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durhamdave

Skywatcher AZ GOTO power supply/battery requirements?

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Hi all,

I have just received my 127 skaymax on the goto mount and wanted to look into a better source of power than eating my way through the duracell factory.....

I've seen that there is a skywatcher 'powertank' but also people recommending just an ordinary 'leisure battery' and that it must be deep cycle etc.

Any advice on what would best? I am only wanting to run the scope so there wont be much in the way of high consumption.

Would one of these batteries, (maybe a 70AH deep cycle leisure battery) with bog standard croc clips to a cigaraette lighter holder, then to the scope be sufficient? Then to charge it I have a halfords fully automatic battery charger which I guess is ok to charge it from ?

Any help would be really appreciated!!!

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I too have just taken delivery of the same scope. I have not yet done a full alignment as no clear skies. However, I have used the hand control to move the scope. ( testing) For power I am using a car jumpstarter power pack that we already had - and it has a cigarette lighter type socket. I have connected the goto handset to the jumpstarter by using a lead from a torch that is charged from the car....as the connections were exactly what was needed. Not sure how long it will give me......but I am sure long enough for a few hours watching. We also have a motorhome, and bought an additional leisure battery which is now connected alongside the original onboard leisure battery. I would be interested to learn if anyone else runs their gear via a motorhome 12v system.

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Would one of these batteries, (maybe a 70AH deep cycle leisure battery) with bog standard croc clips to a cigaraette lighter holder, then to the scope be sufficient? Then to charge it I have a halfords fully automatic battery charger which I guess is ok to charge it from ?

All fine EXCEPT the crocodile clips!! Make a permanent connection to the in line cigarette lighter holder to ensure that you don't run the risk of getting the polarity wrong in the dark with catastrophic consequences!!!

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leisure batteries are fine but blumming heavy, i have a power pack from maplins that was b grade for £25 twin 12v sockets , light which i'm colouring red, and a 230v 200w inverter on the back, 17ah and a nice grip and not too heavy.. always worth keeping an eye out for maplins b grades..

one warning try not to use a car battery as the output is not regulated can vary from 9v - 14v could damage expensive stuff..although most 12v dc stuff has a working range around the same.

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I use a pack of 10 1.2V NiMH "AA" size batteries. I strap them to the arm of my AZ mount, so I don't have to worry about cord wrap. Good for 4-45 hours viewing.

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A car battery is going to be as near to 12V as makes no difference - they only go up to 14V when the engine is running.

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your right mate but for something that is precision engineered to run off 12v stepper motors and gear system are finicky little rats at the best of times, it's not worth the risk as car batteries aren't regulated if they are a little warm they ouput a bit more and if they are cold they ouput less... leisure batteries are around the same price for ah so there is no need to use a car battery ,unless you have one already and dont mind taking a risk...

nothing will probably happen but it could..

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The AZ-GOTO mount requires a voltage of between 11 and 15v DC to operate correctly, a 12v car/leisure/jumpstart battery would not provide more than the mount requires. The mount will, however, perform erracticaly if you use a cheap non regulated mains psu or the voltage drops below 11v.

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Hi,

You don't need much for the skymax 127/Nexstar 127 power wise. Assuming the standard alt-az mount, the it will only draw about .75 ah. The 7ah skywatcher tank will give you plenty for a whole nights use of the scope.

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The AZ-GOTO mount requires a voltage of between 11 and 15v DC to operate correctly, a 12v car/leisure/jumpstart battery would not provide more than the mount requires. The mount will, however, perform erracticaly if you use a cheap non regulated mains psu or the voltage drops below 11v.

Thats ok then as i know some things have a range of voltage for dc wasnt sure about the goto mounts.. but as you say it can affect the performance.. i picked up a lovely maplin 5 in 1 jump starter 17ah one for £25 labelled as grade b but works fine it's was supposed to be £85 , always worth a look out on maplin..

My bad 4-5 hours- good enough for most nights.

lol i thought so mate was just having a giggle..

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My car jump starter does everything I could ask - runs my GOTO for hours and hours. Why pay more?

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I also use a Jumpstarter, it says 900A on the sticker so in theory a 1 Amp scope should run for 900 hours... in theory... but that said, I have been running my dob and primary fans off it all night a number of times and I have never ran out of power. At the end of the night the charge level was still in "green".

Next I'll hook up a dew heater to the secondary of it also and see if the power lasts all night.

 

 

 

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34 minutes ago, MarsG76 said:

I also use a Jumpstarter, it says 900A on the sticker so in theory a 1 Amp scope should run for 900 hours... in theory... but that said, I have been running my dob and primary fans off it all night a number of times and I have never ran out of power. At the end of the night the charge level was still in "green".

Next I'll hook up a dew heater to the secondary of it also and see if the power lasts all night.

 

 

 

The 900A will refer to the max load for jump starting (short burst). The actual capacity (how many amps per hour) will be less. A 900Ah battery would be a massive beast.

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31 minutes ago, Cornelius Varley said:

The 900A will refer to the max load for jump starting (short burst). The actual capacity (how many amps per hour) will be less. A 900Ah battery would be a massive beast.

True.. I expect the unit to be 10-15Ah at most, so that is still going to gove me 7-8 hours when running a 1 Amp scope, a 0.5 Amp dew heater straps/controller and about 0.05A primary fans.

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I did some current measurements on my Skymax 127. (1) Before tracking (handset & mount) 90mA); (2) Aligned and tracking, rate 1, 160mA; (3) Both axes slewing at max rate 9, 350mA.

I tend to use a mains plug-top supply, 12V at up to 2A; but I also have alternatives to the 8-off 1.5V alkalines in the supplied battery holder, as shown below.

 

592c551878db5_PowerSources-Annotated(R).jpg.5fde6e3e53d3f87e38ab207640356a4f.jpg

For portable use, I tend to use the 2-off 6V NiMH battery packs, "borrowed" from radio-control sailing yachts. The 10-cell holder was obtained from a seller on a well-known auction/buy-it-now internet site. The 2-off packs give a more reliable contact than the 10 springs in the black holder. I extended the 12V lead on the PSU with heavy duty bell flex, as it does not need the additional insulation of a mains lead, and the white shows up better in the dark.

Geoff

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AZ Goto has such low power requirement especially when tracking that I found the Celestron LiFePO4 to be quite perfect. Not very expensive, reasonable sealed and works for days without recharge when tracking the sun.

Only issues for me have been that the charge indicator is difficult to read (indicator led lighting splits between spots) and the rubber cover hinges snapped after a cold night. Otherwise perfect.

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I prefer the Tracer Lithium Battery Packs as they're lightweight and a great alternative to traditional batteries.

Edited by Rollageyder
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The double 6V battery pack, 10-cell holder and 2200mAh LiPO sit neatly in the satchel supplied with the mount. I added a stick-on plastic hook on the rotating section of the mount, to hang the satchel, so that there is no lead to trip over and there is no restriction on mount rotation.

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I have a dumb question, would you use a DC 15v-2A to power a Synscan AZ GoTo ? I am going to get a skywatcher 7Ah from UK seller (I am in Italy) so in the meanwhile I would use it with this adaptor, I read carefully that the manual says 11-15v, am I stupidly worrying it is going to be too much?

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Not a dumb question.

The answer depends on the quality of your 15V supply. It should be OK, if it is well regulated, so that the terminal voltage never exceeds 15V. If it drifts up to over 15.5V, particularly without a load, then it may damage the mount.

Geoff

 

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I see, seems I need to measure the output in someway. The power adaptor belongs to a guitar amp head, Orange Micro Dark. Will try to learn more of it.

Thanks !

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On 25/8/2017 at 00:15, stonedzep said:

I see, seems I need to measure the output in someway. The power adaptor belongs to a guitar amp head, Orange Micro Dark. Will try to learn more of it.

Thanks !

Measuring the DC15v 2A gave 15.45voutput hence too much for risking. Then I dusted off a switchable adaptor that goes up to 12v, and measured its output 14.50v(12v setting). I think I Will use this one to power the synscan az goto, but don't know what to think of such high output with every power adaptor...

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25 minutes ago, stonedzep said:

Measuring the DC15v 2A gave 15.45voutput hence too much for risking. Then I dusted off a switchable adaptor that goes up to 12v, and measured its output 14.50v(12v setting). I think I Will use this one to power the synscan az goto, but don't know what to think of such high output with every power adaptor...

That psu might be unsuitable. Check the specifications to see if the output is regulated.

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