Frank
Thanks for the informative reply. You mentioned that the battery pack might
be low on capacity, does this mean that it is near the end of its life (and
needs new cells) or there were low capacity, quick charge versions of the
NiMH battery packs?
TIA
Tony.
> Date: Wed 3-Apr-2002 07:37
> To: tony.kan_at_clear.net.nz (Tony Kan)
> Cc: newtontalk_at_newtontalk.net (No Name)
> From: newtontalk_at_newtontalk.net (No Name)
> Subject: [NTLK] Re - Battery charging currents
> > The MP2000 has battTrax installed on it. Yay. It also has the NiMH
> battery
> > pack. Yay, again. On charging though it says that it is
> charging at over
> > 1,000mA!!! That's a WHOLE AMP! That seems to be a lot of current
> for a
> > piece of portable electronics. I'm worried about frying it.
>
> This isn't likely. There are two built-in gadgets in the battery pack
> that prevent this. One is a temperature resistor which will make the
> Newton reduce the charge current when the temperature in the pack
> gets too high, the second one is a temperature switch that will stop
> the charge current totally until the temperature returns to normal
> conditions. While evaluation of the resistor might theoretically be
> tweaked by software like BattTrax, no software would be able to
> prevent the switch from doing its work.
> > I am using an adapter that provides 7.5V from 240V and is rated for
> 0.9A.
>
> Unless it is an original Apple part, I'd make sure this is
> true by measuring the output voltage while the adapter isn't powering
> anything.
> > am using it quite a lot and so I'm charging it every two
> days. But a charge
> > seems to be done in 10-20 minutes! This is amazingly low. Is this
> normal?
>
> No, it's not. The original cells in the battery pack have
> 1200 mAh. Theoretically this would mean you'd have to charge a
> (completely discharged) pack for 1.2 hours with a charge current of 1
> Ampere. In real life it's a bit more than that. If your charge is
> finished in 10-20 minutes, there can be two reasons:
>
> a) Your charge current is between 3...6 Amperes. This is more than
> unlikely, standard ac adapters can't provide than high a current.
> Moreover, I'm pretty sure the Newton can't handle this current,
> either. And even if it could, I'd expect the temperature switch in
> the pack to cut the connection because the temperature would get too
> high.
>
> 2) Your pack has way less than the normal capacity. This is
> the most likely reason. It will be "fully" charged much faster
> because there just isn't that much juice required to do this.
>
> Frank
>
> Newton hardware and software at http://www.pda-soft.de
>
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>
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