Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Details of a Wireless EAA Setup

  • Please log in to reply
255 replies to this topic

#51 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 17 January 2018 - 07:08 AM

Thanks rac19. Agree raspberry is on the low end. Appeals to me cause I'm cheap, but sometimes cheap just doesn't cut it. Still I'll prob play with one since I have piles of hardware hanging around so can tinker a bit ☺

Yep, I've been there and done that and ended up buying the NUC.

 

I have just been playing with it tonight, for the first time in a real observation session. First impressions are pretty good. There's not much to see by way of solar system targets tonight  but I was able to star-hop quite successfully and learn something about alignment point along the way. I even had my first look at a nebula.

 

I will be interested to see how you get on. There is always more to learn about this stuff.

 

EDIT: It depends what you want the onboard computer to do of course. I can two cameras attached, one low-res (USB 2) as an electronic RACI finder, the other hi-res (USB 3) for image capture. The other requirement is remote access via TeamViewer or similar. This is definitely beyond the capabilities of the Raspberry Pi. Being a long time Raspberry Pi user I would liked to have used it, but it was not to be.


Edited by Rac19, 17 January 2018 - 02:56 PM.


#52 ronpen

ronpen

    Vostok 1

  • *****
  • Posts: 145
  • Joined: 17 Dec 2007
  • Loc: Florida

Posted 18 January 2018 - 11:04 AM

To be fair, RAC19 was running at 20V without mishap and has since had his NUC running at 12V for some hours without problems, but Intel also say that potential damage can occur if less than 11.6v.

I just checked no load voltages my multimeter.
 
NUC power adapter 19.36 Volts
MaxOak K2 “20 Volt” output 19.27 Volts
MaxOak K2 “12 Volt” output 12.07 Volts
 
These would all be a little lower with a load connected but I would need  a break-out-box to get measurements under load, which I might try to do.
 
As always, anyone not prepared to a risk, should stay strictly with the manufacturers advice. Personally, I am happy to use the MaxOak battery on either “12 Volts” or “20 Volts” but I would not want induce anyone else to take a risk that they are not prepared to live with.

Did tension measurement on the 'MAXOAK K2' (185 Wh) (fully charged):
"20 V" output: 19.56 V
"12 V" output: 12.22 V (12.17 V with KODLIX AP42 mini PC connected at ~1/2 load)


Curious has anyone done a measure of the actual watt hours of the MAXOAK K2 as compared to the claimed watt hours?

#53 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 18 January 2018 - 02:09 PM

 

Curious has anyone done a measure of the actual watt hours of the MAXOAK K2 as compared to the claimed watt hours?

I think that fact that it runs for 8 hours powering an Intel NUC 3i is proof enough. I think that I read somewhere that it draws about 20 Watts. I think also that it is normal to de-rate the manufacturer’s claim, by as much as 20%, as you do with official fuel consumption figures for cars,

.



#54 ronpen

ronpen

    Vostok 1

  • *****
  • Posts: 145
  • Joined: 17 Dec 2007
  • Loc: Florida

Posted 19 January 2018 - 08:33 AM

 

 

Curious has anyone done a measure of the actual watt hours of the MAXOAK K2 as compared to the claimed watt hours?

I think that fact that it runs for 8 hours powering an Intel NUC 3i is proof enough. I think that I read somewhere that it draws about 20 Watts. I think also that it is normal to de-rate the manufacturer’s claim, by as much as 20%, as you do with official fuel consumption figures for cars,

.

 

Somehow in my reading I missed it has successfully ran a NUC for 8 hours.  That's good enough for my purposes and sounds close to the rated watt hours.



#55 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 19 January 2018 - 12:17 PM

An update regarding power requirements;..

 

Inevitably, large sensor/megapixel cameras and/or complex EAA set ups will require more processing and battery power, especially where large blocks of data is being processed and then transferred over a wholly wireless and cable free network from a computer situated at the telescope to a remote laptop (e.g. in the warm!). I eventually decided to purchase an Intel NUC i-5 which offers more than the necessary power and room to future proof.  Finding the computing power isn't challenging.

 

Battery power is hence the last conundrum to be solved and it is not proving easy with the Intel NUC and a large data intensive camera.... unless prepared to take a risk (albeit one that from other CN'er experience appears slight).....

 

My Evolution telescope has its own internal battery offering up to 10 hours, so that is one requirement neatly ticked off the list. I then built this simple 'cradle' suitable to hold my Tracer 12v 8Ah battery which is used to power my Atik Horizon and Focuser Motor and to also embrace a '2-Power' 27Ah 19v battery to power my NUC i5. If I want to later adopt (say) a slightly larger MaxOak K2 50Ah I can simply make the inner compartment wider by using 40mm M4 bolts/spacers rather than the 30mm depicted. This arrangement is incredibly compact and it all rotates with the mount (so no cord wrap). It simply straps to the Evolution mount arm using (wide/long) Zacfton cable ties. It is neat, but power remains an issue....

 

Telescope6.JPG

 

The reason I didn't adopt the MaxOak K2 50Ah power bank (n.b. which was highly praised by a couple of CN'ers) was that both its manufacturer (KayoMaxstar) and Intel Support refuse to confirm that its 20v output is satisfactory for the "12v -19v" NUC. KayoMaster even wrote to me (unpromoted) to query my order and to express concern over Intel NUC compatibility. Yet KayoMaster is willing to confirm compatibility with Toshiba, Dell, HP (etc) laptops and with most other manufacturers that specify 20v. Intel NUC's (specified at "12v to 19v", but with a vague reference to + or - 10%) do seem to be a rare beast. I have had mine working perfectly from my Tracer 12v 8Ah. However, Intel Support warned me that if run below 11.6v then damage was also possible (so the Maxoak K2 might have a potential problems at both ends). By contrast, Tracer guarantee power stability at 12v and that is probably why its Li-Po batteries are vastly so much more expensive than lesser known Far East manufactured power banks. The Tracer 12v 8Ah retails at £129.97 which is more expensive than either of the (at least 3 x capacity) 27Ah and 50Ah options discussed here.  .

 

Some CN'ers have tested this further (see posts above) and it appears that the output of a NUC's standard (mains) adapter and the MaxOax K2 both appear to be around 19.3v. There is normally a + or - 5% tolerance, so Intel's (and KayoMaxstar) stubbornness is rather strange. Maybe it is because the NUC is normally a kit computer and the manufacturer has no control over the extra components (but mine is a complete computer). However, Intel Support advised me that if I bought the MaxOak K2 it would be advisable to also get a DEC/DEC converter (£59.99). However, RAC19 has a MaxOak K2 50 Ah (£109.99) and is running his i-3 NUC (I believe that is at 12v) without any mishap. Maybe I am just over cautious? Instead I bought a '2-Power' 27Ah power bank (£118.80) which was the only other compact unit I found at a reasonable price with decent capacity guaranteed to be compatible with a NUC.

 

Most 'Power Tanks' from telescope manufacturers are limited to merely 7Ah to 17Ah. The biggest Tracer compact sized Li-Po is 22Ah and costs £241. The (brick like) Deben Tracer Lithium Phosphate 12v Battery Pack (£215) is merely 16Ah. A Tracer 12v 40Ah Peli case battery is over £700 and hardly 'compact'. I also didn't want to adopt a massive brick of a Lead-Acid battery as these are at least four times the weight and double the price of these compact units, which would defeat the objective of developing a lightweight, wireless, cordless rig (8" OTA) that I can carry fully assembled from my 'office' to its location. Unfortunately, set up times of 30 minutes are wasteful under typical UK skies where the clouds are never far away, hence my quest.

 

Sorry for the long preamble to put things into context, but my reason for posting is to report that I got an encouraging five hours duration from the 27Ah '2-Power' power bank into the NUC when idling (simply running Windows on the NUC). This suggests the NUC has less than 20w consumption when idle. However, I then fully recharged the power bank and put it under an extreme load of APPs (probably circa 50w load) and the duration dropped to merely three hours and twenty minutes. It is clearly quite sensitive to wattage 'load' (as we had earlier predicted). I reckon that with the slightly less demanding Atik camera (note; just processing its data) then FOUR HOURS duration is probably the best case scenario (I am still awaiting delivery of my camera to test it more fully - hurry up Santa!). To be fair, from merely the 8Ah from my Tracer I doubt if I will get any longer duration power for camera and focuser. So four hours of EAA on this battery set up looks like the limit.

 

Three plus hours is fine for me when at home as I rarely get more than a three hour break between the clouds. Also, if I want to be out for longer I do have close proximity to outdoor RCD protected mains power (I then put any adapters in a wholly waterproof socket box). But I suspect folk might be disappointed with three hours if at a dark sky site. However, a Celestron or SkyWatcher 17Ah Power Tank will inevitably last an even shorter duration at 50w (and that assumes you are not also powering a telescope). Most regular laptops will struggle to give you more than four hours without supplementary power, so a second battery does seem inevitable, unless one does purchase a MaxOak K2 (n.b. RAC19 has comfortably had his MaxOak K2 running his NUC for over EIGHT hours - awesome!).

 

Maybe the only battery solutions for longer duration EAA with a NUC and large sensor camera are to buy TWO x '2-Power' 27Ah (or two x Tracer 22Ah); or invest £700 in a 40Ah Tracer; unless prepared to risk the MaxOak K2; or carry the huge 'brick' of a lead-acid or similar. Frankly, if RAC19's NUC is still alive by the time that I next want to venture to a dark sky site (Spring), I will probably succumb to the MaxOak K2. Thanks RAC19 for your bravery. But if anybody has another idea that provides a certain 19V (or a certain 12v - 18v) from a COMPACT battery or power bank  with a capacity above (say) 40Ah then please add to this thread. Or is the Maxoak K2 50Ah unique? Hopefully many more CN'ers will report on their experiences with a NUC (or Compute Stick etc.).


Edited by Noah4x4, 19 January 2018 - 12:48 PM.


#56 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 19 January 2018 - 04:41 PM

 

There is normally a + or - 5% tolerance, so Intel's (and KayoMaxstar) stubbornness is rather strange.

I too think that their reuctance is odd. It may be that neither Intel nor KayoMaxtar will endorse anything that they haven’t tested themselves, as a matter of policy.

 

I have run my NUC 3i quite a few times on the 12 Volt output of the MaxOak K2, no problems so far.

 

Below is page 53 of the detailed Intel Technical Specification which states the the tolerance is +/- 10%. Just what “+12-19  (+/- 10%) V DC” means is open to interpretation I guess. Does it mean 10.8 to 20.9 V DC?

Attached Thumbnails

  • 16D993DA-5DC7-417C-800C-DF26179AF228.png

Edited by Rac19, 19 January 2018 - 05:17 PM.

  • Noah4x4 likes this

#57 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 19 January 2018 - 05:59 PM

 

 

There is normally a + or - 5% tolerance, so Intel's (and KayoMaxstar) stubbornness is rather strange.

I too think that their reuctance is odd. It may be that neither Intel nor KayoMaxtar wiil endorse anything that they haven’t tested themselves, as a matter of policy.

 

I have run my NUC 3i quite a few times on the 12 Volt output of the MaxOak K2, no problems so far.

 

Below is page 53 of the detailed Intel Technical Specification which states the the tolerance is +/- 10%. Just what “+12-19  (+/- 10%) V DC” means is open to interpretation I guess. Does it mean 10.8 to 20.9 V DC?

 

I saw that too RAC19. Very confusing. There is also a very early comment on the Intel Support Forum that Intel had a NUC running at voltages "between 12v to 24v". But "between" is perhaps open to interpretation. Then progressively the comments about its voltage range become more restricted. Some frustrated business users then chip in with challenging questions and eventually we get to a point where the Intel Support advice is strictly 12v to 19v and if any deviation one should use a DC/DC converter. Then in a new thread more specific advice to me that the range is strictly 12v to 19v and explicitly about the dangers of going below 11.6v. Then a user repeated the advice about the desirability of a DC/DC adapter to stabilise voltage where there is doubt (probably more so when connected to a motor vehicle 12v output) . The limited amount of user comment perhaps suggests most owners are using the 19v mains adapter. I guess that is a product of the astronomy community only recently embracing large sensor cameras and NUCs and hence we are possibly the first group needing suitable external power banks/ batteries.

 

I truly hope that your excellent progress with the MaxOak K2 at 12v continues. But given that you measured its 20v output as the same as the NUC mains adapter it seems debatable which end of the scale is best. My 2-Power 27Ah (advertised as NUC compatible) offers 16v and 19v so that should be comfortable. But I wish it was closer to 40Ah to offer me more than its meagre 3 to 4 hours. Frankly, I feel I am probably being far too cautious in avoiding the MaxOak K2, but then a NUC costs over £500 and I doubt if its warranty would cover loss after a voltage problem. Another issue is that the 2-Power offers 10.8v, 16v and 19v hence no 12v. Hence, I need the Tracer 12v. Aaaarrrgh!

 

I am now wondering if the DC/DC adapter (£59) plus MaxOak K2 (£108) is actually the best route forward to ensure voltage stability with 8 hours duration? That combination is still half the price of a single Tracer 22Ah (and for 6 to 8 hours you would need two Tracers). Sadly,  I don't understand DC/DC technology.  It looks to me that the DC/DC adapter is a small pcb circuit. So is that a component that fits inside the NUC? Is it easy to install? Whilst I realise you are willing to take the risk of not using a DC/DC I also know you understand this stuff. So RAC19, how would you put the DC/DC adapter into the circuit? 

 

EDIT

I found this on the Intel Support website. Might it be an easy solution to the MaxOak K2 potential concerns? https://www.bixpower...-dd90m-19v.htm  Cost $67 including shipping to UK.


Edited by Noah4x4, 19 January 2018 - 06:33 PM.


#58 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 19 January 2018 - 07:19 PM

 

I found this on the Intel Support website. Might it be an easy solution to the MaxOak K2 potential concerns? https://www.bixpower...-dd90m-19v.htm  Cost $67 including shipping to UK.

Hi Noah4x4, that little Bix Power gadget seems to tick all the boxes. It will give 19 VDC from an input as low as 9 VDC and has an ample rating of 90 Watts. This could mean that you can use the 12 VDC output from the MaxOak K2 to power any 12 Volt stuff (dew heaters etc) and still run the NUC on 19 Volts. As we know, MaxOak says not to use the12 Volt and 19 Volts outputs at the same time. I don't see why not, as long as you know what you are doing, but that's their official recommendation, to be ignored at your own risk. I might just try it one day, when I am in a risk taking mood.

 

I am going to keep going with the 12 Volt output from the MaxOak. I used it for an actual observation session the other night. After 3 hours only 25% of the storage had been used. I have now Velcro-ed a three outlet cigarette lighter adapter to the battery. I have a plug-in voltage indicator in one outlet, the other two will be used for the NUC and a Dew-Not controller. Strange to have all this 21st century technology plugged into cigarette lighter sockets. I gave up smoking when they went up to 40 cents for a packet of 20.

 

EDIT: I was at Jaycar today and they have a number of devices designed to convert 12 VDC to 19 VDC for running laptop computers in the car. The significance of 19 Volts seems to be that it is the defacto DC Voltage for laptops.


Edited by Rac19, 20 January 2018 - 01:19 AM.

  • Noah4x4 likes this

#59 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 20 January 2018 - 01:16 AM

KayoMaxstar don't have a lot of confidence in their product e.g. "unsure about NUC compatibility"and "don't use 12v and 19v outputs at the same time".  I have also found a recommendation from Intel in its NUC support forum that recommends 19v and suggests that if running at 12v a voltage drop to 11.64v "might have consequences" (but do they simply mean lose your MS-Office work?).  

 

The Bix DC/DC converter ensuring 19v from any 9v to 17v input seems to make sense with any of these cheap Far East battery/power banks. I currently don't need one as my present '2-Power' 27Ah outputs 19v and is guaranteed NUC compatible (but short on capacity). However, I think I will soon get one and a MaxOak K2 50Ah for field trips. Then I can run the Bix with any of my batteries as a safeguard,  Maybe Intel's broad advice about DC/DC converter at 19v does make sense given Kayomaxstar''s lack of confidence!


Edited by Noah4x4, 20 January 2018 - 01:18 AM.


#60 Ulmish

Ulmish

    Explorer 1

  • -----
  • Posts: 63
  • Joined: 17 Mar 2013
  • Loc: New Ulm, TX

Posted 21 January 2018 - 09:44 PM

Thanks to all for this useful thread - I've found lots of good ideas and experience here!

 

I'm in the process of setting up my Nexstar 8se for EAA.  My camera is a Zwo ASI224MC connected to a Celeron-based NUC (NUC6CAYH) with 8 GB memory and 128 GB SSD.  Like everyone else, battery is a big concern as I'd like to have a cordwrap-free setup. 

 

I have a 15 amp hour LiFePO4 battery with a voltmeter/ammeter attached, and ran some quick tests running the NUC off 12V.  It pulls 1.3 amps at max CPU load (running Prime95 on all cores).  With the camera connected and running Sharpcap, the max load was around 0.9 amps.

 

I'm looking at the Maxoak K2 as a battery to power the whole setup.  The specs state its 12V output supports up to 2.5 amps.  Besides the NUC and camera, I need it to power the 8se itself, but it's power draw with both axes moving topped out at 0.6 amps.  So it looks like the Maxoak can deliver enough amperage at 12V with a reasonable safety margin.

 

There seems to be conflicting information about using both the 20V and 12V outputs simultaneously on the Maxoak.  I'm curious if anyone has tried this?  The instructions say not to do this, but in the Q&A on Amazon the manufacturer says this can be done.  It would be nice to be able to power the NUC with 19V and the 8se with 12V.

 

BTW, I did measure the power brick for my NUC - not sure if Intel ships the same brick for the I5/I7 NUC models but for what it's worth here are the specs on mine:

 

Output:  19V, 3.43A, 65W max.  I measured 19.54V with no load - slightly higher than RAC19's.



#61 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 22 January 2018 - 12:38 AM

Thanks to all for this useful thread - I've found lots of good ideas and experience here!

 

I'm in the process of setting up my Nexstar 8se for EAA.  My camera is a Zwo ASI224MC connected to a Celeron-based NUC (NUC6CAYH) with 8 GB memory and 128 GB SSD.  Like everyone else, battery is a big concern as I'd like to have a cordwrap-free setup. 

 

I have a 15 amp hour LiFePO4 battery with a voltmeter/ammeter attached, and ran some quick tests running the NUC off 12V.  It pulls 1.3 amps at max CPU load (running Prime95 on all cores).  With the camera connected and running Sharpcap, the max load was around 0.9 amps.

 

I'm looking at the Maxoak K2 as a battery to power the whole setup.  The specs state its 12V output supports up to 2.5 amps.  Besides the NUC and camera, I need it to power the 8se itself, but it's power draw with both axes moving topped out at 0.6 amps.  So it looks like the Maxoak can deliver enough amperage at 12V with a reasonable safety margin.

 

There seems to be conflicting information about using both the 20V and 12V outputs simultaneously on the Maxoak.  I'm curious if anyone has tried this?  The instructions say not to do this, but in the Q&A on Amazon the manufacturer says this can be done.  It would be nice to be able to power the NUC with 19V and the 8se with 12V.

 

BTW, I did measure the power brick for my NUC - not sure if Intel ships the same brick for the I5/I7 NUC models but for what it's worth here are the specs on mine:

 

Output:  19V, 3.43A, 65W max.  I measured 19.54V with no load - slightly higher than RAC19's.

MaxOak says not to use the 12 Volt and 19 Volt output at the same time so anyone who does so, does it at their own risk. I can see a couple of potential problems.

 

Firstly if you connect the 12 Volt and 19 Volt outputs to the same device, or separately devices that are intentionally or unintentionally electrically connected (by being clamped to the same piece of metal for example) there is risk of ground loop or circulating currents which can cause damage or even combustion. The second possible problem is that if rated current is drawn from the 12 Volt and 19 Volt, there could well be overloading of the battery or internal circuitry.

 

I believe that I have an understanding of how to avoid both of these issues and might give a a try one day, an my own risk.

 

At it happens, I have been using the 12 Volt output to run the NUC and DewNot controller, and it all seems to work just fine, so I think that maybe there is no real reason to use both the 12 Volt and 19 Volt outputs anyway.

 

At the moment, I am using a three socket cigarette adapter with looks a bit amateurish.  I might convert one day to a little distribution box with Anderson connectors, but that would rally just be for appearances.

 

https://www.jaycar.c...-power/p/PP2120
http://www.westmount...ts_id=rr_4004_c


Edited by Rac19, 22 January 2018 - 03:05 AM.


#62 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 22 January 2018 - 02:47 AM

I am persisting with a dual battery set up which can tidily be accommodated using my compact DIY cradle (see post #55). . Weather is still frustrating me, but in indoor test with an appropriate comparative load I am consistently getting over four hours from my Tracer 8Ah and very close to four hours from my 19v '2-Power' 27Ah (NUC i3). 

 

If I need longer, when at home I can use mains power and the 110v to 240v mains regular adapters. However, I am still awaiting delivery of my camera, but suspect it will not demand as much power or processing wattage as the loads in these tests. I am fairly confident my twin battery set up will exceed four hours. A four hours limit is not ideal if away from mains power, but I have since realised that  most holiday parks where I do dark sky activity (example Kelling Heath) offer mains power support to mobile homes etc, so will explore that. However, I am keeping my fingers crossed that you guys have satisfactory experience with the 8 hour + MaxOak K2 50 Ah.

 

If the MaxOak K2 50Ah proves satisfactory I will embrace it. But using a DC/DC regulator seems wise given they are locally available for under £30.  So if I do get a MaxOak K2, I would then run my camera from my '2-Power' 10.8v output using a DC/DC converter to step up to 12v; then run NUC from the MaxOak K2 12v output stepped up to 19v. Hence as the manufacturer has issued a DON'T use both outputs of the MaxOak warning my extreme caution wouldn't risk it. Even so, I am already looking at my dual battery cradle to consider how I can insulate the circuits to avoid accidental shorting across voltages. But as I have a single power cable from 2-Power to NUC and each device has very different plugs this is perhaps paranoia.


Edited by Noah4x4, 22 January 2018 - 02:49 AM.


#63 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 22 January 2018 - 03:51 AM

Below are links to the cigarette socket and Anderson connector options. Looking at the price of the latter and the amount of work required to make bespoke cables, I may not bother.

 

https://www.jaycar.c...-power/p/PP2120
http://www.westmount...ts_id=rr_4004_c


  • Noah4x4 likes this

#64 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 22 January 2018 - 06:33 AM

There is a new 50000mAh  kid on the block...much smaller dimensions to MaxOak K2.

 

https://www.amazon.c...JRD7Z89WKGCW8M 

 

Suggests 20v output is compatible with 19v and 19.5v. But 16v (or 12v with a DC/DC converter to offer 19v) for NUC might be sensible. Mentions every laptop except Intel NUC! "Not supplied with UK power cord"....how odd!


Edited by Noah4x4, 22 January 2018 - 06:42 AM.

  • Rac19 likes this

#65 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 23 January 2018 - 10:50 AM

Sadly, my optimism proved unfounded.

 

Despite enjoying over four hours in an earlier indoor test my '2-Power' 19v 27Ah power bank expired in under three hours yesterday when running my Intel NUC i5 at close to optimum load. So a tad reluctantly, I too have ordered a MaxOak K2 50000mAh. I say reluctantly as there are some risks.

 

It seems care is needed as the MaxOak K2 is rated 20v/3A or 12v/2.5A. Hence, it will charge, but it won't run some laptops requiring over 3A. At 12.5v/2.5A that is merely 30w. An i5 NUC idles at 18w and might be up at close to 50w under heavy load. So it seems advisable to use the 20v/3A output else risk overload at 12v/2.5A (n.b. 50w might require over 4A). The NUC is also rated 19v "+ or - 10%". The user experience is that the MaxOak seems to be typically discharging  around 19.5v (e.g. same as the NUC regular adapter) so one hopes that the MaxOak doesn't spike over 20.9v. It also now starts to make sense why KayoMaxstar advise all users "don't use 20v/3A and 12v/2.5A simultaneously".

 

I am now going to use a MaxOak for my NUC at 20v/3A and a Tracer 12v 8Ah for camera and focuser (my Evolution has its own power). However, it is becoming quite evident that wireless/cable free EAA is challenging as regards computing and consequent power demands if you have a large sensor megapixel camera (such as Atik Horizon or ZWO AS1600). Why isn't an astronomers life ever simple? Maybe that's the real lure......



#66 nic35

nic35

    Viking 1

  • *****
  • Posts: 817
  • Joined: 08 Sep 2007

Posted 23 January 2018 - 01:45 PM

You need to be careful about the published AH ratings. For the one you linked in post 64, the 50AH rating is at 3.7 volts. At 19 volts it is only about 10 AH.  (Watt hours divided by voltage)

 

I suspect the same is true of the maxoak, but theydo not list the WH of their, battery. But the size is similar to theother one, so unless the, power density of their technology is 5x greater I think 50000 is a marketing ploy

 

They say 6 hours to a full charge. Check the output of the c harger they supply. If its not 8 amps (**** big for a wall wart), that's another strike against them.

 

But,   I am often accused of being too cynical.

 

This is one reason I like TalentCell,.  They often tell you the AH ratings at various voltages, or the WH rating of thier batteries.  Makes me less cynical about them.

 

John

 

ps - I never knew before that CN has a "cuss button" !


Edited by nic35, 23 January 2018 - 02:01 PM.

  • Noah4x4 likes this

#67 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 23 January 2018 - 02:26 PM

 

I suspect the same is true of the maxoak, but theydo not list the WH of their, battery. But the size is similar to theother one, so unless the, power density of their technology is 5x greater I think 50000 is a marketing ploy.

Correct, they really should quote Watt hours. The 50 Amp hours is based on the 3.7 Volt output of the Lithium cells. This battery actually has a capacity of 3.7 Volts * 1 Amp * 50 hours = 185 Watt hours.

 

At other voltages, say 20 Volts, you need to divide the Watt hours by the  Volts, 185/20 = 9.25 Amp hours. It is also common practice to de-rate the manufacture's lab test results by as much as 25% (as you do with car fuel consumption numbers) further reducing the number to about 7 Amp hours at 20 Volts, in the real world.

 

EDIT: Quoting the Ah at 3.7 Volts is technically valid and the marketers are no doubt happy to quote the higher number. Whether or not this is deceptive marketing I will leave as an open question, it certainly confuses (and possibly deceives) some of us.


Edited by Rac19, 23 January 2018 - 03:12 PM.

  • Noah4x4 likes this

#68 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 23 January 2018 - 04:01 PM

They deceive, or at least baffle me!

 

So let's talk in 'real money'.

 

Large sensor megapixel cameras require a lot of computing power, especially in a wireless EAA set up. In turn, that requires a lot of battery capacity. How much inevitably depends on the length of your observing sessions and the wattage requirements of your equipment.

 

All I know is that my '2-Power' 19v 27AH power bank will power my i5 NUC for about a meagre 3 hours. By contrast RAC19's MaxOak 20v 50000mAH is powering his i3 NUC for twice as long.

 

Hence.....in real money...

 

A Tracer 12v 22Ah costs £262 on Amazon UK. But its 22Ah is actually a massive 264 Watt hours. The  '2-Power' 27Ah is rated at 97Wh and is the only power bank or battery  listed here guaranteed to be NUC compatible.  I have a Tracer 12v 8Ah and it is excellent, but seriously expensive. But expressed in watt hours (96 Wh) it is easy to see why.

 

A 2-Power 19v 27Ah costs £118 from PSA Parts. That is why I purchased one (also it's NUC guarantee). A MaxOak 20v "50Ah" costs £108 on Amazon UK.

 

If we convert this information into hours of measured 'real life' output per dollar of cost the MaxOak wins easily (RAC19 calculated 185 Wh despite its marketing misinformation regarding Ah). But there are some compatibility risks as identified earlier in this topic. You need to be sure that it's 12v/2.5A or 20v/3A is within your computer's power tolerance.  

 

On reflection,  I question, whether we should we be too critical of the marketing deception of manufacturers that are making our hobby more affordable? My quest has been largely to identify options, limitations and risks. It's been a steep learning curve!

 

EDIT- I have certainly learned something from this evolving thread; and made some corrections above.

 

My apologies for fumbling in the dark, but I guess my misguided exploration of this topic will be of assistance to others that were also struggling. I got an 'F' in physics at school and that was 50 years ago. I must do 1,000 lines; "Ignore the Ah and look at the Wh".


Edited by Noah4x4, 23 January 2018 - 06:17 PM.


#69 nic35

nic35

    Viking 1

  • *****
  • Posts: 817
  • Joined: 08 Sep 2007

Posted 23 January 2018 - 07:36 PM

A couple of points. Why are these batteries so outrageously expensive in the UK?  By way of reference, a 132 WH talentcell battery goes for £45  in the US. 

 

Secondly not all i3's or i5's have the same power requirements. It depends on the CPU you are running, and obviously the demands you put on it.  I've seen "typical" demands ranging from 15 to 30 watts, which would make a substantial difference. You can get a rough idea of your CPU's power demands from cpuboss.com

 

All of which makes me very interested in the core m-3 and core m-5 series of compute sticks. These can much more powerful than celeron or atom CPU based systems, but have a much lower power demand than the core-I series, "typical" being in the 5 watt range. The question will be "can they handle bigger, higher bit depth sensors?".  Not as flexible as a NUC, but I,m looking at this as a single purpose platform, so flexibility isn't all that important.

 

But that might be a topic for another thread!

 

john



#70 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 23 January 2018 - 11:40 PM

 

A couple of points. Why are these batteries so outrageously expensive in the UK?  By way of reference, a 132 WH talentcell battery goes for £45  in the US.

I noticed that too. I bought the 50 Ah MaxOak K2 in Sydney for AUD $200, equivalent to110 Pounds Sterling.

 

I went for the NUC for a few reasons.

 

1. It is more or less a desktop computer in a small box.

2. It has 4 USB ports and I use all of them. ZWO satys that USB Hubs should no be used, especially for the ASI1600MC (hi-res).

3. It has USB 3.0 ports.

4. Power usage, while not extra low, is reasonable.

 

It suits all my particular requirements in other words.

 

Thanks for the CPUBoss.com link by the way.



#71 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 24 January 2018 - 02:26 AM

 

"Ignore the Ah and look at the Wh"

I think that the manufacturers in general are remiss in that they don’t often state the Voltage upon which their headline Ah claim is based. MaxOak, to their credit, do provide a Wh value, but it is still not their headline number.

 

Another issue is that, even when you look are detailed technical documentation from respectable suppliers, there is still room for interpretation on things such as the expected output voltage range and acceptable input voltage range of batteries and computers. In the end the consumer has to weigh up the numbers, the risks etc.

 

My approach is to gather a reasonable amount of data, make a decision, and maybe take my chances.



#72 Noah4x4

Noah4x4

    Vanguard

  • *****
  • Posts: 2455
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 24 January 2018 - 03:50 AM

Why is power/energy in the form of batteries so expensive in the UK? It has always been common for the same $10 electrical item in the USA to be priced at £10 in the UK ($1:£1), which doesn't make sense when the exchange rate is £1 GBP = $1.40461 USD. One might equally ask why is retail unleaded petroleum (gas) so expensive in Europe when the global price of a barrel of crude is the same. Today's average retail petrolum prices (all in US$);

 

Norway          $7.08 per gallon

Sweden         $6.06 per gallon

UK                 $5.64 per gallon

USA               $2.56 per gallon

Saudi Arabia  $0.91 per gallon

 

Supply; taxes to pay for welfare benefits (such as the UK free health service); investment in renewable energy/climate change mitigation (far more activity in Europe than USA); transport costs; exchange rates (post Brexit); all play their part. Norway and Sweden are far ahead in renewable energy implementation, and going 'green' has a huge cost part paid for by taxes on oil products. Hence, energy and transport is generally far more expensive in the UK/Europe when compared to the USA. I guess DC battery power just rides along the same fossil fuel fueled energy economics roller coaster.

 

But that aside, I think this has developed into a great thread. It is quite evident that developing a wireless/cordrap free EAA set up requires an insight far beyond traditional AP domains of telescope/mount, camera and software. Enough computing 'ooomph' and battery power are equally challenging considerations. RAC19 and me have spent a load of money on failed solutions for large sensor megapixel cameras, but we seem to have got there in the end. Hopefully our misfortunes, RACs expertise and my misguided ramblings have helped others


Edited by Noah4x4, 24 January 2018 - 03:52 AM.


#73 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 24 January 2018 - 04:33 AM

As to how I discovered that  the lithium cell voltage was the basis for the headline Amp hours, the way I got there was interesting.

 

MaxOak states the Watt hour capacity (185 Watts) as well as the Amp hour (50) rating, not many of them seem to do.

 

The result of 185 Watts/50 Amps is 3.7 Volts. To my surprise, when I searched for “3.7 Volts”, I found everything that I needed to know.



#74 CityObserver

CityObserver

    Explorer 1

  • -----
  • Posts: 98
  • Joined: 01 Mar 2017

Posted 24 January 2018 - 04:36 AM

All of which makes me very interested in the core m-3 and core m-5 series of compute sticks. These can much more powerful than celeron or atom CPU based systems, but have a much lower power demand than the core-I series, "typical" being in the 5 watt range. The question will be "can they handle bigger, higher bit depth sensors?". Not as flexible as a NUC, but I,m looking at this as a single purpose platform, so flexibility isn't all that important.

But that might be a topic for another thread!

john

That was exactly my thinking — I went for the m3 Compute Stick with hub and it’s been great on my ASI294Pro and asi290. The only thing is you do need extra voltage from the battery — but QuickCharge 3 or the newer Anker IQ type batteries give you that. Don’t mean to hijack the thread, so feel free to pm (or indeed as you suggest start another threat!) if you have any questions.

Edited by CityObserver, 24 January 2018 - 04:37 AM.


#75 Rac19

Rac19

    Apollo

  • *****
  • topic starter
  • Posts: 1403
  • Joined: 05 Aug 2016

Posted 24 January 2018 - 05:44 AM

 

All of which makes me very interested in the core m-3 and core m-5 series of compute sticks. These can much more powerful than celeron or atom CPU based systems, but have a much lower power demand than the core-I series, "typical" being in the 5 watt range. The question will be "can they handle bigger, higher bit depth sensors?". Not as flexible as a NUC, but I,m looking at this as a single purpose platform, so flexibility isn't all that important.

But that might be a topic for another thread!

john

That was exactly my thinking — I went for the m3 Compute Stick with hub and it’s been great on my ASI294Pro and asi290. The only thing is you do need extra voltage from the battery — but QuickCharge 3 or the newer Anker IQ type batteries give you that. Don’t mean to hijack the thread, so feel free to pm (or indeed as you suggest start another threat!) if you have any questions.

 

I had quick look at the M3 Compute Stick and I think that I am still happy with the NUC. Each to their own of course but I like the fact that I can add my choice or HDD or SSD (at additional cost of course). Also, does it need to be plugged in to an HDMI port for power? I am not dismissing the idea, it's probably not for me. Not to mention that fact that I have already made my choice and paid my money,




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics