I have several 6v 4.5a sealed lead acid batteries. I would like to hook one of them up to a solar panel and have it stay charged from the solar panel all the time, but not overcharged. Is there a simple way to do this with an IC or something? I am only a beginner with circuits so I want it to be something very easy to make. Basically, I want it to stay charged all the time so it's available if I need it for a power out or something.Thanks.
Yes, you can purchase a solar photovoltaic array to keep your batteries charged. You will need a Photovoltaic Cell Panel that produces 27 + watts (6volts x 4.5 amps = 27 watts) at 6 volts of electricity, a Charge Controller that allows only 4.5 amps of power through to the battery and will reduce the amps as the battery nears full charge and shut off the Panel when the battery is fully charged, and a 6v. Battery. Figure you will need a photovoltaic panel capable of producing a minimum of 27 watts if you are going to charge a completely dead 6 v. battery in one day. (with a clear sky). The way the system works is the sunlight strikes the cells on the panel and releases the excess electrons in the cells, they travel along central wires to your battery and charge the battery. When the sun sets, the procedure is reversed and the electrons flow backwards from the battery, into the photovoltaic cells. That is where the Charge Controller is needed. It acts a one way gate and lets the electrons go into the battery, but won't let them go backwards to the Panel. Just set your panel in the sun at the optimum angle for the season and your latitude on earth, connect the charge controller and then the battery, and it will keep your battery charged. Don't waste your money on the small wattage solar photovoltaic systems that claim to keep your battery charged. They simply can't do it unless your battery is in like new condition and is fully charged when they are hooked up. If you battery is a few months old, the small wattage photovoltaic systems can't keep up with the loss of power from sulfation inside the battery.
What I would suggest is that you find a panel that is rated for 00 mA, at any voltage higher than 8 volts. A 2 or even 8-volt panel will do, because the voltage will drop to match the battery. Then I would get a diode to put in series with the panel to prevent the battery from discharging through the panel at night. That's called a blocking diode. At such low currents, a charge controller is not worth it. There is not enough power to overheat the battery, which is principally what a charge controller protects against in a larger system. Be aware that you could also simply plug a trickle charger for the battery into the wall outlet, at a cost of less than a penny a day in electricity.
