Tips before purchasing a solar panel.

[ptijean32]

Hello everyone ... here it is simple ... I want to produce electricity via a monocrystalline type solar panel, with 10 Amp regulator, a 500 watt inverter ... and of course one, see two, maybe three special battery for solar. I saw on a brand x that a panel of 100watts monocrystalline can provide up to 600watts / h / day ... so in my logic which is not at all a reference, rather naive by the way ... So I thought I could therefore supply a source of a consumption of 400 watts over about 20 hours / day ... that's my goal ... is there anyone who can enlighten me on the choice of my panel?

[dirk pitt]

if you know how to multiply and divide, you should be able to get by on your own but for that, it must be clear at the level of the units and the notions of power and energy. so I'm giving you a little reminder.

power is expressed in watts
an energy is a power for a given time and it is expressed in Wh and not W / h as we see too often.
so if a solar panel delivers a power of 100W during 6 hours of sunshine, it will have "gathered" an energy of 600Wh
it's quite optimistic for a day with a 100W panel.
the maximum power of a panel is only obtained when the panel is perfectly perpendicular to a large sun and with a temperature of 20 °. in reality, it is not oriented optimally and its surface heats, reducing the yield. you can count between half and 2/3 of the maximum power (on average) for 4 to 5 hours of a beautiful day.
it would rather be 60W x 5h = 300Wh per sunny day.

that’s for the part that has won. that goes into batteries.
the batteries have a voltage in V and a capacity in Ah by multiplying one by the other you get the total capacity of the battery in Wh

the same consumer side. if your device consumes 400W for 20 hours continuously, it needs 8000Wh ....

voila, play with the numbers.

[Did67]

Agree with Dirk.

You add 10% loss to storage. And you have the main elements of the equation.

Basically, without big calculations, your problem will be simple: there are times 4 times, sometimes 8 days without sun ... In winter, you will have great need, but the sun, if it is there, is done stealthy!

So in fact, you should not store the need for a day, but the need for "a certain number of days" which depends on the area where you live (average sunshine) and ... climatic hazards.

So even knowing the elements of the equation, you will still have a share of bets! Because the sun is unpredictable!

It's all the joy of solar!

And the reason why this is best conceived in an "intelligent network", in combination with other sources, which one erases when there is sun, that one relaunches when there is no more.

Playing "solo" is possible, with monstrous storage only! Or with a lot of stoicism (doing without electricity "for a while").

[ptijean32]

Thank you to both of you ... there I believe that I have my answers ... indeed, I'm much too naive and I would have planted myself for my purchase of the panel ... I already have a 10w, battery, regulator and inverter ... which is used for lighting in a converted truck. I already know the concern of the sun, the exposure, the problems with bad accumulators .... in short the initiation to solar passes through these hazards ... but I have already lived for 5 years without solar at l using candles suspended in canning jars ... you see the change that brings me the sun ... I can read without tiring my eyes! .... and yes ... progress is good clever ... compatriots, thank you.

[ptijean32]

Thank you to both of you ... there I believe that I have my answers ... indeed, I'm much too naive and I would have planted myself for my purchase of the panel ... I already have a 10w, battery, regulator and inverter ... which is used for lighting in a converted truck. I already know the concern of the sun, the exposure, the problems with bad accumulators .... in short the initiation to solar passes through these hazards ... but I have already lived for 5 years without solar at l using candles suspended in canning jars ... you see the change that brings me the sun ... I can read without tiring my eyes! .... and yes ... progress is good clever ... compatriots, thank you.

[chatelot16]

we must add the main: a lead-acid battery wears out especially when it is flat ... you could even say that it self-destructs when it stays flat for several days in a row

so it is essential to do everything to never completely discharge a lead-acid battery ... otherwise the good intention of saving energy turns into wasted battery

hell is paved with good intentions

[ptijean32]

Yes about the batteries I know that you have to adapt to the choice provided ... moreover I will ask you again. To date I have not done my calculations to have my answers to my needs regarding only my panels ... remains the batteries, the regulator and the inverter to be adapted ... but it is up to me to do this taf ... you have largely guided me on the subject of watts ... and I am largely convinced of solar ... I also charge my phone and my tablet via a light portable / flexible 3watt depending on the weather .. .but winter is often not possible !!! ... and yes the joys of autonomy often fade in winter ... thanks to you ... long live the sun .... and long live the wind ...

[ptijean32]

Yes about the batteries I know that you have to adapt to the choice provided ... moreover I will ask you again. To date I have not done my calculations to have my answers to my needs regarding only my panels ... remains the batteries, the regulator and the inverter to be adapted ... but it is up to me to do this taf ... you have largely guided me on the subject of watts ... and I am largely convinced of solar ... I also charge my phone and my tablet via a light portable / flexible 3watt depending on the weather .. .but winter is often not possible !!! ... and yes the joys of autonomy often fade in winter ... thanks to you ... long live the sun .... and long live the wind ...

[ptijean32]

Hello to you and thank you for the data you sent me ... this is light for me! ... hihihihi .... in short, actually after calculations it turns out that the budget for solar panels is too large for me ... in the long term this will be considered ... therefore, I move to another solution ... but other technical questions arise ... so if I use a lead battery of 100Ah of 12v, my power will be 1200 watts .... but what does that mean ??? ... with my 400w consumer, I empty my battery in 3 hours if no additional charge? ... and if I therefore use 7 batteries 100w in // of 12v, it will take me 21h to discharge all of them? ... moreover, I do not know if a 400w inverter exists, but it is better that I buy one of higher power ... a 500w, a 750w ??? ... the use of an inverter consumes energy, so you have to plan a little more battery? ... short ... you see, I am really uneducated in the matter ... and thank you in advance for your vote re understanding ... good to you ... thank you.

[ptijean32]

Hello to you and thank you for the data you sent me ... this is light for me! ... hihihihi .... in short, actually after calculations it turns out that the budget for solar panels is too large for me ... in the long term this will be considered ... therefore, I move to another solution ... but other technical questions arise ... so if I use a lead battery of 100Ah of 12v, my power will be 1200 watts .... but what does that mean ??? ... with my 400w consumer, I empty my battery in 3 hours if no additional charge? ... and if I therefore use 7 batteries 100w in // of 12v, it will take me 21h to discharge all of them? ... moreover, I do not know if a 400w inverter exists, but it is better that I buy one of higher power ... a 500w, a 750w ??? ... the use of an inverter consumes energy, so you have to plan a little more battery? ... short ... you see, I am really uneducated in the matter ... and thank you in advance for your vote re understanding ... good to you ... thank you.