Mrs T Posted May 17, 2013 Share Posted May 17, 2013 A bit of an old chestnut perhaps ? Is an 80 watt roof panel enough for normal UK use ? Mrs T Link to comment Share on other sites More sharing options...
BGD Posted May 17, 2013 Share Posted May 17, 2013 That's a bit of a "how long is a piece of string question I'm afraid. I guess it depends upon what you regard as "normal" UK use. What 12 volt kit will you be using, for how long between the times when the engine (and thus alternator) are working or you are connected to mains via EHU? What size leisure batteries are you going to be feeding into/drawing from? As a VERY rough guide, we've got an 80 and a 50 watt solar panel on our MH roof, feeding two 125ah leisure batteries, and we really can go indefinitely without running the engine or being on mains hookup. BUT we are I suspect very low energy users compared to most other people: - We're in Spain. There's loads of sunshine here, even through the winter months! - All internal lights are LEDs. - We only use a tiddly (10 inch screen) table-top 12 volt portable TV/DVD player in the evenings, and only for maybe a couple of hours. We don't even use the DVD function, but watch either Spanish TV, or pre-downloaded films/series/programmes that we've brought with us on USB sticks. - We only very rarely need to operate the fan blower part of the gas heating, and if so then only for maybe 10 minutes to kick-start the van warming up. - we only use a little 300 watt inverter for a few minutes every couple of days ( for my electric razor). - Kathy uses a set of 12 volt hair straighteners once every couple of days or so. (She says they are actually very good indeed once heated up, but they do take perhaps 5 minutes to come up to operating temperature.) Others with far more expertise than I will be along soon I'm sure; but my suspicion is that to have a realistic chance of being self-sufficient for more than a couple of days at any time of year other than high summer, without moving, and without EHU in the UK, you'll maybe want TWO 80 watt panels and a couple of hefty leisure batteries perhaps? Link to comment Share on other sites More sharing options...
lennyhb Posted May 17, 2013 Share Posted May 17, 2013 Need more detail to give a realistic answer, what size batteries have you got? What is your energy usage? Link to comment Share on other sites More sharing options...
colin Posted May 17, 2013 Share Posted May 17, 2013 As bruce say 'how longs a piece of string?', we have a 85w panel and it works for us, but w(h)at(t) is you usage? Link to comment Share on other sites More sharing options...
sambukashot Posted May 17, 2013 Share Posted May 17, 2013 I use 220 Watts solar panels and 2 x 110a batteries that gets me by in the UK, Hope that helps! Link to comment Share on other sites More sharing options...
Mrs T Posted May 18, 2013 Author Share Posted May 18, 2013 Thanks for the comments. This relates to a new VW with a single 110 leisure battery and an 80 watt flexible roof mounted solar panel. 4 days away max. No gadgets. LED lights. Sounds OK to me. MT Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted May 18, 2013 Share Posted May 18, 2013 Yes but at what time of year etc..etc.. It s normal to start with 2 batteries and see how that goes first.... Link to comment Share on other sites More sharing options...
lennyhb Posted May 18, 2013 Share Posted May 18, 2013 As Eddie says when do you intend to use it. Second battery is normally the first option but with solar panels so cheap now it might be worth going down the solar route first. For 4 days in the summer your 110a/h battery might be enough on it's own unless you are a heavy user. Link to comment Share on other sites More sharing options...
crinklystarfish Posted May 18, 2013 Share Posted May 18, 2013 VW may well mean compressor fridge and diesel heater. If so it's there will be more drain than absorption fridge and LPG heater combination. Solar power is rarely the answer. It works well for some but is basically just a feel-good for most... Link to comment Share on other sites More sharing options...
Barryd999 Posted May 18, 2013 Share Posted May 18, 2013 We can last five days in summer on our single 110AH battery with no Solar Panel. Everything in our van is low use though. Gas heater (doesnt use battery), LED Lights, 1.2 AMP TV (Sat uses nothing once tuned in), Gas fridge. I have just purchased a single 100 W Solar panel and I am awaiting the MPPT Controller from overseas to arrive. If I eventually figure out how it all goes together I will let you know how we get on. Our battery drops from 12.7 to 12.2 or 12.1 over five days which is as low as I will let it go. Without getting wound up with all the solar calculators out there I am hoping that a single 100w solar between May and end of September will be enough indefinately but we will see. Link to comment Share on other sites More sharing options...
AndyB Posted May 18, 2013 Share Posted May 18, 2013 Our 85w panel and single 110 a battery are fine, in our coach built so I wouldn't imagine you'll have any problems with your t4. Link to comment Share on other sites More sharing options...
colin Posted May 19, 2013 Share Posted May 19, 2013 Mrs T - 2013-05-18 10:30 AM Thanks for the comments. This relates to a new VW with a single 110 leisure battery and an 80 watt flexible roof mounted solar panel. 4 days away max. No gadgets. LED lights. Sounds OK to me. MT On our old VW we had a 90ah bat and 30w panel, with carefull use in sunny weather it was able to run continuasly. On our present van we have 110ah bat 85w panel, mainly halogen lights, truma heating, not very effiecnt tv with sky digibox and it's been ok using van from march to november. Link to comment Share on other sites More sharing options...
Mrs T Posted May 26, 2013 Author Share Posted May 26, 2013 Thanks again all round, I will report back in 12 months. Mrs T Link to comment Share on other sites More sharing options...
Tracker Posted May 26, 2013 Share Posted May 26, 2013 You don't say what type of heating or fridge you have? The solar panel only works well in very strong sunlight and although it will give some charge even on a dull day and the battery voltage will look healthy, in reality you may well only be getting a fraction of the theoretical maximum 80 watts. If gas operated fridge and heating probably no problem with one battery and solar panel as long as the sun shines by day but if diesel heating and 12 volt fridge then regardless of solar panel you may well run out of battery power after a day or so in winter or typical UK days without sunshine or much light. If you do use diesel heating and/or a compressor type fridge, then I would be thinking in terms of a second battery to make darned sure we didn't ever suffer from 12 volt starvation. I guess you will only know when you use it! Link to comment Share on other sites More sharing options...
Mrs T Posted May 26, 2013 Author Share Posted May 26, 2013 Sorry folks for the mistified replies, its a new one and prpbably still on the production line from the continent. MT Link to comment Share on other sites More sharing options...
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