On Sunday, June 27th, 2021 at 6:41 AM, fxkl47BF <[email protected]> wrote:
> i'm gonna explain my screwup here because this group of folks has a very > diverse range of expertise. enough kiss'n up. if you know of a list that > would be more appropriate please let me know. > i've had a desire for some time to build a gasoline powered battery charger. > i've seen it done several times and thought no big deal. my first thought was > to use a 3 hp engine and a 100 amp one wire alternator. but since i already > had a 6.5 hp engine i decided to go with that and an alternator like this > https://www.ebay.com/itm/NEW-CS130-ONE-WIRE-RED-ALTERNATOR-FOR-CHEVROLET-GMC-CHEVY-220-AMP-1-WIRE-1100665-/283190864732?hash=item41ef7dab5c. > i also added an ammeter like this > https://www.ebay.com/itm/301111474999?hash=item461ba47b37:g:hYUAAOxy4fVTEuR6. > i finished it and was ready to test. i pulled a big battery out of my > tractor, connected a 1000 watt inverter, and about an 800 watt load. i > cranked the engine and connected it to the battery. ammeter showed about a 7 > amp load. i switched on the inverter and it went to about 9 amps. i switched > on the load and it went to about 75 amps. the engine was straining. i > disconnected the the alternator from the battery so the load could draw down > the battery. after about one minute i reconnected the alternator. the ammeter > jumped to about 110 amps and it promptly stalled the engine. i tried several > times with the same results. > all of my feeble calculations led me to believe that a 6.5 hp gasoline engine > was more than enough to power a 220 amp 12 volt alternator. either my 6.5 hp > engine is more feeble than my brain or my calculations are way off. > thanks for any feedback. i've been do'n a little piddle'n on this when life didn't get in the way. i took all of the feedback from y'all and it sounded like less would be better so where my sheaves were originally a 2:1 increase now i have a 1:1. i tried slower, .7:1 decrease but it was too slow. the alternator would barely make 13 volts. to get a little more info i bought one of those point and shoot tachometers. it says this engine runs at 3200 rpm with no load. with a 1:1 ratio i drained down my battery and with a 800 watt load the alternator made 120 amps at 14.3 volts for 20 to 30 seconds before the amps dropped. the tach showed it turning at 3100 rpm. i think to get 220 amps i would need a 10 or 12 hp engine and turn this thing at 10000 rpm. of course it would melt down after about 1 minute. i appreciate all the feedback. _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
