Portable Power Station

Hi Mark,
Not sure about the power, but as I got a CEM26 a few month ago I thought I would give you my thoughts: 
First, I love it! I use the ASIair Plus for control and really like it so far.
But, I am so far ok with the 26 lbs but see that it is limiting. I just got a 6 inch RC telescope and it makes it on the mount. I might have purchased an 8 inch but it put me way too close to the limit. If I had to do it over, I would have gotten the CEM40. Or at least would have thought long and hard about it!
Gary

Hi Mark!
I basically have the exact setup you aim for (CEM26, 533mc, EAF, but laptop instead of Raspberry). I got a pretty cool powertank in a fisherman equipment shop: A Fox Halo Power Pack 96K. It's rugged and very robust, can be charged with USB-C, has two 12V and several USB ports. I love it and it easily brings me through a whole night, if not two. The main power drain is your camera cooling. I go for -10°C with my 533mc, which takes usually 40-60 % power, which results in up to 24 watts. The CEM26 only needs 0.75 amps (less than 10 watts). Your suggested Buetti power tank also looks nice, maybe even too powerful!
I don't know where you are located. The Fox Halo might be a Europe-only device.
Here is a link to the german Amazon. https://www.amazon.de/FOX-Halo-Power-96K/dp/B07Z6HP3VT=hidden-xs

Edit: I missed the Canada part.. ;)

Let me add my calculation I did in before I got the power tank:
Camera: 1.5 amp (average)
mount: 0.75 amp
dew heater: 0.3 amp

sums up to 2.55 amp. With 26 Ah, my powertank can last 10 hours. My laptop holds up a lot on its own battery, but one charge is also possible and leaves me still with 7-8 hours.

Björn Hoffmann:
My laptop holds up a lot on its own battery, but one charge is also possible and leaves me still with 7-8 hours.

Oops, was replying while you were editing. That's good to know. I might try and swap out Astroberry for Stellarmate so I can use an app on my phone and leave the laptop at home. I also found the power:cooling graph in the 533 manual and apparently it takes .5amp to cool to 30 below ambient, which is 6W instead of the advertised 22W max (or 24W in your case).

Off-topic, but how do you like the CEM26?

Also, I love your work! The combination of the small 533 chip and the FL of the Redcat is killer - it looks like stuff done with a longer FL but you're getting that f/4.9 advantage. Nice.

CS,
Mark

Mark Germani:
Thanks Björn!

I had a look at the unit you use, and it has 307Wh. If you can get up to two nights, I should be able to get 6-8 hours on my 268Wh Bluetti without difficulty. Maybe I'll play around with finding the right balance of battery life and cooling temperature. Do you run your laptop on its internal battery, or power it off your Fox Halo?

CS,
Mark

My laptop holds up to six hours on its own battery, then I need to plug it to the powerbank.
I don't know where you got the 0.5 amp for 30 degree below ambient. To my knowledge it draws up to 3 amp in full cooling power.

Mark Germani:
Off-topic, but how do you like the CEM26?

I really like it! It's my first heavy mount, before that I only used a Star Adventurer for many years. The CEM26 is comparabely lightweight, modern and in good nights I have < 1" guiding rms. Together with N.I.N.A. it does an amazing job in making fully automatic mosaics. The only problem I have from time to time is the DEC backlash. But you can adjust that, it's a very common problem and you will instantly find it when you search for experiences and reviews.

I should have written "cooled camera" instead of "cooled CCD" …

Mounts draw every little power while tracking.  Only when slewing to a target will you see it get anywhere close to max draw.  Take that into consideration for total current draw required by the rig, but it's very small otherwise.  Camera and dew heaters are the big draws followed by computer.  Guide camera will draw a little bit, but not a ton.  EAF and EFW will be very little.

I don't have numbers for each device in my rig but I can tell you what the total draw was over a period of time since I track it.  I am running an EQ6-R Pro with ASI2600MM-P and ASI290MM Mini.  I have a Mele PC Stick which is powered over USB 20, 5V.  One 6" dew strap, EAF, and EFW.  Everything is powered through a powerbox advance, including mount, from which I collect telemetry on all sorts of things.

The last night I had this out it was humid (I'm in North Carolina.. it's always humid) and pretty warm.  The camera had to work a bit harder at the beginning of the night but as it cooled down less power was drawn.  I have included a capture of the current draw over the full night averaged over a 1 hour time period.  Fwiw, the max draw at any point was when slewing to a target in the early morning, peaking around 4.3A.

The way I'd read this graph is I want about 3A average for the rig.  It draws less in the winter since cooling is not running as hard, but I personally ignored that.  So shooting for 12 hours (winter night) would be 36AH.  Nominal voltage draw for the powerbox is 12.8V, so 12.8V * 36AH = 461W.  I got the Jackery 1002Wh which is complete overkill but can run my fridge, meaning my wife was a bit more OK with this purchase ;)

It's really a good idea to control your dew heaters based on dew point. Depending on your climate conditions it can save quite a bit of battery capacity. When I started into this hobby I was just mindlessly fixing the dew heaters to my lens / scope and ran them on full power. These days I rarely see them running on more than 30%.

I saw several people mentioning just one dew heater. Is this due to using OAG or are you not using dew heaters on your guide scopes? (If so, why not?)

Clear skies
Wolfgang

Thanks everyone for the feedback - so appreciated!

@Wei-Hao Wang - another great reason to buy a hybrid! I'll be on foot without a vehicle, though, but something to think about when/if I buy one in the future.

Looking at the Bluetti I would be a bit concerned about the shiny display. If you can turn it off it's ok, if not I would hesitate to buy it.

@kuechlew - the display is on for a few seconds, then automatically shuts off. There's actually a bluetooth app I could use instead to monitor power consumption, though I imagine that would use some of the battery. I wonder if I can shut bluetooth off on the battery to conserve power?

I saw several people mentioning just one dew heater. Is this due to using OAG or are you not using dew heaters on your guide scopes? (If so, why not?)

I don't actually have a fancy dew control system, just a basic USB heating strap. I added a "dimmer" so I could control the heat manually, as it would often get REALLY hot otherwise. I don't use one for my guide-scope - I don't think it's ever dewed-up, and if it has it's never impacted my guiding (I image wide-field in poor seeing). Perhaps something to consider if I ever go for a longer FL.

Thanks again to everyone who responded!

CS,
Mark