Ronski's Solar & battery DIY build with whole house backup

I think I've finally updated my Node Red to handle random slots.

I have my system discharge the house batteries between 19:30 and 23:25, it will then charge them between 00:00 and 05:30.

Discharging and charging is not at full power, it calculates the rate so that it reaches the desired target at the end time, this is better for the grid and my equipment.

I've now modified the flows so that in a EV charge slot outside the above charging periods it will charge the houses batteries at a fixed rate, taking into account AC loads, so the batteries never discharge to the EV.
 
Making progress on the heat pump install, weather was rather wet yesterday so I made up the shuttering frame for casting the strip foundations.

Today I got the condensate drain in, and the sub base in and tamped down.



Frame fits, and sub base at the correct level, all ready for concreting next weekend, weather permitting.



The frames been removed for the week so the rain doesn't damage it (its only cheap furniture board), but next weekend I'll fit it in position, and make sure it's absolutely dead level prior to filling the two outer sections with concrete - glad I have a mixer!
 
Good work, quite possibly a bit overkill to hold a 100kg heat pump.

That said mine is not much different, they just used pre-formed concrete blocks on some compacted type 2 to hold the heat pump. The type 2 is covered with some shingle to allow the water to drain away.
 
I've pretty much followed the instructions from Vaillants installer manual, I just didn't dig the complete hole to 700mm deep (that just seemed crazy), just the area where the condensate drain is.

 
b0rn2sk8 said:
Good work, quite possibly a bit overkill to hold a 100kg heat pump.

That said mine is not much different, they just used pre-formed concrete blocks on some compacted type 2 to hold the heat pump. The type 2 is covered with some shingle to allow the water to drain away.
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Octopus are doing mine aswell so have just said to prepare the area - though haven't really elaborated on what they want. Its just grass right now so I guess I'll just dig that out or something. :p
 
My installer just sent a drawing of a plain slab 1200 x 900, it didn't even show where the drainage went for the condensate, just said it was required. It was also not clear what thickness they wanted, as it gave two measurement's, 150mm and 200mm, presumably one was concrete, the other the sub base.

So I decided that the strip foundations that Vaillant specify would look better, so that's what I'm doing.
 
If the soak away doesn’t work, you could just whack it on a drip tray and go into that downpipe.

That said, it’s next to a lawn, it’s not like there is any danger of you creating a huge ice rink on a patio.
 
200sols said:
Digging down to 700mm is ridiculous!
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Its worst than that, if you are in an area with a ground frost, you're supposed to dig the entire hole down to a minimum of a 1 meter, so that would be 1400 x 700 to a depth of at least 1000mm, then in fill it with sub base material to 300mm below the surface :cry:

Somebody at Valliant needs to revise the drawings/instructions, as they seem way OTT, but I suppose they are for worst case scenario's.

The bit I dug down to 700mm was really easy, a few spades, I actually didn't intend to go to 700mm, I put some gravel in, then bedded the down pipe in, and surround with more gravel, like a vertical french drain.

b0rn2sk8 said:
If the soak away doesn’t work, you could just whack it on a drip tray and go into that downpipe.
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The soakaway will be fine. Without it, on a cold winters day, not that it gets that cold here anymore (I remember when the sea froze locally many years ago), but in some areas you would get a build up of of ice, not really a problem where mines located, but given a long enough cold spell it could build up substantially.
 
Have you got IoG up and running now and are your automations handling the random times the car can start charging ok?

todays sunny day reminded me of something I found out the hard way. I'm very much in the habit of plugging in the car when getting home from any journey and when its a nice sunny day like today, Octopus will kick on the car charger in the middle of the day and 'steal' your exports.

The lesson you'll quickly learn is to not plug your car in during the day when you are exporting solar generation.
 
Yes, its all up running. The house batteries are scheduled to charge midnight to 5:30, it calculates the charge rate so they reach 100% at 5am, then the last half hour is used for balancing. The reverse happens in the evening for discharge, from 19:30 to 23:25 it will calculate on the fly the discharge rate, so it reaches 15% SOC by 23:25.

When it detects a dispatch, it will stop discharging if its discharging, and it will then charge the batteries at 4kW, so everything is drawn from the grid during a dispatch.

b0rn2sk8 said:
Octopus will kick on the car charger in the middle of the day and 'steal' your exports.
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Funnily enough I learned that today, and I said to my wife that Octopus was stealing my exports - she was rather confused!

I plugged the car in when I got home last night, it should have charged overnight, I had two slots 00:30 to 01:00 and then 01:00 to 06:00, the first half hour it charged 1kWh, then nothing after 1am.

Turns out there was some sort of glitch on the Zappi, and it still had last weeks charge as the amount charged, so Octopus then thought the car was charged, and didn't start the 1am boost.

So I unplugged the charger, plugged it back in, and this time it reset to zero. I was half suspecting to get a daytime slot, so kept checking, then spotted it charging at 12:26, it had stole 3.15kWh!

Unplugged the car, the dispatch turned off at 12:30 and normal exports resumed, will plug the car back in tonight.
 
IOG. I have my car charger disabled during the day. It will turn on if the house battery gets to 5%, one of my automations kicks in over night, or I manually enable it.

That for my simple mind has been the easiest way to manage things.
 
b0rn2sk8 said:
They do, its called Octopus Intelligent flux, the downside is you end up paying full price for electric all the time as there is no off peak periods on that tariff.
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That's nothing like net metering as you have to have a battery to be on it. The benefit of net metering is you do not need a battery, and can consume your credits that you've built to over summer into the winter.
 
Journey said:
That's nothing like net metering as you have to have a battery to be on it. The benefit of net metering is you do not need a battery, and can consume your credits that you've built to over summer into the winter.
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But that's never going to be a long term sustainable way to run an electricity grid.

I'm pretty sure all the places that originally offered net metering are phasing it out back to something similar to what we have now because its not sustainable and it was only implemented as an incentive to install solar much like our FIT tariffs were back in the day.

Last summer the energy companies were paying well over the odds for our solar for a significant amount of our export at 15p-16/kwh, it was looking like export payments were on the cusp of being reduced but prices have since risen and that is probably not going to be the case this summer.
 
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