From inspection of the circuit diagram, measurement of the unknown
components, and probing of the charger connected to an external power
supply, I discovered that the KX-A46 Battery charger has
trickle charger ( 50 - 250 mA current controlled by a varistor)
reverse circuit protection (diodes) to protect against the
inevitable for the first 50 ms or so.
8A fuses to protect against reverse connection problems after 50 ms.
The weaknesses of the design include:
no provision to rapidly charge (say 5A) deeply-discharged batteries
no provision to suspend trickle charging and/or periodically
initiate rapid (say 5A) charging to churn electrolyte to prevent
dendrite buildup
no provision to sense and/or indicate current charge or drain
no provision to indicate battery voltage
no provision to sense ambient temperature (or better yet,
battery temperatures) to compensate the sensed charge and adjust
charging rate.
I posted more details of my investigation to the forum in 2002.
Best regards,
Paul H. Gusciora
San Rafael, CA
----- Original Message -----
From: David Lesher <[EMAIL PROTECTED]>
To: [email protected] (KXT Mailing list)
Date: Tue, 9 Sep 2008 12:23:47 -0400 (EDT)
Subject: Re: KX-T: Extended Battery Back up for Kx-td1232
On recharging....
If the KX-T has {guess} 4-AH batteries, and its charger makes
{say} 500 mA, that's 8 hours to recharge.
Now take those enormous 120AH batteries. It will take the charger
240 hours to fully recharge those batteries; that's 10 days.
But so what? Unless it's an area where you anticipate another
lengthy outage within that time, you don't need to care. Just let
it charge. After the first day, you'll get usable capacity.
Also: a UPS is not desirable for this. Taking AC to make DC to
make AC again to make DC to run the KX-T...is a waste. You'll
waste a lot of capacity.
[an earlier version got away from me; sorry..]
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