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Powering HEQ5PRO and Laptop 'in the field'...


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Hi

Looking for guidance and advice... as in title. I've seen a few threads about portable supplies.

I am fairly new to this, and image from my front driveway (with lots of light pollution), and am now looking to go further afield. I am only likely to be imaging for a few hours, and have a rather old ACER laptop that holds charge fpr about 2 hours. Is the following likely to power my HEQ5PRO, and help out the laptop over the period of up to five hours? From what I can see, the mount requires about 2A, and the laptop is 65W max.

TalentCell PB240A1 Rechargeable 22400mAh 82.88Wh Lithium ion Battery Pack with 3 Port Output (DC 24/12V and 5V USB)

https://www.amazon.co.uk/TalentCell-PB240A1-Rechargeable-22400mAh-82-88Wh/dp/B07CBVKJ8X/ref=sr_1_4?m=A2HBRWDIXVHM77&qid=1569264538&s=merchant-items&sr=1-4

I really do need a bit of a reserve for the laptop running APT and PHD2; otherwise I would be looking at the Skywatcher/Celestron supplies.

Any ideas?

Many thanks in advance.

Stephen

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Better of with LiIon battery from point of view of weight and ability to maintain steady voltage rather than drop slowly, the big power tanks have LA batteries which are OK if looked after but then you're also paying for a fancy case / light etc.

Some of these manufacturers tend to exaggerate the battery capabilities.

I use a 24ah Tracer LifPo battery that runs everything all night and keeps the laptop fully charged.

Dave

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Your laptop is the big consumer in this case with 65 W... 
The battery pack is 82,88 Wh, that means it can run your laptop at full capacity for just over an hour.

Other equipment as you state is 2A @ 12V means 24 Wh, so in fact you will be out of power quite fast. No chance for 5 hours use...
the mount won't use 2A constantly, only with max slew on both axes, but still 5 hours is impossible. You will get 3-4 hours of use out of it max.
Maybe better choose a bigger battery and preferably a LiFePO4 (Lithium Iron Phosfate) type. Safer, stronger, just better then Li Ion (Lithium ion)

The Tracer batteries are nice, indeed. But if your laptop runs out of power in two hours, you may want to choose a bigger one then the 24 Ah Dave suggests.

Edited by Waldemar
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Hi Stephen,

I am a bit in the same boat in that although my LP is not so bad from my back garden we all strive for darker skies and it definitely is the best way to get good data so have been looking into portable power. And it is a worry that you find a great spot and real dark skies only to pack up after a couple of hours because the batteries gone.

The one you suggest does not look anywhere near good enough for your purpose and is very misleading in the title as it suggests it provides 22.4 Ampere hours. But not at 12V, if you read on it says 22.4 Ah at 3.7V, so when running things at 12V you will have more like 3.2 A hours. 

So I would say do not scrimp and buy something that is an unknown off Amazon or Ebay, I did and they were rubbish. As @Davey-T says manufacturers do exaggerate their capacity or make it misleading as in this case and they do deteriorate to some extent as they get older, although LiPos are supposed to be much better if looked after.

Also as I am sure you will test before leaving your house. Even when imaging from your driveway use the battery you buy and if you can run it again without charging the next night get a good idea exactly how long it lasts.

Also remember that both your mount and laptop will not run at full power all night in fact it will be very little time it does so. Your mount will only ever take 2A when slewing, most of the time when tracking will be less than 0.5 A. Most of time your laptop is not running all the devices such as har drive at full seed or disc drice etc, turn screen brightness right down, it's dark you will not want it very bright. Your laptop does have a battery that you say lasts about 2 hours, use it. But if left plugged into your portable battery your laptop will run mostly from that as it will be charging your laptop battery all the time so if you know it runs for sure for 2 hours then unplug from charging 1.5 hours before end of session but remember to charge when you get home.

In the end I bought the big Celestron Lithium 13.2 Ah LiFePO4 Powertank Pro, expensive I know (although I was lucky and bought 2nd hand off this forum 🙂 ) and there are plenty of  Tracer batteries that are far cheaper but a good one will not be cheap still but all that gear is no good at all without power.

Steve

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13 minutes ago, teoria_del_big_bang said:

Hi Stephen,

I am a bit in the same boat in that although my LP is not so bad from my back garden we all strive for darker skies and it definitely is the best way to get good data so have been looking into portable power. And it is a worry that you find a great spot and real dark skies only to pack up after a couple of hours because the batteries gone.

The one you suggest does not look anywhere near good enough for your purpose and is very misleading in the title as it suggests it provides 22.4 Ampere hours. But not at 12V, if you read on it says 22.4 Ah at 3.7V, so when running things at 12V you will have more like 3.2 A hours. 

So I would say do not scrimp and buy something that is an unknown off Amazon or Ebay, I did and they were rubbish. As @Davey-T says manufacturers do exaggerate their capacity or make it misleading as in this case and they do deteriorate to some extent as they get older, although LiPos are supposed to be much better if looked after.

Also as I am sure you will test before leaving your house. Even when imaging from your driveway use the battery you buy and if you can run it again without charging the next night get a good idea exactly how long it lasts.

Also remember that both your mount and laptop will not run at full power all night in fact it will be very little time it does so. Your mount will only ever take 2A when slewing, most of the time when tracking will be less than 0.5 A. Most of time your laptop is not running all the devices such as har drive at full seed or disc drice etc, turn screen brightness right down, it's dark you will not want it very bright. Your laptop does have a battery that you say lasts about 2 hours, use it. But if left plugged into your portable battery your laptop will run mostly from that as it will be charging your laptop battery all the time so if you know it runs for sure for 2 hours then unplug from charging 1.5 hours before end of session but remember to charge when you get home.

In the end I bought the big Celestron Lithium 13.2 Ah LiFePO4 Powertank Pro, expensive I know (although I was lucky and bought 2nd hand off this forum 🙂 ) and there are plenty of  Tracer batteries that are far cheaper but a good one will not be cheap still but all that gear is no good at all without power.

Steve

Hi Steve , I was looking at buying a large Leasure battery anything from 80 to 110 ah .. but ..

im a bit unsure about connecting up some of the equipment and doing damage .. for instance my laptop has a 10.8 V battery , and I'm concerned about my QSI cameras .. 

your thoughts would be appreciated    ...

Brian 

 

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Take note of the 'specmanship' used by the seller, and read the small print.

In other words  he is misleading you about the battery power storage.

You have a battery comprising 7 cells in series. Each cell is about 3.7V and 3.2Ah.

To obtain 12V, he is most likely using the series connected cells into a switched mode power supply.
Assuming 80% conversion efficiency, then you have something that looks like a 12V 9Ah battery pack.
But how it will handle inrush on a tablet/laptop supply, or a mount slewing is a guess.

If it was me buying, I would buy something from a reputable manufacturer. Tracer for example.
Poorly designed or incorrectly assembled lithium power packs are a big fire risk.
If the switched mode supply plays up, you may end up with expensive mount or laptop damage.

Hope this helps, David.


 

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56 minutes ago, Brian28 said:

Hi Steve , I was looking at buying a large Leasure battery anything from 80 to 110 ah .. but ..

im a bit unsure about connecting up some of the equipment and doing damage .. for instance my laptop has a 10.8 V battery , and I'm concerned about my QSI cameras .. 

your thoughts would be appreciated    ...

Brian 

Yes I know what you mean two expensive pieces of kit there.

And the chemistry of both Li-ion and Lithium Polymer (Li-Po) batteries is a complicated one and I am by no means an expert on them. So please these are only what I have read up on , I probably am no wiser than yourself.

My battery on my Lenovo laptop is a Li-ion and is also 10.8V, I think a common size battery although some laptops have more cells and thus may be higher voltage.

But when I look at the output of my charger it is 16V DC. So my initial thought was that as we use a higher voltage to charge the battery than the battery output voltage it should be fine to just plug the 12V straight into the laptop, Simple!  But my understanding is that is NOT the case. Ther charging circuit in the laptop which is between the charging socket and the battery will be designed for a certain voltage (maybe even a range of voltages) but will almost certainly expect higher than 12V.

I am not sure doing this would damage the laptop or battery (not sure it won't either but I am sure there will be protection diodes and the like inside the laptop to prevent damage to laptop at least)  but it probably would not charge the battery. So you would need to buy a DC to DC converter something like this:

Universal-Adapter-Automatic-Voltage

This seems to have all the common voltages for laptop chargers, as I said mine is 16V but most seem to be 18V.

Regarding the camera I am not familiar with these (but they look a real nice bit of kit and so I really see why you would worry). But my ZWO 1600 the only power is for the cooling fan, the camera itself is just powered via the USB3 and so plugging 12V DC (or even 13.8V DC as you may get from supplies using car batteries) works fine as the camera spec says 9 to 15v in the manual so I would double check what it says for your camera but for sure mine is happy.

My manual states:-

Power consumption
ASI camera
s are designed to have very low power consumption which is around 300ma@5V .
You only need the USB cable to power up the camera . H owever you will need a separate power
supply to activa te the cooler . We recommend 12V at 3 A or more AC DC adapter for cool er power
supply (2.1 mm *5.5 mm , center positive). You may also use a b attery supply from 9 to 15V to
power the cooler

Also whilst writing this @Carbon Brush makes a very important point above. Lithium batteries can be quite dangerous, they can deliver a lot of current very quickly and can set on fire if damaged so I would not try to go cheap on one, and certainly if they are trying to hoodwink you into thinking it has nega power by giving the capacity as a misleadingly high figure than I would avoid.

Steve

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By the way the way I have gone is that I have a stand alone mini computer to run my mount and all the associated software such as APT, Stellarium, PHD2 etc and this runs from 12v dc. I just use my laptop to connect to it remotely to set the plan in progress and to polar align with Polemaster. After that the 12v computer can run on its own. So apart from checking the images as they come off my laptop does very little and I can put it to sleep or even turn it off all together  to preserve the battery, or I can just have a spare laptop battery as turning it off to swap them does not affect the mount or the imaging plan. I find this a real asset.

Steve

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One other aspect to consider maybe if you can park your car near to your imaging site then potentially there is a 12v (or actually more like 13.8V) supply there. Obviously do not go mad as I would hate for you not to be able to start the car in the morning but could at least power your laptop via the supply in the link hence you only need the power pack to run the mount which as I said most of time will be using less than 0.5A.

BUT (always a but) I am sure at some stage you will need to also power at least one dew band maybe a couple and these will probably take 0.5 to 1 A each.

Steve

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