On 12 Sep 2013 at 4:05, Steve Powers wrote: > Do you have any ideas to make a cheap black > box solution for people who aren't Electrical Engineers but have basic > abilities to build circuits from a simple schematic?
I posted this before, but maybe you didn't see it. This is about the simplest charging controller I know of. http://www.evdl.org/docs/c_car_charger.jpg I think this works on essentially the same principle that Rudman Regulators use. When the on-charge voltage reaches the set threshold (determined by zener diode CR6, R4, R5, and R6 and possibly other components), the charger output through SCR CR3 is turned off. Battery voltage then starts to fall. When it falls a little below the threshold, the charger output is turned on again. The effect of this is to create a very coarse PWM, setting an average finishing voltage below the transformer/rectifier's actual output voltage. Thus the voltage can be higher for faster bulk charging, compared to an ordinary regulated-voltage taper charger. In use, the lamp L1 will begin flash during the finishing phase. (It's on when the charger output is off.) As the finishing continues, the charger on (light off) periods become shorter as the battery charges. When the duty cycle goes to light-mostly-on, the battery is full and you can (should) disconnect the charger. You could probably automate the final total shutoff with a slight modification. Being a crude circuit hacker, not an EE, I might try some kind of r/c circuit and relay in parallel with the "done" lamp L1. It might latch a latching relay or trigger an SCR, opening the power input to the charger, when the lamp had been on for some appropriate length of time. Another way of doing the final shutoff might be to have the first blink of L1 trigger a timer which would shut off the charger after some fixed guess at an appropriate finishing time. I used to see stuff like this on the surplus market, but haven't paid much attention in recent years. Lee Hart will probably have a better idea than mine. ;-) David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
