[NTLK] Battery

[NewtonTalk]

> Ok so I bought 4aa Nimh rechargables and a plastic holder for them. I
wired them up to my emate 300
> and the batteries will not charge (says too much power so they wont
charge) and then says fault.
> What am i doing wrong here ?

Most likely you have forgotten to transplant the temperature resistor from
the old pack. See 

<http://www.pda-soft.de/emate_battery_pack.html>

This will also explain why you can, but shouldn't, omit to also transplant
the overcurrent protection switch.

That being said: I'd strongly advise everyone to refrain from using an
off-the-shelf battery holder in his eMate. On and off, I've tinkered with
this for the last 15 years or so, and as yet I haven't found a seller who
was willing, let alone capable, to provide me with a data sheet that sheds
any light on the battery holder's contacts maximum current specification.
Contacts in a holder suitable for an eMate must be specified for a
continuous load of 1.2 Amps or more. This is bacause the eMate will be
charged with 1.2 Amps when using the original AC adapter.

Some years ago, when I tried this for the first time with a normal holder
like the ones you buy at Radio Shack, it took the eMate about five minutes
to melt the plastic surrounding the holder's metal contacts. This was
because the contacts couldn't withstand the charge current and became hot
like hell. Thank God most cheap battery holders' plastic develops a
disgusting smell when melting. So disgusting I was able to smell it one
floor below. Otherwise my house might have gone up in smoke.

I'm not kidding. Either insist on a datasheet and make sure the holder can
handle a continuous load of 1.2 Amps charge current, or forget it. Unless,
of course, you are homicidal or suicidally inclined...

Cheers

Frank

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