KXBC3 – Notes

Today I was reading the KX3 Yahoo Group messages and came accross a conversation regarding the optional internal battery charger on the KX3.

Here are some notes I wanted to remember so I figured I would post them here (my thanks to Mark, KE6BB for his original response to the KX3 Yahoo Group):

• There is a temperature protection feature in the KXBC3 that will display a message of “NOT 0-40C” if the cells go above the maximum specified temperature.
• If the “NOT 0-40C” message appears during a charging cycle…then the charging cycle will resume once the condition is corrected (it is not known if that includes just letting the batteries cool down).
• If using the recommended > 1900mA NiMH batteries it would be difficult to over charge these batteries using the KXBC3 (based on the constant charge rate and temperature protection)
• If using modern NiMH batteries then there is no need to fully charge or fully discharge them to reduce memory effect.
• Going to 100% occasionally is a good idea since that helps level out the voltages of individual cells
• Never let the cells’ voltages drop below about 1v per cell (cell damage may occur and potentially the KXBC3 will not start its charge cycle)
• Lastly, it is good practice to occasionaly check the voltage of each battery, after a good charging, to see if they are still with a few tenths of each other

The KX3 will turn itself off at 7.5V (or 7.0V depending on where you see it in the KX3 manual) so you will likely not run into the risk of going damaging the cells due to low voltage.

KXBC3 Manual is here

Here is more on the errors messages related to the KXBC3 (see image below):

KXBC3 NiMH Battery Charger

So I installed this KXBC3 some time last year but have really only used it once.  Now that my batteries have run down I need to relearn how to charge the batteries again.

Apparently as part of the battery charger setup you must set the KXBC3 charge time based on the power capacity of your batteries.

To find the charge time you use the following equation:

Charging Time (hours) = 1.2 x (cell mAH rating)/200

I have 2300 mAh batteries from Energizer so the estimated charge time is: 13.8 hours

The KXBC3 gives you options for 4, 12 or 16 hour charge times.

I have heard, based on the KXBC3 documentation, that NiMH cells can take some overcharging but I didn’t want to push it so I set it for 12 hours.

Unfortunately I had to stop this process mid-way to pack up for Sapelo Island…so will charge again once I get down there.