When charging a deep-cycle battery, it does not take any more energy (in watt- hours) to put in the tenth kilowatt-hour than it did to put in the first kilowatt- hour (assuming at capacity somewhat larger than 10 kWh). It may take a higher voltage (potential difference) to continue the charging as the battery becomes charged, but voltage is not energy.
(There is an exception at end of charge for certain chemistries, where more energy is used to put in the last few percent of the full charge, but this is no longer charging, but overcharging, sometimes referred to as equalization. A smart charger reduces charging current accordingly in this situation.) When you are putting a gas into a pressurized vessel, it does take higher pressure to overcome the rising pressure in the vessel. It is the work required to create the higher pressure that takes more energy. Darryl McMahon Icarus Solem <[EMAIL PROTECTED]> wrote: > Hello, > > It seems that the same is true for charging a battery system, only in this > case you are working against the electric potential of the battery cell, > instead of the mechanical potential of the pressurized system. If a > hydrogen tank is initially empty, it takes more energy per unit to fill it > as the pressure rises. The same is true for a deep-cycle battery system - > as you run the electrochemical reation to charge the battery, you have to > input more energy to run the reaction uphill? I'm guessing that these > efficiencies can all be improved - just as the efficiency of biomass to > ethanol conversion has increased over the years. > > Cheers, Karus > > On Wed, 30 Apr 2003, martin wrote: > > > An electrochemical reaction where the desired product has to be forced > > out at a relatively high pressure requires more energy to push the > > reaction over equilibrium. > > > > kirk wrote: > > > > >I'm not aware of any change in potential with pressure. You have any > > data to > > >the contrary? > > >Kirk > > > > > >-----Original Message----- > > >From: martin [mailto:[EMAIL PROTECTED] > > >Sent: Tuesday, April 29, 2003 9:29 PM > > >To: biofuel@yahoogroups.com > > >Subject: Re: [biofuel] World's first hydrogen service station opens in > > >Iceland > > > > > > > > >Down goes efficiency. > > > > > >kirk wrote: > > > > > > > > > > > > > > > -- > > --- > > Martin Klingensmith > > http://nnytech.net/ > > http://infoarchive.net/ ------------------------ Yahoo! Groups Sponsor ---------------------~--> Get A Free Psychic Reading! Your Online Answer To Life's Important Questions. http://us.click.yahoo.com/cjB9SD/od7FAA/uetFAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
