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paul1963

Running a laptop or and ipad from solar panels

This old chestnut again I'm afraid.

I am running a Sony Vaio laptop at present (may move to I-pad when that dies and goes to microchip heaven) and I would like to run it from solar but realise the impracticality of that in the UK. I am looking to run a set up along the lines of a Solar Gorilla and a Power Gorilla - charging the Gorilla and than using that to charge the laptop). I will be siting the panel in an upstairs window, behind double glazed panels with all their UV reducing qualities.

Is anybody out there running a similar set up, if so how successful has it been in use. If you are using something different that works but is solar gorilla sized, what are you using and how well does it really work?

The kit is darned expensive so I am approaching this with extreme caution.

Alternatively if you've tried and failed it would help me know what to avoid as well.

Thanks Very Happy Very Happy
vegplot

If you're on mains electric then there really is no point in running a laptop off solar PV.
paul1963

If you're on mains electric then there really is no point in running a laptop off solar PV.


TBH Vegplot that's what I'm starting to wonder, what with the cost of the kit and the comparatively low cost of mains charging Very Happy
vegplot

If you're planning on installing significant PV capacity then it will still be expensive per unit compared to mains but you'll feel good. These little PV chargers are extremely expensive (you can buy a large panel for the same or less) and often fail to perform.
RichardW

VP has it nailed.
chez

That was my conclusion when I looked in to it a few years ago, although I am now about to look at it all again in view of the camper van. As an aside, when we had arvo's vaio, it was the most power-hungry machine we have ever had.
vegplot

That was my conclusion when I looked in to it a few years ago, although I am now about to look at it all again in view of the camper van. As an aside, when we had arvo's vaio, it was the most power-hungry machine we have ever had.


You might be better served installing a second deep discharge battery charged off a spit charger from the engine alternator to power ancillary devices.
RichardW

That was my conclusion when I looked in to it a few years ago, although I am now about to look at it all again in view of the camper van. As an aside, when we had arvo's vaio, it was the most power-hungry machine we have ever had.

You might be better served installing a second deep discharge battery charged off a spit charger from the engine alternator to power ancillary devices.

Depending on how often it will be moved. I would do the split charger & extra battery but also look at solar as well. You dont want to be having to run the engine just to get a small amount of power.
mark

Solar panels really need to be outside - using them indoors behind double glazing reduces their power twofold - the glass reduces dirent sunlight , you don't get diffused light from the rest of the sky , and you can't turn them to face the sun throughout the day!

Also laptops are power hungry - power monkey is ok with short useage times or better with tablet phone. For a laptop go for a big heavy duty leisure batter with big panels on roof and a regulator between panels and battery.

Or do what i do fully charge laptop before you go.. take a fully charged leisure battery (and if you are away for any time steal charges where and when you can!)
boisdevie1

That was my conclusion when I looked in to it a few years ago, although I am now about to look at it all again in view of the camper van. As an aside, when we had arvo's vaio, it was the most power-hungry machine we have ever had.

You might be better served installing a second deep discharge battery charged off a spit charger from the engine alternator to power ancillary devices.

Depending on how often it will be moved. I would do the split charger & extra battery but also look at solar as well. You dont want to be having to run the engine just to get a small amount of power.

I was wondering about a solar panel for my camper but once you add in the cost of a panel, brackets, cable, skin grommet thing, charge controller, it might be best having a second leisure battery and an inverter. That's what I'm going to do with the option of doing a solar panel if it's absolutely necessary.
RichardW

That will only work if you are running the engine anyway to move the camper. As soon as you start to run the engine just to top up the bats the true costs (not just fuel) rise dramatically.

You would be well advised to sign up HERE as they have just the same issue, but have had many many years to suss it out fully.
mark

That will only work if you are running the engine anyway to move the camper. As soon as you start to run the engine just to top up the bats the true costs (not just fuel) rise dramatically.

You would be well advised to sign up HERE as they have just the same issue, but have had many many years to suss it out fully.

I think one of he differences between boating and camping is you can camp a night where they have power hook up - and charge your battery .

I manage to go a week with no probs charging my 7in Andrioid tablet /phone / GPS / vario and other flying intruments from a leisure battery without needing to recharge! I've even had enough juice left at the end of the week to use it to help start a car with a flat batter!y A laptop is a much heavier drain though and though i usually have a laptop with me i use it very sparingly. Not a problem when i can really do most stuff on the tablet.
Penny Outskirts

There are a lot of people who wild camp and live in their campers, using solar power to top up their leisure batteries, which then power their laptops. Seems to work ok, but I don't know the details.

Might be worth researching on wild camping.com and motorhome365 to see what they do?
mark

There are a lot of people who wild camp and live in their campers, using solar power to top up their leisure batteries, which then power their laptops. Seems to work ok, but I don't know the details.

Might be worth researching on wild camping.com and motorhome365 to see what they do?

In general solar charger in the UK do a good job of keeping battery trickle charged and avoiding it running down when not in use. ie keeping a leasure battery on a boat topped up when you are not around. Or caravan batteries charged up when you are not using it much
They also work well in more demanding situations where they can be fixed on a roof and kept orientated to the sun so they get light from dawn till dusk.
They are at their best in May Jun July when daylight hours are lionger and sun more directly overhead - ironically these are the months when most of us don't really want spend time on the laptop but want to get out.
In winter, spring and autumn when you want light to see by and laptops for the dark evening - they just are not up to keeping the battery topped up without a massive (and expensive) array. Sadly the same goes for half the days in the British summer too!

They key seems to be to reduce power where you can
1) use phone or tablet for emails not laptop etc
2) If using laptop try to use in car laptop pwer supply that runs off 12V rather than mains inverter withnormal power supply - you will save double inffeciency of changing 12 V up to 240 V in the inverter and then back down to around 19V the laptop uses - you just do one conversion instead .
Penny Outskirts


2) If using laptop try to use in car laptop pwer supply that runs off 12V rather than mains inverter withnormal power supply - you will save double inffeciency of changing 12 V up to 240 V in the inverter and then back down to around 19V the laptop uses - you just do one conversion instead .

I think all the people I know who use the laptop on a solar charged leisure battery use it off 12v.
RichardW

Mark your post is so wrong / negative its hard to know where to start.

Remarks like solar can only trickle charge or keep it charged when not in use are completely wrong.

Would you consider 80 amps of charge a trickle? Would you consider 7 kWh per day just enough to stop self discharge?

May June & July are not the best months by a long margin.

Ours work well from March till well into late sept or early Oct. Ok Dec & Jan are dire. Peak months tend to be either side of the main summer months as the sun is strong yet the air temp is colder.

"they just are not up to keeping the battery topped up without a massive (and expensive) array"

really? 50p per watt for the panels will hardly break the bank.

Your comments are only valid when the install was done without due consideration to the actual needs or the budget not suitable for the requirements.
mark

I'm talking about wild camping here - for me in a tent that is not practical to have the sort of array you are talking about! - and it is hard to keep a ground mounted panel in the sun all day - as shade from tents and cars get in the way if you don't move it!

But even in a camper van where they can be mounted on the roof there are issues - often theroetical figures assume - the van is parked away from trees and building so the panel is not shaded! - in my experience that is just not always possible!

I'm not being negative- I'm planning 3 months living camping in europe next year where these facilities will matter to me! So I have been researching this widely and really wanted to use solar and have talking to others about the actual NOT theoretical performance they achieve. However having looked at the options I have come to the conclusion I can't rely on solar charging for all my needs alone - so my priority in my budget is to increase my storage so i can last between charges.. (most camping leisure batteries don't like being taken below around 40% on a regular basis and without extra storage that is a real possibility if you get an overcast or rainy week and use a laptop .

I am presuming by your remarks about the install you are talking about a more permanent array optimally placed not one that has to sit wherever you can find to park your van/pitch your tent - and where placement may also have to meet other needs like security when you are out all day when it can't be fixed like in a home!

I think solar is very useful in fixed situations - but I've always been a little disapointed by what can be achieved in real life situation when camping in temperate latitudes. It does hlep but not enough

My laptop with 17" screen uses about 80 watt -

If you know a truly portable light weigh small packing solution that can meet my needs I'd love to hear about it !!
mark

just to add to the above i am also concerned that the use of solar panels just for camping trips tips the the ecological and economic balance the wrong way.

there is a break even point economically and in terms of carbon footprint / eco impact that you need to reach before a solar panel is better than spending a night in a campsite to get a hookup replenish you leisure batteries.

For the same price as a panel i can substantially increase my battery storage which keeps me more independent !
For installations used all day/ all year the eco and financial break even point is reached much sooner!
RichardW

I know of many mobile installs that out perform (over a year) my fixed install.

At least they have the option to move if the weather is bad or there is a high horizon (like I suffer from due to the trees).

The primary issue is that people spend what they feel should be enough & not actually what is needed.

Wild camping = no tech for me.

I do agree that using stuff just for short holiday periods is just adding to the issue.

Bigger storage is ok but at some point you have to fill them up again. The more you have the more you need to refill & a bigger charge source is needed. Its all about balance.


You could easily pole mount a small array to be sited above the tent shade line. Depending on tent type you might even be able to fix it to the tent pole tops.


Edit to add, just spotted that you are going to be using a car. Fit the array to the roof rack & mount the bats in the boot. Simple to just plug the tent into the boot as needed. You could also then add in a split charger system to get the best of both worlds.
paul1963

That was my conclusion when I looked in to it a few years ago, although I am now about to look at it all again in view of the camper van. As an aside, when we had arvo's vaio, it was the most power-hungry machine we have ever had.

Funnily enough Chez, that's what I use and I need a personal Drax power station to run it, only about a one hour battery life Shocked
RichardW


Funnily enough Chez, that's what I use and I need a personal Drax power station to run it, only about a one hour battery life Shocked


Making changes in the power management can make lots of difference in how long it will run on a full charge.
Tarrel

FWIW, I put the power meter on my iPad charger yesterday while I charged the iPad from almost flat. The mains charger took 11W, and used a total of 0.04kWh to charge to full. (It's an iPad 3, which has double the battery capacity of the earlier iPads).

Ignoring inverter losses, you could therefore do this 30 times off a 100Ah battery. Or, another way of looking at it, a 40W solar panel in full sun for one hour would be enough to replace the battery charge used to fully charge the iPad.

Obviously one would be better off using a 12V charger rather than a mains one plus inverter.

HTH.
RichardW



Ignoring inverter losses, you could therefore do this 30 times off a 100Ah battery.

Well you could but you will soon kill the battery. Better to do less than 15 cycles & keep to 50% discharge max.

50% is the rule of thumb for cost effectiveness for recharging costs & battery replacement costs.

Using more will increase battery replacement costs but reduce recharge costs. Decreasing is will reduce battery replacement costs but increase recharging costs.


The above is valid for when the recharge has a cost so less valid when recharging with solar.
mark

the useable range of a leisure battery is about 40-50% of quoted theoretical capacity. They are not designed to be run to flat (you will wreck them if you do that) -and they will cease to power an inverter before they are fully empty in any case - they would certainly cease to power a laptop before this stage..

Inverters can never be assumed to be fully efficient - you are probably best estimating around 20% for a 12V inverter - worse if you then step it up again to power a laptop..and introduce a second ineficiency

I successfully recharge my tablet (7") phone and flying instruments on paragliding holidays for about a fortnight off my battery without recourse to solar power so its not a problem with tablets..

laptops are another matter though .. and can discharge a battery really quickly!
mark

On solar panels the quoted out put is what you can expect on sunny summer day in teh UK at noon if the panel is facing the sun.

In our long summers day the average day produces the equivalent of 4 such hours if we leave the panel out all day and it is facing the sun

In the shorter winter days with a lower sun we only get one hours worth if we leave the panel out all day!

So I reckon mid summer a panel can knock your battery up 13.31 Ah per day if you have it said up out of any shade and facing south or a quarter of that in the winter. ie it will take you over a week to recharge a 100Ah battery .
In reality that's hard to achieve unless its a roof mounted static installation - and it will never be achieved if you can't leave it out all day

That is why if you simply want more power and especially if you camp for a week or so in spring our autumn I recommend you are often better simply taking an extra battery fully charged - if you want to extend you battery life in the cheapest manner !

Of course if you like using solar go for it - but be aware solar panels that are packed away and not used for much of the year have a worse environmental impact than charging from the grid. It is only if you use them for longer ie on your roof at home that the environmental equations shifts in favour of solar.

Having said all that I think they a fun and really wish they were a more practical option!
Tarrel



Ignoring inverter losses, you could therefore do this 30 times off a 100Ah battery.

Well you could but you will soon kill the battery. Better to do less than 15 cycles & keep to 50% discharge max.

50% is the rule of thumb for cost effectiveness for recharging costs & battery replacement costs.

Using more will increase battery replacement costs but reduce recharge costs. Decreasing is will reduce battery replacement costs but increase recharging costs.


The above is valid for when the recharge has a cost so less valid when recharging with solar.

Fair comment. I mentioned it more to give relative scale to the demand from the iPad compared to the capacity of even a fairly modest storage.
RichardW

On solar panels the quoted out put is what you can expect on sunny summer day in the UK at noon if the panel is facing the sun.

No its the rated output under fixed test conditions.

In our long summers day the average day produces the equivalent of 4 such hours if we leave the panel out all day and it is facing the sun

We are finding that in summer on a good day we get 6.6 times it peak rated output. So our 1.2kWp array produces 8kWh. In December & Jan we are lucky if we produce that much in a month due to the low sun & our high horizon. With no shading issues an hours worth per day would be about right.

In the shorter winter days with a lower sun we only get one hours worth if we leave the panel out all day!

So I reckon mid summer a panel can knock your battery up 13.31 Ah per day if you have it said up out of any shade and facing south or a quarter of that in the winter. ie it will take you over a week to recharge a 100Ah battery .
In reality that's hard to achieve unless its a roof mounted static installation - and it will never be achieved if you can't leave it out all day

That is why if you simply want more power and especially if you camp for a week or so in spring our autumn I recommend you are often better simply taking an extra battery fully charged - if you want to extend you battery life in the cheapest manner !

Of course if you like using solar go for it - but be aware solar panels that are packed away and not used for much of the year have a worse environmental impact than charging from the grid. It is only if you use them for longer ie on your roof at home that the environmental equations shifts in favour of solar.

Having said all that I think they a fun and really wish they were a more practical option!

Also do not forget that FLA's (Flooded Lead Acid) batteries can self discharge at a rate of upto 10% per month when not being used.
mark

Please everyone take my comments as relating to 1-2 weeks camping trips! Or trips where there will be substantial driving (to recharge batteries) more than once a fortnight

Different factors such as self discharge come into account for longer trips.

But if you want more power for a typical short holiday the cheapest way to do it is still to buy another battery! It is also the best option if you get a weeks crap weather..

The problem is we all use our laptops and lighting most when it is dark and overcast outside - and most of all on that week when it rains all week so we up indoors - or in the spring holidays when it is dark evenings its not usually the sunny weeks when we put extra demand on our batteries and need the extra boost - as most of us wil go our walking and enjoying the outdoors then ..

now if we could have rain powered generators we'd be fine!!
RichardW

Please everyone take my comments as relating to 1-2 weeks camping trips! Or trips where there will be substantial driving (to recharge batteries) more than once a fortnight

Different factors such as self discharge come into account for longer trips.

But if you want more power for a typical short holiday the cheapest way to do it is still to buy another battery! It is also the best option if you get a weeks crap weather..

The problem is we all use our laptops and lighting most when it is dark and overcast outside - and most of all on that week when it rains all week so we up indoors - or in the spring holidays when it is dark evenings its not usually the sunny weeks when we put extra demand on our batteries and need the extra boost - as most of us wil go our walking and enjoying the outdoors then ..

now if we could have rain powered generators we'd be fine!!

I agree.
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