Circular reasoning (Rolfe's solar energy system)

[Rolfe]

You can tell it to ignore the solar by setting a very high threshold.

 

[johnb80]

How, technically, does Zappi integrate with a solar + battery system? From what you are saying it doesn't seem to discriminate between solar generated vs. battery power coming from your inverter.

It doesnt.

Zappi only 'knows' about the amount of import / export from the grid It has no link to solar or battery at all. If the appropriate mode is selected it can pass any export from 1.4kW upwards to the car by informing the car how much current it can take. The threshold of this can be changed by the 'green %' which is an amount of energy that can be taken from the grid to supplement the inverter output. Most systems are installed with the Zappi feed taken before any sensing for inverters thereby avoiding the problem of batteries being dumped into EV's..

You can tell it to ignore the solar by setting a very high threshold.

It still wont discriminate between solar 'v' battery. The threshold works on the export amount so you could have 5 kW from either battery or solar, Zappi wouldn't know.

 

[Rolfe]

Oh.

 

[Everest]

It still wont discriminate between solar 'v' battery. The threshold works on the export amount so you could have 5 kW from either battery or solar, Zappi wouldn't know.

Oh.

Maybe I'm missing something, but if the Zappi's feed is grid-side of the inverter's CT clamp then the Zappi would only trigger on PV generated and exported power because the inverter will not normally (*) discharge battery power to grid.

(*) apart from a) momentary export when a large load is switched off and before the inverter had time to respond and b) if you had actively forced an export of battery to grid at peak payback times (but then those times won't be the times that you'd have cheap rates).

 

[Rolfe]

The "oh" was meant to signal that I'm quite a long way out of my depth here!

 

[johnb80]

Maybe I'm missing something, but if the Zappi's feed is grid-side of the inverter's CT clamp then the Zappi would only trigger on PV generated and exported power because the inverter will not normally (*) discharge battery power to grid.

(*) apart from a) momentary export when a large load is switched off and before the inverter had time to respond and b) if you had actively forced an export of battery to grid at peak payback times (but then those times won't be the times that you'd have cheap rates).

Zappi would trigger on either an export amount (it doesnt care whether its from battery or solar) or time schedule eg 00:00 to 06:00 off peak grid.

 

[johnb80]

The "oh" was meant to signal that I'm quite a long way out of my depth here!

The CT (Current Transformer) is Zappi's only way of knowing what is going on with regards to import or export to the grid. Your inverter will be responsible for making that import or export happen. There isn't any communication between your inverter and Zappi so Zappi can only respond to what it can see or what it is instructed to do. In terms of grid export usually the threshold is set above the 1.4 kW CCS minimum and the 'green' level set to allow it (or not) to supplement grid energy with solar. The other option of course is a straight forward schedule from its built in scheduler.

 

[Rolfe]

Oh.

 

[Rolfe]

I've had a chat with my installer about an emergency power supply, and he has come up with what sounds like a reasonable proposal. He can sort out something that will enable the central heating to keep running from the house battery if the power is cut, and then rather than making things a lot more complicated by wiring in lighting or socket circuits to keep running, he suggests putting an emergency socket in or near the electrical cupboard. That way I can run an extension lead or leads to wherever I want without going outside at all, and keep the wifi, the computer, maybe a table lamp or the TV or something going. Also the fridge and freezer if the cut gets prolonged, and I think if I switched other stuff off it could cope with a kettle or the microwave.

He doesn't think there's any way to charge the home battery from a battery charger, so there would be no way to feed what's in the car into the house. However if the cut seemed likely to be prolonged or the home battery wasn't full at the start of it, the option of leading an extension lead into the house from the car rather than using the internal socket is still available, to spare the home battery for the central heating.

In reality the power supply to this village is pretty good, very few power cuts since I moved here and none more than a few hours. (Most just an hour or two.) So it's unlikely I'll need this facility. If there were ever to be scheduled power cuts as there were in the 1960s, the times of these are published in advance and so it would be possible to prepare. I think the days-long cuts that have affected some people are very unlikely to happen here, or I'd consider shelling out for a more expensive solution.

 

[Everest]

That's good you have a back-up facility from your existing system then.

He doesn't think there's any way to charge the home battery from a battery charger, so there would be no way to feed what's in the car into the house.

I suspect then, that your solar inverter's battery is one of the (newer) proprietary high-voltage ones. It is only the more generic '48V' battery systems that can be connected to the MG's V2L output via a suitable charger.... & feel free to reply 'Oh'

 

[Bam Bam]

In reality the power supply to this village is pretty good, very few power cuts since I moved here and none more than a few hours. (Most just an hour or two.) So it's unlikely I'll need this facility. If there were ever to be scheduled power cuts as there were in the 1960s, the times of these are published in advance and so it would be possible to prepare. I think the days-long cuts that have affected some people are very unlikely to happen here, or I'd consider shelling out for a more expensive solution.

I got the EPS added. We have the occasional powercut but rarely for long.

The longest was when the local power station cooling towers were demolished and the debris caused a substation to go up in flames.

I really wanted it for the peace of mind, but also to know that if there was a major outage we could live off grid and still get the benefit of the solar.

Which option?
Givenergy now offer several backup options for the hybrid inverter.

We went with the manual switchover option like Tim and Kat from You Tube:

It means that the whole house has power but it is up to us to make sure it doesn't get overburdened with too much draw (it can only handle 16A). So we should switch off the immersion heater and car charger to make sure it doesn't trip/damage the system.

 

[Rolfe]

My installer described all that to me, but it seemed a lot of expense for something that's unlikely to be needed. The ability to keep the central heating on during a moderate-length power cut is the main thing I'm looking for, because if the house is warm everything else can be managed one way or another.

 

[Bam Bam]

My installer described all that to me, but it seemed a lot of expense for something that's unlikely to be needed. The ability to keep the central heating on during a moderate-length power cut is the main thing I'm looking for, because if the house is warm everything else can be managed one way or another.

Yeah, our boiler is wired in so we can't run it off a plug.

This solution was about the same cost as the backup plug option for us, so I went with it.

 

[Gadget Geek]

We have a double socket from our battery. It came in useful last year when one of the phases blew up outside the house. It kept everything running (except the gas central heating) whilst the pavement was dug up and a new cable fitted.

We now have permanent extension cables which can be unplugged from the mains and plugged into the battery which power the router, desktop, etc, and socket upstairs to run table lamps etc.

Edit: forgot to mention I also power the fridge freezer, kettle, microwave and air fryer (but not all at the same time).

 

[decrep]

I'm thinking of drilling a hole in the wall, between garage and house to run an extension cord to the V2L cable. The fridge is the main thing we need, but modem, computer and TV would be nice.
One problem, the roller door motor is hard wired, I'd need to do something about that if we need the cars out.

 

[Gomev]

Yeah, our boiler is wired in so we can't run it off a plug.

This solution was about the same cost as the backup plug option for us, so I went with it.

Could you convert that to a plug and socket. The boiler requires little power in the grand scheme of things (3 amp fuse ???). I believe if you used an unswitched socket or made sure any switched socket was double poled then isolation wouldn't be a problem.
This way you could simply unplug your boiler and re-plug into an extension lead if ever needed.

I would need an electrician to advise and do this for me as I am not qualified and only have info from looking into this on the web (and we all know that could mean anything so could be totally wrong, but this seems a simple/cheap method to maintain heating in the depths of winter should it ever be required.

Advice from the many electricians on here would be useful.

 

[Barrie]

Could you convert that to a plug and socket. The boiler requires little power in the grand scheme of things (3 amp fuse ???). I believe if you used an unswitched socket or made sure any switched socket was double poled then isolation wouldn't be a problem.
This way you could simply unplug your boiler and re-plug into an extension lead if ever needed.

I would need an electrician to advise and do this for me as I am not qualified and only have info from looking into this on the web (and we all know that could mean anything so could be totally wrong, but this seems a simple/cheap method to maintain heating in the depths of winter should it ever be required.

Advice from the many electricians on here would be useful.

That's what I did here. My GCH boiler draws a maximum 150w for the pump and display so I converted it to a mains plug and socket as opposed to having it hard wired into my main fuse board. I can now connect it to my off grid solar system in the event of a power failure - which we have successfully done on a few occasions.

 

[Everest]

Could you convert that to a plug and socket. The boiler requires little power in the grand scheme of things (3 amp fuse ???). I believe if you used an unswitched socket or made sure any switched socket was double poled then isolation wouldn't be a problem.
This way you could simply unplug your boiler and re-plug into an extension lead if ever needed.

I'm not a qualified sparky, but have a related background and some experience. The key issue with this is safety relating to earthing and leakage detection.

See my 2 postings here - the second of which was specific to boilers:-

My thoughts about earthing in MG4 Discharge Cable thread

My thoughts about powering a boiler in MG4 powering other stuff (Vehicle to Load aka ‘V2L’) thread

 

[OriginalBigAl]

I'm thinking of drilling a hole in the wall, between garage and house to run an extension cord to the V2L cable. The fridge is the main thing we need, but modem, computer and TV would be nice.
One problem, the roller door motor is hard wired, I'd need to do something about that if we need the cars out.

Have an extension lead from the V2L but with bare wires on the "socket" end which connect to output side on the breaker for the roller shutter. Turn off the breaker to stop the current going back into the house system . When opened , unplug and disconnect. Turn off at the mains before hand in case the power is restored whist you perform the hack.

 

[decrep]

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.