Re: [NTLK] External Power Packs for Newtons

From: Frank Gruendel (fg2_at_pda-soft.de)
Date: Wed Apr 06 2005 - 13:49:49 PDT


> I'm just fiddling around with a pack I bought and
> testing it out to see how long it lasts. My only
> concern is to understand the caution statement made
> by others regarding the recharging of the Internal
> Rechargeable Pack by this External Rechargeable Pack.

In a nutshell, there are two reasons:

1) Charge current

Newton AC adapters limit the maximum charge current for
a reason. Charging with more than the maximum current
can fry the cells and the Newton.
The power pack is, if I remember correctly, wired in a
way that you have to sets of four serially-wired batteries
that are wired in parallel. Such a setup can for a short
time provide a couple of dozens of amperes as charge
current, which both the cells and the Newton do not like.

2) Discharge current

Even if the current sucked from this battery pack was
limited to a value healthy for the Newton and its internal
battery, which it isn't, this would mean that around 1.2 Amps are
sucked from the pack until the Newton's internal battery is
fully charged. At that current, it'd take but a few hours
until the 8 batteries are a case for the trashbin.

Frank

-- Newton software and hardware at http://www.pda-soft.de

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