I think I took you too literally when you said "50% DOD max".
I understand wanting to have all the capacity you can afford.
I like the last two reasons the most! :)
-Tom
--- In electricboats@yahoogroups.com, Pitt Bolinate <boombolinate@...> wrote:
>
> Solar/wind/regen trickle top up above 85%down to 50% is from here to there if i motor all the way with a half to spare if I want to stay out? Who runs the fuel tank dry when they go out sailing? I want more than I'll ever use but enough to use more if I need it/want it? It's a big boat and I don't want to get stuck for the sake of a few batteries? Cause they arrive next week and it's too late now? I could so I did? There are a few random answers. Thanks for the number crunching.
>
> I am looking for a smart marine electrician / Mentor in the Bay area? Any recommendations?
>
> Sent from my iPad
>
> On Mar 21, 2011, at 20:30, "Tom" <boat_works@...> wrote:
>
> >
> >
> > If you charge 85% and only discharge to 50%, you are using 35% of 540AH, which is 189AH.
> >
> > Dividing 189AH by your 28A charge rate means you'll spend about 6.75 hrs charging, depending on your charging profile and BMS activity.
> >
> > But why do you want to use only 50% of the available capacity?
> > Quality LiFePo4 cells are rated at >3000 charge-discharge cycles at 70% DOD. That's a lot of money to spend just to get 189AH.
> >
> > -Tom
> >
> > --- In electricboats@yahoogroups.com, Pitt Bolinate <boombolinate@> wrote:
> > >
> > > Sorry I would have said drained max1/2 charge charge time up to 85% perhaps?
> > >
> > > Sent from my iPad
> > >
> > > On Mar 20, 2011, at 20:51, "Tom" <boat_works@> wrote:
> > >
> > > >
> > > >
> > > > Hi Pitt,
> > > > We can't answer the time to recharge question without knowing how deeply the cells were discharged. You mentioned charging to 80-85%, but how far do you plan to discharge them?
> > > >
> > > > I have 180AH of CALB cells aboard, I only discharge to 70% DOD, so I have 126 AH available, if I fully charged them. But I don't. LiFePo4 doesn't take well to being overcharged or over-discharged, so I prefer to quit charging before they are near max capacity. This means I have paid for capacity that I never use, but it also means I never operate an expensive battery bank near the ragged edge.
> > > >
> > > > The EU2000i is only rated at 1600W continuous, I doubt you'd be able to run the Elcon 2000+ from this generator for more than half an hour before it complains.
> > > >
> > > > But let's say you discharge your bank to 70% DOD. You have 378AH available, it you fully charged them. The Elcon 2000+ is rated at 28A output when operating at 115V. 378AH divided by 28A equals 13.5 hours.
> > > >
> > > > Performance when powered by the Honda 3KW should be the same.
> > > >
> > > > It may take a bit longer if you have configured your charger and BMS (if any) to run CC-CV.
> > > >
> > > > In my case I charge with an Elcon 1500 at 22-20A and shunt current from the first cells to reach 3.4V until the other cells have caught up. This balancing only takes 15 minutes or less.
> > > >
> > > > By measuring cell voltage and counting AH consumed and AH replaced I know when to quit charging. I don't like the charge profile (much too high voltage for my taste) of the Elcon 1500, so I manually terminate the charge before it completes the CC stage, which is about the same time the BMS says "we're done".
> > > >
> > > > The ELcon and BMS has been working reliably for nine months now, but I still like to be around to keep an eye on the charge process. Not a problem for me, since my shop is about 50 yards from the boat.````````````````````````````````````````````````````````````````````````
> > > > -Tom
> > > >
> > > > --- In electricboats@yahoogroups.com, "Pitt" <boombolinate@> wrote:
> > > > >
> > > > > If I have a lifepo4 battery bank 48V x 540 AH an Elcon 2000 charger. How long would it take to charge the batteries with
> > > > >
> > > > > A~ shore power hook up?
> > > > > B~ Honda 2000i to 80-85% ?
> > > > > C~ Honda 3000Is to 80-85% ?
> > > > >
> > > > > There are people here who seem to gobble up the math for the these questions. That makes it possible for people like me to even consider going electric. Thanks guys.
> > > > >
> > > >
> > > >
> > >
> >
> >
>
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