#21  
Old 25-06-2022, 03:11 PM
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Crater101 (Warren)
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Quote:
Originally Posted by AdamJL View Post
The Gosun (I think) use Lithium cobalt. Not all lithiums are the same. They're not LiFePO4 though, and that's what matters.
LiFePO4 is safer, has more charge/discharge support, and keeps voltage basically until emtpy.
That's why the Bluetti's are great.

Took delivery of it on Friday, and am currently (no pun intended...) charging it up. Then it will be the wait for some clear skies to see how it goes with the HEQ5. Been a bit overcast here of late.


Cheers!
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  #22  
Old 05-09-2022, 07:50 PM
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iborg (Philip)
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Hi All


Just in case anyone of contemplating one of these, they are currently on sale.


Philip
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  #23  
Old 13-01-2023, 07:47 PM
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Not a Bluetti or Jackery, however Jaycar are having a sale of their 'house-brand' portable power boxes.

https://www.jaycar.com.au/portable-5...erter/p/MB3768

505Wh model is down to $699 from $849.

Cheers,
V
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  #24  
Old 29-01-2023, 11:11 AM
geoffl (Geoff)
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Itech world currently have their battery packs on Sale.

https://itechworld.com.au/collection...300w-itech300p
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  #25  
Old 11-03-2023, 02:45 PM
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Hi all,

I just picked up one of these - a 280Wh portable power station from Jaycar. On sale at the moment for $550, down from $700.

https://www.jaycar.com.au/portable-2...erter/p/MB3767

I tested the rig with it and when slewing the HEQ5 at full speed on both axes with the camera cooler running at about 60%, the power draw was 40W. When looping the camera (1 second exposures, continually) and tracking, it was drawing below 20W.

Even allowing a hefty safety margin, that's a pretty solid 10 to 12 hours battery life.

The only issue i have is that when slewing on both axes at full speed, the voltage appears to drop significantly and the HEQ5's power LED starts blinking. It doesn't appear to affect the slewing speed, but I'll keep my eye on it when I am out in the field next.

Cheers,
V
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  #26  
Old 12-03-2023, 01:14 AM
raymo
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Is your mount driven via the cigarette lighter socket on the power supply, which has a 120w [10amp] max output, or the 5.5mm socket, which has a
max of only 60w [5amps]? How long is the cable from the battery to the mount. If it is significantly longer than it needs to be, shorten it; that will reduce the voltage drop. If it is necessary for some reason to use a long cable, use a heavier one.
raymo
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  #27  
Old 12-03-2023, 09:29 AM
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The cable that I'm running from the power station is the cigarette-socket thing that came with the HEQ5. It's probably as short as it'll ever get, unless I found a way of mounting the power station on the tripod somehow.

I chopped the 2.1mm/5.5mm plug off to fit an inline fuse and a new plug that fits my home-made power distribution box. (The fuse is probably redundant, but I'd prefer not to fry all my gear if something does go wrong.)

One thing I did notice about the power station is that it only puts out ~10.5 volts when there's no load on the 12v socket. I was preparing to take it back as faulty but everything seemed to come out ok in the end.

Cheers,
V

Last edited by AstroViking; 13-03-2023 at 06:53 AM. Reason: Missing words. :-(
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  #28  
Old 12-03-2023, 10:46 AM
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A 12v battery should put out around 12.6v-12.8v with no load on it, so that 10.5v needs looking into. If you haven't already, check that the reading is correct with a multimeter. The mount's low voltage light starts flashing at around 11v, which would suggest that the reading is correct. Was the reading at the battery socket, or at the mount end of the cable? If at the 12v socket
I would take it back to the vendor.
raymo
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  #29  
Old 13-03-2023, 06:57 AM
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I was using a multimeter, and measured the voltage at the end of the cable. I'll have another look at it today, and measure what voltage I'm getting in the 12v socket.

If it's not the expected 12v then I'll take it back and see what Jaycar has to say.

I did re-check the specifications for the power station and it says that the on-board Lithium Ion battery is 10.8v

Cheers,
V
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  #30  
Old 13-03-2023, 10:42 AM
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10.8v is no use to you, that means that it is either a 9v unit, or it is faulty. I imagine that Jaycar will help you out.
raymo

Last edited by raymo; 13-03-2023 at 02:10 PM. Reason: more text
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  #31  
Old 13-03-2023, 02:18 PM
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Thanks raymo.

Looks like it's a quick check with the multimeter and then a trip back to Jaycar, then.

Hopefully they have a replacement in stock that does put out a proper 12v.

UPDATE: Tested the unit with a multimeter and getting a solid 12.3v out all the 12v outlets. So it's the SkyWatcher power cable that's resulting in a ~1.8v drop. Next step is to replace it with something a bit beefier and see how that goes.

Last edited by AstroViking; 13-03-2023 at 03:49 PM.
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  #32  
Old 13-03-2023, 06:13 PM
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That is strange, I have been around various skywatcher mounts over the years, and never had a significant voltage drop with any of their cables.
The 40W draw that you mentioned is only 3.3amps, which is well inside the max draw for the cable, so it will be interesting to see how this turns out.
raymo
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  #33  
Old 14-03-2023, 09:10 AM
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The current cable is a pretty small diameter, sort of like heavy-gauge speaker cable. I also discovered that the front of the cigarette plug unscrews to reveal an inline fuse. It came standard with a 5A fuse, so my added inline fuse is redundant...

I'll replace the cable with something like 15A DC power cable and see how it goes.
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  #34  
Old 14-03-2023, 11:01 AM
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15Amp cable is huge overkill, even 10 is way over what you will ever need.
The max you are ever going to encounter powering the mount is about 4
or 5.
raymo
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  #35  
Old 14-03-2023, 11:07 AM
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Yeah, I know it's overkill for handling 12v/5A, max. It's the voltage drop along the cable I'm wanting to reduce / remove. Maybe a 7.5A cable, then...
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  #36  
Old 14-03-2023, 11:51 AM
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I'm not familiar with the late model mounts, are you powering your camera cooling, and maybe other accessories, from a power outlet on the mount, so that more current is flowing through the power cable to the mount, or is the cooler powered separately.
raymo
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  #37  
Old 14-03-2023, 07:27 PM
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Well, that was interesting.

I picked up more cable from Jaycar, some 15A stuff this time (as it was all they had) and rebuilt the power lead. There is zero voltage drop between the power station and the end of the cable now. It's a conservative 2m long, which should be more than long enough to get from the ground up to the distribution box I made.

The stock SkyWatcher cable had a small LED in the cigarette plug, connected (with a resistor in series) across the positive and negative terminals. I did not put this LED back into the new cable.

My electrical knowledge is a bit sketchy these days, but that LED should not create the voltage drop I was seeing, right?

Raymo - I have a home-made power distribution box mounted on the scope's dovetail. From there I have shorter cables running to the mount, camera cooler and the powered USB hub.

Cheers,
V
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  #38  
Old 14-03-2023, 09:22 PM
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No, the LED would not cause voltage drop. So I assume that you have a
cable from the power station to the distribution box, and the SW cable from the box to the mount. If that is the case I don't understand the large voltage drop you had at the mount. Was there any significant drop measured at the
outlet terminal on the box used by the SW cable? In other words was the SW cable the sole source of the drop, or was there already some drop at the outlet from the distribution box ?
Raymo
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  #39  
Old 15-03-2023, 07:07 AM
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Thanks for confirming my suspicions about the LED. Glad to know my brain is still mostly working...

Hmmm. I might not have been sufficiently clear in my description of the power cable setup.

The cigarette-plug cable runs from the power station to the distribution box, then I use 2.1mm DC power sockets/plugs on short cables (no more than 75cm long) to power the equipment.

I was measuring the output voltage at the end of the SW cable, before it went into the distribution box, so it was the sole cause of the drop.

It's all academic now, as the new cable has zero voltage drop when measured at the same point.

Cheers,
V
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  #40  
Old 23-05-2023, 07:33 PM
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UPDATE:

Don't buy the Jaycar power supply that I did. It gives a solid 12v when it's fully charged, but that drops to under 10.5 (or whenever the HEQ5's LED starts flashing) at 75% full.

It's going back for a refund later this week, as it's unfit for the purpose I bought it for. Thankfully I kept all the packaging and what-not.

Cheers,
V
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