The controller should hold this voltage for the remainder of the day after bulk charging the battery.īattery voltage = 13V (battery voltage can vary between say 10.8V fully discharged and 14.4V during absorption charge mode). 3.4V per cell or 13.6V for a 12V battery. Lithium batteries do not have a defined “float voltage”, and therefore the “float voltage” of the controller should be set to be at or just below the “charge knee voltage” (as indicated in the chart below) of the LiFePO4 charge profile, i.e. A related reason is to avoid the rapid and large variation in voltage that will occur in these regions as large loads are switched on and off. Lithium batteries (LiFePO4) do not benefit from re-entry into a bulk mode during the day as the internal impedance of the lithium batteries increases at high (and low) states of charge as indicated by the orange vertical lines in the chart below and it is only necessary to occasionally balance the cells which can only be done around the absorption voltage. This re-entry into bulk mode works well with lead-acid batteries as the voltage drop and droop is worse than it is for lithium-based batteries which maintain a higher more stable voltage throughout the majority of the discharge cycle. if the battery voltage drops below a defined voltage for more than a set time period, e.g.bulk mode > absorption mode > float mode. The most common charge profile is the same basic sequence used on a quality mains charger, i.e. They are especially suited for lithium-iron-phosphate batteries as once fully charged the controller then stays at the set float or holding voltage of around 13.6V (3.4V per cell) for the remainder of the day.

it regulates the current flowing from the solar panel into the battery bank to avoid overcharging the batteries. (If you don't need to understand the why's, scroll to the end for a simple flow chart). As with a regular quality battery charger, various battery types are accommodated, the absorption voltage, float voltage can be selectable, and sometimes the time periods and/or the tail current are also selectable. View All DC Circuit Protection & SwitchesĪ solar charge controller (frequently called a regulator) is similar to a regular battery charger, i.e.Product Warranty and Power Output Warranty.7 Products You May Need With Your Solar Panels.How To Compare Good and Bad Flexible Solar Panels.

Trailer breakaway battery solar charger