Here are a few pics of my battery current alert or BCA. It watches ripple currents induced by the rectifier in a VRLA or other lead acid systems to determine battery health and sets off an alarm if the ripple is too high or too low. It uses a picaxe 14M microprocessor, precision reference, precision rectifier (personal hybrid design using a ZXCT1041- see U1,C1,C2,R7-R9.) The final design replaced the dip switch bank and led shown in the drawing with 2 toggle switches and a buzzer.
