Current Limiter

The Current Limiter is a small plastic box which prevents excessive charging current for the battery type being charged. It has three switch-selectable values.
It also limits the charging voltage.
The battery to be charged is connected to two binding posts, while a 4-pin receptacle accepts a plug on a cable from the Charge Controller.
Batteries can be charged without the Charge Controller, whose sole function is to limit the number of ampere-hours,.
The LP2951 regulator IC contains a shutdown feature, off by default, for the Charge Controller to use. It is a low-dropout type so that the overall voltage drop is also low.
A one-ohm resistor in the battery lead is used by the Charge Controller to measure the charging current.
When shutdwn, the current draw is only 5 MA, which is useful when a 12-volt floating battery is permamently connected to the meter terminals. This extends charging time to night-time.