The overarching goal is to be as efficient as possible by cutting losses.
Every time you convert one voltage to another, you lose some of the power to the process. When you generate power at 120vac and reduce it to 48vdc with a charger you waste some power. When you step 48vdc back up to 120vac you lose some more power. When you boost 48vdc up to 175vdc (your example) you lose power again. Even if your of conversions were 95%, when you stack one conversion on top of another you begin to lose serious amounts of power. That power has to come from somewhere, and that somewhere is usually an onboard generator that is fueled by diesel. Those stacked losses end up being wasted diesel fuel.
The best practice would be to store your power in your battery bank at whatever voltage your biggest load will be. In the case of electric propulsion that would be your motor voltage. Then generate electricity as direct current at the voltage of the battery bank to avoid the loses of converting 120vac into 48vdc or whatever voltage your battery bank is. Now you only need to convert your battery voltage into 120vac to operate your hotel load.
Thanks...
Harry Wilkins,
Research Vessel Carpe Sol
Thanks...
Harry Wilkins,
Research Vessel Carpe Sol
hw@rvCarpeSol.com
To: electricboats@yahoogroups.com
From: p0054107@brookes.ac.uk
Date: Fri, 9 Jul 2010 10:18:28 +0000
Subject: [Electric Boats] Re: Anyone have experience with 144 volt motor systems?
Have you considered using a 48 volt battery bank ? With a large standard inverter which could give 120 v ac for accesories and 175 volt DC for the motor. All sine wave inverters internally convert to high voltage DC before converting that to AC.
Chris S
--- In electricboats@yahoogroups.com , James Sizemore <james@...> wrote:
>
> I seriously looked into a Hi-voltage system, they simply cost less per KW delivered. The problem I keep coming back to was that there where very few accessories above 48 volts. So any money saved on the traction motor was lost buying expensive poorer quality accessories. An example is there are zero pure sign inverters on the market above 48 volts and the few modified sign inverters that take 144 volts where very feature poor and from companies you have never heard of before. Same problem for DC-DC conversion, same for chargers.....etc etc.
>
> I really wish Outback or Mastervolt would put together a decent quality inverter/charger setup for higher voltages. but as it stands now 48 volts seems to be the highest voltage that mass market accessories are made for.
>
> If you do run across a source for pure-sign inverters for high voltage please let me know.
>
> On Jul 5, 2010, at 8:35 AM, Kirk wrote:
>
> >
> >
> > --- In electricboats@yahoogroups.com , "rvcarpesol" <harry8136103219@> wrote:
> > >
> > > I'm trying to decide between 48 volt and 144 volt motor systems for a newly constructed 36 foot catamaran. I'm hoping that there are some people here that have some firsthand experience with the 144 volt systems.
> > >
> > lots easier to electrocute yourself with higher voltage
> > accidents do happen
> > Kirk
> >
> >
>
To: electricboats@
From: p0054107@brookes.
Date: Fri, 9 Jul 2010 10:18:28 +0000
Subject: [Electric Boats] Re: Anyone have experience with 144 volt motor systems?
Have you considered using a 48 volt battery bank ? With a large standard inverter which could give 120 v ac for accesories and 175 volt DC for the motor. All sine wave inverters internally convert to high voltage DC before converting that to AC.
Chris S
--- In electricboats@
>
> I seriously looked into a Hi-voltage system, they simply cost less per KW delivered. The problem I keep coming back to was that there where very few accessories above 48 volts. So any money saved on the traction motor was lost buying expensive poorer quality accessories. An example is there are zero pure sign inverters on the market above 48 volts and the few modified sign inverters that take 144 volts where very feature poor and from companies you have never heard of before. Same problem for DC-DC conversion, same for chargers....
>
> I really wish Outback or Mastervolt would put together a decent quality inverter/charger setup for higher voltages. but as it stands now 48 volts seems to be the highest voltage that mass market accessories are made for.
>
> If you do run across a source for pure-sign inverters for high voltage please let me know.
>
> On Jul 5, 2010, at 8:35 AM, Kirk wrote:
>
> >
> >
> > --- In electricboats@
> > >
> > > I'm trying to decide between 48 volt and 144 volt motor systems for a newly constructed 36 foot catamaran. I'm hoping that there are some people here that have some firsthand experience with the 144 volt systems.
> > >
> > lots easier to electrocute yourself with higher voltage
> > accidents do happen
> > Kirk
> >
> >
>
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