Work out how much power you will need to get back into the battery over what period of time and then pick a device that outputs about twice what you think you need. At this stage work out how high the mast will need to be to meet the manufacturers specified performance curve and what the average wind speed is for the area. At this stage you will probably give up as most will not be effective unless wind speed is at least 10m/s (very windy!).
I have had a small Rutland wind charger for about 20 years and to be honest whilst it works at low windspeed compared with most makes the output is so low it needs ages to get any amount of charge back into a battery. At best it is useful as an addition to PV panels in the winter. To get anything with a decent output you have got to go big and high and there you will hit another problem and that is planning permission.
If you don't know what you are doing speak to Marlec who make the Rutland wind generators but I think they will advise going for a combined solar PV / wind generator system. Marlec They are probably the best bet for a small system and their wind chargers do work at much lower wind speeds than most. Avoid the cheap Chinese ones as they will rarely work as expected and need very high and steady wind speeds. If the wind is gusty they stall and struggle to restart and therefore the efficiency is terrible.
------------- 'A sure cure for sea-sickness is to sit under a tree'
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thx birder99, it sounds far more complex than i thought, think we may stick to bringing battery home and charging it, lol just need to buy new charger now as mine has seen better days, omg the chargers are pretty complex too, lol
we are on site with NO ehu hun, so we have to bring battery home and charge it up, just need t get a good cheapish charger now, well unless we come across some other way of charging them cheapish
A solar panel is the cheapest option, though Maplins had some 50 watt wind turbines on offer that I was very tempted by, but on offer at £160 still seemed a bit steep compared to the price of a solar panel on eBay. The Link
They were on offer for a good reason - they are crap! Constantly stalling in gusty wind conditions, need high wind speed to generate anything like a reasonable output, need to be mounted high up to get clean wind flow and so on... The idea of the vertical turbine is great but it will take someone with some good engineering skills to get them to work efficiently. A PV panel combined with a low wind speed wind generator is probably the best option if you want reliability in all weather conditions but in summer a PV panel is normally ample if sized correctly to your requirements.
------------- 'A sure cure for sea-sickness is to sit under a tree'
Quote: Originally posted by birder99 on 16/6/2012
They were on offer for a good reason - they are crap! Constantly stalling in gusty wind conditions, need high wind speed to generate anything like a reasonable output, need to be mounted high up to get clean wind flow and so on... The idea of the vertical turbine is great but it will take someone with some good engineering skills to get them to work efficiently. A PV panel combined with a low wind speed wind generator is probably the best option if you want reliability in all weather conditions but in summer a PV panel is normally ample if sized correctly to your requirements.
Glad someone else appears to have bought the t shirt, I already have a solar panel and was seriously considering one of these as most of the power is used at night when the sun is in but the wind blows. I find that even on a cloudy day the solar panel does a reasonable job though in fact the only weather that really stops it in it's tracks is when it's covered in snow.
To keep a battery topped up when the caravan is empty then a small solar panel will be more than adequate.