Solar panels and battery - any real world reccomendations?

b0rn2sk8 said:
This is my best paint mock up of what you'd want ideally:

iEUeav0.jpeg


The light green CT clamp enables you to change from solar if you want.
The dark green CT is for your battery so it doesn't cover the CT charger but covers your solar and house so it can charge/discharge properly but not discharge into the car.
The yellow CT is 'if fitted/needed' in the case you have an export limit and your solar inverter needs to curtail its output.

EDIT: of course the battery, solar and house can be combined into 1/2/3 consumer units, that doesn't matter as long as there is physical separation to the EV charger to get that CT clamp on for the battery.
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One more thing, just to be clear in my head, the dark green CT clamp shuts the battery down, if it flows to the left. It can only flow to the house?
Therefore I cannot export/sell my battery to the grid?
 
rodders said:
One more thing, just to be clear in my head, the dark green CT clamp shuts the battery down, if it flows to the left. It can only flow to the house?
Therefore I cannot export/sell my battery to the grid?
Click to expand...
The dark green CT clamp will monitor everything to its right (power draw and export), so the house, solar and battery. It will fill any power draw coming from the house and capture any excess solar going out towards the grid.

It will not cover anything to its left - the EV charger.
 
You can export to the grid.

All the CT does is measure the flow of energy, the battery decides what to do with that information based on how you have programmed it.

The key point of the above set up is that you don’t want it to include the EV charger in that measurement or it will fill that demand as it can’t differentiate it from the house loads.
 
Ok, think I get it, but also raises other questions.

If I say to the battery, don't export 0000 to 0600, whilst the car is charging, the battery will only charge?

But if OIG decides to charge the car 2000 to 2100, then 2300 to 0000, that will drain the battery?

But then I guess that doesn't matter, as from 0000 to 0600, the battery will then charge again at the cheap rate.

Am I getting it? Lol
 
rodders said:
Ok, think I get it, but also raises other questions.

If I say to the battery, don't export 0000 to 0600, whilst the car is charging, the battery will only charge?
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Only if you tell it to charge at those times.

If you are on IOG, charge daily to 100% at 7p and export solar to the grid at 15p (assuming you are not on FIT).

rodders said:
But if OIG decides to charge the car 2000 to 2100, then 2300 to 0000, that will drain the battery?
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If the wiring is set up like above, the battery will not discharge into the car because it can’t ‘see’ that the car is charging (I can only ‘see’ everything to the right of the dark green line).

rodders said:
But then I guess that doesn't matter, as from 0000 to 0600, the battery will then charge again at the cheap rate.

Am I getting it? Lol
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Sort of :p

It does matter because you can get slots out to 6, 7, 8am and if the car charges and you don’t have the writing set up line the above, you’ll wake up to a empty battery as the fixed cheap slots end at 05.30. The extra slots on IOG are random and can change in the night at any time.

You can use third party software like home assistant to charge the battery whenever you get an extra cheap slots end but unless you are techy, it’s not recommended. Otherwise you are best to leave it to charge between 23.30 and 05.30.
 
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I am on FiT, but possibly will change as you get a bit more money exporting @15p

Not massively interested in the HA stuff at the moment. Maybe one day.....

Will just do charge 23:30 to 05:30 and keep it simple!
 
With FIT you want to maximise your self consumption so that probably means only charging to full in winter, less in spring/autumn and not charging in summer at all.

You can always soak up excess into the car also.
 
Yeah, it will be a bit off a trial and error. But was thinking june to sept maybe just rely on the solar to charge it and soak up any little grid consumption at the current rate if needed.
 
b0rn2sk8 said:
With FIT you want to maximise your self consumption so that probably means only charging to full in winter, less in spring/autumn and not charging in summer at all.

You can always soak up excess into the car also.
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No you don't.

There is two parts to the FITS payment.

The generation payment.
The export payment.

Usually it is far more cost effective to do away with the FITS export payment, especially if you have batteries, and move that side to general exports, like Octopus export at 15p kWh, that's roughly three times what you get paid in FITS export

You still keep the generation payment.

I did this as I added more solar and batteries, I always charge my batteries overnight at 7p, and then any excess solar is exported for 15p, also pointless putting it in the car, as it's cheaper to charge overnight.

There are some exceptions, if your export power is limited for example.
 
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To start with on FiTs to consume as much as I can would be best.

If transferring to octopus export, yes your scenario is better.

One step at a time!
 
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