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Nexstar 8SE AA batteriers and external power source


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HI, Just received my 8Se.
Read about using external power source instead of AA batteries, so bought the AC supply.
Every time I unplug, loses times, date, location. 
Was wondering, if I leave the AA batteries in while using external power source, will it fry the batteries?  Is there  a diode to prevent the AA batteries from taking a back charge?
Will the AA keep the time/ date/location?

External Battery pack.  I have many power tools that are 18V and 24V.  I'm sure the 24 V Milwaukee would fry the scope.   Will the Nexstar work on 18 V or is that still too much.
Have a pile of M18, ( at least 10 ) @ 5 amp batteries for power tools. Milwaukee makes an adapter to slide onto batter to give you power leads .  But still at 18V

Or should a guy add a DC Voltage Reducer Converter DC 8V-40V to 13.8V 10A 138W Automatic Step Down Up Voltage Regulator Power Converter. They do make an automatic step down to 12V 

hurts to think about spending $250 for  power tank when I have M18 for endless supply of power.


Last question.  I bought this and it is winter in Montana.  Read about how the screen does not like the cold. some say the display will work, some say it  will  not.
Too cold and it does not display.
Was thinking about taking an old ski glove, cut a flap in the palm and sew it up with some Velcro.  Put some Velcro on the hand cuff to keep it closed.
Slide the hand held controller in glove along with a hand warmer.  The shake and break kind. heat for about 8 hours.  they get pretty warm.  hope not to damage controller from the heat. maybe slide the packet into a finger for first try.
 

milwaukee 18 volt adapter.JPG

power convertor.JPG

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8SE doesn't really work properly on the AA batteries option, they will provide barely enough power to turn the motors, and I think it will lose the time every time you turn off the mount regardless of any AA battery presence (there's no internal clock battery in the handset, though it might store the location data in NVRAM).

If the AC power adaptor is working well for you then I'd say stick with that, however a good portable solution is a leisure battery (the type you might put in a motorhome to drive the inverter) with a simple adaptor cable to plug a standard 12v power lead into (this 12v cable will include a fuse in the plug).  I've never tried the DC voltage converter / regulator option but if you get a reliable one then I see no reason why that wouldn't work, but I would have thought that one of those portable drill batteries wouldn't hold much power compared to a 12v leisure battery, and if you ever had to swap batteries mid-session then you'll be back to square one entering the time and doing 2 star align etc.

Leisure batteries can be expensive but they need not cost as much as an astronomy power tank, you can add multi-socket adaptors, build a wooden crate to house it all in, whatever you want.  Some people build battery cases with USB ports and such, based around several small lead-acid batteries connected in some fashion, I prefer to keep it simple with just a regular sized battery and a cable.

 

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The internal batteries are a joke - you have to use a premium brand e.g. Duracell for it to work, and the option is only provided to make your scope purchase look cheaper, and get you going. You need a +12v external sypply, not 18v! and not 24v!!

There are lots of battery options for this, which members here have used with success, and they need not cost much, ranging from a +12v 7Ah sealed lead acid battery, to a multifunction car engine starter, to a branded astro power tank, to a LiFePo power tank.   On the AC power side, you can use an adequately rated +12v regulated   DC output power supply (at least two amps) and again there are types intended for astro use (outdoors, wide temperature range)

It makes little difference whether you leave the internal batteries in place or not.  But if you forget they are there, they could leak and corrode the battery contacts.

You will lose time & date (but not location) every time you switch off. That's normal.

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I've got the Celestron 9.25 Evo with built in batteries and it still loses the correct date and time when it's switched off. (Although it does remember what you entered last time)

Is it really too much to ask in this day and age that a real time clock be built into these things?

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36 minutes ago, Starwatcher2001 said:

Is it really too much to ask in this day and age that a real time clock be built into these things?

I can only assume that a RTC is omitted in order to shave the initial cost and make the purchase seem more attractive.  A few higher priced mounts include a RTC, IIRC. Having to enter the date and time at power up is one of my pet peeves.   Perhaps if we all rudely demand a RTC as standard, the manufacturers will do something about it.

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There's an article here that might help. I've not tried this out on my 6/8 SE mount but I'm assuming the accessory output socket in a car would work, with a long enough lead. Our Vauxhall its rated at 12v with max of 120, so about 10 amps.

https://www.nexstarsite.com/OddsNEnds/PowerSources.htm

Edited by Alfian
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On 25/10/2020 at 17:03, Just A DarnNice Guy said:

Every time I unplug, loses times, date, location. 

It's a long while since I used mine, but I don't recall it losing location info. The problem with an in-built clock is that it might not be accurate enough and you'd need to keep resetting it. Without the GPS module I used to use https://time.is/ and use that to give me the accurate time. I've got the impression that accurate timing is important if you want accurate alignment.

Ian

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These are a selection of my 12V supplies

141468159_PowerSources-Annotated(R).jpg.df591139d2d70717987a33f2dcf61f29.jpg

The battery packs, with springs for the negative terminals of each of the cells, tend to give a high internal resistance, unless they are very clean. The plug-top PSU was recycled from a scrap Ethernet switch, but similar devices are sold to power the LED lighting strips. I have also "borrowed" the supplies from older desk-top external hard drives.

I measured the current consumption of my mounts

187165886_ConsumptionTable(2).jpg.06f4330333b73eb14dfe6d0ba8f5bfb3.jpg

 

The Skyprodigy handset has an RTC built-in, but, as mentioned above, does drift, and probably needs resetting about once a month. The Synscan handsets remember the last date when the mount was used, but reset the time to 8pm at each power-up. The CubePro and Solar Quest (no handset required) mounts have built-in GPS receivers, so always accurate for time and location.

Geoff

 

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if you can get a buck converter to wire the M18 pack to that should be able to step the volts down to 12v regulated, I do that with a 20AH LiPo car starter pack since that pushes 15+v with no load and I wasn't looking for it to blow my SynScan mount. You'd need to ensure the buck converter is suitably rated for the load, the one I got was 5A and runs just fine. You will need to obtain a suitable flylead with the correct plug for the scope and have that all securely wired up but I can see no reason why it'd not work. Bear in mind the longer the lead the thicker the wire you'd want to use to avoid voltage drop.

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On my 8se I use a TalentCell Rechargeable 36W 12V/6000mAh 5V/12000mAh DC Output Lithium Ion Battery Pack.

I have it attached to the mount via an old Garmin gps bag, and it last for ages.

Found here: https://www.amazon.com/TalentCell-Rechargeable-12000mAh-Multi-led-indicator/dp/B00ME3ZH7C/ref=sr_1_2?dchild=1&keywords=TalentCell+Rechargeable+36W+12V%2F6000mAh+5V%2F12000mAh+DC+Output+Lithium+Ion+Battery+Pack&qid=1603995224&sr=8-2

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I use a car jump start pack to power my EQ5pro mount

Gives reliable power source, and mine also has USB and dual cigarette lighter outlets to power ASI Air and ASIZWO camera

Pic of my ED80 on EQ5pro mount

The ED80 on a HEQ5 mount in background, also shows external battery

 

Had a issue a while ago with a club Meade mount, where internal batteries had not been removed, and corroded the battery compartment

John

 

Jump Start Pack.jpg

Skywatcher ED80.jpg

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Thanks for all the reply.

You can add a real time clock to a raspberry PI for about $5, guessing cost celestron about $1 to build into board.  Seems odd to lack it on a $1200 unit.

Going to stay away from a M18 battery setup.  too bulky and for the cost.

The car jumper ideas look like the way to go.
I have a 22000mAH  ion car jumper  with a cigarette out adapter. Going to give it a try. ordered the cigarette plug for scope.

 

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Being I am a new buyer of the Celestron 8SE,  I am going tell Celestron what I think about the worthless battery situation and no RTC.
Raise the price $40.  add a RTC.  Get rid of the AA batteries and just use external ion pack. 
Amazon sells 12,000mAH ion packs in the $40 range. Guessing bulk price be in the $20 range thus the added $40 price increase to the scope.
$40 is a small price to pay for something that would actually work instead of the disappointment of the AA batteries.

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36 minutes ago, Just A DarnNice Guy said:

Thanks for all the reply.

You can add a real time clock to a raspberry PI for about $5, guessing cost celestron about $1 to build into board.  Seems odd to lack it on a $1200 unit.

Going to stay away from a M18 battery setup.  too bulky and for the cost.

The car jumper ideas look like the way to go.
I have a 22000mAH  ion car jumper  with a cigarette out adapter. Going to give it a try. ordered the cigarette plug for scope.

 

do check the output voltage with a meter first, the one I have gives >15V hence I added a buck converter to regulate that to 12v. Other than that it gives good use and after a couple hours still shows full charge. I'm only running the SynScan off it tho, no dew strips etc which will drain the pack harder of course.

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49 minutes ago, Just A DarnNice Guy said:

Raise the price $40.  add a RTC.  Get rid of the AA batteries and just use external ion pack. 
Amazon sells 12,000mAH ion packs in the $40 range. Guessing bulk price be in the $20 range thus the added $40 price increase to the scope.
$40 is a small price to pay for something that would actually work instead of the disappointment of the AA batteries.

For a few dollars they should be able to add GPS - even more useful. I understand that a GPS chip costs only a few dollars these days.

The Evolution version of the C8 has an internal rechargeable battery in the Evolution mount.

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