User manual
65
Fig. 059: Circuit diagram charging controller
With the charging controller built on the plug board, you can understand the prin-
ciple of a serial shunt controller (longitudinal controller). The longitudinal transistor
used for the charge control controls the current owing from the solar module to
the rechargeable battery and the voltage. In the test setup the control is achieved
by manual cycling (manually) of the supplied current (cycle length and frequency)
with the switch S1. This cycling happens electronically in automatic controllers.
Then more current ows if the breaks from one cycle to the next are reduced and
the cycle frequency is increased. During charging, the rechargeable battery is thus
given short current impulses that are shorter or longer depending on the charge
voltage height (pulse width modulation). Control of the charging current is adjusted
electronically via the longitudinal controller depending on the charging voltage of
the rechargeable battery.
Another benet of the longitudinal transistor is the fact that it prevents the charged
rechargeable battery from „reverse“ discharging at night again.