My experience with this is charging the 12V battery bank down at my storage container (no grid power) from the Sevcon 128V/12V DC-DC converter in my Rabbit. I also happen to have a 140W mod-sine inverter to run the fluorescent lights (the standard long tube 40W type, 2 of them) hooked up to the 12V battery bank. On the one or two occasions that I've had both DC-DC converter and the inverter going at the same time, the fluorescents really start to flicker, about 1 to 2Hz or so. Nothing smoked, but I have to ask myself whether that phenomena is doing the electronics any good, especially if one were to have it going on a long-term basis.
Chuck Hursch Larkspur, CA www.geocities.com/nbeaa ----- Original Message ----- From: Prasad <[EMAIL PROTECTED]> To: ev discussion list <[EMAIL PROTECTED]> Sent: Saturday, August 17, 2002 9:33 PM Subject: Re: 120 VDC Inverter > Will a converter-inverter arrangement work. Since 12VDC - 120VAC is > available in the market, and a DC-DC converter must also be available, why > not use them in series. > > Prasad > www.geocities.com/aquariangenius > > ----- Original Message ----- > From: "Lee Hart" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Saturday, August 17, 2002 12:07 AM > Subject: Re: 120 VDC Inverter > > > > Jim Coate wrote: > > > So with my 176 volt pack I just need to add a FET to turn it on/off > > > at 60 Hz to make a crude square wave inverter? > > > > Rod Hower replied: > > > You'll need at least 2 FETs, or you could use 4... your standard > > > H-bridge... Or you can replace Fet's 3 and 4 with capacitors > > > and pulse Fet 1 and 2 complimentary (make sure you have some dead > > > time in between turning one on and the other off. If you use IGBT's > > > make sure you have anti-parallel diodes on every device. > > > > The simplest inverter is probably just an H-bridge (4 semiconductor > > switches). It intrinsically delivers a square wave. You'll want some > > inductance in series with the load (which can be the motor itself if you > > only use it for driving motors). You'll also need some capacitance to > > filter the sharp edges and voltage spikes. The larger the L and C values > > you can stand, the closer the output can approach a sinewave. > > > > If you use only 2 switches with 2 series capacitors for the other two > > legs, the capacitors have to be HUGE at 60 Hz and high power levels. > > But, it has the advantage of being intrinsically current-limited. The > > capacitors also guarantee no DC offset. > > > > If the DC input voltage happens to be different that the peak AC output > > voltage, you'll need an autotransformer (or transformer if isolation is > > also needed). At 60 Hz, a transformer will be big and heavy. The size of > > an autotransformer is proportional to the voltage difference it needs to > > provide; if you only need to boost the AC output voltage 10%, the > > autotransformer is 10% of the weight of a transformer. > > -- > > Lee A. Hart Ring the bells that still can ring > > 814 8th Ave. N. Forget your perfect offering > > Sartell, MN 56377 USA There is a crack in everything > > leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen > >
