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Post by fatwelshbuddha on Jan 22, 2018 9:29:12 GMT
serious thread coming up - which will no doubt descend into mayhem.... now that we have the new motorhome, I have the opportunity to spec solar panels for the roof and have what looks like quite a large area available. in the forum's opinion what wattage size should I go for which will be good for a few days off-grid living in summer?? I'm thinking 160-200w should do it but I bow to the forum's experience. I'm not a full time wilder and will use campsites and EHUs at times so am looking for, say, up to a week off grid. dimensions of said panels may ultimately define what wattage I can fit up top. ta muchly
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Barry B'stard
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Post by Barry B'stard on Jan 22, 2018 9:45:44 GMT
If you get it right from April to the end of September you should have enough power to stay in one place indefinitely especially June, July and August with just the Solar panel for power. We just have a 100w panel, clever MPPT controller (thats the important bit) and a single 125ah battery. Mid summer its fully charged each day by mid to late morning. Main thing that takes power in our van though is charging and using laptops probably. TV is very low power and the heating is totally gas and uses no battery (not that you generally need heating in summer unless your in the UK).
How many batteries do you have? If you have just one like us then a single 100 or 120w panel should be ok but if you have two then you might want to consider 2 x 100w. Depends on your usage and battery bank really.
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Post by fatwelshbuddha on Jan 22, 2018 10:06:34 GMT
cheers Baz
I've just spoken to Sunstore over near Worthing and they said similar to you. in their view 120w should do the trick as we aren't heavy consumers and like you mainly charging phones, tablets and possibly a laptop (I can use an inverter for that). we don't have a TV - it does have an aerial but not a TV and we probably won't bother (never have had a TV in over 12 years of motorhoming) - I might use the aerial hole in the roof for an iBoost Connect, but only if we get pissed off with the current iBoost directional system we've had for about 5 years. the fridge is gas if no EHU, and heating is diesel so no need for lots of electricity when static. I will need to check the ampage of the leisure battery which is the standard Chausson fitted one - anyone know what factory fitted leisure batteries rate at??
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Post by Sir Rowley Birkin on Jan 22, 2018 10:26:14 GMT
Good reply from Baz, mirrors my thoughts. Don't bother below 100w, that's minimum. We tour all the time, summer and winter, so my requirements are different. But I still make do with 100w (plus Battery to Battery charger) for two 120ah batteries. We tour and move most days (which charges the batts) but have happily stayed for up to five days in one spot. Your diesel heater takes a wallop from your battery (I believe), so maybe factor in another battery plus the solar panel if you currently only have one battery? If you have room, go up to a 200w panel(s), but I can't see you needing that. I think it more important having the storage capacity, ie two large ah batteries, so that you can use the solar energy even when the sun's gone. Finally, get a good controller, not one of the many cheapies available.
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Barry B'stard
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Post by Barry B'stard on Jan 22, 2018 10:27:54 GMT
Dont scrimp on the controller though. At the time when I Got mine everyone was recommending these. www.ebay.co.uk/itm/MPPT-300W-12V-25A-solar-charge-controller-regulator-LCD-battery-charger/320756044451?epid=19009969121&hash=item4aae8cd2a3:g:sWwAAOxyzfNRrD19I think mine came from a recommended seller called "Maximum Solar" from China. Good kit. Shows you the battery status, amps going in etc and the power usage of any devices directly connected to the controllers load input. I attached a bank of 12v sockets to mine so anything you plug in shows up on the screen so you can see how much power its using. My tv uses 14w but if I plug in USB speakers it goes up to 16w. I like pressing the button to see how much charge is going in. Interesting the highest reading we have had was on the Isle of Arran not the southern Mediterranean.
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Post by Sir Rowley Birkin on Jan 22, 2018 10:29:56 GMT
Right... Now bring on the mayhem!
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Post by fatwelshbuddha on Jan 22, 2018 11:02:28 GMT
cheers chaps - useful feedback. the guy at Sunsolar suggested there's not much extra benefit in going above 120W and said the only real benefit you're getting with more powerful panels is reliability i.e. better generation in lower solar levels for example when it's a little overcast. a 2nd battery might be a good option.
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Barry B'stard
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Post by Barry B'stard on Jan 22, 2018 11:20:13 GMT
As said for a single battery there probably isnt much point going over 120w. probably more panels will cope better very early spring or late September October. Generally its October we start to have to be a bit more careful with power and start having to think about hookup or conserving power but for us we are summer campers anyway generally and if we go away in the Winter which we have often done sod being off hookup for long anyway. Even 250w of solar in the winter wont be enough without you sitting in the dark or having no TV or laptop.
Might be worth checking what that diesel heater uses though as I seem to think as Boggers says that they can hammer the batteries.
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Post by 747 on Jan 22, 2018 13:12:14 GMT
Rule of thumb. Battery capacity (in Ah) should match solar array (in Watts). If you want your engine battery charging also, you need to factor in its capacity as well.
We manage over 95% of the time with a 100 watt panel charging 2 x 110 Ah plus 90 Ah engine battery. We can stay stationary indefinitely between March and end of October. I carry a 90 Watt freestanding solar panel for long spells of dull or wet weather. I have only needed it on average twice a year.
I have never used an MPPT controller, just a good quality PWM one (not the cheap shite that so many people buy). The difference between them is minimal.
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Post by Keith on Jan 22, 2018 16:27:25 GMT
We have an 80W Solar Panel and two Leisure batteries and until November, when I knew we wouldn't get away for a while, we hadn't been on hook up more than half a dozen times in four years whatever the weather and time of year.
Not having a TV helps as they take a fair bit of power but a good pair of leisure batteries, solar panel, B2B unit and you can go virtually anywhere without worrying about hook-up - and over the years it saves you enough to pay to keep the wine cabinet full.
Mind you, a few extra panels help power the wife's hair curlers .......
s17.postimg.org/pqzqg8t73/SOLAR_1_600_x_333.jpg
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Post by Kaytutt on Jan 22, 2018 19:04:13 GMT
Having met a solar panel installer at a motorhome rally recently we had quite an interesting chat. We had a MPPT controller fitted to our old van (the same controller as Barry has mentioned) and were considering swopping the cheaper one fitted in our current van for an MPPT but according to the installer unless you have a very large bank of solar panels and storage options there's really very little point in the additional expense of an MPPT controller because the actual difference between the two in terms of maximising output was minimal in a small setup
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Post by Kaytutt on Jan 22, 2018 19:05:26 GMT
And I should have read shortarses Jims post properly before spouting myself
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Barry B'stard
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Post by Barry B'stard on Jan 22, 2018 19:31:16 GMT
I think that controller was raved about on FUCTS and the wildies a few years ago which is why I bought it. I have nothing to compare it to of course as its the only one I have ever had but many old hands claimed it was much better and more efficient. Maybe things have moved on though I dunno. I suppose you should be able to tell Kay if your current one performs as well as the old one.
Anyway I like it as it you get to press a button to see whats going into the battery. Im easy pleased.
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Post by Kaytutt on Jan 22, 2018 21:36:34 GMT
I think that controller was raved about on FUCTS and the wildies a few years ago which is why I bought it. I have nothing to compare it to of course as its the only one I have ever had but many old hands claimed it was much better and more efficient. Maybe things have moved on though I dunno. I suppose you should be able to tell Kay if your current one performs as well as the old one. Anyway I like it as it you get to press a button to see whats going into the battery. Im easy pleased. I have a button to press too To be honest there's no noticeable difference between the 100w solar panel and MPPT controller on our old van and the 100w solar panel and PWM controller on the newer van but I have to admit I dont really spend much time studying the controler display, if the lights go off then it hasnt worked, who needs a button
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Barry B'stard
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Post by Barry B'stard on Jan 22, 2018 22:37:05 GMT
I need a button!!! And and and! it shows me how many watts stuff uses AND it shows me that when I plug my speakers into the TV it uses an extra 2 watts of power. Thats important! probably. Ah feck off! EDIT: You dont need one of them Fats.
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