Power draw question - Mount, Laptop, & DSLR

[Helmann]

Just wondering what the power draw would be for an average laptop and DSLR.
Am about to buy a battery to run a HEQ5 Pro but want to future proof myself for when I start AP.
I am led to believe the HEQ5 draws about 1.5 Ah ? Does that sound right?
I would like to get 2 full nights out of the battery before recharge.

Brett.

[RobF]

The laptop is likely to be the real slug to your battery Brett, particularly if its not one of the new small format ones. Around 1-1.5 sounds right though, unless you're doing a lot of slewing about. Depending on battery you want to leave a healthy reserve if you're likely to be doing this regularly.

[DavidTrap]

Hi Brett

I've just been doing this exercise and have measured a couple of things.

Mount - most draw under an amp when tracking, but that spikes when slewing (hopefully little of this while doing long imaging runs). Allow 1amp draw.

Camera - Most internal batteries are ~1000-1500mah and last for ~1-2 hrs of long exposures. If you extrapolate this to what a 12V adaptor would consume, you're probably looking at another 1amp.

Laptop (the killer) - my 15inch laptop draws a maximum of 3.25amp at 20V. I measured the draw from the 12V adaptor at ~6amp. This was whilst turning on with a flat internal battery. Hopefully with a charged battery and computer running a moderate workload with screen dimmed, this may reduce to ~3amp draw from the 12V battery.

Already you're at 5-6amps. What about dew heaters - another 3-5amps.

If you plan to use an inverter to produce 240V power and use your normal laptop & camera adapters, your inverter will be ~80-85% efficient, so add another 2amps to the calculations to be safe.

I'd estimate my setup will draw ~10amps (including dew heaters). In winter, starting imaging at 7pm and finishing at 3am, I'll be looking at 80amps. Big & heavy batteries are called for...

DT

[GrampianStars]

http://www.onlinebatteries.com.au/catalog/product_info.php?products_id=404 :thumbsup:

This will cure All your power Ailments :lol:
heavy beastie 30Kg and will need to be trickle charged daily.

[Helmann]

So what are these new Atom based net books like on power. I would assume alot better.
Would they be alright for running a mount on?

$179 for a 105Ah battery sound ok? That was a quoted price from my nearest battery world.

[GrampianStars]

Car / Truck batterys are no good
MUST BE DEEP CYCLE
http://www.onlinebatteries.com.au/catalog/product_info.php?products_id=403
go back and ask "for deep cycle" price $

[Helmann]

That was his price for a deep cycle. He also offered me a sealed unit for $10 more.

[RobF]

I should have also mentioned I get about 8-9 hrs with just my 15" laptop and HEQ5Pro from a 45AH deep cycle battery. Takes it down to between half and 2/3 used up. I've only ever run the DSLR off 3 batteries I used to cycle (one charging, one spare, one in use). With an Atom PC you might be able to get through the night (possibly even 2) on one battery in laptop and one spare to save drawing on your deep cycle. Less weight to carry around too.

I never thought it would work out this way, but I always seem to be near 240V whenever out with other people, and a good powersupply and extension lead is all I'd by this time around if I had another go at it. Save the money for other astro toys :D
Depends where you're planning to go of course....

[Helmann]

Well, I live in a townhouse complex and have about a dozen street lights within 100m of me so I am forced to travel.
But I have sourced myself a 120Ah deep cycle battery for $165 now so I am pretty well set up for power.
I think that should do me nicely with plenty of expansion room.
Going to put the battery in one of these : http://www.bcf.com.au/online-store/products/BCF-Battery-Box-Power.aspx?pid=131929#Description