How do you power your mount? Charging "pack" or something else?
Hi,
I'm buying my first powered mount (Celestron AVX) and need to understand my options for providing electrical power. The mount doesn't seem to include any kind of power supply.
The shop I'm buying from suggests a Celestron Charging Pack for $299, which sounds a bit expensive.
I already have a charger for 12V car / motorbike batteries, so I'm wondering whether there is some kind of rig using a car battery that would work on the mount? I imagine the power supply needs to be very "clean" and regulated to work with a mount.
For home use, what do people use to convert 240V AC to 12V? Are the physical power connectors used on EQ mount standard?
Hi John.
From my experience, most people use a 12v deep cycle battery.
The size you decide upon will depend on what else you power from that same battery, and how long you want to run.
Generally, 17 Ah (Amp/hours) is a minimum, and these are often found in inexpensive Jump starter packs. (see image for example). But even these will be around $100.
If you have several dew heaters powered off it as well, you may need more.
I run a 36 Ah deep cycle battery from Waeco (image2) but it cost me $330.
Have a look at camping places like Rays Outdoors for other options.
+1 what Allan said, those power tanks from Celestron/SW are really pricey for what you get, there are lots of other options.
A while back I bought a Fusion AGM battery, I got the 55Ah for $180! I got that capacity so that it'd have enough juice to power my scope and dew heater, even my little netbook for a long weekend without any worries. If you search for that type of battery, you'll find many capacities around, just get one to suit your requirements. Assume the scope will use 0.5-1.0A, then another 1-2A for the dew heater, and extrapolate that out for a full night, if that's all you need. It soon adds up
I use my battery even when at home, as even the best types of batteries like to be topped up at the wall regularly, so I figure it's a good way to keep on top of that.
I use a big deep cycle battery. I think it's around 70 Ah. I think it was a bit under $200 when I bought it a few years ago. Bought a clip on adapter from Jaycar to provide the cigarette lighter port thing. It weights a lot.
I picked up a 105Ah AGM battery recently for... I think $230 from a place in Brisbane. I use that to power my mount and camera, and a separate 27Ah AGM battery to power my dew heaters.
For me at both home and on the field, I use a 350W computer PSU to convert 240V to a stable 25A 12V DC. You can use devoted "Din Rail PSU's", but they are much more expensive. On the field, this is by a 2000W generator as apposed to a wall outlet at home. From there, the 12V goes into a little box that gives me both dew heater control and a few "cigarette" sockets and USB charger for phones and tablets. I have also rigged in a voltmeter for a 9ah battery that only gives me about 4hrs when running my AZ-EQ6 without a generator.
For me, it suits as my generator is quiet and only takes about 0.4L of fuel for about 15hrs. It also (obviously) powers my laptop and any other device I throw at it. It has also lasted me 15 years so far, so I can not complain about longevity.
Hi John
My portable setup is a 33Ah gel deep cycle battery
Easy to carry and has never let me down
I've added a twin ciga adaptor with a 1.5 lead for convenience, and use a 7amp smart charger to top up before and after use
I am not at all knowledgeable about things electrical but gee, they look like they do the same thing assuming the plugs are the same. I would imagine you would have to fit an inline fuse with the cheaper job.
Checkout Jaycar...I bought a bunch of cigarette lighter plug to 2.1mm cables from there that are the same as what Celestron/Skywatcher use. Get one of the guys to check they're centre-positive if you're in any doubt.
I am not at all knowledgeable about things electrical but gee, they look like they do the same thing assuming the plugs are the same. I would imagine you would have to fit an inline fuse with the cheaper job.
Most cigarette plugs are fused, you just unscrew the tip and a glass fuse will pop out.
As Dunk said Jaycar will have them for $5. I picked one up just last week. No need to spend more than $5 for a simple cable.
The ebay ones will work too. 3M might be a bit too long though.
Apologies if I appear to be highjacking your thread John but as I am possibly asking the same questions as yourself I hope you wont mind.
The specs on my mount nominate a power supply of DC 7.5 to 12v 100mA.
Is 100mA equal to 1A ? If so, what size in line fuse should I use ?
And a bit off topic. I've just done a rough total of my 'portable' astro imaging kit.
HEQ5 mount 9Kg
Tripod 6Kg
Counterweight 5Kg
Camera + lens 4Kg
35AH Gel Battery 14Kg Total 38Kg
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Thank gawd they are all individual bits and I have a 4WD to get me right to my set-up location.
The specs on my mount nominate a power supply of DC 7.5 to 12v 100mA.
Is 100mA equal to 1A ? If so, what size in line fuse should I use ?
I think your looking at the synscan handset power requirements which is only needed for firmware updates. The handset natively gets its power from the mount
HEQ5 mount power should be similar to the EQ6 which is 11-16v, 4A minimum.
The shop staff weren't able to tell me but said "probably", which doesn't fill me with confidence...
It seems to me that having a regulated power supply is highly desirable for a telescope mount, and I'm reluctant to experiment with a $1500 device which specifically states that use of non-Celestron PSUs will void the warranty.
My limited understanding is that a regulated supply should supply the specified voltage for all loads up to the maximum rated current (7.5A in this case). I measured the DC voltage without load at 13.2V - which seems high for a 12V device. The AC "ripple" (measured putting the meter to AC volts, and observing the changes), was 200-300mV. I have read that anything more than 100mV ripple voltage *may* indicate a non-regulated supply.
Can anyone advise whether it would safe to use this PSU on my mount?
When a battery has been taken off the charge, it is generally at that 13.2V mark and gradually drops as it loses charge. The specs of the mount suggest that is needs 12V and 3.5A (full load), so you will be fine with it as a power supply. You would likely see the voltage drop when the load changes (as I do by about 0.2V with 4A of full load for my mount and the same again with heaters on my 25A PSU).
I'd be hoping others here would say the same and instil you with confidence.
Field Battery Power
