Re: (ET) Solar charging, part 2 :using a stationary pack

["Jeremy" <nagidog starband net>]

Hi there,

OK, I'll admit it.  After a long winter with marginal solar power I decided
to take my e-12 to a friends house to get a good solid charge.  I haven't
had my elec trak long, and am still figuring it out.  The charger seems 
very
primitive, charging continuously at a constant amperage.  Solar charge
controller ease off the charge as the batteries reach their fill, which is
much better for the batteries.  It seems like we are all paying a price to
fully charge our batteries using the onboard charger.  Charging via solar
panels and charge controller would allow for a more complete charge, and
better control over an equalizing charge.  A good compromise between total
solar charging from panels and charging from a main battery bank via on
board charger would be to somehow get 36 volt charging out of my existing
solar system without major modifications to the setup.  I run 12 panels in
three series of 48 volts, which gets bumped down to the 24 volt battery 
bank
by the Solar Boost 3048 charge controller.  I think the best approach to
this would be to take the 24 volts from the bank and bump it up to 36+/-
volts DC and run it through a charge controller to the elec trak bank.
Anybody already doing this or might know how to do it without changing the
configuration of the main battery bank.

Jeremy

----- Original Message -----
From: "Christopher Zach" <czach computer org>
To: <jbc coate org>; "elec-trak" <elec-trak cosmos phy tufts edu>
Sent: Wednesday, April 23, 2003 6:33 AM
Subject: Re: (ET) Solar charging, part 2 :using a stationary pack


>
> Yes, that is another possibility. I use a 100 watt grid-tie inverter
hooked
> to my main battery pile (300amps at 24 volts) to divert surplus sun power
> from my panels into the grid. I do like inertae: it is the best way to 
> get
> efficiency out of a solar panel setup.
>
> However I will say that the efficiency of my solar charger is pretty 
> close
> to 100%. The efficiency of the Elec-Trak's on-board charger is nowhere
near
> as good (lot o' heat). Thus by using the grid-tie approach, it is not as
> efficient as charging directly from the panels.
>
> The typical "solar" way is as follows:
>
> Tractor gets top priority for charging
> Bringing the shed batteries to 25 volts gets second priority
> Rest is sold to the grid.
>
> The batteries in the shed typically get a full charge during the morning
> (the panels can put in up to 15 amps, the inverter takes out 4 tops) and
> then get discharged down to 70% or so during the afternoon. The size of
the
> battery core is large enough that I can run tools, toys, lights in the
> evening without dropping the pack below 40%.
>
> Works pretty well actually.
> Chris
>
> ----- Original Message -----
> From: "Jim Coate" <jbc coate org>
> To: "elec-trak" <elec-trak cosmos phy tufts edu>
> Sent: Wednesday, April 23, 2003 9:13 AM
> Subject: Re: (ET) Solar charging, part 2 :using a stationary pack
>
>
> >
> > Another variation is to use a grid-intertied system. For those of us
> > already on the grid, this can be done with out any stationary battery
> > pack (although won't have the blackout backup). Any solar power
> > available goes into "the grid" when the sun shines and the ET is 
> > plugged
> > in and charges from the grid (regardless of the amount of sun shine at
> > that moment). I have just two smallish panels and an intertie 
> > controller
> > (Chris Zach may have had one first that I read about??) for a 100 watt
> > system. Similar to what Jeremy and Eric and all have been saying, this
> > gets the most power possible from the panels as there is always some
> > place for it to go.
> >
> >
> > Eric wrote:
> > >    In my opinion I think charging a stationary pack instead of
directly
> > > charging the Elec-trak gives you the freedom to do more (than just
> charging
> > > the ET). Coupling together the ability to recharge the ET along with
> other
> > > uses makes the investment in solar panels a wise investment. Don't
> forget to
> > > explain to the wife how if the electricity goes off again at least we
> have a
> > > back up system to hold us over till the electricity in our area is
> restored.
> > --
> >
> > _________
> > Jim Coate
> > 1992 Chevy S10
> > 1970's Elec-Trak
> > http://www.eeevee.com
> >
> >
> >
>
>
>