Charging Battery Direct From Solar Panel

The bulk phase first stage the bulk phase is primarily the initial stage of charging a battery using solar energy.

Charging battery direct from solar panel. For example your solar panel delivers 18 volts dc and 5 8 amps to the charge controller and the wire length is 40 feet. The position of the sun in the sky can impact a panel s charging speed. Divide the wattage of the solar panel by the voltage of the battery to get the number of amps your charge connector needs to handle. If you keep the panel connected as shown in your diagram it will absorb some power when it is not getting sunlight.

Add a blocking diode on the positive rail between the battery and the panel or as previously suggested and the best solution imho use a small solar charge controller. To charge a battery with a solar panel connect a charge connector to the solar panel. When sunlight shines directs on a panel the charging speed gets a boost and charging cycles slow down on a cloudy day. Voltage drop in a single panel system as you can see in the calculation the voltage drop is 4 09 which will reduce the overall power delivered to the charge controller.

Generally a fully discharged 12 volt 100ah battery needs 1200 watts of energy to be 100 recharged. If a battery is totally drained a solar panel can energize the cells within five to eight hours. The bulk phase will initiate when the battery reaches a low charge stage and that is usually when the charge is below 80.