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Equipment Discussions >> Equipment

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cirrus1500
member


Reged: 04/09/13

Loc: California
New Celestron Power Tank 7Ah comes with USB ports
      #6108675 - 09/30/13 04:30 AM Attachment (10 downloads)

I just bought one from Amazon and am negatively surprised that the new model has 2 USB ports instead of the 3V, 6V, 9V outputs. I usually use the 6V output for my StarSeek WiFi module, so is a little disappointing that I have to depend on batteries now. From my limited experience, USB ports are not really that useful for astro-related equipments. What accessories are powered by the 5V USB ports? Why would Celestron make such a change to the Power Tank, as an astro power solution?

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Chucky
sage
*****

Reged: 04/16/10

Loc: Dublin, Ohio
Re: New Celestron Power Tank 7Ah comes with USB ports new [Re: cirrus1500]
      #6108761 - 09/30/13 07:33 AM

<< Why would Celestron make such a change to the Power Tank, as an astro power solution? >>

Celestron doesn't 'make' this battery. They just stamp their name on it.


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AlBoning
professor emeritus


Reged: 03/06/11

Re: New Celestron Power Tank 7Ah comes with USB ports new [Re: Chucky]
      #6108777 - 09/30/13 07:47 AM

With any luck at all you can get enough juice out of one of those USB ports to power your WiFi. Course you'll likely have to make up the cable yourself.

BTW how how are you charging that thing?

I strongly urge you ditch the charger and replace it with a Battery Tender Jr.


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cirrus1500
member


Reged: 04/09/13

Loc: California
Re: New Celestron Power Tank 7Ah comes with USB ports new [Re: AlBoning]
      #6108815 - 09/30/13 08:21 AM

Hi AlBoning, the Starseek Wifi module needs 6V to operate, so 5V from the USB port will be inadequate. I may find a way to use one of the 12V outputs power my Starseek module. Btw, i have a battery tender 800 charger, similar to the one you recommended (which wasn't available when i bought my 800 a few months ago). I bought it to use with my other Celestron 17Ah power tank when the charger got lost. These battery tender chargers work great and i have no worries about maintaining the new 7Ah one

Btw, i noticed that the included charger might have changed as well. The charger of my older 17Ah power tank was big and heavy with output current around 0.8A. This one is small and light with output current only 0.5A. Hopefully, it is more durable than the previous version which is notorious in this forum for breaking after a few uses


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AlBoning
professor emeritus


Reged: 03/06/11

Re: New Celestron Power Tank 7Ah comes with USB ports new [Re: cirrus1500]
      #6109013 - 09/30/13 10:28 AM

I would check the voltage of the USB ports. Voltage output tends to be on the high side of spec. The electronics are rather simplistic in these units. I suppose it is possible to alter the voltage output of the USB ports if one wanted too. Perhaps all it would take is swapping a resistor.

In case you are interested ...

I have routinely recorded the open circuit voltage of my Orion Dynamo Pro 12 before and after use over the course of the 22 months I've had it.

Since the open circuit voltage of a battery changes in an approximately linear manner with the percent State of Charge (SOC) monitoring the battery gives one a means of keeping an eye on the health of the battery. I've a spreadsheet to keep track of the data and calculate charge use per hour. If either the max voltage the DP12 charges to starts to decline, or the charge use per hour starts to go up then I know the battery is approaching the end of its useful life. When it finally does give up the ghost I plan to replace just the battery. There are replacements available in the neighborhood of 40 bux that claim to be deep cycle.

Going from 100% SOC to 0% SOC is a mere voltage difference of about 1.5V, starting at about 12.9V and going down to 11.4V, varies a bit among batteries.

Keeping my DP12 hooked up to a BTJr continuously (when not powering a mount) has kept it as good as new for all 22 months.

One of the reasons I selected this power supply was because of the 3/6/9V outputs. Considering the bad rap these get I fully expected I'd replace it inside a year and the purchase was made out of convenience, but now I expect a long useful service, all because of the BTJr. In addition to the 12V outputs powering my Atlas and cooling fan, I use the 6V to power the Dual Axis Drive of my SkyViewPro and if I wanted to slow the fan down a bit I could switch it to 9V. I've got no use for USB ports.


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HeyJP
sage


Reged: 12/11/10

Loc: Boulder, CO
Re: New Celestron Power Tank 7Ah comes with USB ports new [Re: AlBoning]
      #6109764 - 09/30/13 06:28 PM

Most smartphones and tablets (and many other portable electronics these days) have standardized on USB recharging... So this is a useful pair of ports to recharge a slug of devices. Heck, my bicycle headlight and tailight, a portable headphone amplifier, and 2 different rechargeable batteries I have use USB for recharging them.

I use iPhone and iPad for controlling my Canon 6D and CPC1100 wirelessly all night, so having a single recharge source is nice.

I use SkySafari's SkyFi for my WiFi.. and it accepts a range of input voltages... I use 12v for it.

I'm guessing that Celestron is seeing fewer and fewer requirements for 3, 6 and 9 volts and LOTS of requests for USB and 12v sources.

Jim in Boulder

Edited by HeyJP (09/30/13 06:40 PM)


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cirrus1500
member


Reged: 04/09/13

Loc: California
Re: New Celestron Power Tank 7Ah comes with USB ports new [Re: HeyJP]
      #6111038 - 10/01/13 11:36 AM

AlBoning,
thanks for the open circuit idea to gauge the health of the internal battery. I will certainly use it to check my battery when it is suspected to be near the end of its life. For new units, I think the battery tender will do a good job for quite some time. I too do not have much use for the USB ports. In fact, the 12V sockets can very easily and cheaply be converted into USB ports (cost less than $1 on eBay) so if I need USB ports I can always get the cheap converters. The 3,6,9V outputs will certainly be nicer to have. I think Celestron just want to reduce cost with this new model.

Jim,
From what I understand, although SkyFi can take 6V to 12V input, the excess voltage above 6V will only be converted into heat, and the heated circuitry would most probably result in shorter lifespan of the circuit board. I always try to feed as much voltage as required, maybe slightly more (0.5V - 1V above is okay), to maximize the lifespans of electronic devices. The SkyFi is great but it is quite costly so hope it will last a long, long time


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Astronewb
scholastic sledgehammer
*****

Reged: 09/19/11

Loc: Connecticut
Re: New Celestron Power Tank 7Ah comes with USB ports new [Re: HeyJP]
      #6111048 - 10/01/13 11:42 AM

Good info, I wasn't aware of that change either. Since it has USB ports, I won't be purchasing it.

I have the original, as you, and use the 9V outlet to power my Dslr camera. If I need a USB port, I can always plug in a cigarette lighter to USB port plug.

I replaced the 7AH battery with a 9AH unit just this year, after 2 years of use. Easy install with the benefit of a few extra amp hours in the same physical space.

I don't think Celestron had any input on the new design. More likely the Chinese manufacturers not realizing the needs of stargazers or AP'ers and just jumping on board the Smartphone bandwagon. Imho.

Thanks for the useful info,

Paul


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