(also posted on AAC)
My neighbor's golf cart is showing signs of chronic undercharging of its flooded lead-acid deep-cycle batteries (uneven voltages between groups of cells, low capacity). It has 18 cells; nominally 36V. Under charge using the **broken link removed**, the batteries barely reach 38.0V (2.12V/cell), which is not enough to top them up. The end-of-charge voltage should be at least 45V (2.5V/cell). The charging current tapers to zero prematurely (too soon)
The Lester charger is dirt simple. Here is the schematic. Big transformer, 115Vac primary, center-tapped secondary, two rectifiers with common cathodes which make the +; - taken from the c.t., i.e. full-wave rectifier. The tranny has an extra winding which is paralleled with an 6uF 660Vac AC capacitor, with no other connections. AFIK, it is some sort of ferro-resonant regulator.
I have checked continuity, and everything appears good. Diodes good, fuse good, transformer windings all show continuity, no shorts between windings. The only thing that looks suspicious is that the resonating capacitor measures 2.94uF instead of the marked 6uF.
Is this the reason why it is not charging the batteries? Not resonating properly? How does this regulate?
My neighbor's golf cart is showing signs of chronic undercharging of its flooded lead-acid deep-cycle batteries (uneven voltages between groups of cells, low capacity). It has 18 cells; nominally 36V. Under charge using the **broken link removed**, the batteries barely reach 38.0V (2.12V/cell), which is not enough to top them up. The end-of-charge voltage should be at least 45V (2.5V/cell). The charging current tapers to zero prematurely (too soon)
The Lester charger is dirt simple. Here is the schematic. Big transformer, 115Vac primary, center-tapped secondary, two rectifiers with common cathodes which make the +; - taken from the c.t., i.e. full-wave rectifier. The tranny has an extra winding which is paralleled with an 6uF 660Vac AC capacitor, with no other connections. AFIK, it is some sort of ferro-resonant regulator.
I have checked continuity, and everything appears good. Diodes good, fuse good, transformer windings all show continuity, no shorts between windings. The only thing that looks suspicious is that the resonating capacitor measures 2.94uF instead of the marked 6uF.
Is this the reason why it is not charging the batteries? Not resonating properly? How does this regulate?