Hello Willie, There is a way to do this if you do not worry about cost. I not only use a inverter for a emergency back up for outboard AC power, but also for onboard three heating systems, AC water pumps and cooling fans. If I ran all these AC devices at the same time, the 12 volt DC input to the inverter could pull over 120 amps.
To power the 5kw inverter which can surge to 6kw is a true 60 hz sine wave at a maximum load of 50 amps which would be about 500 amps at 12 volt DC input. I am using a 145 AH 12 volt deep cycle battery which is use as a buffer between four DC-DC 45 Amp converters fuse at 30 amps each that are connected in parallel. These converters are on while the main motor drops to below 1200 rpm. A 145 amp inverter-alternator where the inverter is rated at 7kw and the alternator is rated at 13.5 to 16 volts takes over when the motor rpm goes above 1200 rpm. I have a SOC indicator for the 12 volt battery which has been running since 2008 which still shows 100% SOC. The inverter-alternator, DC-DC converter and the battery are all connected in parallel. I can see this change over in the converter ampere and inverter-alternator as the main motor rpm approaches 1200 rpm. The 1200 inverter-alternator is the excitation point where this rotation machine starts to generates current. The DC-DC converters then drop to 0 amperes. Up hill runs, the converters are on. Down hill runs the converters are off and the inverter-alternator is on which provide selected loads up to 120 amps AC to the onboard AC devices. This method provides a direct current to these devices which provides some type of regenerative braking which I will need in a few minutes. The hills are glare ice this morning and I will have no problem driving these roads, unlike the neighbors small baby buggy car which cannot make it out of the driveway. Roland ----- Original Message ----- From: "Willie McKemie" <[email protected]> To: "Electric Vehicle Discussion List" <[email protected]> Sent: Sunday, February 10, 2013 8:19 AM Subject: [EVDL] EVs as power source > I tried my 120vac chainsaw on a 45 cell EV pack yesterday. Too high > voltage, I guess. I guess I need something like a 100 vdc pack to make > a 120vac motor happy? Can someone suggest a way to drop the pack > voltage some? > > I guess (I'm doing a lot of guessing here) I should consider an > inverter. Has anyone seen a 2-3kw inverter that accepts 140-160vdc > input? Alternately, I guess I could use a 12vdc inverter, a big 12v > battery and depend on my car's DC-DC to eventually recharge it. If my > Belktronix DC-DC will do 300w, I guess I would need to use only a 30% > duty cycle; use ~1kw only 1 hour out of 3. > > Comments? Suggestions? > > > -- > Willie, ONWARD! Through the fog! > http://counter.li.org Linux registered user #228836 since 1995 > Debian3.1/GNU/Linux system uptime 207 days 23 hours 36 minutes > _______________________________________________ > 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) > > _______________________________________________ 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)
