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Celestron 4SE + AA batteries

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#1 Dave_L

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Posted 19 June 2019 - 11:38 PM

Howdy all. New to the forum. I operate a Celestron CPC 1100 and a Celestron NexStar 8SE here in the California desert using a couple Celestron PowerTank 17's. Well, I picked up a cute little NexStar 4SE and it is really convenient as a quick grab and go scope! My question is about the 8 AA batteries that power the little scope. I read somewhere that people had issues with the batteries (unreliable, it is a pain in the butt to replace them, you have to start the alignment process from the beginning, etc).

 

I haven't had any of these issues. I have operated quite a few nights with the same AA batteries and have enjoyed flawless performance. I was thinking about buying another PowerTank or even the little A/C adapter that you plug into a wall, but so far it doesn't seem necessary. Has anyone had problems simply relying on the AA batteries as the power source? The batteries aren't that tough to swap out and I am quick and proficient at a manual two star alignment. Thanks everyone.



#2 Noah4x4

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Posted 20 June 2019 - 12:02 AM

AA batteries are fine with a 4SE in isolation, but can be expensive over the long haul given their replacement cycle. . However, in the UK, a pack of 10 can be purchased for around £1 from many budget outlets. A fresh pack should see you through at least one overnight session.

 

Your problems are likely to start when you add any accessories, such as Starsense, GPS or similar. The added power consumption requirement  means their discharge curve then becomes steeper and faster and user frustrations will then set in as you will enjoy fewer hours. But if you are just enjoying the 4SE in isolation, then AA batteries are fine. However, for a larger SE scope demanding more power, then ever less so.as you add more OTA weight etc.

 

If you do buy a Li-Po battery and/or store your telescope for long periods, remove the AA batteries. If left unused for long periods then they can corrode and leak and cause damage.. I left some in simply for "back up" and forgot them; but got lucky in that the battery box  terminals were undamaged.


Edited by Noah4x4, 20 June 2019 - 12:05 AM.


#3 Michael_Swanson

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Posted 20 June 2019 - 12:03 AM

Hi Dave,

 

Good quality AA batteries will work well for a few hours in the smaller mounts though not so well in near or below freezing weather.  Dollar store AAs - not so good.  In any case, it probably won't take more than a couple of months before you will have spent enough on batteries to have purchased one of the small, convenient lithium power packs.  See these two pages at my website for details:

https://www.nexstars...owerSources.htm

https://www.nexstars...umBatteries.htm

I specifically use the TalentCell YB1206000-USB (available in the US on Amazon) to great advantage on my NexStar 8SE and old NexStar GT mount (both pictured in the first link).

 

Best regards,
Mike Swanson
Author of "The NexStar Users Guide II"
Author of "The NexStar Users Guide"
Author of "NexStar Observer List"
https://www.nexstarsite.com



#4 sg6

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Posted 20 June 2019 - 02:34 AM

They work and it sounds as if you have been fortunate in that you say they have lasted a few days, usually I expect one night maybe two  and that is not heavy use. Tracking is usually fine it is a slew that causes trouble.

 

For 1 to 1.5 hours use a set of low cost ones seem OK. But as mentioned changing means a restart and alignment and it takes time out of the evening.

 

As above I now use a Lithium, Talenetcell or Safaridrive item, there are lesser cost ones and the one I had was fine. Sort of blue plastic shrink wrap outer, I was the cause of its demise, I didn't charge it. I did have to make a small converter for the type of socket.

 

If you head down that line then look at 6800mAh. Mine is 4800mAh but used for say 2 to 3 hours outreach at a time. Problem with Lithium (always a drawback) is they start at say 12.6v the drop fairly quick to around 11.6v, then sit at that voltage for some time before giving up. So the scope needs to be able to run at around 11.6v trouble free.

 

I use the smaller ones as they sit nicely at the front of the scope on the base unit, bigger units have to slide under more and can stop the rear of the scope pointing high. Self adhesive velcro helps.



#5 Dave_L

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Posted 20 June 2019 - 11:07 PM

Excellent advice. Thank you gents. It sounds like AA batteries will work but it not cost effective in the long run. I'll purchase one of the other options.



#6 Cajundaddy

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Posted 20 June 2019 - 11:41 PM

I use Eneloop rechargeable AA batteries in my SLT mount and typically get 8+ hours of tracked observing.  I tend to set the scope and hang out on my target for a while so if you need to slew all over the place chasing the Messier marathon, use an aux power supply.

 

Alkaline AA batteries have gotten so bad in terms of leakage over the past few years I see no reason to use them in anything of value.  My whole house is now converted to Eneloop rechargeables which have typically 2-4x the useful run time and never leak.


Edited by Cajundaddy, 21 June 2019 - 12:00 AM.

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#7 Dave_L

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Posted 24 June 2019 - 11:16 PM

Just curious... If I am running an A/C power adapter or a TalentCell, is there any reason/advantage to keeping AA batteries loaded in the scope?



#8 Michael_Swanson

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Posted 24 June 2019 - 11:20 PM

The mount usually keeps running if you pull the external power cord (intentionally or accidentally).  But, old batteries tend to leak so I never leave batteries in any device that doesn't give me a warning when the batteries run low.

 

Best regards,
Mike Swanson
Author of "The NexStar Users Guide II"
Author of "The NexStar Users Guide"
Author of "NexStar Observer List"
https://www.nexstarsite.com



#9 Noah4x4

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Posted 24 June 2019 - 11:39 PM

Just curious... If I am running an A/C power adapter or a TalentCell, is there any reason/advantage to keeping AA batteries loaded in the scope?

Not really. As I said before, I kept them in as a 'back up' until I noticed that they had started to leak and corrode.

 

The better idea if you fear that your TalentCell might run out mid session is put a pack of AA batteries in your pocket. You can usually tell when your main battery is flagging as slews become slower and performance starts to drop. You can always insert the AA batteries when that starts to occur. But do take them out at the end of the session, especially if the weather or similar means that you won't use your scope again for a period. Corroded battery box terminals won't be easy to fix. 


Edited by Noah4x4, 24 June 2019 - 11:40 PM.


#10 Ski-Patroller

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Posted 26 June 2019 - 03:21 AM

I use Eneloop rechargeable AA batteries in my SLT mount and typically get 8+ hours of tracked observing. I tend to set the scope and hang out on my target for a while so if you need to slew all over the place chasing the Messier marathon, use an aux power supply.

Alkaline AA batteries have gotten so bad in terms of leakage over the past few years I see no reason to use them in anything of value. My whole house is now converted to Eneloop rechargeables which have typically 2-4x the useful run time and never leak.



#11 Ski-Patroller

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Posted 26 June 2019 - 03:24 AM

I use Eneloop rechargeable AA batteries in my SLT mount and typically get 8+ hours of tracked observing. I tend to set the scope and hang out on my target for a while so if you need to slew all over the place chasing the Messier marathon, use an aux power supply.

Alkaline AA batteries have gotten so bad in terms of leakage over the past few years I see no reason to use them in anything of value. My whole house is now converted to Eneloop rechargeables which have typically 2-4x the useful run time and never leak.


I’m surprised you can get Eneloops to work on a Nexstar mount. The voltage (1.2) was too low for my 5i.

#12 Cajundaddy

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Posted 26 June 2019 - 11:12 PM

I’m surprised you can get Eneloops to work on a Nexstar mount. The voltage (1.2) was too low for my 5i.

I think this is a misunderstanding of typical AA battery performance.  According to comparison testing, both the Eneloop and Alkaline batteries start out at nearly the same voltage (1.4VDC).  The difference is that both fall off to 1.2v quickly but the Eneloop maintain useable 1.2v up to 3x longer.  Plug in various battery types and see the comparisons for yourself:

 

http://lygte-info.dk...Acomparator.php

 

Where this test falls apart is under extremely cold weather where all batteries produce less voltage and have far less capacity.  My experience has been all above 40*F and the Eneloop had no issues driving the SLT mount all night.   If you are often running a mount in 20-30*F you will need much higher capacity than the AA batteries typically supply.


Edited by Cajundaddy, 26 June 2019 - 11:19 PM.


#13 Ski-Patroller

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Posted 27 June 2019 - 03:22 PM

I think this is a misunderstanding of typical AA battery performance.  According to comparison testing, both the Eneloop and Alkaline batteries start out at nearly the same voltage (1.4VDC).  The difference is that both fall off to 1.2v quickly but the Eneloop maintain useable 1.2v up to 3x longer.  Plug in various battery types and see the comparisons for yourself:

 

http://lygte-info.dk...Acomparator.php

 

Where this test falls apart is under extremely cold weather where all batteries produce less voltage and have far less capacity.  My experience has been all above 40*F and the Eneloop had no issues driving the SLT mount all night.   If you are often running a mount in 20-30*F you will need much higher capacity than the AA batteries typically supply.

So according to the tests, the 1.2 v NMHi batteries are very similar to the alkaline.   I may give them another shot, but my first attempt was not successful.   It was not very cold so I don't think that was the issue.  The 5i may take a bit more power than your SLT mount, since the 5i has the same mount as the 8i and essentially the same as the 8SE

 

I run my 5i with a 2.7 ah.   AGM battery that hangs on the side of the mount. 



#14 Ski-Patroller

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Posted 03 July 2019 - 03:45 PM

So according to the tests, the 1.2 v NMHi batteries are very similar to the alkaline.   I may give them another shot, but my first attempt was not successful.   It was not very cold so I don't think that was the issue.  The 5i may take a bit more power than your SLT mount, since the 5i has the same mount as the 8i and essentially the same as the 8SE

 

I run my 5i with a 2.7 ah.   AGM battery that hangs on the side of the mount. 

OK, the 5i will run on Eneloop batteries.   I haven't had it on for any length of time, but it definitely fires up, aligns and tracks ok.   I'm going to try using them on a regular basis.




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