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Small, Light, Rechargeable Pack for NexStar?

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#1 Sarkikos

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Posted 30 July 2014 - 09:56 AM

I want to buy a small, rechargeable battery pack for my NexStar SE 6/8. I have been using 8 rechargeable NIMH batteries but the results have been inconsistent. Some nights OK, some nights not so good.

I don't want to buy throwaway AA alkaline batteries.

I have an Orion Power Supply that I take to dark sites, and it works very well, but it is too heavy for quick and easy grab-n-go.

I want something light, portable, rechargeable, that plugs directly into the NexStar mount and will fit onto the top of the battery compartment without being hit by the OTA. I'm not doing anything that isn't off the shelf. No electrical work for me.

Some observers have talked about battery packs from onlybatterypacks.com. They look like something that would work for me. But is this company out of business? I can't access their website.

What other options do I have? Please no recommendations for big & heavy power supplies, hooking to AC, hooking to a vehicle, or electrical DIY.

Mike

#2 Doug Culbertson

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Posted 30 July 2014 - 10:25 AM

Mike, I use the previous generation of the Starizona Powerpack II. Works well for me on my CPC, but not sure about clearance issues for the NexStar. Expensive for what it is, but it works for me. Of course mine was $30 cheaper.

#3 Midnight Dan

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Posted 30 July 2014 - 10:44 AM

Hi Sarkikos:

I just accessed onlybatterypacks.com without problem. Here's the link for the page of 12V, 10-cell NiMH battery packs:
http://www.onlybatte...items.asp?db=37

Keep in mind that NiMH batteries (like lithium), have a very flat discharge curve. That means that, unlike a lead-acid battery, you can use nearly 100% of the rated capacity. With a standard lead-acid jup starter or Powertank, you get about half that. So a 5 amp hour NiMH pack will provide the same run time as roughly a 10 amp hour lead acid.

Here's the units I have. This one lasts about 2 hours running the scope and dew heaters, and weighs 11 ounces.:
http://www.onlybatte...ItemID=11731.37
This one runs for 4-5 hours and weighs 2 pounds:
http://www.onlybatte...ItemID=11075.37

I use this charger, most because it's cheap - but it's also slow:
http://www.onlybatte...items.asp?db=12

They sell other ones that will charge faster if you want to pay more.

-Dan

#4 Sarkikos

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Posted 30 July 2014 - 10:47 AM

Thanks, Doug. It's 3-1/4" high. There might be enough room for my C5. Probably not enough for the C90, since that has to sit lower in the saddle. Might be too tall for the C6, as well, depending on what I have connected to the visual back.

Maybe I can attach it somewhere else, perhaps with Velcro or a strap. Ideally, I want the battery pack to travel with the arm to prevent cord wrap.

Mike

#5 Sarkikos

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Posted 30 July 2014 - 10:48 AM

Has anyone used the Starizona Power Pack II on their NexStar SE 6/8 mount? Where did you place it? How did it work for you?

Mike

#6 Sarkikos

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Posted 30 July 2014 - 10:51 AM

Hi Sarkikos:

I just accessed onlybatterypacks.com without problem. Here's the link for the page of 12V, 10-cell NiMH battery packs:
http://www.onlybatte...items.asp?db=37


Nope. Not working at all for me. Here is the error message I receive:

"An error occurred on the server when processing the URL. Please contact the system administrator.
If you are the system administrator please click here to find out more about this error."

When I "click here" it sends me to some Microsoft page with this heading: "Running Classic ASP Applications on IIS 7 and IIS 8." Programming mumbo-jumbo. I would understand Latin better than this mess. I'll just try it when I get home.

All of the links in your post give me the same result.

Makes me wonder, though, about a website that will work on some systems but not others.

Mike

#7 Sarkikos

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Posted 30 July 2014 - 11:01 AM

So far I like the Starizona unit because it's self-contained. No additional charger to buy. The charger is supplied with the power pack. A light indicates when the unit is fully charged. You can order it with Celestron or Meade power plug.

Mike

#8 Doug Culbertson

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Posted 30 July 2014 - 11:03 AM

So far I like the Starizona unit because it's self-contained. No additional charger to buy. The charger is supplied with the power pack. A light indicates when the unit is fully charged. You can order it with Celestron or Meade power plug.

Mike


Like I said, it's expensive for what it is but, for those of us who don't want to cobble things together, it's a great unit that is easy to operate and comes with the charger. My old one is getting to the point that it doesn't hold a charge as well, so when it dies I will buy the new model.

#9 Sarkikos

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Posted 30 July 2014 - 11:11 AM

I see from other threads on CN, that the Starizona will last about 4-5 hours. That is plenty for my grab-n-go sessions at home, which is what I want the pack for.

Mike

#10 Doug Culbertson

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Posted 30 July 2014 - 11:12 AM

FWIW, you might want to call Starizona and ask if they know about the clearance with the NexStar mounts. Those guys are really very helpful.

#11 Midnight Dan

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Posted 30 July 2014 - 12:32 PM

Hi Sarkikos:

Doesn't work for me either now. You must've broke it. :grin:

I've been using them and accessing their site without a problem for years. Must be some temporary glitch - maybe they got hacked or something.

By the way, not sure of the size/shape of the starizona supply, but you don't really need full clearance to mount it using velcro. Here's my larger pack on the base of the 8SE. I just used a strip of sticky velcro on the base and on the battery pack:

Posted Image

The nice thing about onlybatterypacks is that you can get the same set of cells, but arranged in different configurations. This particular pack can be had in a flat-pack where all the cells are arranged side by side. This kind of pack can fit vertically on the inside of the fork arm, again attached with velcro.

-Dan

#12 Sarkikos

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Posted 30 July 2014 - 12:47 PM

Hi Sarkikos:

Doesn't work for me either now. You must've broke it. :grin:


Sorry about that ... :shrug:

:grin:

#13 Motorhead1977

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Posted 30 July 2014 - 07:01 PM

http://www.tracerpow...tery-packs.html

they are too expensive for what they are IMO.

#14 Sarkikos

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Posted 30 July 2014 - 07:34 PM

What are too expensive? The Starizona Power Pack II's, the onlybatterypacks or the TracerPower Battery Packs?

Which of these TracerPower Battery Packs would be best for the NexStar SE 6/8 Mount? Are there any adapters I'd need to hook it up? Would I need a separate charger? How much would all that cost?

Mike

#15 sonny.barile

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Posted 30 July 2014 - 07:39 PM

Mike
You were on my thread discussing this a couple of days ago......The power bank I just bought clears the mount and is only $50. Comes with the cable to hook up to the SE mount and the ac charger + a car charger. .....and it will fit in your shirt pocket. Look at this post from a few days ago, I put pictures. It cost half as much as the cheapest pack in the last link. I think it was 4 ah for $99. This says 100000mh, but it equates to 3 amps at 12v. for $50

http://www.cloudynig...exstar/Numbe...

#16 Sarkikos

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Posted 30 July 2014 - 07:42 PM

The Starizonas are 12v 8Ah, include a charger and cost $129.

The Tracer 12V 8Ah Lithium Polymer Battery Pack includes a built-in "fuel gauge" and a "compact 1.6A Smart Charger." "A rapid 3A charger is available as an optional upgrade." It also costs $129.

Mike

#17 Sarkikos

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Posted 30 July 2014 - 07:49 PM

Mike
You were on my thread discussing this a couple of days ago......The power bank I just bought clears the mount and is only $50. Comes with the cable to hook up to the SE mount and the ac charger + a car charger. .....and it will fit in your shirt pocket. Look at this post from a few days ago, I put pictures. It cost half as much as the cheapest pack in the last link. I think it was 4 ah for $99. This says 100000mh, but it equates to 3 amps at 12v. for $50


Yes, I was interested in the power bank that you bought. Everything we need in one package for $50 is a great deal.

But in the thread you said you had only tested it in the house. Have you done a field test yet? How did it perform?

Mike

#18 Sarkikos

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Posted 30 July 2014 - 07:56 PM

Here are the technical details of the XTPower 10000mAh External Battery Pack.:

Technical Details:
- Battery Type: Rechargeable Li-polymer battery
- Capacity: 10000mAh / 37Wh
- Input: 9-15V 1000mA
- Output: 2 USB 5V 2100mA and 1 DC 2000mA 9V/12V
- Size: 4.9 in X 2.99in X .90in or 125mm X 76mm X 23mm
- Weight: 10.2oz or 290g


So would it work with the NexStar SE 6/8 mount and how well would it work? It's been about 45 years since I had an electronics class. The NexStar manual says that the power supply requirements are "12 VDC-750mA." So "DC 2000mA 9V/12V" from the XTPower should be plenty, unless the NexStar manual is misleading or I'm not understanding the electronics, either or both of which are possible.

Also, the XTPower has about a 1/4" shorter profile than the Starizona, allowing better clearance when the XTPower is set between the OTA and the top of the NexStar battery compartment.

Mike

#19 sonny.barile

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Posted 30 July 2014 - 08:44 PM

Well......you've mixed some up...... :jump:

The power adaptor to the SE power adaptor label states the output is 12v 2500ma. That doesnt mean the mount is drawing 2500ma. It means the adaptor can handle outputting up to 2500ma. The XtPower is 10000ma. (one more zero than you had). But that is at the lowest voltage output rating of 3.7v. At 12 volts it is approximately 3 amps. The wattage is 37wh. If you divide 37wh by 12v you get 3.08ah. It is important when choosing a power source that you know the watts and voltage to determine how much capacity you truly have.

So the smallest capacity Tracer powerbank listed above is approximately 50wh. It will give you about 4ah at 12v. It cost $100 The XtPower Bank I recently bought will give about 3/4 of that (3ah) but for half the price. There is a 20ah version for $69 on Amazon. You will realize about 6ah of it at 12v. This is about the same size and cost as a Power Tank but it will fit in your shirt pocket. I still believe that large deep draw lead acid batteries give the best bang for the buck but they bang your lower back too..... :lol:

The powerbank devices may not be able to have the capacity of some of the other solutions but they are certainly more elegant. :grin: They can also be used in an emergency to charge your phone during a power failure. There is a host of connectors included to provide power to other items you may already own.

Hope this helps.......

Sonny

#20 Sorny

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Posted 30 July 2014 - 09:19 PM

It's a 2Ah battery pack, so 1/4 of the run time a Starizona pack offers. Depending on how often you're slewing it could last 2 hours, or 4 hours, or maybe even 6...
The NexStar SE uses very little current while tracking; but uses somewhere north of a half amp while slewing both axis at high speed.

Velcro tape makes the size difference a bit of a moot point. I'd go strictly off capacity and decide how long you want to be able to go at a time.

#21 Sarkikos

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Posted 30 July 2014 - 10:19 PM

Sonny,

The power adaptor to the SE power adaptor label states the output is 12v 2500ma.


As I stated in my post, the NexStar manual says that the power supply requirements are "12 VDC-750mA." How does that square with what the SE power adapter label says? So what does the NexStar require, 12v 750mA or 12v 2500mA? If the NexStar only requires 12V 750mA - as the manual seems to be saying - why all this talk about higher amperage? What the mount actually needs is what is important.

The XtPower is 10000ma. (one more zero than you had).


Yes, I read that in the technical details. BUT I also read this: "Output: 2 USB 5V 2100mA and 1 DC 2000mA 9V/12V." Isn't this telling me that the XtPower outputs 12V 2A? So which is it? 10A or 2A?

So the smallest capacity Tracer powerbank listed above is approximately 50wh. It will give you about 4ah at 12v. It cost $100 The XtPower Bank I recently bought will give about 3/4 of that (3ah) but for half the price. There is a 20ah version for $69 on Amazon. You will realize about 6ah of it at 12v. This is about the same size and cost as a Power Tank but it will fit in your shirt pocket. I still believe that large deep draw lead acid batteries give the best bang for the buck but they bang your lower back too..... :lol:


The 20ah version sounds attractive. I don't want to buy cheap and buy twice. I want a power supply that will not falter during an observing session and start causing quirky behavior in the NexStar. But I also would like it to be light weight, easily recharged, and to fit between the OTA and the mount.

Mike

#22 Sarkikos

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Posted 30 July 2014 - 10:41 PM

Sorny,

It's a 2Ah battery pack, so 1/4 of the run time a Starizona pack offers. Depending on how often you're slewing it could last 2 hours, or 4 hours, or maybe even 6...
The NexStar SE uses very little current while tracking; but uses somewhere north of a half amp while slewing both axis at high speed.


When I go to my dark site, I observe for up to six hours. Here at home I usually don't observe more than two or three hours. When using goto, I do a lot of slewing. I use the NexStar sometimes at home, sometimes at the dark site.

Velcro tape makes the size difference a bit of a moot point.


Well, not exactly moot, since I want to attach the battery pack somewhere on the part of the mount that moves in order to prevent cord wrap. If I Velcro the pack, where do I Velcro it? Will there be enough room? Will the pack be secure? Will it get in the way of the OTA when slewing?

I'd go strictly off capacity and decide how long you want to be able to go at a time.


What capacity do you guesstimate I should shoot for?

Mike

#23 Midnight Dan

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Posted 31 July 2014 - 06:47 AM

Hi Sarkikos:

Lot's of confusion above. :grin:

Supply power vs. mount spec - The power brick says 2500ma. That means is can deliver 2500ma, NOT that the mount needs 2500ma. The mount spec says what the mount supposedly needs, which is 750ma max. I have measured the actual power usage of my mount and iI got about 250ma while tracking, and 500ma with both motors slewing. Current usage will vary depending on scope load, balancing, etc.

The XtPower is 10000ma. (one more zero than you had).

Yes, I read that in the technical details. BUT I also read this: "Output: 2 USB 5V 2100mA and 1 DC 2000mA 9V/12V." Isn't this telling me that the XtPower outputs 12V 2A? So which is it? 10A or 2A?


I think you're mixing up mA and mAh. Milliamps (mA) is the maximum current that the battery can deliver to the load at any point in time. In this case, 2 A at 12V. It has nothing to do with capacity, so no impact on how long it can deliver that 2 A.

The "10000ma" that is being quoted is actually 10000mAh (milliamp hours). This is a rating of the capacity of the battery (at some low voltage), NOT how much current it can deliver at one point in time. From info in the other thread, I think the actual capacity at 12V worked out to something like 3 Ah for the battery.

So, the battery is capable of delivering a maximum of 2Amps of current, and it has a 12V capacity of 3 Amp hours.

-Dan

#24 sonny.barile

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Posted 31 July 2014 - 06:27 PM

Dan Thats me with the mixing up of amp-hours and amps. I have been doing that when I write it out since 4th grade science class. :grin:

Sorry for the confusion. I type haphazardly and my ability to get what I think in my head to come out of my finger tips is not so good.

Mike This battery clears the ep and diagonal when it is sitting on the battery compartment lid.

The USB outputs are for where you plug phones in to charge. One is for an iPhone and the other is for a Galaxy. (That is what the other lower voltages and current were spec'd for) The USB is not for the scope.

There is an additional output that has a switch. 12 volts or 5 volts. A plug in cable is supplied for that one. It has the 2.1mm connector on it. (fits the se mount).

Sounds like you run your scope for a long time. Thats why I suggested the 20a model. It will have 6amps capacity at 12v. The 20amps rating is at 3.7volts and not at the 12volts.

The battery comes with an ac wall charger.

The Battery will fit in a dress shirt pocket. It weighs about 10 oz.

Hope this helps some.

#25 sonny.barile

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Posted 31 July 2014 - 06:27 PM

Dan Thats me with the mixing up of amp-hours and amps. I have been doing that when I write it out since 4th grade science class. :grin:

Sorry for the confusion. I type haphazardly and my ability to get what I think in my head to come out of my finger tips is not so good. I tend to ramble....

Mike This battery clears the ep and diagonal when it is sitting on the battery compartment lid.

The USB outputs are for where you plug phones in to charge. One is for an iPhone and the other is for a Galaxy. (That is what the other lower voltages and current were spec'd for) The USB is not for the scope.

There is an additional output that has a switch. 12 volts or 5 volts. A plug in cable is supplied for that one. It has the 2.1mm connector on it. (fits the se mount).

Sounds like you run your scope for a long time. Thats why I suggested the 20a model. It will have 6amps capacity at 12v. The 20amps rating is at 3.7volts and not at the 12volts.

The battery comes with an ac wall charger.

The Battery will fit in a dress shirt pocket. It weighs about 10 oz.

Hope this helps some.






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