[Elecraft] charger recommendation for k2 internal battery

[rlewis@staffnet.com]

DO NOT connect any automatic charger (including the PowerSonic unit) to the power input of the K2. It will not properly charge the battery and may damage the K2 from over-voltage. Automatic chargers MUST be connected directly across the battery in order to properly sense the battery voltage. The K2's internal diode and charge current limiting resistor will disrupt this.

If you want to use an automatic charger on the K2 internal battery you will need to add a separate charging connector. I recommend that an additional polyfuse be placed in this line (inside the K2) to prevent the possibility of shorting the battery from the charging connector.

Also be aware that it is possible for the K2's receiver to fool the automatic charger into over-charging the battery *IF* the receiver is left on for long periods of time (24 hours perhaps) with the charger connected. The PowerSonic (and other) automatic chargers sense current draw to determine when they should drop back to a "float" charge. If the receiver is drawing current, the charger will not switch to "float" mode because it thinks the battery is taking this current and still needs charging.