Slater, There is no harm to be done as long as the outside power supply voltage is higher than the battery voltage - with your 14.2 volt supply, that supply should operate the K2 while also charging the internal battery. It is the situation where the external supply is less than the battery voltage that requires the switch be turned off (with the switch in the ON position, the battery will supply the K2 until its voltage drops below the external supply voltage).
The internal battery will not charge with the switch in the OFF position - but it would seem from you post that it had been ON for some time and the battery failed to charge for some reason. If that is the case, perhaps you do have something wrong with your wiring. Check the orientation of the diode and the wiring of the resistor, unfortunately these components are now ensconced inside the heat shrink, so you would have to remove the heatshrink to check - do that only if the following items do not check out properly: One way to check the resistor is to do a continuity check - disconnect the wire at the battery positive terminal, make certain the switch is in the ON position, and check the resistance fron the Faston connector to the red lead on the Aux DC connector - you should measure close to 6.2 ohms. Next switch your DMM to read diode forward voltage drop and use the same points for the probes - you should find the voltage drop to be 0.2 to 0.3 volts (you may have to reverse the probes). If either of these readings is incorrect, open the heat shrink and check your wiring against the diagram in the manual. The other thing you can do is check the voltage at the battery terminals with your 14.2 volt supply connected and powered on (remove the faston connector from the battery for this check) - you should read 13.8 to 14.0 volts with a power supply delivering 14.2 volts (this voltage will be lower when the battery is connected unless your battery is fully charged). If everything above checks out OK, read the battery voltage directly with your DMM. If you read something less than 13.2 volts, the battery is not fully charged - reconnect the battery, connect your 14.2 volt power supply, put the internal battery switch in the ON position and wait 2 days before checking the voltage again - if it is still low (and the wiring checks out good), you may have a bad battery on your hands. I believe that covers most all the bases on the internal battery situation - there is nothing really complex about it - the resistor should limit the current to the battery and with your 14.2 volt supply: - if the battery voltage is 9.6 volts, the current will be about 700 ma, but with a fully charged battery (13.2 volts terminal voltage), the charging current will be about 32 ma. 73, Don W3FPR > -----Original Message----- > > As with most folks, my hindsight is perfect. This applies to the > reading of manuals > > I have the K2 internal battery installed and neglected to read that > the switch should be OFF when using outside power. As a result (I > assume) my internal battery voltage is low at about 9.6 volts. > > A few days ago I did put the switch in OFF and hoped that the charge > would come back. Not so. > > I have a 14.2 volt reading on my power supply plug to the K2. > > Any suggestions? > > Is it possible that my construction might be at fault? > > 73 and thanks > > Slater VE5OA > Wolseley, SK Canada > K2 - 4519 > > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
