[NTLK] Battery Question

[Dan]

Hi Noah,
While I don't know ALL the details I do know a bit.  The Newton uses both voltage and the thermoister (I think that is how you spell it) to determine how long to charge for a rechargeable battery pack (for a 2100 and emate anyway).  With a battery sled it always assumes they are alkaline and won't charge them in the Newt normally (although there are ways around that).

There are several apps that you can use for monitoring the battery and find out what is going on.  The Newt's Battery is one.  Nick made one as well I think it is part of his Nicks Test (double checked...it does).  And there are others.  They tell what type is being used, temperature, charge status, etc.  Try them and see, they should give you insight into what is going on.  I suspect those batteries are doing a bit more heat than other types which is triggering the 'full' message after they have been used for a while.

Also there are apps/packages that tell the newton what battery type is being used (to override the usual methods).  Double check that it is thinks a NiMh is being used, if it doesn't that will change the charge limits/method.  Also if I recall there is a package to set the max charge limit so that it only charges to less than 100% (which you define) but I don't recall the name.

By the way, did you ever try putting those same batteries back into a pack and see if they still did the problem after having them charged a few times externally?  It could be it built up a bit of a memory and the external charger (which are  much better these days) dealt with it/refreshed them.  I know reinstalling them inside a pack likely isn't worth the trouble (especially if they still do it) but it would be a interesting test.

-Dan


On 4/26/2026 12:59 PM, Noah Leon wrote:
> Does anyone know how the Newton’s battery system works? Specifically, how does the Newt know to stop charging?
> 
> I’m having a persistent problem with my re-celled battery packs. I used IKEA NiMH cells to refurbish them, since they’re cheap and plentiful. However the same thing has happened twice now, that the newt says “charged” when it only shows as about a quarter full on the little graph, and the battery only lasts a short time. This is using the default Newton ac adapter, the problem affects my 2100 and eMate.
> 
> The weird thing is that I can take these batteries out and use them for many years if I charge them with a wall charger and just use the AA battery tray.
> 
> Something about the newt’s circuitry seems to tell it not to charge all the way, either voltage or temperature, but I don’t know what.
> 
> Noah
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