AC to DC power

[Seraph_69]

Hi all,

Seeing as I do most of my observing in my back garden, and wish to start using my laptop and other equipment which requires power, I have been pondering AC power, rather than always using my Power Tank. 

I know using a step up & step down converter/inverter (not sure of the difference) wastes a lot of power (although I'm on Economy 7 so not the end of the world). 

I found this froMaplin:

http://www.maplin.co.uk/p/12v-5000ma-car-accessory-socket-ac-dc-power-supply-l25ay

...would it work? Is it basically a compact converter/inverter?

I think it has inbuilt surge protection but would I need one at the plug socket in the house too?

Also it has some pretty dire reviews but I don't know if people are just using it with the wrong equipment? Any alternatives people can vouch for?

Ideally I want to be able to power my mount, laptop (will probably just go straight into the 240v extension lead with that), DSLR and dew heater controller (as and when I get those last two)...will this also require me to get a little cigar socket hub?

Thanks!

[ChrisLX200]

Personally I avoid having any mains power outside, I have DC PSUs inside and run (15m) cables out to the mount and cameras etc. How many different voltages do you need? Would 12v and 19v (for the laptop) cover it? If so, you can use a small step-up adapter for the 19v laptop which runs off the 12v supply running to the mount. All you need then is a meaty 12v power supply indoors (say, 20Amp) and perhaps some new cables. I have a 12v power outlet box on the pier which uses water-resistant plugs and sockets and it powers most things, but my 10Micron mount needs 24v so I had to install a second PSU indoors and run the cable for that separately. All my cables are now buried underground (including USB and Ethernet) which makes life easier, prior to that I had to roll out the cables each time.

ChrisH

[Stub Mandrel]

That looks fine, although it has the worst connector known to man (except for SCART) on the end. I would fit a better quality polarised plug.

All the bad reviews appear to be people trying to use things that nominally use 4 amps but probably take more at switch on. If your equipment has a big switch-on surge you may be better off with a traditional transformer-based unit.

[Seraph_69]

Thanks guys, but I am really n00by in the realms of electricity, so if you could provide some links/examples that would be great, because I don't know what a "traditional transformer-based unit" is!

Chris - can you explain why you avoid mains outside? Is it simply the risks due to moisture etc.?

And I have no idea what voltage I need for laptop etc. I just know I definately want to run my HEQ5 Pro, Dell XPS L702X laptop, soon to buy canon EOS 6D and in future, dew heater controller. 

I can't think of much else I would need to run off it. 

One elegent solution would be lovely but I fear it doesn't exist!!

So Chris - are you basically kinda suggesting the same idea, except instead of trailing the AC outdoors using an extension lead to the converter, you have the AC to DC PSU in the house, and long leads taking the DC power out to the scope etc?

And that for something on a voltage other than 12v ie a laptop, I would need to stick some sort of step up between the 12v and the laptop?

Thanks

 

 

[ChrisLX200]

8 minutes ago, Seraph_69 said:

Thanks guys, but I am really n00by in the realms of electricity, so if you could provide some links/examples that would be great, because I don't know what a "traditional transformer-based unit" is!

Chris - can you explain why you avoid mains outside? Is it simply the risks due to moisture etc.?

And I have no idea what voltage I need for laptop etc. I just know I definately want to run my HEQ5 Pro, Dell XPS L702X laptop, soon to buy canon EOS 6D and in future, dew heater controller. 

I can't think of much else I would need to run off it. 

One elegent solution would be lovely but I fear it doesn't exist!!

So Chris - are you basically kinda suggesting the same idea, except instead of trailing the AC outdoors using an extension lead to the converter, you have the AC to DC PSU in the house, and long leads taking the DC power out to the scope etc?

And that for something on a voltage other than 12v ie a laptop, I would need to stick some sort of step up between the 12v and the laptop?

Thanks

 

 

Yes, one of these will supply the 19v (or voltage whatever - it's adjustable) from a 12v supply:

ChrisH

[Stub Mandrel]

A transform,er is a big lump of iron and copper wire that converts one AC voltage to another, the one you are looking at is a SMPSU (switch more power supply unit) a modern alternative that is much lighter and generally cheaper. The transformer base units are generally more tolerant of a big starting surge.

[Danny83uk]

1 hour ago, Seraph_69 said:

Thanks guys, but I am really n00by in the realms of electricity, so if you could provide some links/examples that would be great, because I don't know what a "traditional transformer-based unit" is!

Chris - can you explain why you avoid mains outside? Is it simply the risks due to moisture etc.?

And I have no idea what voltage I need for laptop etc. I just know I definately want to run my HEQ5 Pro, Dell XPS L702X laptop, soon to buy canon EOS 6D and in future, dew heater controller. 

I can't think of much else I would need to run off it. 

One elegent solution would be lovely but I fear it doesn't exist!!

So Chris - are you basically kinda suggesting the same idea, except instead of trailing the AC outdoors using an extension lead to the converter, you have the AC to DC PSU in the house, and long leads taking the DC power out to the scope etc?

And that for something on a voltage other than 12v ie a laptop, I would need to stick some sort of step up between the 12v and the laptop?

Thanks

 

 

I got One of these to run my EQ-5 synscan from a rcd extension lead. plugs directly into the unit. As for your lappy if you turned you power usage to low and your screen dimmer (will help outside) You should get a decent life out the battery.

 

[Seraph_69]

2 minutes ago, Danny83uk said:

I got One of these to run my EQ-5 synscan from a rcd extension lead. plugs directly into the unit. As for your lappy if you turned you power usage to low and your screen dimmer (will help outside) You should get a decent life out the battery.

 

My laptop battery is horrible - even if I got a new one my laptop is essentially a desktop replacement so it wouldn't last very long at all it 100% needs mains power. I just ddon't really understand what I need to be able to run it off of 12v power or if that's even possible. 

[Putaendo Patrick]

I'm a radio ham and use a "switching" transformer to power my transceiver, similar to this: http://www.ebay.co.uk/itm/12VDC-30A-LED-Switching-Power-Supply-Adapter-Transformer-Silver-Tone-/191638956981?hash=item2c9e926bb5:g:ULgAAOSwFqJWnzEO

Mine is rated at 30 amps, other lesser capacities are available but I would go with more rather than less. Personally I would think the Maplins gadget you link to is underpowered. Do please check, but mine has worked very well for me for several years for a radio with a big difference in the power drain between receive and transmit, so it may work for your needs.

 

[Danny83uk]

6 minutes ago, Seraph_69 said:

My laptop battery is horrible - even if I got a new one my laptop is essentially a desktop replacement so it wouldn't last very long at all it 100% needs mains power. I just ddon't really understand what I need to be able to run it off of 12v power or if that's even possible. 

Gotta love laptops for doing that. I cant offer any more help. Personally id run a normal AC supply from the house then your laptops sorted and you just need the adaptor for your mount to plug into an AC supply.

[RuralBill]

Hi,

the adapter you linked too is the sort of think you are looking for, but you would,probably need a higher power one, 5amo may not be enough for all the items you want to run, so keep that in mind.

Bill

[Charic]

3 hours ago, Seraph_69 said:

Hi all,

(although I'm on Economy 7 so not the end of the world). 

I used to have  E7  many years ago,  and  wondered why my bills were still high, "where's the savings" I kept questioning myself?

Then an electrician ( arrived to fit new immersion heater )  suggested  not to use so  much electricity  during the night! as the  electrical discount  provided from E7 only applied  to  domestic hot-water heating and electrical storage heaters , everything else 24/7 was charged at the same rate, so the more I used at night the dearer it became?
Not sure how the system could tell when I was heating radiators or water, or just running the washing machine and tumble dryer through the night, which is where we thought we could be making our savings? 

Reading today about E7 it says........."An Economy 7 tariff is best suited to people who have electric storage heaters and a hot water tank. The idea is that you heat up the electric storage heaters overnight and that they slowly emit the heat the next day, and that you heat all your hot water for the next day overnight too. If you heat your home and water with electricity, but don't have storage heaters or a hot water tank, Economy 7 probably won't be so cost effective for you.

Could this be the reason I was duped into a false sense of saving some money back then.

 

As for using AC in the garden, I do it all the time, mainly during the day, using trimmers, lawn mowers, drills,  literally anything that is suitably earthed and protected with an RCB ( Residual Circuit Breaker).
My workshops are powered too, backed up with battery for the alarms, so even shorter cable runs in the garden.
Even so, to keep things simple, I would probably get most of my power from one of the many 'power-tanks' available,  when I go down the powered route for my next system, and even when used in the garden, as you do now, I suppose its still possible to run a lead out and into the power-tank, if the power-level is near or nearing the dead-side.

I have some serious dark skies in my part of the World, only mins away, and better still,  about 45 mins drive away, so would have to rely on a power pack for astro-photography. But I also think, even having my mobile phone on with its red screen is still too bright for my visual needs at present, so I don't rely or need any electrical supplies for a manual/visual system just yet, and I suppose there are  still many folk who use camping gear, that can hook up to the live grid, on some sites, where its available, just do it safely. 

My main point here was about E7's  savings.........or not!
 

[Cornelius Varley]

6 hours ago, Seraph_69 said:

Hi all,

Seeing as I do most of my observing in my back garden, and wish to start using my laptop and other equipment which requires power, I have been pondering AC power, rather than always using my Power Tank. 

I know using a step up & step down converter/inverter (not sure of the difference) wastes a lot of power (although I'm on Economy 7 so not the end of the world). 

I found this froMaplin:

http://www.maplin.co.uk/p/12v-5000ma-car-accessory-socket-ac-dc-power-supply-l25ay

...would it work? Is it basically a compact converter/inverter?

I think it has inbuilt surge protection but would I need one at the plug socket in the house too?

Also it has some pretty dire reviews but I don't know if people are just using it with the wrong equipment? Any alternatives people can vouch for?

Ideally I want to be able to power my mount, laptop (will probably just go straight into the 240v extension lead with that), DSLR and dew heater controller (as and when I get those last two)...will this also require me to get a little cigar socket hub?

Thanks!

That particular psu is not suitable for your equipment because it does not have a regulated output according to the spec.

[ronin]

For general scope powering I use a small Maplins item: L06BR

I see the present cost is £20, however if no rush Maplins have them reduced at regular intervals, think that both mine were £10 at one time or another.

They do a "heavier" one for more output, no idea what the reference to it is however, and the Maplin site is not great for searching.

I tend to have the scope outside and the bag of assorted bits, so what I do is sit a 4 way extension block on or in the accessory bag and plug into that with the above supply. Does mean one converter per scope item but it works for me.

The mains supply is RCD protected also, equally most houses are these days.

Just make sure at least 3 times that you have the polarity correct. Skywatcher's are notoriously intolerant of incorrect polarity, which for the sake of a small diode as protection seems totally stupid.

[RuralBill]

Economy 7 is ok if you don't use any electric in the day at all, I used to have it for 15 years but did not use electric it at night, (storage heaters removed when I bought the house)  but thought that was ok, but then spoke to someone who also did not use at night, but was on a normal meter, and there bill was really low compared to mine, so I investigated, and to my horror found out that when on economy 7 the electric is reduced at night, BUT the daytime rate when on it was nearly double, so I was paying nearly double for 15 years without realising, so it is a complete con, if you use most of your electrical items in the day.

 to make it pay you have to do everything at night, and I mean everything, so I had the dual meters removed and a single rate meter installed.

bill came down by 45%

so for anyone that has economy 7 and doesn't really use it, GET RID, as you are paying way over the odds for your daytime electric.

Bill

[michael8554]

I have storage heaters and Economy 10, which gives you cheap periods in the afternoon and evening, as well as overnight.

If you have gas central heating and hot water, E7 or E10 are not for you.

Michael

[Stub Mandrel]

E7 & storage heaters was a bad deal, but prices have evened out and now E7 is comparable to gas central heating again. But We had a gas boiler put in for hot water and it saved a fortune over heating water with leccy!

[tonylumley]

just a thought. if you are using 240 volt supply outside. it would ere on the safety side to plug your supply lead into a rcd plug, at least if there is a short you will be safe and the electric will stop, you can pick one up in Argos for about £10. or google it. Lum

 

[cjdawson]

On 7/10/2016 at 12:37, Seraph_69 said:

Hi all,

Seeing as I do most of my observing in my back garden, and wish to start using my laptop and other equipment which requires power, I have been pondering AC power, rather than always using my Power Tank. 

I know using a step up & step down converter/inverter (not sure of the difference) wastes a lot of power (although I'm on Economy 7 so not the end of the world). 

I found this froMaplin:

http://www.maplin.co.uk/p/12v-5000ma-car-accessory-socket-ac-dc-power-supply-l25ay

...would it work? Is it basically a compact converter/inverter?

I think it has inbuilt surge protection but would I need one at the plug socket in the house too?

Also it has some pretty dire reviews but I don't know if people are just using it with the wrong equipment? Any alternatives people can vouch for?

Ideally I want to be able to power my mount, laptop (will probably just go straight into the 240v extension lead with that), DSLR and dew heater controller (as and when I get those last two)...will this also require me to get a little cigar socket hub?

Thanks!

Here's an alternative approach.

Rather than having 240V outside, I've got one of these

http://www.maplin.co.uk/p/375w-linear-dc-variable-voltage-bench-power-supply-rp10l

This is in my shed, connected to the mains.  The point here being that it's inside.   then connected to the terminals, I have a long (10 meter) cable, with an auto socket on the end.  I then have that connected in turn to a 4 way splitter.  You could always have the 10 meter cable end in the 4 way splitter directly ;-)

 

Then for your laptop use something like this.

http://www.maplin.co.uk/search?text=12V+Auto-Voltage+Car%2FAir+Laptop+Adapter+with+1A+USB+Socket+%2B+12+Charging+Tips

 

And your other devices can plug into the other three sockets.

 

The big advantage of this setup is that there's only one cable running from the shed/house etc to the observing area... and that cable is 12v DC instead of 240v AC.  This makes it much much safety to use on dewy nights.

I've done this successfully and have run my laptop (including 2 usb cameras), scope, dew heaters (2 of them) and a relay box (for autoguiding).

I'd still use an RCD with the power supply just to be on the safe side.

 

 

Just a word of warning on the 12V laptop power supplies. I've found them to be extremely temperamental. if you are running from a mains supply it'll most likely work just fine.  Running it from a 12v battery on the other hand can be a real problem.  I gave up trying to use one with my old Sony Vaio (from about 2003) as it didn't like running from anything under approx 12.5v.