# Battery won't take a charge after storing for a couple of weeks.



## ifoxbox (Dec 18, 2006)

I know a guy who uses a Sonicare Advance toothbrush. Inside the handle are two AA NiCd batteries. He said he has been using the handle for quite a while, but recently stored it for a couple of weeks (in working order), but now it will not take a charge. I am pretty sure that the charger is a trickle charger. I have heard of the same thing happening to a couple of other people as well. What would cause this? Is this common for NiCd batteries?



Thanks in advance for any info.


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## hank (Dec 18, 2006)

Yep, it happens. (If anyone wants my second one, for the induction charger and components, pm me). It's a block of epoxy inside, couldn't find any way to replace the batteries on those.

On my 3rd, I'm now leaving it unplugged most of the time, and only putting it back on the charger when it starts to run down, hoping to extend the lifetime vs. having it always on charge.


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## ifoxbox (Dec 18, 2006)

Hi Hank,

Thanks for your reply. Any idea as to why this happens with NiCd cells? I have heard of people storing their NiCd cells for years at a time, and they say they still work fine. What would cause a working battery to stop taking a charge after being stored for only a couple of weeks? Do you figure it was on its last few cycles before it was stored?


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## N162E (Dec 18, 2006)

ifoxbox said:


> I know a guy who uses a Sonicare Advance toothbrush. Inside the handle are two AA NiCd batteries. He said he has been using the handle for quite a while, but recently stored it for a couple of weeks (in working order), but now it will not take a charge. I am pretty sure that the charger is a trickle charger. I have heard of the same thing happening to a couple of other people as well. What would cause this? Is this common for NiCd batteries?
> 
> 
> 
> Thanks in advance for any info.


This is a very common event with electric toothbrush batteries. Dead toothbrush batteries are known not to charge when plugged into a popped GFI. Check and make sure the GFI is working first, older ones tend not to have indicator lights and if the toothbrush is the only item plugged in it is easy to miss. When working properly the induction base should be slightly warm.


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## ifoxbox (Dec 18, 2006)

He said he has another handle that he uses in the same charger, so he knows that the charger is working. 




N162E said:


> This is a very common event with electric toothbrush batteries.



Any ideas as to why? Is it the way the charger (trickle charge) charges the cells?


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## N162E (Dec 18, 2006)

ifoxbox said:


> He said he has another handle that he uses in the same charger, so he knows that the charger is working.
> 
> Any ideas as to why? Is it the way the charger (trickle charge) charges the cells?


Like any other battery these things do not last forever. I went through 3 of them over a ten or eleven year period. Check the warranty and if there is a way to call do it. If you take the brush off and look inside there is a serial number inside and they may still pro-rate an exchange. After five years I got my first replacement for free, four years later second replacement was 30 bucks when that one died I bought a spin brush. I tried pretty hard to make them last as long as possible, only charging them when they ran down and never more than about 18 hours at a stretch. They are well made and should last a long time although IMHO overkill.


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## ifoxbox (Dec 18, 2006)

N162E said:


> Like any other battery these things do not last forever. I went through 3 of them over a ten or eleven year period. Check the warranty and if there is a way to call do it. If you take the brush off and look inside there is a serial number inside and they may still pro-rate an exchange. After five years I got my first replacement for free, four years later second replacement was 30 bucks when that one died I bought a spin brush. I tried pretty hard to make them last as long as possible, only charging them when they ran down and never more than about 18 hours at a stretch. They are well made and should last a long time although IMHO overkill.




Thanks for the info. I actually repair these handles, so he may just send it to me, but I will let him know what you said about Sonicare prorating them.

I have heard of some people storing their NiCd batteries for years, and charging them up with no problems. I was just curious as to why his handle would die after a couple of weeks in storage, when it was working fine when he put it in storage.


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## Handlobraesing (Dec 18, 2006)

My first Sonicare died like that too. How does he store the handle between use? NiCd or NiMH don't really like being discharged 5% and put back on trickle charge twice a day every day.


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## ifoxbox (Dec 19, 2006)

Handlobraesing said:


> My first Sonicare died like that too. How does he store the handle between use? NiCd or NiMH don't really like being discharged 5% and put back on trickle charge twice a day every day.



He told me that he keeps the handle on the charger all of the time. I told him that it was better to only charge the handle when it needs it. 

What is it about storing NiCd cells for a couple of weeks (without a charge) that just makes them die when you bring them back out? I know the cells were probably on their last legs, but he tells me that they were working before he put it away.


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## Handlobraesing (Dec 19, 2006)

ifoxbox said:


> He told me that he keeps the handle on the charger all of the time. I told him that it was better to only charge the handle when it needs it.
> 
> What is it about storing NiCd cells for a couple of weeks (without a charge) that just makes them die when you bring them back out? I know the cells were probably on their last legs, but he tells me that they were working before he put it away.



Well if the battery was on the last legs it might have developed an internal leakage and the trickle charger can't overcome it. When that happens, battery is pretty much done anyways. If you can get the disassemble and reassemble the body, definitely replace the batteries.


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## ifoxbox (Dec 19, 2006)

Handlobraesing said:


> Well if the battery was on the last legs it might have developed an internal leakage and the trickle charger can't overcome it. When that happens, battery is pretty much done anyways. If you can get the disassemble and reassemble the body, definitely replace the batteries.



That makes sense. Thanks for the reply. I do replace the batteries in these handles. I have done quite a few of them, so I can now get the handle apart and back together with no problems. I am happy to be able to recycle the handles rather than just throwing them away just because a couple of NiCd batteries died.


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## Handlobraesing (Dec 19, 2006)

ifoxbox said:


> That makes sense. Thanks for the reply. I do replace the batteries in these handles. I have done quite a few of them, so I can now get the handle apart and back together with no problems. I am happy to be able to recycle the handles rather than just throwing them away just because a couple of NiCd batteries died.



it would be interesting to fit some eneloops in there. However, I'm not certain if the factory charger can provide enough current to fully charge 2,000mAh cells.


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## SilverFox (Dec 19, 2006)

Hello Ifoxbox,

NiCd cells often develop shorts inside that result in a very rapid self discharge. In two weeks, they can become completely drained to 0 volts. I am not sure how the charger handles low voltage conditions. 

A common solution was to briefly hook the battery up to a higher voltage (we used a 12 volt car battery) and blow the short away. This will give you a few extra cycles, but is not safe. These shorts appear at the end of the useful life of the cell, so it was probably time for replacement.

Tom


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## ifoxbox (Dec 19, 2006)

Handlobraesing said:


> it would be interesting to fit some eneloops in there. However, I'm not certain if the factory charger can provide enough current to fully charge 2,000mAh cells.



That would be interesting to try. I have never used enloops before. I have tried some cheap Marathon 2400mAh NiMh cells, and they seem to work fine. They charge to 1.38 volts. What if the factory charger does not fully charge the cells? Would that have a negative affect on the batteries? 




SilverFox said:


> Hello Ifoxbox,
> 
> NiCd cells often develop shorts inside that result in a very rapid self discharge. In two weeks, they can become completely drained to 0 volts. I am not sure how the charger handles low voltage conditions.
> 
> ...




Thanks for the info Tom! I figured that his batteries were probably near the end anyways, but just was not sure what would cause them to stop taking a charge when they were receiving one before. I think you are correct when you say it is probably how the charger handles low voltage cells.


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## N162E (Dec 19, 2006)

You have not said how old the handle is. IF its more than 3 years old and has been used on a regular basis I would say its living on borrowed time. No good explanation for sudden failure, I think Tom gives as good a reason as any. I know they are real well built, could this one have been dropped REAL hard-like on a bathroom tile floor? Try a different brush head.

I really can't see rebuilding one of these, if you do maybe you could take some pictures and share them with us.


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## mchlwise (Dec 19, 2006)

N162E said:


> You have not said how old the handle is. IF its more than 3 years old and has been used on a regular basis I would say its living on borrowed time.



I've got one that I've been using regularly for about 3 years.


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## ifoxbox (Dec 19, 2006)

N162E said:


> You have not said how old the handle is. IF its more than 3 years old and has been used on a regular basis I would say its living on borrowed time. No good explanation for sudden failure, I think Tom gives as good a reason as any. I know they are real well built, could this one have been dropped REAL hard-like on a bathroom tile floor? Try a different brush head.
> 
> I really can't see rebuilding one of these, if you do maybe you could take some pictures and share them with us.



The handle is not mine. It belongs to someone who emailed me, and is going to send it to me. He did not tell me how old the handle was, but I assume that it was at least a couple of years old. Like you said, Tom gave a good explanation as to why it could have died after being in storage.




Thanks everyone for the good info.


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## MrAl (Dec 20, 2006)

Hi there,

Just a note, that i have repaired an electric shaver that had internal NiCds
and they were dead and since they were so very small cells i decided that i 
would upgrade the whole thing while i was at it and i happened to have
a few NiMH cells (much larger AA size) laying around doing nothing. The
cells would not fit inside so i simply taped them to the outside of the case.
It's a little wider now to hold while shaving, but it packs a lot more power
so it works overall much better.
If you cant get to the cells but you can get to the wires that lead to the
cells perhaps you can do the same thing, and bigger batteries are really
nice to have running stuff like this.


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## ifoxbox (Dec 20, 2006)

MrAl said:


> Hi there,
> 
> Just a note, that i have repaired an electric shaver that had internal NiCds
> and they were dead and since they were so very small cells i decided that i
> ...


 Hi Al,

what kind of cells did your shaver have in it before? Does your charger charge the larger AA size cells just as well? 

The Sonicare takes 2 NiCd AA cells, and they fit snugly under the PC board. I do not think I would be able to fit any other cell that is larger than an AA size underneath.



I could do what you said you did with your razor and put them on the outside, but I do not think that I would be able to seal the handle back up properly. Also, it would probably be difficult to hold the handle with 2 cells that are larger than AA size on the side. The 1200mAh AA cells do a nice job. They last for about 2 weeks before needing a recharge. 

I would like to try some enloops like Handlobraesing suggested, but I am not sure if the factory charger will properly charge the cells.


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