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Daz69

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Posts posted by Daz69

  1. On 10/09/2016 at 17:55, trogre said:

    Hi All. Just looking for advice on a 12v 10000Ah lithium battery for sale on ebay uk. I did notice that on ebay.com (USA) they have the same battery for sale. The one I am looking at is available in the UK but the rest come from either China, Hong Kong or Guernsey.

     

    I have no experience in lithium batteries and to me it does seem cheap @ £20.78 inc p.p, Ebay UK No 152224745914            
    The same batteries (and photos) on sale on ebay.com are between $22-25 inc p.p, Ebay.com No 182063039389 .

     

    It could well be that 12v lithium batteries are coming down in price anyway. The things that puts me off is the description on the ebay seller has the charger included but seller then states the charger is not included which means another £10 on top of that price. Another thing is the seller has 209 negative feedbacks for one month!! Not good!!

     

    The specs if you do not have a look are:-

     

    DC 12V 10000mAh Rechargeable Protable Li-ion Battery Lithium-ion+UK Plug Charger

     

    Specifications:
    input voltage: 12.6 VCD
    output voltage:12.6-10.8 VCD 10000mAh
    Capacity: 10000mAh
    Charger AdapterUK


    Package Included:
    1 X Lithium-ion battery
    1x Charger Adapter !!!!!!!!!!!????????

     

    I will hoping if this is ok to power a dew heater strap & controller for a 8” sct for about 2 hours. If power is not enough and the item seems too cheap for what it is I will give it a miss.

     

    Thanks for any input.

     

    P.S No idea why some type is highlighted in a white box,sorry

    Avoid this battery. It will not be 10000mah. A good lipo of that size will cost you well in the region of £100-£150. General rule of thumb is expect to pay £10 for every Amp with these batteries. They are a lot cheaper than they were 5 years ago, as demand has increased as the model flying market had a big boom (no pun ntended). The charger will not be any good either, unless it is a balance charger in order to get the 3 cells perfectly balanced at around 4.2v per cell, otherwise a cell will blow and you cannot stop it. I use Lipo's for my large RC planes, and the chargers are expensive for a good safe brand. 

    Stick with a deep cycle SLA battery like used in mobility scooters and kiddie carts. You can get a 10 amp off ebay for around £25 delivered. They are designed for long slow current draw, unlike a car battery. Do not go for the alarm or PSU style back-up batteries as they will not tolerate constant repeated slow draw. I use a 9 amp one for long fishing sessions to power an LED strip light, and charge my tablet and phone. After 48 hrs usage it has gone down by around 1 - 1.5v from 13v. Been using mine for around 3 years now. 

  2. 4 hours ago, Charic said:

    ....only half the scope! The Mrs won't even notice? he he!
    Best of luck, and I hope the scope arrives safely. 
    Do remember the two 200P Skywatchers are different with respect to their focal length and focal ratios.

    It's an f/5 which is the same as my 130. Think the Skyliner is f/6? Just checked the tracking on the parcel and it's on the truck. What I didn't factor in was that the Mrs is off today, they must have a 6th sense!

  3. I'd rather the fuse blow too soon than get to the point where the nichrome wire is burning through the strap and damaging the scope/eye piece. My understanding was to keep the heater band just above the air temp around it to stop the dew, not to heat it up so it's much hotter? A lot of people keep their E/Ps in their pocket to keep warm, so I based my theory on that, and from what I've read on here about dew bands and temps.

  4. Nice build. What gauge nichrome wire did you use, and what was your ohm's calculation for the band shown? 5 amp fuses for each channel are a bit big for this IMO. I used 1x 5 amp master fuse for the whole of my box, and 1 amp for each double heater channel, and even that is likely to be too big and may need changing. I used 0.5 amp fuses for my adjustable voltage channels to run my DSLR's. 

     

  5. On 16/01/2017 at 12:07, Helen said:

    We're off to the US for the eclipse :biggrin:, but are making it a special month-long holiday (to celebrate our 25th wedding anniversary).  We'll be taking an Alaskan cruise as well as visiting quite a few national parks etc.  I always struggle keeping within a weight limit  :rolleyes: so packing for a month, including cold and warm weather gear, would be bad enough, but with adding astro kit for an eclipse, this time is going to be a real challenge!!  So any small savings in weight will be useful.  

    I'm looking for a mirrorless camera that will be able to cope with all the usual holiday photo requirements but also be good for night shots too.  Mike's hobby is photography so we have lots (!!!) of Canon gear and usually that would be my first choice, but from some initial research the canon mirrorless offerings are very underwhelming.  So I'm wondering what other people are using and would recommend.

    Thanks 

    Helen

    I haven't read all of this thread, so it may have already been said, but why don't you send the majority of your clothing on ahead of you to the hotel/s you're staying at, and just carry your astro stuff and some clothing/essentials? Do the same for the return home. Those that cycle coast to coast across America do this, to save them carrying all of their kit on the plane across. Takes a bit of planning, but at least if you're getting hire cars etc when you get there, weight doesn't matter and you can carry everything in the car.

    • Like 2
  6. 5 hours ago, laudropb said:

    If this is purely for visual why not go for a Dobsonian mount.

    I would like to progress to AP at some stage, and I have found a new EQ5 with tripod for £251, but it will have to wait. I've no issues making a dob mount as I have various machines, inc a bandsaw, a big tablesaw and router table in my workshop, a pile of .5" ply, and I'm good with wood, but how would I make this type of tube fit onto a dob? Will have to research that. I suppose I could screw 2 wood circles on the sides through the tube, and if I ever went to AP and a tripod, just blank the holes?? 

  7. Evening all.

    My second hand SW200p scope is coming on Wednesday. It is coming with tube rings, dovetail bar and 9x50 finder, but no mount. Which one will I need? I cannot afford a GOTO so will have to be Alt/Az or Equatorial, but I have no idea of the weight. 

    Any advice greatly appreciated.

    Kind regards

  8. 3 hours ago, gtis said:

    Thanks for the links that's my next project, would you put the battery in a box as well

    Not necessarily. Depends on if you were thinking of adding extra ports for things like dew bands, power sockets etc, something like I built which can be found in this forum. Also if you're likely to bash it about (Not being rude but some people can be heavy handed) then a box might be a benefit to protect it. I think the boxes are around £25, so depends on budget really.

  9. Yep that'll be even better than a smaller one, as you'll get more nights from it without charging. Also worth getting one of these (they can be found in red too) http://www.ebay.co.uk/itm/DC-3-30V-Blue-LED-Digital-Display-Panel-Voltmeter-Voltage-Gauge-Car-Motor-UK-/152069880968?hash=item2368123c88:g:S20AAOSw6kxXIWdD  just to simply hook up to check what's left, saves you guessing. Just remember you'll get a slightly lower reading if you're using a heater strap at the same time, best to let the battery rest 10 mins before checking. Stick inside a small plastic project box with pos and neg wire coming out via a momentary push switch http://www.ebay.co.uk/itm/Miniature-Momentary-Push-to-Make-Switch-Mini-SPST-/251697459778?var=&hash=item3a9a567242:m:m6D5J_-whwECWoVoS-0iDxQ and attach it to the battery with velcro. Jobs a good'un!

  10. Car batteries aren't designed for long periods of continual drain, just leave your side lights on and see how quick it will kill your battery. They are designed for quick punch high current drain as in a starter motor. Depending on how much drain your straps use over a given time will depend how quickly that battery will go flat. 

    If this is to be a regular use, then you are really better off getting a deep cycle battery for this sort of application. They don't drop voltage as quickly until they reach the end of their charge, then drop suddenly. That's why they're used in kiddies toy cars/trikes and mobility/golf carts etc. You can get say a 9 or 10Ah deep cycle battery for £20 off the bay. I use them in portable 12v power boxes for fishing and emergency use. I will also be using one (or two together to give me 18Ah) for my scope's power supply. Make sure it is a deep cycle battery which is normally black, and not the cheap "alarm" or PSU type battery, which are normally grey in colour. Something like this http://www.ebay.co.uk/itm/VIPOW-12V-10Ah-Deep-Cycle-Maintenance-Free-Sealed-AGM-Gel-Battery-Scooter-Yacht-/121500443251?hash=item1c49fda273:g:qN4AAOSwPYZU7FYD The bigger you can get the better, but the prices can rise quite steeply. Also, as your needs grow, perhaps with powering or charging a tablet/phone then it will still be capable. I can go fishing for 48 hours and power a 18" LED strip light, charge my iphone and tablet and still have 10v at the end. 

    So roughly this battery will give 10 amps per hour or 5 amps for 2 hours, etc. until it drops off. Like any rechargeable battery, drop it too low or too many times, and you'll lose the battery. Never go below 9.6v is my limit.

    A cheap 3 or 4 stage computer controlled charger can be had for around £20 as well which are ideal for deep cycle batteries. My large caravan battery is left hooked up on my 4 stage charger every day when it's not in the 'van. Something like this will do you nicely http://www.ebay.co.uk/itm/MARXON-12V-4-Amp-3-Stage-VRLA-Golf-Battery-Charger-/132099616076?hash=item1ec1c02d4c:g:tygAAOSw4CFYp0AB Recharge overnight ready for the next day! This will get your battery to around 13v off charge.

    Hope this helps.

  11. Hi Gina. 

    Where would an absolute newb start with these Raspberry Pi's? This all looks extremely technical and scares the jeepers out of me even wanting to begin to learn how these things work.

    I see so many people use these for all sorts of projects, so they are clearly versatile devices, and I would love to bring one into my projects. I'm just feeling like its all way above my head.

  12. 1 hour ago, Uplooker said:

    Hi Daz,

    That is a very comprehensive "box of tricks", well done. I have noticed from a number of your posts that you are in no shortage of ingenuity.

     

    Thank you for you very kind comments dear sir. 

    I enjoy tinkering, and sometimes making things go bang when I don't expect them to :D 

    First rule of tinkering with electronic components, buy several of each item! 

    Second rule, if something goes "POP", don't rebuild it the same way you built it when it did go "POP"!

    Third rule, find a new way of building it because your several items have now become one item. 

    Fourth rule, don't touch the soldering iron by the hot bit, or the item that you've just "tinned".

    Fifth rule, don't stick your finger on 240v supply (many times LOL :D

    I find these fundamentals akin to Newton's third law.

     

    To make something that works from a pile of bits is an accomplishment, a challenge. To do it without any electronics background is to me even more of challenge, and it keeps my mind off my TN. Mind you, that is similar to getting zapped with 240v, albeit in your face and mouth, and usually 30-40 times a day! 

    • Like 2
  13. ........Yes!

    I made this so that I can take it anywhere and power it from a portable 12v power source that I made some years ago, or use it at home powered from an old PC PSU that I have stripped down and separated the individual 12v, 5v and 3v supplies. I use this as a bench power supply to test my electric RC plane models various components, as well as other projects.

    Anyways, this has 2x variable 12v RCA sockets, where one will be used to power my DSLR, and the other is for whatever else I haven't yet thought of. 

    Then I have 2x PWM dimmers divided to give 2x channels each. 

    The main power switch is fused at 5A, then the heater channels are fused at 1A. The variable channels are rated at 0.5A. 

    The camera channel also has a further simple circuit after the variable circuit, which is also fused at 0.5v, and that limits the power to 8.5v should the variable power board give out. Should that happen, the power board from what I understand, will still allow the full 12v to pass through, and "possibly" damage the camera. This simple circuit will only give 8.5v regardless. 

    There is plenty of room inside to put more stuff in as the need arises (if ever?).

    Here's some photos:

    Dist%20box%201_zpsdwpge8ln.jpg

    Dist%20box%202_zpswjohxfgi.jpg

    Dist%20box%203_zpsqfmk0wra.jpg

    Dist%20box%204_zpslka5nxxj.jpg

    If there is anyone who wants to build one of these, or similar, I can draw up a simple schematic diagram with a parts list. Whole cost was around £25 give or take a £ or two. 

     

    • Like 5
  14. 2 hours ago, SyedT said:

    I don't see why it wouldn't fit, although I don't have any personal experience of having an observatory. You're right though, you would end up needing steps to reach the EP, and the positioning can be quite awkward; however, you can always loosen the rings and adjust the position. You'd also need sufficient clearance between the pier and roof to allow the scope to swing around without hitting the roof as it's a decent-sized scope. 

    Thanks for reply. It's only a thought at this stage. If I did build one, it would have a roll off roof so I'll have the complete sky. Probably would have drop down sides to 2 aspects as well, or half of the 2 sides would slide with the roof. 

    LOL, didn't think about sliding it down the rings :D

  15. T'was my first (and only so far) nebula. Not had many nights out with my scope so far due to weather etc. I think so far, my best viewing has been the Pleiades. It looks like a scattering of ice blue diamonds on a black table cloth, breath taking IMO.

    Another gob smacker was the Garnet Star. You think Betelgeuse is red? Wait until you see this beauty! 

    • Like 1
  16. Thanks guys.

    Got to finalise the courier as it's in Scotland and I'm in Hampshire :shocked: but fingers crossed we should be good to go. 

    1 hour ago, triton1 said:

    Congrats a very capable scope should have years of enjoyment from it

    Thanks Triton. 

    18 minutes ago, Charic said:

    Should be a difference  between the  130 once correctly setup and if your skies are better on the NE Lincs coast, the scope will perform even better, easily transportable in a car.
    Mine works well enough from my back garden, have seen a stunning crystal clear image of Jupiter, with a Moon transit shadow, and can just make out the  very tiny smudge of  M31.
    Taken to a darker site,  M31 fills the eyepiece, the difference is stunning,  questioning, how can the scope be so different? Its all down to the conditions, get those right, and the 8" is a great scope. In-fact ANY scope will work better if correctly setup and used from a darker site than your present site, unless you already have the darkest site.

    I haven't got the darkest skies unfortunately where I live due to an atomic weapons establishment about a mile away, however we still get a fairly good night sky. At my parents house it is much darker, so I am looking for a big difference. 

    The one I'm hoping to get has a black tube on which it pivots. How does this break down?

    Daz

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