Advice on portable power supply for EQ6-R Pro and ASIAIR Pro

[Ade Turner]

At the moment I take my photos from my garden so access to power isn’t a problem.

However, I’m considering taking my rig to a dark sky site and would appreciate suggestions on a suitable portable power solution please (budget is tight).

Currently I run DC power via 2 cables to my EQ6-R Pro and ASIAIR Pro from a Nevada regulated supply.

Accessory wise I power my ZWO focus motor, 2 dew heaters (8” Astrozap and 3” Lynx) and the ZWO Vonet wifi extender from three of the 12V outlets on the ASIAIR Pro.

I already have a Celestron 7Ah Power Tank, but I’m not convinced it would be ‘beefy’ enough. What do your think, would it work and be reliable?

Thanks.

[Clarkey]

If you are on a budget I would make my own. I have an excessively large power supply with multiple 12v and USB power supplies fed from a 12v battery. It is excessive as it 110 Amp hour but it will run all my kit with dew heaters, mount, camera etc for a 12 hour session without issue - even when cold. (If really cold I have a small heat mat to warm the battery). I suspect it would do 2 nights but I have not tried it. I think you are right in saying your 7Ah power tank would struggle. At a guess the two heaters probably draw an amp or so, plus a similar amount for the mount guiding only. If you add another amp hour for the other stuff the unit you have will give you a couple of hours. You could just buy a small leisure battery 40 Ah or similar and make up the connections required. I think you could probably get the whole set up for about £60. The other option is a jump starter from Halfords or similar. As long as it is rated to give the power you need that would be OK. There are a number of Lithium versions that will work well but will cost more.

[Ade Turner]

17 hours ago, Clarkey said:

If you are on a budget I would make my own. I have an excessively large power supply with multiple 12v and USB power supplies fed from a 12v battery. It is excessive as it 110 Amp hour but it will run all my kit with dew heaters, mount, camera etc for a 12 hour session without issue - even when cold. (If really cold I have a small heat mat to warm the battery). I suspect it would do 2 nights but I have not tried it. I think you are right in saying your 7Ah power tank would struggle. At a guess the two heaters probably draw an amp or so, plus a similar amount for the mount guiding only. If you add another amp hour for the other stuff the unit you have will give you a couple of hours. You could just buy a small leisure battery 40 Ah or similar and make up the connections required. I think you could probably get the whole set up for about £60. The other option is a jump starter from Halfords or similar. As long as it is rated to give the power you need that would be OK. There are a number of Lithium versions that will work well but will cost more.

Thanks very much. I’ve seen mentions of home-made power supplies but I’d need to find some clear, blow-by-blow instructions if I went down that route. In terms of needing a supply to last 12h, it’s unlikely I’d need to run my rig that long, so 6h tops maybe.

in terms of power draw, I don’t think I’ve seen it draw more than about 3A in total, that’s with everything running and the mount slewing, but admittedly I wasn’t paying close attention.

I’ll take a look at leisure batteries and jump starters, thanks for the suggestions. I suspect Lithium would be beyond my budget unfortunately.

[teoria_del_big_bang]

The celestron 7Ah will certainly not run all your gear for any meaningful length of time.

There are so many threads on SGL alone about remote site supplies so well worth a search on here.
It is also a tricky subject and one that does not come cheap (well not very cheap).

By the sounds of it you only need 12V and not 5V as well (many need 5V for their RPi if running Astroberry, or Stellarmate etc on a Rpi) which makes things easier.
Also when people need to power a laptop as well also becomes more difficult as they normally need around 19V and also consume a fair bit of power, but I assume you are using your phone or tablet maybe to communicate with Asair ???

With what you have listed I am assuming the following: 
ZWO focus motor - may take around 1A
2 dew heaters (8” Astrozap and 3” Lynx) - probably around 1.5 A between them maximum
ZWO Vonet wifi extender - It says typically 5V at 2A but I would be surprised if more than 1A
ASIAIR Pro - normally a RPi is 5V 3A but this runs on 12V so I would guess will take around 2A.
EQ6-R - Requirement is 4A but again probably will not take much over 2 to 3A and then only whilst slewing to target, when tracking probably more like 0.5 to 1A.

Now a lot of assumptions because difficult to determine the actual power needed without actually measuring consumption current. Focus motor in essence will take practically nothing when not focussing and that does't happen all the session, mount only takes a high current when slewing to target, and again this doesn't normally happen often, but some nights may be more than others, dew heaters, Asair and wifi extender will be fairly constant but difficult to say exactly how much they will take.

So a very round about guess is you will take around an average of 5A for your setup.
So 5A at 12V is 60 Watts (Watts = power).
So for a 4 hour session you need a 12V capable of 4 x 60 = 240 W h (Watt Hours). Which is actually a fair bit of power. Again I may have well over estimated this and you would have to measure the current drawn but is going to be between 3 and 5A average I am sure. (After I wrote this I see you said around 3A measured when tracking - so for safety say 4A average)

So if it is 12V only at 4A you basically have a few choices. Each has their advantages and draw backs.

1.  Some form of 12V leisure like battery set into a box with connectors to suit your requirements.  Advantage is that this is probably the cheapest option, disadvantage is they are heavy and need looking after. You cannot run them right down otherwise they will not recharge properly and will be permanently damaged. So you need a supply capable of a higher Wh than needed and you must keep them charged so when not in use you need to get them out and charge them say once a month or leave on trickle charge. So something like This Battery Box , This battery and a Charger
2. You can buy a car jump starter pack similar to This . This is just a lead acid type batter with some jump leads and in essence similar to option but a smaller battery and will come with a trickle charger. So same issues with it needing kept charged and often difficult to determine what the Wh actually is as many give misleading specifications stating only the maximum current they deliver. Some are only 7.2 Ah batteries and most will be no more than 20Wh. So I do not recommend this option, but many do use these or some form of them that are not necessarily made to start cars with dead batteries such as This  but at 17 Ah you cannot get all that 17Ah out of it without damaging it so say 12Ah is may last you 3 at 4A hours but I would say count on 3 hours not 4. 
3. A lithium power pack. Much lighter than the leisure battery option, also no issues with damaging them with leaving discharged and can use the full available powr without damaging them. Disadvantages are the price as these are not cheap. This is a good one. and although only 13.2 Ah (less than the 17Ah above) you should get all of that if fully charged so would get a similar time out of it to the one above at 3 to 4 hours. But as £260 is a major investment.

If on a budget I would suggest maybe the celestron 17 Ah powertank and then use your 7 Ah Powertank as well. Run your mount from the smaller one and the rest from the bigger one. You should get a good 4 hours from them, maybe a bit more, just be careful with making sure you do not drain them fully in a session and then keep them topped up when at home.

Steve

 

Edited May 3, 2021 by teoria_del_big_bang

[Ade Turner]

On 03/05/2021 at 15:33, teoria_del_big_bang said:

The celestron 7Ah will certainly not run all your gear for any meaningful length of time.

There are so many threads on SGL alone about remote site supplies so well worth a search on here.
It is also a tricky subject and one that does not come cheap (well not very cheap).

By the sounds of it you only need 12V and not 5V as well (many need 5V for their RPi if running Astroberry, or Stellarmate etc on a Rpi) which makes things easier.
Also when people need to power a laptop as well also becomes more difficult as they normally need around 19V and also consume a fair bit of power, but I assume you are using your phone or tablet maybe to communicate with Asair ???

With what you have listed I am assuming the following: 
ZWO focus motor - may take around 1A
2 dew heaters (8” Astrozap and 3” Lynx) - probably around 1.5 A between them maximum
ZWO Vonet wifi extender - It says typically 5V at 2A but I would be surprised if more than 1A
ASIAIR Pro - normally a RPi is 5V 3A but this runs on 12V so I would guess will take around 2A.
EQ6-R - Requirement is 4A but again probably will not take much over 2 to 3A and then only whilst slewing to target, when tracking probably more like 0.5 to 1A.

Now a lot of assumptions because difficult to determine the actual power needed without actually measuring consumption current. Focus motor in essence will take practically nothing when not focussing and that does't happen all the session, mount only takes a high current when slewing to target, and again this doesn't normally happen often, but some nights may be more than others, dew heaters, Asair and wifi extender will be fairly constant but difficult to say exactly how much they will take.

So a very round about guess is you will take around an average of 5A for your setup.
So 5A at 12V is 60 Watts (Watts = power).
So for a 4 hour session you need a 12V capable of 4 x 60 = 240 W h (Watt Hours). Which is actually a fair bit of power. Again I may have well over estimated this and you would have to measure the current drawn but is going to be between 3 and 5A average I am sure. (After I wrote this I see you said around 3A measured when tracking - so for safety say 4A average)

So if it is 12V only at 4A you basically have a few choices. Each has their advantages and draw backs.

1.  Some form of 12V leisure like battery set into a box with connectors to suit your requirements.  Advantage is that this is probably the cheapest option, disadvantage is they are heavy and need looking after. You cannot run them right down otherwise they will not recharge properly and will be permanently damaged. So you need a supply capable of a higher Wh than needed and you must keep them charged so when not in use you need to get them out and charge them say once a month or leave on trickle charge. So something like This Battery Box , This battery and a Charger
2. You can buy a car jump starter pack similar to This . This is just a lead acid type batter with some jump leads and in essence similar to option but a smaller battery and will come with a trickle charger. So same issues with it needing kept charged and often difficult to determine what the Wh actually is as many give misleading specifications stating only the maximum current they deliver. Some are only 7.2 Ah batteries and most will be no more than 20Wh. So I do not recommend this option, but many do use these or some form of them that are not necessarily made to start cars with dead batteries such as This  but at 17 Ah you cannot get all that 17Ah out of it without damaging it so say 12Ah is may last you 3 at 4A hours but I would say count on 3 hours not 4. 
3. A lithium power pack. Much lighter than the leisure battery option, also no issues with damaging them with leaving discharged and can use the full available powr without damaging them. Disadvantages are the price as these are not cheap. This is a good one. and although only 13.2 Ah (less than the 17Ah above) you should get all of that if fully charged so would get a similar time out of it to the one above at 3 to 4 hours. But as £260 is a major investment.

If on a budget I would suggest maybe the celestron 17 Ah powertank and then use your 7 Ah Powertank as well. Run your mount from the smaller one and the rest from the bigger one. You should get a good 4 hours from them, maybe a bit more, just be careful with making sure you do not drain them fully in a session and then keep them topped up when at home.

Steve

 

Thanks very much for taking the time writing such a comprehensive breakdown Steve, much appreciated.

As you say, my situation is straightforward in that everything is 12V, and I am controlling everything from the ASIAIR Pro/iPad Pro so there's no laptop in sight.

Looking at it I would love to go the Lithium route, it's so light and compact, but £260 is on the heavy side for the amount of use I'd realistically get from it.

That said, the downside of keeping traditional batteries healthy, along with their weight and bulk, is nudging me towards to investing in it as a more robust, and 'cleaner', solution... 

I need to do some thinking (and probably a lot of sweet-talking...) 

Thanks again, its great to get a bit of clarity rather than me trying to half guess at a solution 👍

[teoria_del_big_bang]

RVO also sell the Celestron 13.2Ah Powertank  slightly cheaper at £238, FLO will probably price match it.

Also there are tracer batteries many people use like THIS , the one here is slightly less power at 10 Ahr but is cheaper, also can get these elsewhere with a similar capacity and still cheaper than the Celestron  like THIS and you may get them cheaper if you search about. Not sure about the connections though so they may take some messing with to get you connected.
Unfortunately these batteries just are not cheap and to be honest would be a bit wary of any that are cheap on Ebay or even Amazon.

Steve

 

Edited May 4, 2021 by teoria_del_big_bang

[callisto]

14 minutes ago, teoria_del_big_bang said:

RVO also sell the Celestron 13.2Ah Powertank  slightly cheaper at £238, FLO will probably price match it

Not sure if they will...I was looking at the 7.2Ah version from Bristol cameras for £125, so I messaged FLO for a price match but they gracefully declined 😢

[powerlord]

have a look at my post:

If all you need is 12v it's really simple.

the cheapest way (assuming you want to avoid massive lead acid battery), is as large a 4s lipo as you can afford from hobbyking. A mains lipo charger (to mains charge it), and regulated 12v output DC to DC converter (the one I used (10 amp 12v out) runs on 24v, and will work down to 15v = 3.75v per cell, which is still a fair bit of charge, but tbh it will keep cells working a long time and saves you worrying about discharging too much (if you used 5s, even at dangerously flat 3v it is pushing out 15v).

https://www.amazon.co.uk/gp/product/B07P9Q3TB8/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

If all that scares you, another option is a lifepo4 lead acid replacement battery - these are for light replacement of car//bike batteries and charge via standard car charger but they are not cheap.

Edited May 4, 2021 by powerlord

[Ade Turner]

On 04/05/2021 at 21:17, teoria_del_big_bang said:

RVO also sell the Celestron 13.2Ah Powertank  slightly cheaper at £238, FLO will probably price match it.

Also there are tracer batteries many people use like THIS , the one here is slightly less power at 10 Ahr but is cheaper, also can get these elsewhere with a similar capacity and still cheaper than the Celestron  like THIS and you may get them cheaper if you search about. Not sure about the connections though so they may take some messing with to get you connected.
Unfortunately these batteries just are not cheap and to be honest would be a bit wary of any that are cheap on Ebay or even Amazon.

Steve

 

Those Tracer batteries look promising, must admit I’d not come across them before, thanks.

[Ade Turner]

On 04/05/2021 at 21:37, callisto said:

Not sure if they will...I was looking at the 7.2Ah version from Bristol cameras for £125, so I messaged FLO for a price match but they gracefully declined 😢

Worth a shot though. I guess there are some occasions where it just wouldn’t be doable.

[Ade Turner]

On 04/05/2021 at 21:53, powerlord said:

have a look at my post:

If all you need is 12v it's really simple.

the cheapest way (assuming you want to avoid massive lead acid battery), is as large a 4s lipo as you can afford from hobbyking. A mains lipo charger (to mains charge it), and regulated 12v output DC to DC converter (the one I used (10 amp 12v out) runs on 24v, and will work down to 15v = 3.75v per cell, which is still a fair bit of charge, but tbh it will keep cells working a long time and saves you worrying about discharging too much (if you used 5s, even at dangerously flat 3v it is pushing out 15v).

https://www.amazon.co.uk/gp/product/B07P9Q3TB8/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

If all that scares you, another option is a lifepo4 lead acid replacement battery - these are for light replacement of car//bike batteries and charge via standard car charger but they are not cheap.

Thanks, but honestly I wouldn’t know where to start! I’d certainly end up frying something important 😂 I do appreciate the cost savings and flexibility of a home brewed supply, but for safety’s sake I’ll give it a miss I think 👍

[SteveWolves]

Ade there are several members of Wolverhampton A.S. who are in the process of making their own power supplies, message me for info.

[Ade Turner]

On 09/05/2021 at 11:31, SteveWolves said:

Ade there are several members of Wolverhampton A.S. who are in the process of making their own power supplies, message me for info.

Thanks very much for the offer Steve, although tbh I’m much more likely to buy one of the commercial options once the pennies allow. 

I was briefly a member of Wolves A. S. back in the mid 70s. I remember getting advice from a chap named Astle or Astley when I was looking to grind my own mirror. Circumstances changed and I didn’t take it further. The availability of astro kit now is just astonishing, and getting good quality optics seems far more affordable than it was.

[SteveWolves]

You can join again at the price of £10 we have an observatory site now and can loan kit to members. All meetings on Zoom at the moment but have observing sessions when we can.

[SupernovaF1]

I did my own LiFePo4 36Ah battery for not a lot of money condieringthe costs of these batteries.

All you need is a battery box like this 

https://www.ebay.co.uk/itm/Trolling-Motor-Battery-Power-Box-12V-output-USB-and-Lighter-socket-/133497906091?_trksid=p2349624.m46890.l49286

And connect it witha screwdriver to the battery.

https://www.batterymasters.co.uk/li36-12-12v-36ah-lithium-iron-phosphate-lifepo4-high-capacity-deep-cycle-battery-charger-included.html

If 36Ah is too much or not enough  you can replace it with a battery that suites. 

[wookie1965]

I built my own out of an old tool box I am going to do it again with a smaller box but for the parts only cost me £20 at most.

[pete_81]

Hi Paul @wookie1965
That looks pretty neat and on the cheaper side than the genuine ones.
I've been pondering the power supply when I eventually get around to getting to a dark(er) site than back garden and expecting during summer months that this is relatively pointless for the couple (if even!) hours of darkness we get so staying on the patio and just learning and doing seems sensible, and using a portable pack in winter is a clever move, using the extended darkness.

Anyway, ignoring ones thoughts, I've had a look at the stuff you have in your box and have seen most/all of it available on this website.

Have you got a component list you'd like to share on here?
What blade fuses have you set things up with (ratings)?
What's the component in the 2nd/3rd image that you're holding?
Can I ask about the battery you are using - what spec is it (link could be great to see too)?
I'm sure this would also help other folks that might want to (carefully!) do the same!

Obviously, I'd love to get a Jackery battery, but that's not going to be any time soon!
Thanks!

[wookie1965]

Obviously prices have gone up now  but these are what I have got now all from the bay, you can search that site for the comparable items see which are cheaper. I have done a quick search and just picked the ones I have, not the cheapest because wanted to reply asap.

I have added a couple of extra pieces now for my homemade dew strips. 

https://www.ebay.co.uk/itm/363151739649?hash=item548d87cb01:g:w~sAAOSww35ggRz9

https://www.ebay.co.uk/itm/113899409910?hash=item1a84ef11f6:g:M6UAAOSw8S9eTql7

https://www.ebay.co.uk/itm/393138957332?hash=item5b88e86c14:g:9UoAAOSwggRfoFBi

https://www.ebay.co.uk/itm/124256718400?hash=item1cee470e40:g:3uEAAOSwQTle~Mfw      0.5 will carry 11amps get thicker pieces for the positive and negative terminals of the battery. 1.5mm carry's 21 amps  should be sufficient.

https://www.ebay.co.uk/itm/363476062512?hash=item54a0dc9130:g:EZAAAOSwDWVgPLj0

https://www.ebay.co.uk/itm/384325503792?hash=item597b95cb30:g:vXcAAOSwfStfv6Bl

https://www.ebay.co.uk/itm/393304272976?hash=item5b92c2f050:g:NZEAAOSwNMNglFUI

https://www.ebay.co.uk/itm/222544569773?epid=15023443414&hash=item33d0b0a5ad:g:vOsAAOSwHLNZP777  inline fuse holder 3rd picture

https://www.ebay.co.uk/itm/253263731634?hash=item3af7b1dbb2:g:ilwAAOSwc0FUm0pP  I have added these for dew strips

https://www.ebay.co.uk/itm/252452734645?hash=item3ac75b06b5:g:P58AAOSwU9xUMbN3  attach to voltage and amps so it is not on all the time.

https://www.ebay.co.uk/itm/265220802929?epid=18017013600&hash=item3dc0644971:g:1dQAAOSwW6pgbIOV

 

I hope this helps you and everything is explained.  my components have 5amp fuses in as far as I can remember I will check tomorrow just to be sure and obviously inline fuse is 20amps.

Paul

 

 

Edited August 17, 2021 by wookie1965

[pete_81]

Thanks Paul,
This is great and hope it may help others that have the same dilema!

Pete

[wookie1965]

Very welcome Pete hope it has helped. 

Paul 

[wookie1965]

What I am going to do is get some of these so I can charge the battery without lifting the lid. 

https://www.ebay.co.uk/itm/New-5-16-Stud-Premium-Remote-Battery-Power-Junction-Post-Connector-Terminal-Kit-/202660185532?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0

[pete_81]

For further progress on this project, I have purchased all the bits to make a battery box containing all I need at this stage. I have no cooling (DSLR) and no electronic focuser or electric filter wheel (manual wheel just acquired), so think that is my go-to setup.

The following kit needs power:
AZEQ6 mount,            12V, 4A (slewing power requirement, not tracking/guiding)
DSLR (Canon 550D), 8V, 2A
RPi (pi4, 4GB),            5V, 3A
Dew Heaters (USB),   5V, 2A, x2

So following Paul's @wookie1965 plan above, got a master switch, in-line fuse and blade-fuse box (included -ve busbar) to supply the following connections:

The 5-switches on the 12V panel will control (individually):
Cigarette Socket (for AZEQ6 connection using existing power cable)
Voltage Supply Reading (for temporary viewing of battery supply)
USB ports (double 2.1A) to supply dew heaters when used (one for main scope, 1 for guide scope)
Banana plug socket, for feeding power to Buck Converter
DC Connector (2.1/5.5) for powering step-down converter

Also adding the Battery Studs for easier charging of the battery.

Total cost for the above: just over £35.

Already used with the Nevada unit, I have the cigarette socket and banana connector similar to above.
(I've also made a male-banana to female-banana/DC connector, so this splitter is identical to the 2 single components above, so connections are transferrable). I've not used the heaters yet, but at home can use power bank battery to feed them, but would like to do all (or at least be able to do all) from one supply, hence the panel purchase.

So I have already got some of the above implemented with my setup as below:
For the female banana plug socket, I have male plugs attached to a 12V-5V buck converter, and this then powers the RPi via a USB_A to USB_C cable.

The DC socket connector feeds into a 12V-8V Step Down Battery for the DSLR.

That's it, all connections and cables obtained and ready. So successfully used this setup at home, hence trying to resemble the same for in the field - the connectors at the top would be connected to the 'dark-site kit' that I'm hoping to utilise in the colder, darker evenings - how many dark sites have power to them is the main reason for all this I guess!

Still have to decide on what battery to get, but for the specs above, I estimate the following power required:

Mount:         12V x 4A = 48W (overkill, but work with maximum requirement)
Camera:       8V x 2A   = 16W
RPi:               5V x 3A   = 15W
Heaters:       5V x 4A   = 20W
                                       =====
                                       100W (rounded up and assuming all converters are efficient)
So at 12V, realistically no less than (100W ÷ 12V) 8A required, and during winter, hours of darkness are pretty decent - I'd guess one could easily look at >6hrs imaging a night at dark site with no other sources of power, so 54Ah - I reckon I'm going to be looking at no less than a 110Ah leisure battery?! (to ensure not running it to 50% capacity which is what I think I've seen around)!
What are others using and recommendations based on the above?

Edited September 17, 2021 by pete_81