What inverter to run laptop?

[cadman342001]

I'm going to use my old monster 4x4 battery to run my mount and want to run to my laptop for the polemaster, stellarium (inc. scope control), backyard Nikon, etc. and will be guiding eventually as well for capture.

So I need an inverter.

What are your thoughts eg brands, size, type? etc. I seem to recall they can have a tendency to catch fire / melt if you get the cheapest/wrong one ? :eyepop:

Thanks in advance.

Andy

[Atmos]

I'd say, Powertech 180W Pure Sinewave Inverter. Not the cheapest but it will easily run your laptop and be able to charge your Nikon batteries while imaging :)

[RB]

Andy, I made this back in 2006.
Took it to many a star party with great success.
Just to give you some food for thought.

The Hot Seat (http://www.iceinspace.com.au/forum/showthread.php?t=8150&highlight=hot+seat)

RB
:)

[cadman342001]

Or can I just get a laptop car charger that plugs into cigarette lighter ?

[AndrewJ]

Gday Andy
I bought the following
https://www.jaycar.com.au/2-9a-12v-notebook-power-supply/p/MP3463
One interesting thing to check tho.
My lappie calls for a 18.5V input, but i later found out that it will also happily run off 14-15V, but it automatically disconnects the internal battery charging circuit :-).
By doing this, you get much better battery life in the field as you arent using one battery to charge another.
An inverter will give you 12V DC to 240V AC, but you wil still need to step that back down to feed the lappie, so possibly more losses compared to a simple 12V DC to 15V DC converter.

Andrew

[vlazg]

This is what i use, works fine but i do use 2 batteries, a small deep cycle , 35 amp hrs for the laptop, and 100 amp hrs for the rest.

[jenchris]

I have a battery driven inverter that steps up 12v dc to q5. 16. 17. 19 .24 volts by using a shjnt resistor which you swap out.
It works very well and is only quite small.
No loss of energy stepping up to 240ac and back down.
Cost 46 dollars from Jaycar.

[muletopia]

Hello Folks,
My setup:-
Inverter Jcar 200 watt pure sine wave
Batteries a pair of 12 volt nz70 batteries recycled from my truck
Charging 100 watt solar panel

This is obviously for a permanent set up. The batteries are housed in a weather proof battery box, connected in parallel to deliver the notional 12 volts. The inverter is powered directly from the batteries, it powers a Lenovo Think Pad. The mount takes its power from the "load" connection on the solar panel regulator. The wiring is 6mm and the supplies are each fused.
The Lenovo USB ports power two ZWO cameras and runs PHD2 and Sharpcap.
If I am using my Canon 60Da then the inverter can also run the 230 volt Canon power supply.

This system has never suffered from any electrical short comings.

Cheers
Chris

[cadman342001]

Hmmm plenty to think about, thanks for all the replies.

I'm leaning towards just running the laptop off a car adaptor for now but it would be nice to have 240ac for charging the camera batteries and or running the camera via an adaptor so it may well be an evolving project.

Unfortunately, I'm not good with making things involving electricketry !

Andy

[Nebulous]

Hi Andy,

I share your level of skills at DIY electrickery. :) It's all witchcraft to me... But why do you need to run your laptop off a car battery? Doesn't its own internal battery last long enough for an observing session, or are you planning extended trips?

At a guess, I'd imagine that converting from 12v DC to 240v AC and then back again to maybe 19v DC (?) would involve a fair amount of energy loss just to run all the conversions. Adding 240V AC into the chain could apparently also be a potential hazard in wet dewy conditions. Is a new or spare laptop battery an option or are they too expensive? Or could it be possible to use a simple 12v to 19v DC converter instead (assuming your laptop uses 19v of course) ?

We got enthusiastic about camping a while back and I took the opportunity to have fun buying all manner of goodies - including an expensive box that carries a second battery and has various outlets. Plus an inverter, plus a range of lamps and torches that use power ranging from regular AA batteries through to 12v and 240v. And, of course, a small camping generator with a "quiet" setting on it. In the end, the only time I used the inverter was when I tried it out to see if it worked, and we mostly got by fine with regular torches and a single i2v light... :shrug: But I did enjoy the buying spree... :lol:

I guess that in some locations the noise from a generator might not be welcome, but you could set up a stall at star parties - "Volts and Amps! Volts and Amps! Get 'em while they're hot... " ;)

[Atmos]

My setup is as follows.
200AH Lead Acid battery.
360W Pure Sinewave Inverter

This supplies a serge protected 6 point switch board which I think has individual isolatoers for each point.
I then run regulated 240V to 12V connections into 12V devices. It all just gives multiple levels of protection.
Over kill? Maybe.

[raymo]

AP sessions can last many hours, longer than the life of most laptop batteries.
Shutting down your laptop in the middle of a session to change the battery could be inconvenient to say the least, depending upon whether you are
controlling the mount and camera with the laptop , or only viewing the image
for instance. Batteries can be expensive, and sometimes not that easy to change. The power loss when using an inverter is typically around 5-6%, so not too significant. I used to power my laptop and my Canon 1100D with a $25 ebay 200W inverter [not a pure sine wave one of course at that price.]
raymo

[ausastronomer]

Hi RB,

I remember the hotseat very well from our numerous nights at Kulnurra.

It was an exceptionally well built unit. Not only could you sit on it all night long, you could have probably driven the 4 x 4 over the top of it without causing any damage.

It was just a bit too heavy for me, but for a younger fitter person than me, it was a great piece of work.

In my old age I try to stick with Li-Ion batteries the size of a small box of chocolates that weigh less than a kg :) Funnily enough a 22ah one of these cost me about $120 and can run the 18" Obsession with Servocat, Argo Navis, 5 x Dew Heaters and 3 x Fans for 2 nights without a recharge. I can appreciate however that imaging requires a lot more power reserves than a visual only scope.

Cheers
John B

[cadman342001]

As raymo says, switching batteries mid session isn't good. My laptop seems to use power rather quickly too (6 year old Sony Vaio i5 15" 8gb ram, 256GB SSD).

I see no reason not to run the laptop off a 12v to 19v car adaptor though, the camera can also run off a dummy battery mains adapter which also may not NEED to be run off 240 AC ?

(My daughter's partner is a spark (I'm visting them in Surfers) and wife's mate's fella is a spark too and he has set up stuff for camping involving batteries, solar etc. so I might bend his ear when the time comes (he's in Weipa though) and a mate I used to play soccer with is a spark.)

My plan for the rig so far -

https://www.bunnings.com.au/portacart-68kg-capacity-hand-trolley_p3360519

and

https://www.bunnings.com.au/award-26l-multistack-grey-storage-crate-with-lid_p2583144

Battery - 301 x 171 x 225 H inc. terminals

26L Crate - 380 x 286 x 332 H

Andy

[cadman342001]

The camera adapter (Nikon EH-5 or equivalent) apparently supplies 7.4V DC

So I need to convert 1 supply for laptop UP from 12V DC to 19v DC
and 1 supply DOWN from 12v down to 7.4V DC

Anyone got a link for the latter ? I can find the former on ebay. Listed as Car adapter for laptop, 12v to 19v.

Andy

[Nebulous]

Hi Andy,

Yes, I tend to forget how long observing sessions can go and how hard laptops may need to work during that time. My own sessions are usually quite short, and only a few metres from the house, so the considerations are very different.

For what it's worth, the inverter I bought is a WAECO PerfectPower 150w device which plugs into a cigarette lighter socket. I don't have much relevant experience to relate but here's a review from somebody who had very similar requirements to me.

http://www.blokespost.com/cars-4wd/accessories/waeco-perfectpower-can-size-inverter-review/2810

Apparently, car circuits can have maximum draw capacities through the lighter socket but of course you can buy a separate socket with clips that can go straight onto the battery if you think you might need to exceed that.

My thinking with the unit (which was not expensive - whereas some big inverters can run into quite serious money) was that I would only need to run one device at a time - mostly charging iPads, phones, etc. 150w isn't much but was enough for charging small devices. It worked fine when I tested it, but in practice we never stayed out long enough to need it.

I imagine that generators wouldn't be welcome at many astro-gatherings, but for solo sessions they could be useful. I believe that the camping fraternity has similarly wide views - some love them and use them a lot, and some hate them and find them intrusive.

We regularly get power cuts here (over 20 outages most years) and so I have a decent sized generator that's been professionally wired into the house circuit so that I can switch from one source to the other. It's been incredibly useful over the years we've had it. It's noisy, but as it's behind a shed you can't hear it in the house. I've also occasionally used the small camping generator (a Honda i10) on the verandah with a lead through the window to run just a computer and the noise was "acceptably low" - although of course any noise at all would be unacceptable in some circumstances.

Good luck with your research.

[Nebulous]

Disclaimer! :)

I don't know how important "pure" power is, or when it becomes a critical issue. When I bought the generator for the house I picked one (a Gentech) that claimed to have "cleaner" power than some of the units that are mostly used to run power tools and the like. But I couldn't find any data to clarify exactly when and where that might be important, or what those claims where actually worth. All I can say is that we've been using it for well over a decade - sometimes for days at a time - and there's been no obvious effect on the modems, computers, DVD players, TVs etc that are in daily use.

Your strategy of chatting to sparkies first sounds like a good plan. :)

Oh, and that looks like a neat trolley from Bunnings too... :thumbsup:

[ausastronomer]

Well a lot of sparkies could go a whole lifetime and never come across this type of low voltage / battery scenario. It depends entirely on the type of work they undertake on a regular basis. A sparkie that spends his entire life working as a contractor to a builder of new houses isn't going to see much of it and neither is a sparkie who works in heavy engineering, for instance in a mine. Some sparkies may have some exposure to it, because of specialised jobs, but they would be in the minority.

Its more the type of work in the domain of an electrical engineer, or an electronics technician, although most sparkies would probably have a better idea of it than someone off the street.

Cheers
John B

[Nebulous]

You are of course right John. :)

But I was responding to Andy's own comment that he knew a sparky who had experience with setting up camping systems - not to the generic sparky in your example.

[mynameiscd]

Hi Andy
Just my 2 cents worth.
Ive been living off grid now for nearly 10 years now and have have learnt a lot (by mistakes generally).
We started with the a simple 12 volt system and marine batteries and a modified sine wave inverter.
3 big mistakes for a house anyway.
Cooked a laptop and lots of car batteries along the way.
Now its a 48 volt 4000k inverter/charger with genset backup and no problems.
I still use an adjustable 12volt dc to 18volt dc step up power supply to run my loptop off a heavy duty car battery and works all night for my use but you will probably need a 100ah to run any extras.
I found when you have only have car batteries and use inverters the power losses add up pretty quickly to step up to 240 ac to then step down to 18 volt dc.
Best scenario is to get a deep cycle 100ah and a good quality pure sine wave inverter but you still could have noise problems with powered usb hubs etc
Hope this helps
Cheers
Andy

[cadman342001]

Thanks Andy. Where did you get that 12V to 18V step up power supply ?

[mynameiscd]

Hi Andy
Sorry about the delay.
I bought an off the shelf one from jaycar and also bought a kit and made my own as well.
The one I made can handle 20 amps at 19 volts so its got heaps of headroom.
This one
https://www.jaycar.com.au/150w-car-laptop-power-supply/p/MP3472

works fine and has reasonably clean electronics.
Hope this helps
Andy
PS
Is everyone called andy here?

[RB]

Ah, "The Hot Seat", it brings back a lot of nice memories John.
Yep it was quite heavy but it could handle a decent load out on the field and lasted well throughout the various star parties.

:)

[RB]

Yep.

:lol:

[xelasnave]

Not overkill ...smart man.
Alex

[xelasnave]

Just because they say you can discharge to 20% does not mean that's what you do...
Think it thru out in the cold ...batteries don't like the cold so be kind to them ... More amps than you may use is good.
Alex

[Atmos]

That's true, my battery lives in my car while I'm out. Still gets ruddy cold but at least it isn't out in the elements as such.

[xelasnave]

And you can bet most folk think you use a battery until its flat then you recharge...
Letting a battery go flat signs its death warrant.
J car sell little units that, in the case of solar prevent over charge, cut the power going to your items...lap top whatever so you can make sure not to take too much power..
The inverter usually has a cut off but I like to cut off before that..
Alex

[kramenyak77]

Ive always used this adapter and never had any problems with my MacBook Pro. It allows for high amperage, and can be hooked up to the cigarette lighter socket on my battery. It also regulates for any possible power fluctuations.
http://mikegyver.com/store/index.php?product/page/2095/MCT%3AMikegyver+Macbook+Pro+Touchba r+USB-C+Car+Adapter+Charger+%26+External+ Batteries