hi all. auto repair shops that machine brake rotors and drums have piles of iron filings. good source of usually free samples.
apologies for interjecting this torrid torroid discussion,but after reading some mainstream wisdom on the topic of commercial battery desulphators, i think the reason i haven't had success with restoring lead acid batteries is because individual collapsing field spikes are just too brief. i think cap dumping is an essential addition to a medium current joule thief circuit, in order to succeed.
pic 1 is a joule thief concept that sends charging pulses back to the source,the charge battery with a trickle charger hooked up.the plan is to charge the cap up to say 50 volts,then close both switches near simultaneously,the cap and battery equalize,maybe with a short ring down.switches open and the blocking oscillator resumes for say 98% of each cycle. the other 2% the switches are on.
so i'm open to any suggestions as to how to switch between oscillate and dump.
is there a fairly simple way to stop the transistor from turning on during the dump cycle,as obviously it would short the cap,when the dump switch is closed. just after that close the dump switch, open the dump switch,then resume oscillations for the set period.
im thinking maybe mechanical switching or relay contacts might survive as the dump goes through the primary winding,the small delay in current buildup might afford some protection to points or contacts on closing and current drops to zero by the time the points or contacts open,maybe with the addition of a condensor.but also considering scr's, solid state relays,flip-flop circuitry, a 741 chip,opto isolators or using a modified computer fan or something.
*looks like a 200uf flash cap goes from 13.5 to 50v in about .8 of a second.a relay might do it.just need to energise the relay coil with 2% duty cycle every .8 sec.
** ok, pic 3 runs,but backwards to how i intended.the relay has about a 98% duty cycle.so i just had to swap n.o. with n.c. and it does the job.i guess there could be losses if the relay contacts bounce or ark. i should devise a way to monitor or measure the pulses.
cheers.
apologies for interjecting this torrid torroid discussion,but after reading some mainstream wisdom on the topic of commercial battery desulphators, i think the reason i haven't had success with restoring lead acid batteries is because individual collapsing field spikes are just too brief. i think cap dumping is an essential addition to a medium current joule thief circuit, in order to succeed.
pic 1 is a joule thief concept that sends charging pulses back to the source,the charge battery with a trickle charger hooked up.the plan is to charge the cap up to say 50 volts,then close both switches near simultaneously,the cap and battery equalize,maybe with a short ring down.switches open and the blocking oscillator resumes for say 98% of each cycle. the other 2% the switches are on.
so i'm open to any suggestions as to how to switch between oscillate and dump.
is there a fairly simple way to stop the transistor from turning on during the dump cycle,as obviously it would short the cap,when the dump switch is closed. just after that close the dump switch, open the dump switch,then resume oscillations for the set period.
im thinking maybe mechanical switching or relay contacts might survive as the dump goes through the primary winding,the small delay in current buildup might afford some protection to points or contacts on closing and current drops to zero by the time the points or contacts open,maybe with the addition of a condensor.but also considering scr's, solid state relays,flip-flop circuitry, a 741 chip,opto isolators or using a modified computer fan or something.
*looks like a 200uf flash cap goes from 13.5 to 50v in about .8 of a second.a relay might do it.just need to energise the relay coil with 2% duty cycle every .8 sec.
** ok, pic 3 runs,but backwards to how i intended.the relay has about a 98% duty cycle.so i just had to swap n.o. with n.c. and it does the job.i guess there could be losses if the relay contacts bounce or ark. i should devise a way to monitor or measure the pulses.
cheers.
Comment