How many panels is safe

Discussion in 'Solar Power' started by UK Pete, Jan 18, 2014.

  1. UK Pete

    UK Pete Read Only Funster

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    Hi, my van has 1 x 135w solar panel, and two 110amp lesuire batteries,
    at the moment i have a pwm solar controller which looks small and cheap, anyway here are my questions, can i mount 2x 80w panels in addition to my existing 135w panel and use this mppt http://www.ebay.co.uk/itm/140661388530
    I was also going to add another 2x 110ah batteries making 440ah total so that i have the solar power and battery bank capable of powering all my stuff which i am hoping will include an inverter and microwave in the near future
    Basiclly i want to be self sufficient for power most of the year
    At the moment i can get two days running a tv , lights, compressor fridge, thermotop heating/water, and laptop, then i have to start the van and charge up using the sterling bat to bat charger, i would like to be able to do at least 4 days and hopefully more in sunny summer conditions
    All suggestions welcome
    thanks pete
     
  2. Snowbird

    Snowbird Funster Life Member

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    I have 330 amp battery bank, charged by 250 watts of solar. I can sit indefinitely with this in summer without hookup. I have a wind generator for when the sun is not shining. I also have a solar tracker that is ready to be fitted when we have time. This will hopefully make it possible to manage without hookup in winter.
    PS, I carry a Kipor generator to help Old Mo out when he is stuck for power :RollEyes:.
     
  3. ShiftZZ

    ShiftZZ Funster Life Member

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    Have you considered the extra weight?

    I have two 100 w solar and 2 110 ah batteries, along with all LED lights and have so far never run out...

    Microwave, may be a problem, I think other will be able to better inform you...
     
  4. Mikeco

    Mikeco Funster

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    I'm just surprised that you have the roof space on a van conversion unless you have no rooflights.

    Mike
     
  5. Techno

    Techno Funster Life Member

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    Safe in what respect?
     
  6. bobandjanie

    bobandjanie Funster Life Member

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    Hi, you have to way up, how you are going to use the van.
    We tour in the summer, but in winter normally on a site. :Smile:
    So our last motorhome had 2 x 113ah leisure batteries and a 80w panel, moving every 4 or so days no problem.................................but we had some disappointing days when the sun never appeared. :Doh:
    And thought about covering the roof with panels at 10kg each, or buying a Honda eu 1.0 generator that worked whatever the sun decided to do. :Laughing: That's the way we went.

    When we changed to a panel van conversion and a caravan for long stay, we went through it all again. :RollEyes:
    This time the van is our only vehicle, so moves more often, when we here in Spain if it does not move for a while it gets plugged in, when we leave here we will be touring moving on every few days. :thumb:
    So we have 3 x 85ah leisure batteries, and a stirling battery 2 battery 50amp charger, and that seems to be working for us. :BigGrin: Bob.

    Sorry I meant to put the weight of all your batteries and panels, I would say the 4 batteries would be getting on for 100kg and another 10kg each panel.
     
    Last edited: Jan 18, 2014
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  7. UK Pete

    UK Pete Read Only Funster

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    Is it safe to use the ebay mppt http://www.ebay.co.uk/itm/140661388530
    with two 80w and one 135w panels, also now as mentioned by shiftzz, i have to consider the extra weight, something i have not thought about

    I have read several of your posts Techno100 , your definetly the man in the know, perhaps you might be able to advise me if i would be wise to carry out my intended upgrades, reading through various posts it seems like i need 4 batteries and so about 300w of panels to maintain /recharge the battery bank, so i can safely run with a microwave with a 1500w inverter,
    pete
     
  8. Techno

    Techno Funster Life Member

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    Yes the regulator is 300 watt rated. I run mine with 300 watts, you will be within that.
    Yes the weight is a MAJOR consideration.
    Will they fit?
    Will you have any room left at all for anything else?
     
  9. UK Pete

    UK Pete Read Only Funster

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    I have thought about the generator side of things, but then i suppose using my engine and sterling batt to batt is more efficient
    my set up as it is should be good in the sunny summer months , it is not to bad now really, my thing is i reallly want an microwave oven, but when you add up the cost of everything i need to make it work it becomes an expensive option, and as pointed out a huge weight increase bearing in mind i will have a motorbike on board as well, however i am still running through the options, maybee only 3 batteries and one less panel than i was thinking,
    i need to hear from someone who runs a microwave to see what works best
     
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  10. UK Pete

    UK Pete Read Only Funster

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    Ok thats the regulator sorted,
    i do have room for two more 80w panels, even with the 4 roof windows and vents and existing 135w panel, so room is not the problem on the roof, it will be a bit tight finding a spot for the micro inside though
    as for weight, perhaps reduce the batteries to 3 and reduce the panels to two , so that will be 330ah battery bank and 215w solar panels, maybe that will meet my demands?
     
  11. Techno

    Techno Funster Life Member

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    We don't have a microwave on this install but we use the kettle /hairdrier/ toaster
    all are circa 1350 watts which is more than a 750/800 microwave will pull (1100 ish)
    I have 300 watts simply because I have room and payload and winter light is less productive so it gives me the best I can get with no negatives.
    If I had to choose between more solar or more batteries to extend play time it would be batteries but bear in mind they need hooking up to recover.
    My own system is pretty well balanced for all year and I have surplus for 7 or 8 months of that.
     
  12. seanoo

    seanoo Funster

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    "If I had to choose between more solar or more batteries to extend play time it would be batteries but bear in mind they need hooking up to recover."


    do you mean in bad weather . if you had a few good sunny days your batteries would be fully charged again without the need for a hook up? cheers sean
     
  13. funflair

    funflair Funster Life Member

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    Hi

    We have only 160 ah of battery and run 2kw inverter for microwave coffee machine hair dryer etc, when the 320watt of solar panels have some summer sun on them there is no problem keeping fully charged in a field for weeks on end but in the winter its a different story as the inverter would take out more than we can put back. When these batteries need replacing i would add an extra one making total 240 ah and was thinking about a fuel cell for the winter/dark days. this is a new fuel cell not on the market in the UK yet but lots of dealers on the continent, cost is 3200 euro plus fuel and fittings.

    http://www.dynad-hydromax.com/en/

    Martin
     
  14. Techno

    Techno Funster Life Member

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    As Martin said
    If you heavily discharge a large battery bank at this time of year the solar is not enough. There are often periods of a week of grey days, it is not good for the batteries to be left depleted like this.
     
  15. seanoo

    seanoo Funster

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    good job i'm in spain then !! had 10.5 amps coming in from my 210 watts of solar today at lunchtime . i have 375 ah of batteries (3 alphaline dc31's) and my 130 watt panel tilts to get the best from the low winter sun . cheers sean
     
    Last edited: Jan 19, 2014
  16. UK Pete

    UK Pete Read Only Funster

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    Thanks everyone for your input, , i am going to do the maths as best as i can to establish my current payload, the van has a 1.55 tonne /1551kg payload as standard, i will see if i can take it to a weight bridge or something to see how i am at the moment,
    If weight alllows then my power system willl be as below

    4x110ah batteries
    sterling battery to battery charger
    1x 135w+2x80w = 295w solar panels
    PCM3012 25A MPPT solar charge controller

    Things i will need to power below

    12v Waeco cr50 compressor fridge
    15 inch lcd tv
    8x LED spot lights
    circulation pump on diesel water/ interior heating
    Fan blower for occasional heating
    Shower/ sink pump
    usb powered sound system connected to tv
    Satelite system
    phone charging

    I have yet to decide wether to get an inverter and microwave, the only reason i wanted this was my van has no oven so my cooking is just grilll and 4 hobs, which restricts what i can cook, coleman used to do a hob top oven which was ideal for heating pies etc, unfortunately they no longer sell them however i might attempt to make a smallish hob top tin oven, or some sort of dutch oven then i will have no need for a power hungry inverter (any suggestions on this welcome)

    so to sum it up if i opt for my above power system, and dont bother with inverter and micro, i recon i will have plenty of power, and no need for hookups if going away for trips up to two weeks my camping season being spring till early winter




     
  17. Peter_n_Margaret

    Peter_n_Margaret Read Only Funster

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    I have a somewhat different view.
    It starts with the premise that you can't have too much solar. This is especially true when the weather goes pear shaped.

    On the other hand, extra batteries are not much use if you can't recharge them, so you need an alternative charge system. That might be a decent alternator link or DC-DC charger, a fuel cell or as a last resort, a generator.
    If you have that alternative, it may as well be used instead of carrying an extra half tonn of batteries.

    Our Oz MH has 600W of PV and 460Ah of batteries.
    The MH in Europe has 425W of solar and 260Ah of batteries.
    I would not consider a microwave with either, but we do run electric blankets and small electric jug and 2 compressor fridges etc etc in Oz.

    The other point to note is that while the sun is shining, the power developed by the PV panels feeds the loads first, before charging the batteries, if there is some left over. This means that in good conditions, you can still often use power that the batteries can't store.

    Cheers,
    Peter
     
    Last edited: Jan 21, 2014
  18. UK Pete

    UK Pete Read Only Funster

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    I agree that you can never have enough, i have thought about my situation for a good few days now and have concluded that i will get as much solar as i can fit on my roof, and enough battery power for my needs, the battery to battery charger will help me recharge as i intend to move around every2 -3 days
    i do have a geny but i dont want to upset peoiple using such a noisy thing and also if wild camping draw attention to myself
    my van when at home is on permanent hook up, if i go holidaying in it with my missis i will probably do electric hook up, so i only need to be self sufficient when wild camping on my own or on cheap basic facility campsites, so i recon 440ah batteries and 295w solar panels will see me alright, i only want a micro for heating up the odd pie or micro meal, usually 3-4 mins cook time so the drain wont be to bad, if i could find someone selling the double skillet pan set then i could use that for my pie heating that way i would not need the micro, but i would still like to have an inverter and big battery set up for other 240 needs when they arise
    pete
     
  19. hilldweller

    hilldweller Funster Life Member

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    We manage 4 days on 110Ah using gas cooking and heating. So do you need solar at all ?

    Is all this just for the microwave ?

    Gas is the best energy for cooking and heating. You can store masses of energy in a small space and refill in minutes. Do you have refillable gas ?
     
  20. UK Pete

    UK Pete Read Only Funster

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    Hi Brian, i have the gas plumbed in so i can fill up with lpg at petrol garages, but the only thing in my van that uses gas is the hob and grill, the heating and water is diesel powered everything else is 12v, at the moment i can get 2-3 days from my set up which is 135 solar panel and 220ah leisure batteries, but as i expand my 12v set up there is need for more power, it is not only just for the micro although that is what started me off wanting more
    pete
     
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