‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Monday, July 12th, 2021 at 11:23 AM, Chris Albertson <albertson.ch...@gmail.com> wrote:
> Sorry I sent the message too soon. Getting max power out of an engine means > running it at a pathological where the load is exactly matched of just one > RPM. But youengine is over powered as it should be so you only need to run > a wide open throttle at any RPM where thecurve is able 3.5 (or whatever) HP. > You are still going to need two automatic control systems or a full-time > skilled human operator. > 1) the first control system measures battery voltage over time and > computesthe rate of charge and uses a MOSFET switch to limit rate of change. > All current battery charges today use a microcontroller and software to do > this. Again a skilled human operator could watch a meter and maybe move > switches if it had charge rate chart as reference. This is best left to > automation. > 2) You are going to need an RPM sensor on the motor and an actuator on the > throttle so that RPM stays constant ouder different loads. Or maybe smarter > use an algorithm that runs the engine at the minimum RPM needed to produce > the power required. Again a microcontroller and software is needed. Or a > skilled full time human operator. > One other thing. The battery charge controller will produce a varying load. > At first, it will "bulk charge" and then taper off the power delivered to the > battery. I'd thing it a good idea if the battery charger software could > communicate to the engine controller software. But this is a "version 2.0 > step. > You likely also want a display so you can monitor what's happening inside. > Certainly during development you need to watch it closely while you do things > like tweak PID constants and the like. If the control computer where > something like a Raspburry Pi it could put all the data on a web page. Then > you can remotely monitor the charger over WiFi on your phone or desktop > computer. > In the old days they used mechanical governors with pushrods to the > carburetor for RPM control but today you put a rotation sensor on the output > shaft that does a pulse each revolution and send that to the engine controller > On Mon, Jul 12, 2021 at 9:02 AM Chris Albertson <albertson.ch...@gmail.com> > wrote: > > The 6.5 rating on that engine is at "wide open throttle" at the RPM tha > > produces peak power. > > > > I don't know the power curve of that engine but its peak power speed is > > likely faster than you want to listen to, 6,000 RPM maybe. Your first > > step is to use the correct pulley ratio to let the engine run at its peak > > powerpoint. The next step is to implement some kind of automatic throttle > > unless you want to manually operate it. > > On Sun, Jun 27, 2021 at 4:44 AM fxkl47BF via Emc-users > > <emc-users@lists.sourceforge.net> 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. what you describe would be very cool. i wanted a charger that can start a machine with a low battery or get a low battery "mostly" charged quickly. i always planned for it to be a hands on manual process not a set it and forget it. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
