Hi folks! I'm looking around for one of those 12v rechargeable power pack thingies. Just pulled the latest Supercheap Auto cattle-dog out of the mail box and they've got a couple of models on sale: a 12AH red job and a 17AH yellow one. I figure the 12AH model is all I'd really need to run an LX90, and at the "special" price of $38 I'm sorely tempted. Here's a link to those items on their web site:
Truf, you can get a dedicated laptop power supply from Jaycar.
Part# MP-3462. Variable volts out @ up to 3 Amps. My old cat. price is $89.50. but may have changed since 04.
(www.jaycar.com.au) in power supply section.
HTH. L.
The Gel cells in most field batteries shouldn't be drained below 40-50% of their capacity. This means that a 17Ah battery really has a useable capactity of about 9Ah. Assuming that the LX90 pulls 1 AMP, that would give you 9 hours of use before the battery should be recharged. I think the LX90 pulls about 750mA, which would extend your time to 12 hours.
I've used a 15A jumpstarter pack to power both my LX200 and my laptop (with an adapter) but not at the same time. It ran both with no problems, the laptop for over 7 hours taking avies and processing them.
TO ALL CONCERNED. The item stated is a converter. It is designed to put out variable voltages ABOVE 12 volts input to between 15 volts & 24 volts, @ up to 3 AMPS.
TRUF, please look in Jaycar cat. as I suggested. This is the cheapest and best way to run your comp. L.
ps. Tony?????
I should have pointed out that it is possible to draw all 17 Ah from a 17Ah gel cell battery; however, this will significantly reduce the battery life. One thing I have noticed is that the Auto jump start batteries in the 17Ah class usually have a starting current rating of 500 amps, whereas the Celestron 17Ah Power tank (sold elsewhere under a variety of names) has a starting current rating of only 250 amps. This would imply that the auto batteries have thinner plates and will wear out sooner. Personally I've been using one of the 17Ah auto batteries for about three years. Unfortunately I only get to use it about six nights per year, so that doesn't represent much of a field test. OTOH, I have used it to jump start about a half dozen cars.
Originally posted by RAJAH235 If you have a 100 a/h battery, you can draw 1 amp for approx. 100 hrs. but you will NOT be able to draw 100 amps for 1 hr. Not capable! L.
Yep amp hour ratings are usually based on a 20 hour discharge, ie 100a/h = 5 amps for 20 hours.
I think I'll forget about powering the laptop for the time being, because it looks like I'd have to run two power sources. It'll run for about 3hrs from its own internal battery anyhow. I'll just concentrate on running the scope.
Rajah, was your comment about the item being a CONVERTER, referring to the Jaycar item for running the laptop? Not a reference to the Supercheap Auto item? Would you give me the 'go-ahead' to grab the Supercheap Auto 12AH power source? Or is it a resounding "No, Truffo, get something else!" ?
I'm thinking (ignorant of such things as I am, so it makes my brain hurt!) that if the LX90 is nominally rated at drawing (is that the right word?) 1amp, surely that would be at 'maximum slew'. Most of the time it would be drawing (there's that word again) much less than that just driving the scope sidereally. So, here's where my feeble brain pipes in, wouldn't a 12AH source run the scope for many, many hours of 'normal' use?
Anuvver fing... the DC input socket on the autostar control box on my old LXD55 AR6 was 'centre positive'. I believe the LX90/200 is the same. Are the plugs on these portable power supplies centre-positive? Is that a 'standard' thing? Or do I run the risk of unknowingly connecting a 'centre-negative' source to my scope and blowing it to smithereens? eeeeeeeeek!
Rajah, was your comment about the item being a CONVERTER, referring to the Jaycar item for running the laptop? Not a reference to the Supercheap Auto item? Would you give me the 'go-ahead' to grab the Supercheap Auto 12AH power source? Or is it a resounding "No, Truffo, get something else!" ?
I think he was saying that the supercheap thingy has 12v output but your laptop needs 18v input
I run the Waeco battery system for both the Lx200 and laptop when I am in the field. These batteries are great but they cost over $400. Surveyors and serious campers use them for their reliabililty. It will run a laptop and LX200 for over nine hours without recharge.
The old LX200 classics had an ammeter on the control panel. My 10-inch LX200 classic draws just under 1 amp while tracking, and over two amps while slewing at full speed. The LX90 should draw a little less current, and 750mA is an educated guess. You could just use the #607 DC power cord that plugs into the cigarette lighter port in your car. Most car batteris have 70 Ah or more capacity.
What you find is that most people will always suggest to get the biggest battery you can afford..specialy with a goto......yes the 12amp will be fine to run for a while but as the battery gets older and you may start to thinking about running accessories of the same battery....(not recommended) but still possible...then the higher amp's will be their to be used....
look for that price...get the battery pack...its a start and its only $38 you cant loose.
Paul, the Waeco battery looks impressive, but, considering I've just forked out for a new scope, not to mention all the accessories beckoning obscenely (as I type I've just ordered 2 Meade QX eyepieces, the 20mm and the 26mm from Bintel)... it's a bit out of my league at the moment. This is the first time I've seriously considered a power pack and riding the learning curve has been fun! I'll certainly keep the Waeco in mind for the future.
Astro, yep, the cig lighter adaptor would be the way to go when I'm using the scope near the car. Which would be most of the time. I'll definitely look at that option. I just know that there will be times when I'll need to separate the scope and the car!
Tony, that's what I wanted to hear! I can't see myself running much else off the battery and, as you say, at that price I've got nothing to lose. The sale at Supercheap runs all week, so I'll think about it... but probably grab one before the sale finishes!
You guys have been most helpful. Much appreciated!
L.
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