Charge rate up to 40%

[Gregory OConnor]

Shure sounds like more to it. I did some simple math and got this
crude result:
*Ross 100ampCharger 2 hour 47min = 167min
167 min 100 amp = 315 ah
167 min 1 amp = 3.15 ah
1 min 1 amp = .01886 ah
53 min 1 amp = 1 ah

*Ross 75ampCharger 4 hour 10 min = 250 min
250 min 75 amp = 315 ah
250 min 1 amp = 4.2 ah
1 min 1 amp = .0168 ah
59 min 1 amp = 1 ah


Don,
Are you saying 200 amp would charge your example in in 4 1/2 hours?
your bulk charge numbers agree with Ross. maybe there is charger
technology out there that could top off the batteries quicker?? Or
it may be cause to get a honda 2000watt minigenset for balance of
charge??




--- In WanderlodgeForum@yahoogroups.com, "Don Bradner"
wrote:
>
> In general it is true that bigger is better. With 3-stage
chargers, though, you do not get 33% faster full charge with 100
amps than you do with 75 amps
>
> That is because, after the initial bulk charge has brought the
voltage up to 14.x volts the amps start to drop. Once the output of
the 100-amp charger has dropped to 75 amps the time advantage has
been exhausted, and the remainder of the charge will take the same
amount of time with each charger.
>
> My charger puts out 105 amps peak. When my 660AH of batteries are
around 50% depleted it runs at that 105 amps for about 1 hour before
reaching peak voltage and beginning to drop. At that point it still
has over 200AH left to put into the batteries, and will take several
hours to get there. Real-world says that 100 amps would do it in
about 5 hours, and 75 amps in about 6 hours.
>
> Because of that, when boondocking, I don't run the generator to
anywhere near full charge most of the time. Once the charge rate
drops off to between 60 and 80 amps I turn the generator off.
>
> This is not the best thing for the batteries, and shortens their
life by some percentage, but when you figure the cost of running a
15KW generator just to put 30-40 amps into the batteries to top them
off I figure to save enough on fuel to make the loss of battery life
(which will still be many years with AGMs) reasonable.
>
> With my method, having more amps of charging is a good thing. I
wouldn't mind having 200 amps of charge, but you have to realize if
you do that it will finish bulk really quickly and rapidly drop off
from there.
>
> On 2/22/2008 at 8:20 PM Ross MacKillop wrote:
>
> >How much faster would 110a (two 55's) be over a 75?
> >
> >With three 210 Ah batteries half discharged
> >
> >2 hours 47 minutes--- generator run time with 100 AMP charger or
> >4 hours 10 minutes-- generator run time with 75 amp charger.
> >
> >100 amp Overkill? No By this article maximum charger could
higher.-- from
> >boatus ttp://www.boatus.com/boattech/battchg.htm
> >
> >If you own a small boat and
> > you only need battery power at dockside intermittently
for things
> >like
> > lights and bilge pumps, an SCR (silicone-controlled
rectifier)
> > charger may work best for you. It varies its charge to
keep your
> >battery
> > at a constant 13.4 volts. The ones we carry are fully
automatic
> >and have
> > multiple charging capabilities.
> >
> >
> > Live-aboards and larger boats with many 12-volt
accessories
> >usually
> > have ferro-resonant chargers that put out 12 volts
continuously
> > to keep up with constant power demands. Ours are fully
> >automatic, self-regulating,
> > and ruggedly built to give many years of dependable
service.
> >
> >
> > Experts agree that the best way to replace the energy
you
> >consume from
> > your boat's batteries is through a controlled, multi-
stage
> >process.
> > Both conventional lead-acid (flooded) batteries and gel
cells
> >will charge
> > faster and last longer if they are charged in distinct
phases
> >that take
> > into account their chemical and physical complexities.
The
> >recommended
> > three-stage charging process works as follows:
> >
> > 1.
> > Bulk Stage: This first stage provides a constant
amperage bulk
> >charge
> > of 25-40% of the battery's capacity (in amp hours, Ah)
up to
> >about 14.4
> > volts (14.2 for gel cells). This bulk charge will
restore about
> >75%
> > of the battery's total capacity. It takes less time than
> >tapering chargers,
> > like ferro-resonant and SCR chargers, because the smart
charger
> >delivers
> > greater current to the batteries which can accept
greater
> >current loads
> > when they are discharged.
> >
> > 2.
> > Absorption Stage: The remaining 25% of capacity is
restored at a
> > decreasing rate. Maintaining the battery at 14.4 volts
(14.2 for
> >gel),
> > the amperage is steadily reduced. The battery is
considered
> >fully charged
> > when it will accept only 2-4% of its amp-hour capacity
at 14.4
> >volts.
> >
> > 3.
> > Float Phase: The charge amperage has declined to 2-4%
of the
> >battery's
> > capacity, and voltage drops to 13.5 (13.8 for gel
cells). This
> >maintains
> > the battery without losing electrolyte from gassing.
> >
> > 4.
> > Equalization: Applies to lead-acid batteries only. This
fourth,
> > manually triggered stage prevents lead-acid batteries
from aging
> >prematurely
> > by applying a small, constant current until the battery
reaches
> >16 volts,
> > which dissolves the hardened lead sulfate crystals on
the
> >battery plates
> > and prolongs battery life.
> >
> >
> >
> >
> >
> >
> > Looking for the perfect gift? Give the gift of Flickr!
> >
> >http://www.flickr.com/gift/
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
>