I bought off ebay. I did this again in 2019. So, it appears the NMH batteries for these worked for around 4 years and then wouldn't hold much of a charge.
I decided to try using an Eneloop AA instead, because they are long-slow discharge and are marketed as being able to maintain good functionality over thousands of charges. Only problems might be fitting in the toothbrush and my ability to connect the battery. The replacement batteries I'd bought had tabs that could be soldered to the circuit board of the toothbrush, which the Eneloops lacked.
A few years back I encountered a video that showed how to swap out the battery in an Oral-B toothbrush (different model from mine) with an Eneloop battery:
I managed to solder flexible solder removal wick to the Eneloop AA, and that to the circuit board. This was maybe a year or two ago. It worked. Recently it hasn't held a charge super long but has been good for maybe a dozen uses or more between charges.
So, about a week ago I inadvertently drop the toothbrush. The LCD display went blank, suggesting to me that probably a solder joint to the Eneloop AA battery had broken off. I opened up the toothbrush and saw that this was the case. Now, touching the braid to the battery end (negative), the LCD lit up. However, I would have expect it to show at least a 1/2 charge like it was showing before the mishap. Instead it showed the pattern that indicates that it is virtually discharged and wants to be charged. I didn't think too much about that but proceeded to resolder the braid to the negative end of the battery. Once that was accomplished I reassembled the toothbrush insides to the body. The instructions I used said to fully charge the toothbrush after replacing the battery, "12 hours." It's a real good video:
I put the reassembled toothbrush on the charger. When the LCD indicated that it was almost fully charged (3/4 plus), I took it off the charging stand and turned it on, just to make sure that the toothbrush still worked after having sustained the fall a couple days before. It turned on fine but damn, after about 14 seconds it turned off and showed the flashing icon indicating it was virtually discharged and needed a full charge!!! WTF! Oh, oh, I figured, something's really wrong here. The battery appears to be fully charged, I turn on the toothbrush and it only works for 14 seconds and is discharged. Maybe the circuit board is damaged or there's a short. I put it back on the charger and this time allow the LCD to get to where it indicated the battery is fully charged, over 12 hours. Once there, I turn it on and begin brushing my teeth. Full cycle is 120 seconds, I usually turn it off at that point. However it went to about 110 second this time (more than the ~14 seconds the first time) and then turned off and showed the battery was depleted and needed to be charged. Hmm. I put it back on the charging stand. I let it charge to where the LCD indicates it's fully charged.
At this point in the goings-on, I'm thinking the battery's gone bad, will only hold a minimal charge and I probably have to swap out that Eneloop AA with another (I have a lot of them, could even use an Ikea, which is rated at something like 2300mah, I think), but decide since I don't have a lot of Ikeas I'll stick to Eneloop AA.
I try the "fully charged" toothbrush again to see what will happen. It actually works for a full 120 seconds! The LCD indicates it still has a full charge. After turning it off I put the TB on the charging stand again. Next time I use it (today) it works for the full 120 seconds, LCD still shows full charge.
Well, I'm wondering why it appeared that the battery couldn't hold a charge after I resoldered the braid to its negative terminal. I'd thought that maybe the battery was damaged due to the heat from the solder iron (a 25 watt solder iron, IIRC), but now the battery appears to maybe be capable of holding a charge. I don't typically keep the toothbrush on the charging stand, or if I do, I unplug the charger unless the toothbrush shows the charge is low or I sense that the toothbrush doesn't have the oomph it does when fully charged.
What do you make of this?
Last edited:
Facebook
Twitter