Solar panel power

[meddyliol]

I am thinking about buying the Kyocera 135W system from Aire and Sun Power Systems for my Rapido 986M. At the moment it only has one leasure battery at 90Ah. Would this kit be OK if I fitted another battery as well? If I only use one battery is 135W a bit over the top? Should I buy the 95W system?

 

Thanks

 

Brian 8-)

[w1ntersun]

Hi,

 

Batteries first. If you fit a second battery Ideally you need two matching ones as the least efficient battery will draw power off the newer more efficient one.

 

If you can afford it then go for the 135w solar panel because you never get what they say they will deliverer. IE you should get 8 amps in ideal conditions but conditions are never ideal so you may average a lot less than that. So a smaller panel will deliver even less

 

Richard

[thebishbus]

Hi Brian, I would go for the largest panel I could afford or have room for , the regulator will control the charging rate.

Brian B.

[Brian Kirby]

meddyliol - 2010-07-21 8:16 AM I am thinking about buying the Kyocera 135W system from Aire and Sun Power Systems for my Rapido 986M. At the moment it only has one leasure battery at 90Ah. Would this kit be OK if I fitted another battery as well? If I only use one battery is 135W a bit over the top? Should I buy the 95W system? Thanks Brian 8-)

First, why do you need the panel?  How long are you trying to survive in one place without hook-up?  Could you achieve the same end with increased battery capacity?  How old is the existing battery: if more than 3-4 years it may well be giving you a lot less that it's claimed 90Ah.  Besides which, 90Ah is not much of a battery for a van the size of yours, is it the largest that will physically fit, and is there space for another?  I.e, could you get two 110Ah batteries in? 

The point of all this is that more battery power, pound for pound, is far better value generally than solar panels, unless you need the solar charging because you spend weeks at a time in one place without hook-up.

[747]

If you go down the solar route, look at www.stonewindandsolar.co.uk.

 

I have just bought a 90 watt panel from them. The full kit including vat and postage is £315. I was surprised how lightweight it is compared to an older 12 watt Maplin panel. It appears to work very well, although it has not had a proper trial yet. I have purposefully put it in the shade and limited light conditions and I am certain that I will get a reasonable charge in less favourable conditions.

 

I followed a lot of threads on various forums before I bought one and I am of the opinion that a cheap panel (as sold on ebay) gives a poorer performance. This is possibly due to the maker using lesser quality materials.

 

The advice seems to be that it is pointless buying a very large panel unless you have plenty of battery storage to soak it up.

 

If you decide to buy the same one as me then the cost saving will more than pay for your 2 new batteries.

[spospe]

Unless you can guarantee full sun all the day, fit the largest panel you can. In hot climates you will be wanting shade and shade dramatically cuts a panel's output. Use a good regulator to stop the battery frying and you should be all right.

[crinklystarfish]

Assuming about 200Ah battery capacity and moderate use of sensible on-board equipment you would be OK for approx 3 to 4 days in summer, maybe 2 to 3 in winter without the need for external charging. A couple of 100 / 110Ah batts are definitely the first thing to install. 

Not many people actually need solar panels, but many fit them anyway. 

Don’t forget that when you really need them, ie when it’s cold, wet, and the days are short, they’re virtually useless. When you don’t actually need them, ie when it’s warm, dry and the days are long, much of the power they generate will be wasted in heat generation and/or the gassing off of your electrolyte. 

For most users they’re all about feel-good. I personally feel better having saved my money on something I don’t actually need.

[747]

Mr Starfish (can I call you Crinkly?) has got it half right.

 

With my 2 x 110 AH batteries we can last 3 days in winter conditions but I have to regulate my wife to `soaps only`. With a 90 watt panel, we should be able to go at least one more day in the worst of light conditions.

 

It all depends on your equipment and your usage of aforementioned gizmos. If you feel the need to do without something, keep the solar panel. If you always use sites with hook up then you do not need one in the first place.

 

For Europe, use aires or whatever with a hook up. It is a lot of money to spend for only occasional use.

 

BTW It is safe to leave a large solar panel plugged in. It will not fry your batteries as the regulator is there to stop it.

 

Oh, I nearly forgot. If the winter weather is terrible and blowing a gale, I also carry a wind turbine in the garage. It can be used separately or together with the solar panel.

 

If I can find enough wildcamping spots beside rivers, I am contemplating a 12 volt Hydro-electric setup as my next project. Anybody got one? :D

[colin]

crinklystarfish - 2010-07-21 5:52 PM

 

Assuming about 200Ah battery capacity and moderate use of sensible on-board equipment you would be OK for approx 3 to 4 days in summer, maybe 2 to 3 in winter without the need for external charging. A couple of 100 / 110Ah batts are definitely the first thing to install. 

Not many people actually need solar panels, but many fit them anyway. 

Don’t forget that when you really need them, ie when it’s cold, wet, and the days are short, they’re virtually useless. When you don’t actually need them, ie when it’s warm, dry and the days are long, much of the power they generate will be wasted in heat generation and/or the gassing off of your electrolyte. 

For most users they’re all about feel-good. I personally feel better having saved my money on something I don’t actually need.

 

One of the most commonaly asked questions on this forum is about flat batteries, usualy after vans have been laid up for a few weeks.

Often times the batteries will have been damaged or severly reduced in capacity due to being discharged too low.

In most cases this would not happen if a solar panel had been fitted, so I would say that most people would benifit from fitting a solar panel.

[crinklystarfish]

Reasonable points chaps (and crinkly is fine ta, I have been called much worse previously). Of course, only individuals can decide if the outlay and routing of cables etc is worth the return. For me personally, the prospect of eking out another day in winter just wasn’t worth the hassle. After all, we all have a splendid generator on board in the form of our engine, and to be honest, three days in the same place in winter would drive me stir crazy. Far better, for me, to move on to a change of scenery, get a bit of heat in the engine, maybe call at the shops etc. Furthermore, given the light in winter, I’m not convinced that even a large panel adds a great deal to the mix. 

Flat batts from lay-ups are easily avoided with a bit of routine care and solar panels are an expensive and overly-elaborate fix for what shouldn’t really be a problem in the first place. Again though, entirely a matter for individuals. 

I accept that if a proper batt management unit /regulator is fitted then batts won’t gas, but excess current in this case is just wasted in heat generation. 

When I lived on my boat I would routinely moor up for a long periods and not run the engine. I had solar panels and a wind generator at that time and for that use they were invaluable. I’m not anti-solar, just anti wasting money on fad and fashion. 

If you only camp off EHU and spend day after day in the same place, you just might need one. In this case I fully accept that for such people they might offer benefit given good strong light, but maintain that for most they are just bling. If users really need one go for it, the biggest and best quality (or an array) is the solution in this case. If users just want one, I’d advise to just stick a crappy one on and feel good for less outlay.

Intuitively they are superb but when all the maths are done, for most users, I'm not so sure.

[colin]

crinklystarfish - 2010-07-22 11:14 AM

 

Flat batts from lay-ups are easily avoided with a bit of routine care and solar panels are an expensive and overly-elaborate fix for what shouldn’t really be a problem in the first place. Again though, entirely a matter for individuals....

Intuitively they are superb but when all the maths are done, for most users, I'm not so sure

 

The reason I like solar panels is they are practicaly a fit and forget item. Sitck a panel on the roof, a controller inside, couple of wires to link them to batteries, job jobbed.

On the newer sevel products (and maybe other makes?) just a couple of weeks laid up can result in a flat vehicle battery, maybe I'm getting lazy, but I want to spend less time messing about with vehicle maintenance nowadays and getting on with what seems an endless list of other jobs and activities. In winter if I've been on a fly away holiday for a few weeks, when I come home I just want to jump in the van and turn the key and drive.

[Frankkia]

So far no one is right or wrong. Before you decide on solar panels, or for that matter any other form of auxiliary battery charging, you should decide what you need it for. If you always go on site with an electric hook up don't bother. If as we do you rarely if ever go on site and don't move off every day then you may need the extra charge.

 

We spend our winters in Portugal and late summers in Germany and very rarely have a hook up there fore we rely on our 3 x 120Ah batteries and 2 x 120w solar panels. In winter we stay in some places for as much as 4 - 5 weeks without hook up - we have an extra 60w panel on a stand which we point directly at the low sun which helps give everything a boost (fitted with a long lead and plug which is plugged into a socket in the 'van which in turn is wired back to the controller.

 

Our solar panels have paid for themselves over and over as we have had no need of sites and when we do go on site we still choose (where possible) not to have a hook up.

 

We have sky satellite tv and enough lights (all changed to LED) to put Blackpool to shame and we also charge the laptop from the system.

 

As I said above it depends what you want to do - If you want to rely on solar and you intend to camp off hook up in winter then get the biggest array you can afford / fit on the roof and ample battery storage to keep what you collect. If your power consumption is low and you move regularly then merely increase your battery capacity.

[Freewheeler]

What no one has yet mentioned is the downside to fitting solar panels.

 

i.e. The vehicle will consume more fuel because of the adverse affect to the aerodynamics as well as the extra weight. Also, the extra weight is on the roof, exactly where you don't need it. Again, this will affect handling charecteristics. In addition, solar panel efficiency deteriorates with age.

 

Some people will dismiss these comments, no doubt, but remember the laws of physics still exist, wether you accept it or not. Contributors who have advocated using a motorhome before one decides if solar panels are required, are, IMO, correct. Personally, I haven't found the need in all my years as a motorhomer.

 

In the UK, many campsites, CL's/CS's include electric as part of the pitch fee, so, particularly in the colder months, when solar panels and batteries perform poorly, an electric hookup is often useful, and you might be paying for one anyway.

[747]

I am afraid that technology has overtaken you my friend.

 

I have just bought a 90 watt panel (120cm x 54 cm) and it is very light indeed. It is probably lighter than the 12 watt dashboard trickle solar charger I got from Maplin some time ago.

 

It will not affect my aerodynamics either, as it is carried in the garage. I have made up a box for it, I open the small rear hatch and slide it out. I did this because my Burstner is very tall and has a completely flat roof. It would have only been a matter of time before I damaged it.

 

As Mr.Mott pointed out on another thread, there is not much difference in the output of different types of panel but there does seem to be a weight difference.

[colin]

Freewheeler - 2010-07-22 7:15 PM

 

What no one has yet mentioned is the downside to fitting solar panels.

 

i.e. The vehicle will consume more fuel because of the adverse affect to the aerodynamics as well as the extra weight. Also, the extra weight is on the roof, exactly where you don't need it. Again, this will affect handling charecteristics. In addition, solar panel efficiency deteriorates with age.

 

I've no dought that many solar panels are fitted such that they adversly affect fuel consumption, but, a carefully thought out instalation will have little affect or could (as in the case on my T25) improve the aerodynamics.

The panel I have weighs 3kg.

[Dave Newell]

Additional fuel consumption due to extra wind resistance of a fitted panel and its weight is all but unmeasurable outside of a laboratory. Effects on handling are so minimal as to be inconsequential. Effect on your bank balance is likely to be somewhere between "sore" and downright "painful" depending on your financial well-being and your outlook on motorhoming independence.

 

I have a 100 Watt solar panel and three 110AH batteries, I am about to fit another solar panel of at least 100Watts rated capacity, why?

 

Well simply because our motorhome is our business, we spend up to five nights in one spot without moving at a motorhome show and power our entire stand from our leisure batteries. Our display stand consists (presently) of a 17" LCD TV, a 11" LCD TV, two sat receivers, one Freesat one FTA, an audio amp and speakers, three rear view camera systems. Total current draw for this lot is around 7-8 Amps unless I put a DVD on which can bump it up by another Amp or so. This lot will be running for at least eight hours a day for three days. We also have a 100 litre 12 volt compressor fridge plus normal motorhome requirements of lighting and water pump so our total power requirement is somewhere in the region of 100AH per day!

 

Without the solar panel we would manage three days at a pinch but wreck our batteries in short order in the process. We have just done the Great Northern Show at Northwich and managed to survive the weekend without going below 11.5 volts, approximately 55% discharged which is why I am about to fit another panel.

 

Without doubt the necessity of a solar panel is based on your camping style and power usage. We are power hungry because of demonstrating our wares, I would hazard a guess that few motorhomers use morte power from 12 volt sources.

 

Try your van out to see how long you can last without your leisure battery(ies) dropping below 12 volts (roughly speaking 50% discharged). If you have one battery and can manage two nights then a second battery of similar capacity will give you a four night getaway.

 

If your intended usage pattern involves staying in one place without hookup for more than four nights then I'd say consider a solar panel as a viable option. If however you will mainly stay in one place for only a night or two before driving for an hour or more to a new location then a good battery to battery charger will be money better spent.

 

D.

[crinklystarfish]

Mr Frankkia and Mr Newell exemplify the kind of users who would genuinely benefit. I maintain that unless intended use is along these lines, save your cash. As previously posted, I have.

No disrespect intended to anyone else who has fitted a panel or two and I accept the argument for keeping lay-up batts charged if cost is no object.

Dave - 12.4 volts after no charge / discharge for a few hours is perhaps a better threshold? I realise it's hard to measure in the real world though.

[Dave Newell]

Cheers Crinkly, after 24 hours inside my workshop (after being fully charged by a 4 stage charger) my batteries display 13 volts, this is without any charge or load being applied to them. Measured on the on board display and via good quality digital multimeter. I work to the rough and ready figures of 14 volts = fully charged and charging, 12 volts = 50%, 10 volts = flat/totally discharged. If 10 volts is regularly acchieved then expect your battery(ies) to be FUBAR in short order. I accept this is rough and ready and not accurate for all lead acid battery types but it works for me.

 

D.

[Freewheeler]

Dave Newell - 2010-07-22 9:16 PM

 

Additional fuel consumption due to extra wind resistance of a fitted panel and its weight is all but unmeasurable outside of a laboratory. Effects on handling are so minimal as to be inconsequential.

 

A little bit economical with the truth, Dave, but I quite agree that it would be impossible for most of us to measure this as it would for, for example, a roof rack, but this is a well known user of extra fuel.

ANY extra weight uses more fuel.

Calculating fuel usage itself is almost impossible, because of the difficulties of inacurate quantities involved in the calculations, but people still try to do it.

If people want to fit Solar panels, fine, but at least be aware that they are not going to provide something for nothing. Manufacturers and installers seldom mention the downside of anything that they make/fit.

[crinklystarfish]

There are several reasons not to fit, but extra weight is not one of them. We are talking maybe 10KG tops on something that weighs 3,500. The effect is immeasurable, don't forget many HGVs achieve almost the same unladen as when hauling 40 tonnes.

Aerodynamically too, trifling difference given the profile and placement. Air flow will already be turbulent at the time it hits the panel and may well even hit the panel going forwards because of eddies. If we were arguing about fitting one on an F1 car I'd agree, but we're talking about a commercial vehicle with a huge frontal area and all manner of peripherals hanging into the airflow.

Can't agree I'm afraid - red herring I reckon.

[Dave Newell]

crinklystarfish - 2010-07-23 10:13 AM

There are several reasons not to fit, but extra weight is not one of them. We are talking maybe 10KG tops on something that weighs 3,500. The effect is immeasurable, don't forget many HGVs achieve almost the same unladen as when hauling 40 tonnes.

Aerodynamically too, trifling difference given the profile and placement. Air flow will already be turbulent at the time it hits the panel and may well even hit the panel going forwards because of eddies. If we were arguing about fitting one on an F1 car I'd agree, but we're talking about a commercial vehicle with a huge frontal area and all manner of peripherals hanging into the airflow.

Can't agree I'm afraid - red herring I reckon.

I'm in total agreement with Crinkly. ;-) D.

[Yeoman]

We've always done plenty of 'aire' and offsite camping, but we don't tend to stop in these places for more than a few days.

We have two leisure batteries and they don't seem to deplete at all.

 

What exactly can you run off a solar panel? A toaster? Kettle? How many watts? 500? 700? Or is it purely to keep the batteries charged, which maybe wouldn't be necessary if you don't have too many calls on them - little gadgets that people seem to have?

 

Generators are clearly unpopular, especially where lots of motorhomes herd together, but they seem a better bet as you can really run things with them. We saw a man using a proper spin dryer. His genny was only running for the 10 mins or less it took to spin his clothes, and frankly it wasn't particularly noisy. Less noisy than the vehicle engine would have been.

That seems to me to be much more useful than something that depends on the weather, which does little more than top up batteries.

 

Don't you think generators are quieter than they used to be? Couldn't there be an unwritten rule that everyone switches on at a certain time or something?

 

I await the furore!!

 

 

 

[Brian Kirby]

Dave Newell - 2010-07-23 11:50 AM

crinklystarfish - 2010-07-23 10:13 AM

There are several reasons not to fit, but extra weight is not one of them. We are talking maybe 10KG tops on something that weighs 3,500. The effect is immeasurable, don't forget many HGVs achieve almost the same unladen as when hauling 40 tonnes.

Aerodynamically too, trifling difference given the profile and placement. Air flow will already be turbulent at the time it hits the panel and may well even hit the panel going forwards because of eddies. If we were arguing about fitting one on an F1 car I'd agree, but we're talking about a commercial vehicle with a huge frontal area and all manner of peripherals hanging into the airflow.

Can't agree I'm afraid - red herring I reckon.

I'm in total agreement with Crinkly. ;-) D.

Me too.  Any extra weight or increased aerodynamic characteristic will increase fuel consumption.  The question is, by how much, and whether that increase in running costs is significant, either relative to the costs of owning and running a van, or to the benefits from the panel.  Put another way, if the increased fuel costs arising from the presence of a solar panel - assuming you can calculate/measure them - puts you off buying and fitting the panel, you can't really have wanted it in the first place!  The cost benefit, in terms of "free" battery charging, for those who would benefit from that, will many times outweigh the, at best, marginal increase in running cost.  Discounting capital cost, therefore, but focusing on costs in use, the panel wins hands down!

So, solar panels lose efficiency over time.  But, so do batteries.  So do engines.  So do we all.  So what?  How can that be a reason not to buy?  The argument is worse than a red herring, IMO, because it is fallacious and misleading, and so, unhelpful.

[Brian Kirby]

Yeoman - 2010-07-23 12:25 PM ...........What exactly can you run off a solar panel? A toaster? Kettle? How many watts? 500? 700? Or is it purely to keep the batteries charged, which maybe wouldn't be necessary if you don't have too many calls on them - little gadgets that people seem to have? Generators are clearly unpopular, especially where lots of motorhomes herd together, but they seem a better bet as you can really run things with them. ...............................Don't you think generators are quieter than they used to be? Couldn't there be an unwritten rule that everyone switches on at a certain time or something? I await the furore!!

Solar panels run nothing, they merely re-charge the batteries.  They do this silently, at most times of day, in most latitudes, providing they can "see" the sky.  They are beneficial mainly to people who spend extended periods of time static and without hook-up, or whose vans are not kept on hook-up, but are in the open, when out of use.

Generators produce 230V power, not nominal 12V power.  They can charge batteries, though must be run for extended periods to do so, and can do this any time of the day or night.  They can also run mains voltage equipment directly, and can be plugged into a van's mains input to "liven" everything in the van.

Their main drawback, as you say, is noise - to which I would add fumes for anyone down-wind.  The unwritten rule would, IMO, be useless, as would a written rule, because it would not be universally observed.  Besides which, a noise is a noise. 

We walk the south downs, and revel in the lark song - until some idiot in a light plane, or a powered hang glider, happens by and drowns out the lark song.  It doesn't go on all day, but it shatters the spell at that time.  It becomes a gross intrusion.  Why?  Because someone else wants to do something that inflicts needless noise on others, while pursuing their form of leisure.  So, I submit, with generators.  Non-essential, because others, quiet, means of achieving the same end, are available, and so, inconsiderate and selfish.

[Yeoman]

You say "quiet, means of achieving the same end, are available, and so, inconsiderate and selfish."

 

However, it is NOT achieving the same end is it?

You have said that the generator can run anything and 'liven' the sockets in the van. Somewhat different from merely charging the batteries.

 

Surely by now they have invented quiet generators or baffle boxes to put them in?

 

Haven't they just got a bad name by people using ancient noisy and smelly ones?