Using an iPad for flats?

[cjdawson]

A picutre is better than 1000 words so

Here's the front view

and here's the back view

The cigarette lighter cable that I have running into the back is one that I made myself with some speaker wire and a 2.5mm DC plug.  The box on the back is the driver for the panel.  The panel itself is under two sheets of tracing paper.

The whole project took me about an hour.   I'm still thinking about added a couple of blocks to the top frame so that I can hang it on the front of the scope.

Out of curiosity, I just put an ammeter on it.  The panel pulls 1.06A of power, so I'll get 70 hours of use from it with my battery

This is going off topic, but I think it's worth putting up.  I'd suggest that if anyone wants to discuss this, we can make a new thread.

Why the 70Ah battery, instead of the usual 17Ah?

well, it's overkill but serves me well. I used to run a laptop with my scope, so needed the extra juice to be able to run an Inverter.  Also I found that my battery didn't last long enough when I was away, so decided to over estimate.

My total power requirements are now.

2A for scope (max, only needs about 200mA normally)

6Ah for heater (again max, tend to use about 200mA normally)

200 mA for Auto guider (This is new, and has replaced the old inverter)

200 mA for SkyFi (again, new and helps to replace the inverter)

So in total I need to be have about 9A availble per hour.  With a 70Ah, I should be able to run everything as full power for about 7 hours.

The reality is more like

200mA for scope (tracking)

200mA for heater that's about 10% of the heaters capability.

120mA for autoguider

150mA for SkyFi

So in normal operation, that means that the whole setup is pulling less than 750mA now.  With that, a 17Ah battery should be plenty for an evenings observing.   But that does mean that if there's a long night, alot of slewing, or alot of dew, things eat up the power very quickly.  So, 70Ah will mean that I should never have to worry about power.