Circular reasoning (Rolfe's solar energy system)

[johnb80]

Oh my, do it the easy and SAFE way, have a changeover switch fitted, your whole house can be supplied then conveniently and without danger.

transfer switch

Transfer switch £30, shouldnt cost much to have it installed if you dont want to DIY it.

No drilling holes in walls, no hassle in connecting bare wires to circuit breakers, no conflicts. Power goes off, switch off major loads, flick the switch over to generator, plug car in, JOB DONE

 

[Bam Bam]

Oh my, do it the easy and SAFE way, have a changeover switch fitted, your whole house can be supplied then conveniently and without danger.

Indeed!

As I mentioned, our electrician charged the same for the changeover switch as he would have done to add the two sockets.

I'm not 100% sure but it is quite possible you have to switch a changeover switch to use the two sockets as well!

 

[johnb80]

Indeed!

As I mentioned, our electrician charged the same for the changeover switch as he would have had to add the two sockets.

Yep I can believe that it's a simple job and makes it so much more convenient AND the whole house can be supplied upto the capacity of your inverter.

 

[OriginalBigAl]

Nah, I'd just cut the incoming cable to the motor, and put extension lead plug and socket on them, simple C/O when required.

That would work.

 

[Bam Bam]

Was this the thread discussing @Rolfe's issue with home battery discharge?

Gary does solar has the same set-up and discusses the options here:

 

[Abersoch5]

It goes like this.

1. I really should get a home charger.
2. If I get a home charger, I need a variable electricity tariff.
3. A variable electricity tariff will make my daytime usage more expensive.
4. The answer is to get a home battery and fill it with cheap electricity overnight.
5. Look at your roof, if you have a home battery it would be criminal not to install solar.
6. That will be £13,700 altogether.
7. But I could buy a hell of a lot of electricity for that. Um.
8. But I really should get a home charger.

How do you get out of this loop?

I charge mine with the 13amp cable that came with the car. It charges to 80% overnight and if i go on a very long journey it can charge to 100% but the last bit is slow.

On another response i would say. I had an old oil boiler and now have a heat pump. How i wish i had the old boiler. The house is cold,it takes forever to reach and maintain temperature, the pump noise on the internal tank permeates the whole house and it is more expensive than oil to run. Make sure you have a log burner or something to keep the house warm in winter if you have an air source heat pump. I believe ground source heat pumps are better but only if you have underfloor heating.

 

[Gadget Geek]

On another response i would say. I had an old oil boiler and now have a heat pump. How i wish i had the old boiler. The house is cold,it takes forever to reach and maintain temperature, the pump noise on the internal tank permeates the whole house and it is more expensive than oil to run. Make sure you have a log burner or something to keep the house warm in winter if you have an air source heat pump. I believe ground source heat pumps are better but only if you have underfloor heating.

I have a Tepeo Zero Emmision Boiler, and the response from turning the radiator on to it being hot is less than a minute. Handy if your wife has no patience.

 

[johnb80]

I charge mine with the 13amp cable that came with the car. It charges to 80% overnight and if i go on a very long journey it can charge to 100% but the last bit is slow.

I dont know what size battery you have but you must have very long nights to fully charge overnight with a granny charger. A granny charger at best will charge at around 2.5 kW MAX, a 50 kWh battery is going to take at very least 25 hrs to fully charge. A 7.2 kW wall box would charge it in around 7 hrs. I suspect your car is a Plugin Hybrid Electric Vehicle ? this will have a relatively small battery by comparison to BEV's.

On another response i would say. I had an old oil boiler and now have a heat pump. How i wish i had the old boiler. The house is cold,it takes forever to reach and maintain temperature, the pump noise on the internal tank permeates the whole house and it is more expensive than oil to run.

All of this smacks of very poor system design and/or installation.

Make sure you have a log burner or something to keep the house warm in winter if you have an air source heat pump.

A backup no matter what sort of boiler you have is always a good idea.

I believe ground source heat pumps are better but only if you have underfloor heating.

Nah, thats not right, the two are not connected.

Ground source heatpumps have a more consistent heat source to extract the heat from. They cost more to install but have higher efficiencies in terms of COP.
Underfloor heating is better for all types of heating system but especially good with heatpumps as it can work more efficiently at lower temperatures. The effective radiator size with UFH is huge, response times can be slower especially if you have carpets down.

 

[Bam Bam]

How i wish i had the old boiler. The house is cold,it takes forever to reach and maintain temperature, the pump noise on the internal tank permeates the whole house and it is more expensive than oil to run. Make sure you have a log burner or something to keep the house warm in winter if you have an air source heat pump. I believe ground source heat pumps are better but only if you have underfloor heating.

Do you run the heat pump the whole time or only some of the time? I believe some people run it constantly in order to get better efficiencies.

 

[Rolfe]

Was this the thread discussing @Rolfe's issue with home battery discharge?

Gary does solar has the same set-up and discusses the options here:

It's the Home Assistant solution. I really don't want that. I've got a system that works OK for me. It means I never get Octopus's extra slots, but what good do they do me if I don't know in advance when they're going to happen?

 

[Bam Bam]

It's the Home Assistant solution. I really don't want that. I've got a system that works OK for me. It means I never get Octopus's extra slots, but what good do they do me if I don't know in advance when they're going to happen?

He did also mention the 'move the clamp' solution.

 

[johnb80]

He did also mention the 'move the clamp' solution.

Moving the clamp can only work IF the feed for Zappi is taken independently to the rest of the house.

 

[Rolfe]

This is the first day I've seen the real "Ayres Rock" formation, although I think it was there on 22nd February as well except a scaling glitch on the web page meant it wasn't so obvious. In December and January the sun hides behind a neighbouring house after about 11.30, so the afternoon generation is curtailed. So it looks as if I get eight months with the panels seeing the sun all day.

 

[Everest]

This is the first day I've seen the real "Ayres Rock" formation

Great that you're getting full sun over the whole day now.

But that's a lot of clipping for this time of year! I don't see any numbers on the graph but fascinated to know what sizing of panels vs. inverter you have and whether you have any grid export limitations set? (reason for asking is I'm thinking that if your inverter is not big enough you could be wasting a lot of energy that could otherwise be stored in Caliban over the summer).

 

[Rolfe]

I'm limited to 5 kw export by the terms of my G99 certificate. I had to talk my installer up from an initial proposal for 3.5 kw and wait three months to get that! Yes there is energy being wasted on sunny days but that's the nature of the beast.

 

[Everest]

That makes sense then - so it's the export limit that is causing the plateau, but if you're charging the car then you can use the spare energy

 

[Rolfe]

The only way to use the spare energy is to charge the home battery. No, don't ask me why, I have no idea.

 

[Bam Bam]

The only way to use the spare energy is to charge the home battery. No, don't ask me why, I have no idea.

The inverter can only output 5kW AC.

However, as it is a hybrid inverter the DC from the solar can go straight into the DC battery if there is any battery capacity available.

Use some of the battery up at 11am (charge the car at 5kw for 45 mins or something) and you'll be able to refill it with some of that otherwise wasted DC power at 12.

There are losses in the conversion from DC-AC though, and so the gains might be limited unless it is a really sunny day.

 

[Rolfe]

It's a bit of a faff for not much gain. Thanks for explaining how it works though.

 

[johnb80]

It's a bit of a faff for not much gain. Thanks for explaining how it works though.

Easy option would be add another battery.