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Recommendations Needed: Power It All?

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#1 Thundermoon1994

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Posted 21 July 2019 - 09:42 PM

Hi all,

 

My current power source is on the fritz, and I'm looking for a new device to power all my imaging gear.  Currently, I use a car battery jumpstarter to power my Atlas mount and my dew heater, and I've got a long outdoor extension cord from the house powering my laptop, camera cooler, and USB hub.

 

Any recommendations on a device that I can use to power all of these things and eliminate my dependence on being near an A/C power source?

 

 

Thanks!

Damien



#2 TikiTom

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Posted 21 July 2019 - 09:57 PM

Check out this one from Amazon. 

Been using it since the 2017 eclipse. Does a great job. 

USB, AC plugs & 12V cig plug connectors: 

 

https://www.amazon.c...uct/B004EIAADG/


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#3 gezak22

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Posted 21 July 2019 - 09:57 PM

Hi all,

 

My current power source is on the fritz, and I'm looking for a new device to power all my imaging gear.  Currently, I use a car battery jumpstarter to power my Atlas mount and my dew heater, and I've got a long outdoor extension cord from the house powering my laptop, camera cooler, and USB hub.

 

Any recommendations on a device that I can use to power all of these things and eliminate my dependence on being near an A/C power source?

 

 

Thanks!

Damien

I used to use two 100 Ah AGM batteries. One for the laptop + mount, and the other for the CCD (and fans when needed). I really like DC power as I have found some AC sources to be dirty enough to show noisy images. The idea behind two batteries is two-fold.

1. In case of a failure, I could power everything from one battery.

2. By using two batteries, the discharge in each battery after one session is low enough to result in a longer battery life.

 

The big downside is that your back will hate you for carrying all that weight.

 

When using batteries, I also recommend having a spreadsheet where you log the battery voltage before and after each session and after each charge. Tracking the voltage of your batteries will help you spot failures before they happen.


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#4 Thundermoon1994

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Posted 21 July 2019 - 10:19 PM

Check out this one from Amazon. 

Been using it since the 2017 eclipse. Does a great job. 

USB, AC plugs & 12V cig plug connectors: 

 

https://www.amazon.c...uct/B004EIAADG/

That's actually the same or very similar to the one I've got.  I made the mistake of trying to power a hair dryer (for dew removal from an SCT) when I first got it, and the A/C outputs have never worked since. 

 

Are you powering a laptop, camera cooler, mount, and dew heater with it?  You find that it last you full imaging sessions, even in the winter?



#5 Thundermoon1994

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Posted 21 July 2019 - 10:21 PM

I used to use two 100 Ah AGM batteries. One for the laptop + mount, and the other for the CCD (and fans when needed). I really like DC power as I have found some AC sources to be dirty enough to show noisy images. The idea behind two batteries is two-fold.

1. In case of a failure, I could power everything from one battery.

2. By using two batteries, the discharge in each battery after one session is low enough to result in a longer battery life.

 

The big downside is that your back will hate you for carrying all that weight.

 

When using batteries, I also recommend having a spreadsheet where you log the battery voltage before and after each session and after each charge. Tracking the voltage of your batteries will help you spot failures before they happen.

Would you be able to share a link to the product you're using?  It would be much appreciated.



#6 Jerry Lodriguss

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Posted 22 July 2019 - 04:16 AM

That's actually the same or very similar to the one I've got.  I made the mistake of trying to power a hair dryer (for dew removal from an SCT) when I first got it, and the A/C outputs have never worked since. 

 

Are you powering a laptop, camera cooler, mount, and dew heater with it?  You find that it last you full imaging sessions, even in the winter?

Look for a 12-volt hair dryer. They make them. I have one.  I've used it many times when I forgot to turn on the dew heaters. :-)

 

Jerry



#7 Phil Sherman

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Posted 22 July 2019 - 08:07 AM

To run your scope, camera and computer for a full night, you'll need at least an 85AH deep cycle battery. Get a DC power adapter for the computer and DC-DC switching converters for voltages other than 12V. If your mount runs on 12V,  you may want a DC-DC buck/boost converter between the battery and the mount to stabilize its voltage.

 

An alternative to a lead acid battery is one of the newer lithium types. LiFePO4 batteries have the longest cycle life but won't be usable if you intend to image in temperatures much below freezing. They are much more expensive than lead acid but weigh much less. They also don't have lead acid's loss of capacity at near freezing temperatures or the voltage drop as the state of charge (SOC) decreases.


Edited by Phil Sherman, 22 July 2019 - 08:08 AM.


#8 gezak22

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Posted 22 July 2019 - 08:37 AM

Would you be able to share a link to the product you're using?  It would be much appreciated.

Here you go.


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#9 CharlesW

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Posted 22 July 2019 - 10:12 AM

You’re thinking about this bassackwards. First, going to battery is a step in reverse. AC makes all things possible. Second, this is an opportunity to start imaging from inside your house. Put the extension cord on an $8 Home Depot reel. Makes it easier to roll up in the morning. Get a Pyramid power supply for 12v and a regular power strip. It’s expensive but get an Icron Ranger 2304 USB over Ethernet extender to bring the laptop inside. 



#10 gezak22

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Posted 22 July 2019 - 10:48 AM

... AC makes all things possible... 

Can you elaborate? The way I see it, with a DC supply, you can image from anywhere.

 

Edit: A laptop, mount, and camera all need DC, so having an AC source will result in potential conversion losses. Also, not all AC sources give you a clean power source (see the figure here).


Edited by gezak22, 22 July 2019 - 11:01 AM.


#11 davidparks

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Posted 22 July 2019 - 02:05 PM

Separate the power requirements of the laptop from the rest of the gear.

 

Find out the peak amp draw of your gear, aka the mount when it's slewing in both axis, dew heaters on highest setting, etc.  This will give you an idea of how many amp hours you need to get through your typical session.  It's best to use a meter, but you can go by Output listed on any AC adapters.

 

For example:  My mount, 2 dew straps (main/guide), focuser, rotator, and camera never draw more than 2amps peak, and most of the time (not slewing) it is much less (1.2amp).  I use the Suaoki Lithium Power, it will run my gear all night easily, and often two nights.  Small, lightweight, delivers consistent voltage and can use the whole thing  (Lead Acid should only be discharged to 50%)

 

Your laptop is a whole other beast entirely, and depends on the make/model of laptop.  Many laptops require 15-19volt, and inverter losses take a significant toll.  Older laptops may have batteries that no longer perform like they once did.  Maybe a new replacement internal battery will get through the night (for an old battery scenario).  Your laptop may have an external "clip on" battery designed specifically for it, check your make/model.  In any case, I would divide and conquer, most astro gear doesn't draw much power and is quite happy with small, lightweight lithium packs/batteries.  Keep your 12-volt needs separate from your laptop needs, or at least explore the possibility, sometimes solving 2 power needs is easier/cheaper and more elegant than combining into 1 solution.

 

I keep my system ultra-light and ultra-portable without compromising any functionality, so I use a Microsoft Surface Pro laptop, which is very happy running on 12-volt(2.5amps).  Not only does the battery last 12 hours, but I can charge it from the same Suaoki Lithium Power if I need using the common 5.5x2.1 DC plug  (doing this will reduce the Suaoki to just one night of operation)  Not all laptops can do this, and my point is, know your gear and what it needs, designing a solution is far better than just throwing lead acid amp hours at it (your back and legs and arms will thank you!)

 

Those "portable jump starters" are terrible for what your doing.  They are designed to deliver a lot of power all at once (Cold Crank Amps), discharging quickly... yes you can plug AC into them because they have a built in inverter, but it's meant for emergency use, and it's extremely inefficient.  These are not meant for sustained draw, steady discharge, like true deep cycle.  If you must use a lead acid battery for your AC plug laptop, then get a true deep cycle (not a marine), and a small inverter, you'll get much more mileage out of it (mind the 50% discharge limit).


Edited by davidparks, 22 July 2019 - 02:06 PM.

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