panel wiring with battery

[OlivierYunnan]

Hello,

I am currently building a small photovoltaic installation. I did some research on it, and on how to wire the different elements but I only have very limited notions of electricity, and I do not know if the diagram I thought hold the road or not ... Thank you very much for your opinions.

Here is the situation

I live in an area where there are regular power outages, which can sometimes last.

As I do not have the immediate means to buy enough panels and batteries to cover all of my consumption, the idea at first is at least to have a minimum of current during cuts , even if they occur at night or on days without sun, and therefore to have permanently charged batteries just in case.

However story of not using my solar installation THAT during cuts, I would like to be able to use it the rest of the time, while keeping the safety batteries full.
(In the future the idea is to increase the number of panels / batteries to be completely autonomous)

So I thought of this scheme:



The idea is to charge 2 sets of batteries, one for everyday use, the other for safety.

The current batteries are connected via a 220V converter to an automatic switch: When there is a battery, it is used, when there is no longer the switch switch on the 220V network.

In the event of a power cut, and if the main batteries are empty, the switch (in red, above "24V - 220V") is manually switched to use the safety batteries.

Is my scheme right and can it work like this?

Thank you for your help!

Olivier

[Forhorse]

There are a lot of LEDs for a lot ...

Already those on the side of the panels are useless, you might as well wire the panels in series on a MPPT type regulator (which accepts the VOc voltage of the string thus formed and which is intended for 24V batteries naturally)

Then those between the regulator and the batteries will make the regulator simply not work because it will be unable to measure the voltage of the batteries.

At the output there is at least 1 extra, on the backup batteries I would not put any, it is useless.

1 diode = loss of energy which can quickly become significant in this kind of small solar installation.

But hey, rather than all this gas plant, I would just put manual inverters.
And if not, there are battery couplers / separators for camper cell batteries.

After in terms of the starting postulate, that is to say to have two sets of batteries that are discharged in turn rather than a single big one that would be able to cover the consumption over a typical period of a cut, I'm not sure it's the right choice.
In the end, if it is absolutely necessary to have an energy source after a very long cut, a generator seems to me more suitable (a photovoltaic installation for short cut, and the group takes over in the event of a much longer cut, even take it bigger to be able to recharge the batteries and avoid having the group running 24/24)

[OlivierYunnan]

Thank you very much for this detailed response!

For the diodes of the panels, the had put them to avoid that current passes from a panel to the other in the case where for example a panel would be shaded ...

Can we really do without it?

(I prefer to keep the panels in parallel, because finding regulators here that support more than 24V is difficult is very expensive, and I intend in the future to add other panels, staying at 24V total)

Otherwise I have reviewed the diagram with your advice:



I put a coupler / separator in place of the 2 original diodes.
And replaced the output diodes with a manual inverter.

does it seem ok like that?

For the basic postulate, in fact the idea is to use the solar to the maximum (for the moment with 2 batteries, which I intend to gradually increase), and to automatically switch to the network when I have more battery (the auto switch will be given priority over batteries).

Only if a power outage occurs when I have very little battery, I find myself with nothing. In this case I can switch to the backup batteries, limit my electrical consumption, and have at least light and a minimum of current while waiting either for the batteries to recharge or for the current to come back ...

[chatelot16]

the more a battery works at low power, the more its efficiency increases and the less it wears out, both when charging and when discharging

it is therefore better to use all the batteries at once, than successively one then the other

it is therefore better to put all the batteries in series and put a 48V 220V inverter

for reliability we can wonder what happens if one of the batteries is faulty: the ideal would be an inverter capable of operating at reduced voltage: if a 12v battery is dead, we delete it and we run at 36V: many inverters are theoretically capable of doing so given their power circuit, but there is no possibility of adjustment to do so

now there is no illusion: if there is already 220 available lead acid batteries at normal prices are never profitable

when we divide the price of the batteries by the energy stored over the foreseeable lifespan of the batteries, we come across a price comparable to the price of EDF electricity: therefore no interest ... and even risk of loss if the battery lasts shorter time

currently a system with battery is profitable only in front of the price of electricity of a generator: therefore for isolated site where it is impossible to have EDF

with the EDF forget the batteries, use solar energy only when you can consume it directly and let loose stupidly if there is too much

organize its consumption to make the maximum number of devices run as a priority when there is sun: freezer, washing machine, pool pump ...

this non profitability of the batteries is not definitive: it will be possible to manufacture cheaper batteries ... and the price of electricity will continue to increase

[Gaston]

with the EDF forget the batteries, use solar energy only when you can consume it directly and let loose stupidly if there is too much

organize its consumption to make the maximum number of devices run as a priority when there is sun: freezer, washing machine, pool pump ...

All of this is correct, except that OlivierYunnan seeks above all to be autonomous during EDF blackouts ...

[chatelot16]

when the goal is mainly a backup power, we leave the battery quiet so as not to use them to store electricity, so with this shema the solar panels would only be used when there was a power outage to drain the battery ? pity

when the goal is a backup power supply, it is better to make the photovoltaics profitable by injecting 220V into the network to compensate for part of its consumption

Conversely when there has been a power cut and the batteries are discharged, you must also have a charger on the 220V to recharge as soon as the 220V returns and be ready to withstand another cut without waiting for recharging by the sun.

Finally I speak as for a usual emergency power supply where breakdowns of 220V are rare ... it could be otherwise in a place where cuts are very frequent, or in a place where the electrical network is very expensive

to answer exactly all the data count to choose the scheme