Excellent summation of battery usage Jack. Correct on all counts.

The only thing that I would add is that you can't actually get all of a
rated usage out of a battery. That is, even if the battery is sitting at
the proper temp, I thought I remembered a number like only 90% of that being
usable. So for my 115AH marine battery, I only count on about 100AH usable
life (at 60-70 F), and as you mentioned, less as it gets colder (much less
near/below freezing, like 10-25% of total capacity).

Gotta love those Wisconsin winters!

Anthony J. Kroes
Green Bay, WI

> -----Original Message-----
> Jack Dembicky
> Sent: Thursday, June 07, 2001 2:31 PM
> To: David Power
> Subject: Re: [M]: Re: RE: RE: LX200 DC option
>
>
> I am not a battery expert (ie., correct me if I am wrong). I
> don't know if
> anybody has mentioned this yet or not, but if memory serves me
> draining a car
> battery repeatedly (to nearly dead) is really bad on the battery
> itself. This
> is why they sell Deep Cycle marine batteries for trolling motors
> or in our case
> telescopes. These batteries are built to be nearly completely
> discarged and
> then get charged back up.
>
> I seem to remeber that a typical car battery can be deep cycled
> (drained to
> nearly dead) maybe about 5-10 times before actual physical
> internal damage to
> the battery occurs. The Deep cycle batteries have heavier plates
> and are built
> to take that type of drain repeatedly. I think the same applies
> to the gel
> cells (not sure) in that they can be repeatedly charged/drained
> which these
> little jump start packs you buy have in them.
>
> Just a thought for those who are thinking of using their car
> battery and then
> jump starting the dead car every morning to charge the battery back up.
>
> Also, It seems like I read that even though a 17AH battery (one
> of the gel
> cells in those little jump start packs) read that you can draw
> 17AH, they are
> rated at this draw for a certain temperature. In cold weather
> they don't put
> out that much and your mileage will vary. Just something to
> think about when
> the weather gets cold, your battery won't last as long. My 12"
> LX-200 will go
> all night (one night, MAYBE partially into the next) using a 17AH
> gel and an
> inverter (350W) to power just the scope. I forgot what the
> current draw was
> with the scope alone, but when I hook up the laptop/CCD it was
> close to 4A
> (which also corresponded to my battery lasting about 3 hrs
> outside running all
> of it).
>
> Also on inverters, Look at the no load Amperage draw. Smaller is
> better here.
> It basically means if you just hook up the inverter (ie leave it
> hooked up) but
> don't plug anything into it (Power supply for telescope, etc) how
> much drain
> the inverter itself will have on the battery. I use a 350W
> inverter and have
> no problem running the LX-200 (12"), laptop, and CCD (either
> Cookbook or MX7C
> alone).
>
> Jack
>
> Moderator of Yahoo!EGroups Astronomy Star Parties
> http://groups.yahoo.com/group/StarParties
>
> ============================================================
> = Personal =
> ============
> Toll Free Fax/Voicemail: 1-877-457-8207
> Web: http://galileo.apo.nmsu.edu/~dembicky/
> AOL Buddy Name: Astrman
>
> ========
> = Work =
> ========
> Work Phone: 505-437-6822
> Fax: 505-434-5555
> Web: http://www.apo.nmsu.edu
> ============================================================
>
>
>
>
>
>
> > I purchased mine recently and took it to the TSP. I ran the scope, dew
> > heaters and laptop off it for several nights between recharges. It
> > wasn't
> > cheep but worked flawlessly and makes a very nice compact portable power
> > solution. I've even jumped one of my kids cars off of it by using a dual
> > cigarette lighter adaptor I made. I haven't had mine for more than a
> > couple
> > of months so I can't make any claims as to its longevity.
> >
> > David
> >
> > ----- Original Message -----
> > Sent: Thursday, June 07, 2001 6:18 AM
> > Subject: [M]: RE: RE: LX200 DC option
> >
> >
> > > Is anyone using the Kendrick battery pack? It is a 33 amp hour unit
> > and
> > has
> > > an 18 volt output for the LX200. I am considering buying one of these
> > and
> > > would like to know what other's recommendations are on this item.
> > >
> > >
> > > Stan Rife
> > > Houston, TX
> > > 1999 Gold Wing (Red Ryder)
> > > 1999 R 1100RT (The Batcycle)
> > > GWRRA
> > > BMWMOA 86491
> > > AMA 274008
> > > TMRA 33117
> > > WD5EWA
> > > NRA CLH6808H
> > > TSRA 111251
> > >
> > >
> > >
> > > -----Original Message-----
> > > RebelPPC
> > > Sent: Wednesday, June 06, 2001 11:23 PM
> > > Subject: [M]: RE: LX200 DC option
> > >
> > >
> > > Okay, taking collective advice from all of you, I have assembled the
> > > components for my first non-110 volt available star party. Components
> > are:
> > >
> > > *** ($34.95) Marine Deep Charge Battery. It's a 75 Amp-Hour/100
> > Reserve
> > > Capacity Trolling Battery
> > > *** ($19.92) 2-6 amp charger
> > > *** ($34.94) 140 watt Continuous/250 watt peak Power Inverter.
> > >
> > > Total cost $89.91 or in the same neighborhood as the cost of Meade's
> > DC
> > > driven power supply.
> > >
> > > I charged the battery up till it was just drawing a couple of amps
> > which
> > > gave me 12.65 volts at the posts. Hooked the scope up to the Meade
> > 110
> > > power module which was then plugged into the inverter which was then
> > hooked
> > > up to the battery. Switched on the scope and battery voltage slowly
> > dropped
> > > to and stabilized at 12.51 volts. Set the scope up to do tracking and
> > left
> > > it alone except to go in and do 5 minutes worth of slewing at a slew
> > rate
> > of
> > > 4 every half hour. This has been going on for 8 hours now and the
> > battery
> > > voltage is now showing 12.28 volts. The inverter instructions say
> > that it
> > > can provide 110 volts as long as the battery has 10.5 volts left in
> > it.
> > So.
> > > at the present amperage draw, it looks as if I can do a full night's
> > viewing
> > > if not more on this setup.
> > >
> > > Also, if it is a two or more day event, all I have to do is crank the
> > truck
> > > up, attach the inverter to my truck battery and plug my battery
> > charger
> > > into the inverter to charge up the marine battery for the next night's
> > > viewing.
> > >
> > > Thanks to everyone that helped me out with this decision and component
> > > needs...
> > >
> > > I'm happy...
> > >
> > > Regards
> > > FLag
> > > 8" f/10 LX-200 #845198
> > > 36:10:32.754 N
> > > 82:43:31.098 W
> > >
> > >
> > >
> > >
> >
> >
> >
> >
>
>

View index by [date] [author] [subject]
Previous message: [M]: Re: Price of telescope parts, Frank Schwartz
Next message: [M]: Re: Blown fuses on LX200..., Chris Frye
Previous message in thread: Re: [M]: Re: RE: RE: LX200 DC option, Steve Brown