Hi folks, My apologies for the length of this post but the question of solar power has arisen once more and I'm wondering whether any of you good folk can offer advice on the subject.
Even allowing for the fact that the financial 'payback' period is unlikely to be within my own lifetime, I do feel that there has to be some advantage - if only in terms of pure convenience and reduced genny running time and thus fuel costs. Being a penny-pinching pensioner (who, for the first time in many decades actually enjoyed having his hair cut - at 'OAP prices', of course .. LOL ..) I think its also a double shame that [a] we can't get a similarly reduced tax scheme for petrol - as we presently do for diesel, or [b] government grants for using non-fossil fuel electrical/heating systems - but that is another subject entirely :( Anyway, levity(?) apart, where do you think the 'minimum' line in terms of solar unit(s) sizing should be drawn for a live-aboard? I'm also interested in just how much efficiency is likely to be lost during cloudy, wintry days, when the sun is lower in the sky, and the advisability (or not - apart from the obvious difficulties of enforcing warranties on doubtful goods sourced from China) of buying kits/panels from sources such as Ebay. I presently still run my mains powered refrigerator occasionally (5 amps drawn) and use a mixture of 12v/15 watt fluorescent lights, usually with a maximum of only two ever being on at any one time, and 240v/11 watt low power lighting - although, when I occasionally need a little more light during the evenings I occasionally resort to using a single 240v/40 watt halogen lamp instead. Generally I guess that lighting is on for a maximum of about 12 hours per day. Apart from adding the vacuum toilet pump, the water and shower drain pumps, the only other users of electrical energy I can think of are: # the 3kW inverter - which probably uses as much power to run as I ever draw from it (!) # a 12v 'Maestro' Gas Safe alarm system with three sensors (it originally came with a one amp mains adaptor - although I run it permanently on 12 volts - but I have never actually checked out the current draw) # a 12v ex-car radio/cd player which is on more or less 18 hours a day, and # my laptop, which is fitted with a 19v/3.42 amp power supply and which is used for maybe a couple of hours max per day - maybe slightly more if I watch a DVD in the evening - on average. I've no TV, and no real plans to put one in either yet. The Mikumi 40 domestic water heater/blown air central heating system should, hopefully, be commissioned this week so I can't really add much about that - other than to say, at the present time anyway, I tend to bank up the 'Squirrel' overnight (no back boiler unfortunately) and have yet to feel the need to have an additional source of heat, although the very idea of having the luxury of 'running hot water' is actually quite enticing ..lol! When I need to use/recharge my power tools I will invariably use a 2kw petrol genny - and then take advantage of the extra power to use the electric kettle, toaster, washing machine, slow cooker, etc.; but, with the exception of the washing machine (if I don't plan to return home before running out of clean clothes) these mostly live unused in the back of a cupboard. Without the refrigeration being 'on', my battery bank (4*120a/h newish flooded batteries) lasts around 2 days before it hits 11 volts - which might seem to indicate a minimum average usage of around 80 amp/hours per day. This is backed up by the 40 amp, four stage mains charger taking roughly an hour to hit 14.5 volts before going into stage two. My calculations from the above, however, only suggest a total usage of about 500+ watts over a 24 hour period - unless I am going seriously wrong somewhere :( It seemed to me, albeit it is very early in the morning(!), that I would need about 500watts/6 charging hours, i.e. a bare minimum of 80 (ish) watts (before any corrections due to loss of efficiency), with occasional use of the genny, to maintain my batteries in winter, based on the calculations; and 80amps*12volts (or 960watts) /6 hours = 160 watts (again before any corrections) of solar panel, based on battery performance. (BTW, my electrical power generation is usually via a 2kW genny; as I tend to travel slowly around the system I have more or less discounted any electrical power obtained from the engine whilst underway - especially as I have yet to iron out what may be a problem with the recent 'Adverc' modification to improve the charge rate of the OEM 70amp alternator.) All comments / advice / suggestions based on your own knowledge and experiences of solar panels would be gratefully appreciated - as would any suggestions of reasonably priced (prices seem to vary enormously according to sources and types available) units and/or suppliers of panels/kits, new or second user - I'm not rich enough to be proud .. LOL .. :)) Cheers, Trevor nb 'Wyrd' on the wet above, besides, and below, K&A [Non-text portions of this message have been removed]
