KC8AON's QRP PROJECTS

GEL CELL CHARGER/MAINTAINER

KEEP YOUR GEL CELL CHARGED AND READY FOR WHEN YOU ARE READY

CHARGES AND FLOATS (MAINTAINS) YOUR GEL CELL

FROM NOW ON YOUR BATTERY WILL BE READY WHEN YOU ARE !

NO NEED TO WORRY ABOUT OVERCHARGING

WILL CHARGE AND MAINTAIN THE CHARGE WITHOUT OVERCHARGING

IF YOU OPERATE PORTABLE USING GEL CELL BATTERIES, YOU NEED THIS CHARGER

This little charger/maintainer is a simple little circuit that requires few parts and uses any 15 to 18 VDC source of at least 1 amp capability - I used the transformer and rectifier from an old 12 volt 1 amp wall wart power supply in mine - it measures 18 volts DC with no load and works perfect. Just be sure and set the output voltage of the charger to 13.4 volts by adjusting the 5K ohm variable resistor in the charger circuit. The charger has a charge/float indicator in the form of a small meter salvaged from an old CB radio, or you can use an LED as the indicator. To use the charger, you simply connect the gel cell to the output and turn it on. If the battery needs charging, you will see the meter deflect or the LED will light depending on which you use. As the battery becomes charged, the meter will read lower and lower or the LED will go dimmer until the meter reads near zero or the LED goes out. At this point, the battery can be left connected indefinitely to the charger as it will float charge (maintain) the battery at a constant level keeping it ready for when you need it without the worry of overcharging or otherwise doing damage to the battery. I have used the one I built to charge batteries up to 20aH, and it may charge higher capacity gell cells too but will require more time to do so - the bigger the battery, the longer time it requires. If you use a very large gel cell battery to operate with and want a quick charge, you may want to use a heavier duty charger to bring it to full charge and then switch it to this one to maintain that charge when in storage.

HERES A PICTURE OF THE CHARGER I BUILT

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