What size solar panel do I need?
Been looking at solar panels for some time now, caravan has a 120ah battery, motor mover, alarm and same new version of my caravan have a 40W panel on them. However many kits are 100W or even greater so if I wanted to use my van purley off the battery/gas
and still have a fully charged battery to use the motor mover at the end of a week or two what size solar panel would do the job? or more to the point minimum size panel...
Comments
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I have a 150w free standing solar kit. From april onwards it keeps me going without mains electricity. I use all the usual stuff, 12v telly, radio, fan on the heater, lights, motor mover to get on and off site. On a Sunny morning, battery is fully charged
by 11:30 ish. Cloudy days, it might not fully charge, but plenty of usefull power so as no to ba a pain. Just use what you need, and think about conserving power. Its good fun.0 -
We have an 80W free standing panel and last summer did 8 nights without hookup, with a couple of hours tv per night no problems and still had full battery for motor mover when we packed up. We like the ability to use CLs without hook up when we want as there
are some really nice ones, although getting harder to find without electric. They tend to be cheaper as well although never been convinced of economics as the fridge has to be on gas all the time, no facts and figures one way or the other but am willing to
pay for the gas in order to use some of these Cls.0 -
I have been using a 120 watt roof mounted panel with a 110 amp leisure battery for 18 months running a tv, lights etc and it sometimes has fully recharged the battery in sunny summer mornings by 9-30am. In winter with dull weather it can take most of the day. As yorkyladandlass has found 80 watts certainly can be sufficient in summer but if you are planning more year round trips I would go for a larger panel.
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We have an 80W free standing panel and last summer did 8 nights without hookup, with a couple of hours tv per night no problems and still had full battery for motor mover when we packed up. We like the ability to use CLs without hook up when we want as there
are some really nice ones, although getting harder to find without electric. They tend to be cheaper as well although never been convinced of economics as the fridge has to be on gas all the time, no facts and figures one way or the other
but am willing to pay for the gas in order to use some of these Cls.its this part of the cost equation that has driven many to turn to cheap refillable gas (safefill for caravanners or Gaslow etc for MH ers) which costs around 25% per ltr of calor exchanges.
yes, like the solar panels, theres an upfront cost but after that its gravy.....(as they say
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We have used panels all year round for about 4 years now. In winter we rally but usually have a hall in the evening. From spring to autumn we stay in van in evening and often watch tv for about 4 hours. We have been 10 days off EHU on many occasions. 110
ah battery. We have 80 watts on roof which is enough from April to end August. From Sept to March i also use a portable 90 watts. We have mover and truma combi which is quite battery hungry and never had a problem. I find the portable more effective as I can
adjust angle etc.0 -
Lot of smoke and mirrors arround MPPT controllers IMHO. They can have advantages if you link a number of panels in series but they are more expensive than a PWM controller unless you by a fake off eBay. You are probably better off and cheaper if you buy
a slightly bigger panel and a good PWM controller.0 -
Perhaps there is Boff but the largest panel I could get on my roof was 120 watts. I wanted a bigger one but no room so opted for an MPPT controller to compensate. So far it is proving the right decision.
peedee
Actually there are only 2 types of solar set ups those that meet your needs and those that don't
Everything else is a trivial
detail.Actually the question asked by the OP is vey common and almost impossible to give a definitive answer. Simply because everyones usage is different.
In general I would suggest the biggest you can fit on your roof bearing in mind weight and size A roof mounted panel is much less efficent than a freestanding one so that is another consideration. But outside of mid summer I think it is unlikely that
a 40W panel on the roof is going to keep up with demand.Top tips. Buy a decent controller, don't buy a panel from a Caravan dealer look on eBay etc. Use some of the money saved to change your bulbs to LEDs if they arent already. Imho it is well worth doing and pays off in terms of extra flexibility.
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There is a very good thread on here somewhere about how to calculate your requirements and I think it had a link to a spreadsheet to make it even easier but sorry I cannot find it but if you do a Google search on "solar panel calculator spreadsheet" you
will get some answers.peedee
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I have 130w (2 panels 40w & 90w) roof fitted and we did 15 day rallylast July, even with a TV hungry wife. Usualy fully charged up by 10 on nice sunny days.
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We have a free standing 140w panel which I simply point South rather than move it around. We have just returned from 16 days away without hook up and my battery is still fully charged (even though it is getting s bit long in the tooth now and discharges
quicker than a good new one). We rally all year round and have never found the solar panel to be insufficient to keep us going. For average usage during summer 80w should be big enough but the bigger the better is the rule. You just need to take into account
your power usage, whether you caravan during the winter, what you can afford and how much weight you can carry.0 -
Ours is a free standing I think 120W although could be 140W. During the summer we can have the TV on all day and the battery will remain nearly full till the sun goes down. During the winter we are a bit more careful as battery does get lower but it suits
our needs and lets us watch a good few hours on an evening still but we are more careful.0 -
I have an old 150W inverter that I bought from Maplins about 15 year ago. I use this occasionally to charge a camera, battery, laptop, and rechargeable drill. Everything else is 12v or not used.
Ps by occasional I mean a couple of weeks ago I decided to charge the drill. I couldn't remember where I'd put the inverter so I didn't bother. I subsequently found it in the last place I looked
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Just out of interest do any of you guys use inverters or just keep to 12v useage
Yes I have a 700w one permanently wired in, Relays enable it when off hook. It means I can charge 36 volt bike batteries when off hook and keep various other battery powered device charged up via their mains chargers. Don't use it for anything else.
peedee
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We have a free standing 140w panel which I simply point South rather than move it around. We have just returned from 16 days away without hook up and my battery is still fully charged (even though it is getting s bit long in the tooth now and discharges
quicker than a good new one). We rally all year round and have never found the solar panel to be insufficient to keep us going. For average usage during summer 80w should be big enough but the bigger the better is the rule. You just need to take into account
your power usage, whether you caravan during the winter, what you can afford and how much weight you can carry.Write your comments here...Excuse the ignorance, but.. does your free standing panel have a built in charge controller etc? and do you just hook it up to the battery with leads and croc clips?
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Write your comments here...Excuse the ignorance, but.. does your free standing panel have a built in charge controller etc? and do you just hook it up to the battery with leads and croc clips?
Yes it does have a built in controller. It is permanently wired to the battery via a standard battery connector and an inline fuse. I would advise against crocodile clips as they create a high resistance point thus reducing the efficiency from the solar
panel. They can also slip very easily and create a potential fire hazard.0 -
Write your comments here...Excuse the ignorance, but.. does your free standing panel have a built in charge controller etc? and do you just hook it up to the battery with leads and croc clips?
Yes it does have a built in controller. It is permanently wired to the battery via a standard battery connector and an inline fuse. I would advise against crocodile clips as they create a high resistance point thus reducing the efficiency from the solar
panel. They can also slip very easily and create a potential fire hazard.Write your comments here...Thanks, the croc clips did concern me. Presumably you have some sort of plug/socket in the leads for when the panel isn't deployed?
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The plug/socket is the battery connector I referred to like this one:
Mine came with the panel.
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This is a not an easy question to answer as we all use different levels of 'power'. I have a folding 160 watt panel which keeps two of us going all year round with use of TV etc, If by chance the battery starts to get a little low, which it has on a couple
of occasions we just cut back demand. Guess the best advise would be get the biggest output you can afford and wish to carry. Must say we are impressed with ours which is 3 years old now.0 -
As a very rough guide in Northern Europe, one watt of solar power per one amp of battery power - so a 100 amp leisure battery, get a 100 watt sold.
Russ
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