Solar power questions (some are silly!)

Discussion in 'Motorhome Chat' started by DanielFord, Feb 6, 2016.

  1. DanielFord

    DanielFord Funster

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    We have finally got around to booking the van in with VanBitz to have tonnes of things fitted, amongst these are solar on the roof and a 1800w inverter.
    My first question, for all those who have panels and inverters, we will really only use the 220v to power our coffee machine (1400w) possibly the microwave every now and then (it's a 650w, but no idea what it's power consumption is) and the wife will want to use the hair dryer. We will have 2 x 110a leisure batteries, and 150w on the roof. How long is that going to provide power for when off grid? I know that is very much a how long is a piece of string type question.
    The second question, and this is possibly the silly one, how is the fridge going to know to go over to gas rather than use the 220 supplied by the inverter? Do I have to manually select gas?
     
  2. Boringfrog

    Boringfrog Funster

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    One quick answer, your fridge won't run off the inverter/leisure battery.
     
  3. hilldweller

    hilldweller Funster Life Member

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    Don't recall ever seeing coffee machine on an inverter before but is probably the best way to destroy your batteries.

    1400W at 12V = 120A or so for quite a long time, depending on machine type of course. Gas is for Heating !

    A 650W microwave takes about 650W. So a fair old load depanding on what you are cooking. Gar is for cooking.

    Hair dryer, well the only thing more damaging that a hair dryer is the divorce lawyer.
     
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  4. Techno

    Techno Funster Life Member

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    I have 500ah of batteries that only feed my inverter and nothing else. 300watt of solar keep them topped up during the good months.
     
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  5. Tweedie

    Tweedie Funster

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    Hi Daniel if your booked in with VanBitz I would suggest you give them a call to discuss exactly what you want, and what to expect from what your having fitted. Don't be worried about asking them silly questions, they are very good at putting you at ease and sorting out the best solution for you, they don't bite :LOL:. I can vouch for that am not at all technical and had to phone them with a very basic query, Ash soon put me on the right track. Am sure you will be very pleased with their quality of work.
     
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  6. DanielFord

    DanielFord Funster

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    It's one of those pod machines, so it is only powered up for about a minute. We are coffee snob! :D

    (y)
     
  7. DanielFord

    DanielFord Funster

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    I'll run all these questions by him, but I was also looking for experiences from everyone who has such a system as well. :D
     
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  8. JeanLuc

    JeanLuc Funster

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    As Brian says, the more heating you can do with gas, the better. The coffee machine will take almost 120 amps and in good sunlight (i.e. clear skies in high summer) you might get 8-10 amps from the panel in the middle of the day - assume a generous average of 8. So, your coffee machine alone will consume electricity 15 times faster than the panel can restore it. That means that if the coffee machine is on for 15 minutes or so, you will need about 4 hours of sunshine to replace the current used.
    A stove-top Bialetti Moka Express is a less power-hungry option!

    p.s. just seen your later post - I did not realise a pod machine needed to be switched on for such a short time. My Gaggia traditional machine needs 10 minutes to get the brewing head good and hot (at home of course).
     
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  9. Doctor Dave

    Doctor Dave Funster

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    You may well find that your inverter won't run the microwave as its start up current could be well over 1400 watts - I assume the inverter is PSW?

    Dave
     
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  10. hilldweller

    hilldweller Funster Life Member

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    That sounds doable. A proper cappuccino machine would be a different matter.

    Basically the energy stored in gas is huge, in a lead acid battery quite small.
     
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  11. Don Quixote

    Don Quixote Funster

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    I have 3 x 110 batteries, 200watts of solar, 1800w pure sine wave ( you will need this for coffee maker ) and a B2B charger. I can go for weeks/months without EHU, but do use EHU when it's in the price of a site.
    I draw on average per day 25amps and 95% of my time is off EHU. In Spain on a good day I can have fully charged batteries by 14:00hrs using a good MPPT solar controller. In France and UK I cannot replace the amps taken out via solar because of the lack of full sun. This is were the B2B comes into use. I can have fully charged batteries after 30/40 minutes of engine running. Now the coffee maker will draw loads of amps from your batteries and the hair dryer will be the same. I can use a coffee maker, but chose to use a simple cafetiere, which works for us.
    You are going to the best man to advise and I'm sure Eddie will sort out your requirements.
     
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  12. Techno

    Techno Funster Life Member

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    This will be on the specification plate near the cable entry on the back. A 650watt will probably draw about 950 tops.
    From memory my 850watt panasonic drew 1100
     
  13. Robert Clark

    Robert Clark Funster Life Member

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    We have a similar set up to you fitted by @Vanbitz

    We have a 2kw Victron inverter/charger which powers on a daily basis;
    Nespresso machine
    1200w hair dryer

    We also have a mini washing machine and a Dyson vac which we use less frequently

    We have 4 80W Gell Batteries, 2 x 100w solar panels, and a B2B charger

    We've just come back from a winter trip to Spain
    When not travelling (using the B2B charger) we can go for about 2-3 days using the hair dryer and Nespresso
    Its useful to go onto hook up and fully charge the batteries when you have the chance
    We're also now turning off the inverter when not in use
    We also charge all our phones and ipad from the 12V circuit when driving

    Hope this helps?
     
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  14. hilldweller

    hilldweller Funster Life Member

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    Just looked up the numbers.

    1kg of Butane contains 50,000,000Ws = 50E6 / 3600 = 1400Wh of energy.
    100Ah x 12v = 1200Wh.

    But a tank of gas is 20Kg so over 40 times as much energy on tap.

    I rest my case.
     
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  15. hilldweller

    hilldweller Funster Life Member

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    Pandora meet Box, Box meet Pandora. You naughty doctor, you.
     
  16. The Wino

    The Wino Funster

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    Could you put hot(ish) water in the coffee machine it would use quite a bit less power to heat the water up
     
  17. funflair

    funflair Funster Life Member

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    If you can get more solar up there I would, we have 320 watts and sometimes we still get next to nothing out of it, if you have plenty of spare solar a Votronic solar regulator will run the fridge on 12volts with it, regarding the fridge if it's on "auto" it will try to run off 240 volts when the inverter is on so you will need to switch it manually to gas if you don't want it to, but for the few minutes the coffee machine will be on it would not hurt.

    We run all the bits of kit that you want to and it all works fine, as others have said inverter needs to be pure sine for the coffee machine, some people say use gas but the sunshine is free so why not use that and it's so much easier to warm milk in a mug in the microwave than mess about with a pan and then have it to clean, rice in a bag only takes a minute job done.

    Martin
     
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  18. funflair

    funflair Funster Life Member

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    We have been in France and Spain for two weeks now with not the best of sun and we have made 400ah from 320 watts of solar feeding 4x80 ah gel batteries, we have run this set up but with only 2x80 ah gel batteries for nearly 4 years and the batteries were a few possibly 6 years old when we got the van, so if the inverter kills your batteries buy better ones next time, EXIDE gel's.

    Martin
     
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  19. DanielFord

    DanielFord Funster

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    Yes, Ash went into great detail about why I needed one, so I just got my cheque book out :D
     
  20. Lenny HB

    Lenny HB Funster

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    ech
    Panasonic microwaves use inverter technology and only draw about 30% more that their rated output at start up, cheap microwaves usually draw double their rated output at start up.
     
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