1.5 to 5w solar panel Q&A

Discussion in 'Solar Power' started by Heyupluv, Feb 25, 2010.

  1. Heyupluv

    Heyupluv Read Only Funster

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    Hi Funsters I need a question answering.

    Serious :helpsos:..and Humour :Rofl1:.. Wit and Sarcasm :Angry:..all welcome,

    Because that is what this forum is about, Help and light hearted fun

    Reason for the question...my motorhome (2008 Fiat 130 mutijet new shape) vehicle battery totally ran down flat after being left for about three months winter months NOV,DEC,JAN of no use, due to the immobiliser being on.............somebody mentioned to me to fit one of those small solar panels that are supposed to give out a trickle charge 1.5 w to 5 w...hoping this would be enough to charge the battery back to normal and to compensate what the immobiliser is taking out

    Question 1 :......do they work...............or just a waste of money

    Question 2 :......I was always lead to believe correct or incorrect to charge a battery you needed to remove the battery cable as the diodes in the alternator could be damaged on charging(with a battery charger of coarse on a trickle charge 2amp..4amp )or are these solar panel giving out too small a charge to damage the diodes in the alternator

    Question 3 : if these small solar panels do work would they compensate for the loss of charge / life in the battery..would you fit them direct to the battery terminals...or could the solar panel crocodile clips be connected to the points on the front of the of the Fiat that you would use to jump start,..... or would the loss of so LITTLE ( I emphasize little)electricity..be a waste of time :Doh:...(after traveling through the cables and bodywork of the vehicle before it reached the battery.......

    to remove the battery or the cables is not a possibility as it is needed for the immobiliser, then the radio code, as the motorhome is stored in a barn of a neighbour (no electricity) the motorhome already has a 110amp solar panel but I think that is just for the habitation battery not the vehicle, ...and as it is under a Dutch barn and the winter sun I am afraid if any charge would be little to nothing........if these small cheap solar panel do work I would place one in the front window pointing out hoping to catch a little sun???.

    Answers and suggestions gratefully and thankfully received

    Mel :Eeek::thumb:
     
  2. olley

    olley Funster

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    Hi in the winter, a panel of that size will be useless. You won't damage the alternator, if it could, you would have read about it on here, after all hundreds have been fitted.

    Olley
     
  3. Mick H

    Mick H Read Only Funster

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    Hi Mel,

    Number 1 is the answer. They are a waste of time, even if sited in direct sunlight all day.

    Sorry to be the bearer of bad tidings, but you might already have damaged your battery already. By that I mean that it almost certainly won't be capable of holding a full charge any longer.
    Three months is too long between charges, two or three weeks is the norm, especially when the immobiliser and radio are connected.
     
  4. Heyupluv

    Heyupluv Read Only Funster

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    Olley... You and the other funster Mick H are just confirming what I thought, BUT I had to ask the question not knowing the full facts myself....thank you for your kind reply :thumb:

    Mel
     
  5. Heyupluv

    Heyupluv Read Only Funster

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    Mick ...I have just replied to Olley, and you are both just confirming what I thought, BUT I had to ask the question as the person that mentioned it is quite a knowledgeable person having RVd for many years .....
    The battery issue I understand what you are saying and hope my battery is ok, after a good charge and replaced the vehicle back to the Dutch barn..it started when needed two weeks later in very cold weather in fact snow and ice, and having just done a 5016 km trip to south of France (Atlantic side) and through Spain to Portugal (Lagos, Albufeira, in the Algarve) with Derek (Smudger) and Rodger(Wildman) and back again in three weeks as the weather was that bad in Portugal with rain every day except a odd afternoon of sun..we returned back home to France...........now France and Spain all or most of the water was frozen or turned off due to it being so cold......but the motorhome fired up every time without any problem and ran like a dream......what I am saying hopefully fingers crossed it has not done any damage and my battery has survived this winter....thank you for your kind reply :thumb:

    Mel
     
  6. atakd

    atakd Read Only Funster

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    I've used a 5W panel to maintain batteries over winter on both a boat and a MH and it certainly works. Average daytime output was ~0.5W @ 18V = ~30mA. Not a huge current but enough to compensate for clock, immobiliser etc.
    There's no danger of overcharging if panel is less than 10% output of battery size in Ahs, e.g. a 5W panel must have a battery bigger than 50Ah.
    A couple of things to bear in mind: efficiency falls by 90% if the panel is behind glass ( I pushed mine through a roof vent above the battery box onto the roof) and connect directly to battery terminals so the panel is not switched off.
    I don't think a 1.5W panel would be big enough but 5W will be fine. I agree that your existing battery will probably be kaput .
     
  7. Heyupluv

    Heyupluv Read Only Funster

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    Now Atakd you have just thrown a spanner in the works .....................:Doh:

    thank you for your reply .....Mel
     
  8. olley

    olley Funster

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    Hi Mel, if there's no way you can get power to the motorhome, then you have a couple of choices, visit every week or so and run the engine or a small genny for a couple of hours.
    Buy another battery and swop them over every week or so, taking the other one home to charge it.

    You could of course remove the battery completely and stick it on trickle charge at home, that obviously means your alarm won't work, so that would depend on how secure you felt the motorhome was, wherever you have it parked.

    Olley
     
  9. Heyupluv

    Heyupluv Read Only Funster

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    Olley
    Not so secure :Angry:......quite open :cry:........but it would mean it would have no battery to start the engine unless they use the habitation battery.

    Mel
     
  10. Heyupluv

    Heyupluv Read Only Funster

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    Now removing the batteries.......This asks another question :Blush: .......as I have not found where they are situated yet????....:Eeek:

    The reason is, having not needed to remove or replace any of the batteries .....(2008 McLouis steel 463 130 mutijet, so if anybody knows could you please enlighten me)

    How difficult to remove both vehicle battery and habitation battery.........:Doh::Blush:

    Mel
     
  11. atakd

    atakd Read Only Funster

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    Or use a solar panel:Cool:
     
  12. Heyupluv

    Heyupluv Read Only Funster

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    atakd
    or use a solar panel

    Mel:thumb:
     
  13. olley

    olley Funster

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    Hi just a few figures about a 5w panel, at 100% efficiency your maximum output will be, less than 1/2amp, realistically in summer you might get 3.5w out of it, that's a 1/3amp, in winter? 1-2w? and then only for 8 hours a day max.

    I freely admit I don't have any personal experience of such a small panel, but looking at those numbers I don't see how it could work. I would suggest an 80w bolted on the roof would be much more likely to solve your problem, but at a cost.

    Olley
     
  14. JJ

    JJ Funster

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    Hi Mel and Christine,

    My sources tell me (I have no direct knowledge myself) that the damage done to flat batteries is caused by sulphating which causes the plates to be ruined.

    The same source tells me that the small, solar charger, while being practically useless at CHARGING UP a big, flat battery does create enough "whatever" to stop damage by preventing sulphation taking place...

    Maybe the "Spirits" are trying to tell you to use you motorhome much more often...

    JJ

    PS. Before you disconnect your battery make sure you know the code to your radio. If you have a factory fitted one I understand this can cause a problem when reconnecting...
     
  15. atakd

    atakd Read Only Funster

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    Olley, if anything your figures for the panel are too generous. However, whilst 50mA, the current from a 5W panel operating at 10% efficiency, may not seem much, a car radio in the off position only draws ~5mA. Likewise, the draw from a clock or immobiliser is similarly small so the panel still produces net input.
    I have no doubt about this as my boat comes out of the water for 5 1/2 months over winter and the only means of charging the 2 x 100Ah batteries during this time is a 5W panel - there is no 230V and I can't run the engine out of the water. I have used this system for over 10 years and the batteries are fully charged at the end of this period at 12.8V so it must work.
    BTW, JJWagon is correct in saying that even the smallest charging current will inhibit crystallisation of sulphate on battery plates so if the batteries drop they can still be recovered with a good charge.

    Andy
     
  16. Mick H

    Mick H Read Only Funster

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    Many of the contributors are being economical with the truth.
    The reality is that 1.5 or even 5 watt solar panels, used in the situation that mel described in his original post, WON'T prevent the battery from discharging.
     
  17. Wildman

    Wildman Read Only Funster

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    I wonder how many of the people who have stated 5W won't work have actually tried.
    The beast has 5W panel on the engine batteries (2 x 85amp/hr) and 50Watts on the seperate Leisure batteries. (2x120 anmp/hr) none of the batteries lose charge in the winter. So for me it works, maybe a modern engine with all of its electronics will consume more power as does an alarm. My car battery goes flat in 5 weeks when stored. and my landrover battery and no panel holds the charge sufficient to start it every time all winter, (no imobiliser, clock, or radio) So there you go make your own mind up but as has been said a panel will prevent sulpation in the event of a flat battery. for what is would cost, fit one and fix it to the roof or roof rack. Job done.
     
  18. Heyupluv

    Heyupluv Read Only Funster

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    Roger.. I have taken onboard what you have said with others ......which is best way to go ????:Doh: ....the simplest is a 5 watt solar panel..........the cheapest is to remove both batteries and keep on a small charge and discharge unit (this I already have and use on one of my lawn tractors over the winter period):Doh: :Doh:

    Mel :thumb:
     
  19. pappajohn

    pappajohn Funster Life Member

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    yours maybe do work roger but do you store the beast in a dutch barn over winter.

    this will probably cancel out what meagre bit of sunlight and daylight we do get in winter that MIGHT provide a charge.

    also, with only a few hours per day of weak winter sunlight it isnt going to compensate for 24 hours per day of battery drain via the radio memory, alarm, clock etc.
     
  20. Wildman

    Wildman Read Only Funster

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    The beast is stored in the open and I would expect anyone with a modicum of common sense to realize solar panels rely on light levels storage in a barn will reduce or negate those levels. Luckily most people will think of that (Mel certainly has). I merely pointed out that in general they can and do work.:thumb::thumb::thumb:
     
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