You my want to try replacing the 1K resistor on the led that indicates 13.5 or so volts with a reed relay with 1k coil resistants.
Then you would have a shunt type regulator you could turn on a dump load Or disconnect the panels to keep the battery from over charging. It wouldn't add that much to the cost and would protect a more costly battery. Just a thought.
Old F
Good idea, thanks.
Also, I think I've messed up a bit there and built a circuit that will fry trimpots if they're incorrectly adjusted - I think I should be using a lower-voltage zener with a 1k resistor between it and the trimpot. (ie. zener->resistor->connection to the transistor bases->trimpot).
I'll post an updated diagram once I've sorted that problem.
BTH[ Parent ]
How about, insteading of grounding the tap of the trimpot and hooking the diodes to the top, grounding the bottom of the trimpot and hooking the diodes to the tap?[ Parent ]
That would probably work too, but I gave this a try yesterday and now the whole thing works pretty much the way I intended it to:
If you want to increase the voltage spacing between the LEDs you can add an extra diode in series (as I've done with Q1).
I've revised the PCB layout a bit to accomodate the changes, and it now measures 100x25mm (4x1"). I'll post the artwork here if anyone is interested.
Then you would have a shunt type regulator you could turn on a dump load Or disconnect the panels to keep the battery from over charging.
While reed relays have considerable hysteresis, you may still find that turning on the dump load will drop the voltage enough to cause it to drop out, creating an oscilator. B-(
I though of a way to give you an adjustable cutin/out with just a few more components but it's a tad too elaborate to go into here.[ Parent ]
