Solar PV Diverter setup - "Head Scratch"

[swisscheese]

PV is on the roof and functioning.

 

(this is may be a bit half baked at the minute and I can firm up on some detail when I get home and double check)

 

So thinking out loud.

 

I now want to get a PV diverter functioning to kick off the immersion.

 

As I see it my problem is one of distance.  My incoming Electric supply is into my garage where I have one consumer unit, as a consequence my Solar PV array inverter and generation meter are also located in the garage.

 

From the Garage incoming supply I then run 2 80A cables into the house and into a second and third consumer units - This is really because the house is built in two distinct blocks/levels(shorter runs).

 

The Consumer Unit with the immersion connected is about 30 meters away from the incoming Suppy and Solar PV equiptment etc.

 

I do have some cat6 running from the garage into the house and I think I have a spare unterminated piece of Cat6 close to the immersion CU.  - I will have to check.

 

So I'm thinking what options do I have?

 

Wifi:  Solar iBoost type thing and hope the wifi signal "stretches" from the garage - through the solid garage door past external house doors and into the cupboard, I don't really want the unit external to cupboard - but might have to if it's the only way to get a signal. (can this be boosted?)

 

Wired? - how does this work, can I use data cable for this?

 

Anybody overcome any similar issues?

 

Thanks

 

 

 

 

 

 

[Declan52]

I have the iboost and it has about 10m to send the signal.  This travels through the block cavity wall,  and at least 2 internal block walls plus a ceiling and floor.  Never had any issues with it. 

[ProDave]

Your Cat 6 is 4 twisted pairs.

 

These things work on a current transformer to send import / export measurement.  I am pretty damned sure the current transformer will hapilly send it's signal down one of the twisted pairs.  Well I damned well hope so as that is exactly what I am intending to do. (except my twisted pairs happen to be in a bit of spare armoured telephone cable I had spare)

[swisscheese]

7 minutes ago, Declan52 said:

I have the iboost and it has about 10m to send the signal.  This travels through the block cavity wall,  and at least 2 internal block walls plus a ceiling and floor.  Never had any issues with it. 

 

OK good to know, but when I have tested device connectivity over this distance at home in the preferred locations, it has been at best flakey. What protocol is the iBoost using?  I am no network specialist.

[ProDave]

2 minutes ago, swisscheese said:

 

OK good to know, but when I have tested device connectivity over this distance at home in the preferred locations, it has been at best flakey. What protocol is the iBoost using?  I am no network specialist.

I don't know that particular model, but at the most basic level, there is a current transformer that clips onto one of the meter tails.  The output from that will be a 50Hz current proportional to the current being imported or exported.  That should hapily pass down a twisted pair.

 

Of course if they choose to put some electronics in the CT and use some other protocol that may not hold true.

 

I will be building my own (actually just redeveloping a previous one)

[swisscheese]

1 minute ago, ProDave said:

I don't know that particular model, but at the most basic level, there is a current transformer that clips onto one of the meter tails.  The output from that will be a 50Hz current proportional to the current being imported or exported.  That should hapily pass down a twisted pair.

 

Of course if they choose to put some electronics in the CT and use some other protocol that may not hold true.

 

I will be building my own (actually just redeveloping a previous one)

 

Thanks @ProDave

 

That will be out of my league I'm afraid - so looking for something off the peg that will work  - I must say they all seem over priced, to me so appreciate your sentiments.

 

My thoughts are the twisted pair as a Current Transformer guarantees connectivity, if it's supported by the product but I don't really know which way to jump  - the iBoost seems a simple wifi enabled solution.

If you were "buying" wired have you seen a simple schematic of the over distance installation, and best options?

 

 

[Jeremy Harris]

Just been reading up on a battery inverter/charger unit that uses a CT on the tails to sense export and adjust the charge current (same thing as a PV diverter, in essence).  They use paralleled pairs in Cat5e cable to be able to locate the inverter up to 30m away from the CT, so that option should work with any PV diverter, as they all use an external CT AFAIK.

 

My homebrew one uses a wireless link from the external unit out by the meter box to transmit data for use anywhere in the house, and in practice that has a range of well over 30m outdoors, but a bit less if it has to go through several walls.  I'm using off-the-shelf licence-exempt, approved wireless modules, so would assume that the performance of any PV diverter with a similar wireless link should work OK, if you don't want to extend the CT cable with a bit of Cat5e.

[Declan52]

Could something as  simple as a plug in WiFi extender work to carry the signal to where you need it.  A tp link type device plugged in at each location and standard cable to carry the signal between them. 

[Jeremy Harris]

16 minutes ago, Declan52 said:

Could something as  simple as a plug in WiFi extender work to carry the signal to where you need it.  A tp link type device plugged in at each location and standard cable to carry the signal between them. 

 

Depends if the unit uses wifi or not.  Mine uses lower frequency licence-exempt transceivers, as they have a longer range than wifi.  I can't easily find out what frequency wireless links some of the popular diverter units use, but Solar iBoost say their unit has a range of 500m line-of-sight outdoors, 30m indoors, so should be OK for sending a signal from a detached garage to a house 30m away I think.  That long range makes me think it uses the 433 MHz band, as that tends to give much greater ranges than the 2.4 GHz/5 GHz wifi bands.

[Roundtuit]

We've got an Apollo Gem; the sensor cable can be extended up to 100m with something like cat 5.  I thought we might need to do that as our incoming meter is in a box on the boundary, but the sensor is fine on the tails into the consumer unit in the house. Installation diagrams/user manual is downloadable from their website https://www.apollosolarelectric.co.uk . Not sure it matters where your pv inverter is?

[Jeremy Harris]

It's vital that the current sensor (CT) is on the supply on the grid supply side of the whole property electricity supply.  This means that it's fine to have the CT on the meter tails, no matter what the installation, but only OK to have the sensor on the consumer unit tails when there is no outlet or PV inverter connection between the CT and the incoming supply at the meter.

 

Our case illustrates this.  We have our incoming supply and meter in a box mounted in a fence.  The supply from there feeds the house and the main consumer unit, via a length of 25mm² SWA.  The PV inverter is connected to this main CU.  The supply from the meter also feeds a small CU outside that supplies power to the garage, the car charge point, the treatment plant and our water supply pump.

 

If I was to fit the CT in the house, on the consumer unit tails, then we could be importing power from the grid when the diverter thinks we are exporting, as it won't be sensing the loads from outside the house, some of which could be high (the car charger draws up to 7 kW, for example).  With the CT fitted at the meter tails, it correctly reads the whole house import/export and will only divert if we are exporting.

[swisscheese]

1 hour ago, JSHarris said:

It's vital that the current sensor (CT) is on the supply on the grid supply side of the whole property electricity supply.  This means that it's fine to have the CT on the meter tails, no matter what the installation, but only OK to have the sensor on the consumer unit tails when there is no outlet or PV inverter connection between the CT and the incoming supply at the meter.

 

Our case illustrates this.  We have our incoming supply and meter in a box mounted in a fence.  The supply from there feeds the house and the main consumer unit, via a length of 25mm² SWA.  The PV inverter is connected to this main CU.  The supply from the meter also feeds a small CU outside that supplies power to the garage, the car charge point, the treatment plant and our water supply pump.

 

If I was to fit the CT in the house, on the consumer unit tails, then we could be importing power from the grid when the diverter thinks we are exporting, as it won't be sensing the loads from outside the house, some of which could be high (the car charger draws up to 7 kW, for example).  With the CT fitted at the meter tails, it correctly reads the whole house import/export and will only divert if we are exporting.

 

explains the crux of the matter precisely.  Exactly why I need the Current sensor in the garage.

 

The question though remains to see if I get the wifi or go through walls and distance or go for a wired option.

 

[Jeremy Harris]

25 minutes ago, swisscheese said:

 

The question though remains to see if I get the wifi or go through walls and distance or go for a wired option.

 

 

I'm pretty sure that it's not wifi, but a lower frequency wireless link I think, at least for the Solar iBoost, which has a claimed outdoor range of 500m and an indoor range of 30m.  Wifi won't manage that sort of range, as I had to fit a directional patch antenna and a separate AP in the loft just to be able to get wifi down to our garage, which is barely 20m from the router in the house.  On the other hand, the 433MHz wireless signal that's transmitted from my PV diverter can be received anywhere in the house, even down in the garage around 30m away from the meter box.

[scottishjohn]

If it were me 

I would suck it up and make it hard wired for long term reliability 

a bit of conduit buried and cable through it.

short cuts don,t always work out better in the long run .

but I am a  ludite  by nature 

simple is best  .LOL

also leaves easy upgrade potential for other sensors etc 

Edited January 23, 2019 by scottishjohn

[swisscheese]

3 hours ago, JSHarris said:

 

I'm pretty sure that it's not wifi, but a lower frequency wireless link I think, at least for the Solar iBoost, which has a claimed outdoor range of 500m and an indoor range of 30m.  Wifi won't manage that sort of range, as I had to fit a directional patch antenna and a separate AP in the loft just to be able to get wifi down to our garage, which is barely 20m from the router in the house.  On the other hand, the 433MHz wireless signal that's transmitted from my PV diverter can be received anywhere in the house, even down in the garage around 30m away from the meter box.

 

sorry - yep me being lazy - definitely wireless not wifi - thats what happens when you have a teeneage daughter it "wifi this wifi that"

 

[Jeremy Harris]

This is what the Solar iBoost FAQ has to say about range:

 

Quote

What is the distance range between the Solar iBoost and the wireless sender?          
Approx. 500m line of sight, or up to 30m within a building. The strength of the signal can be affected by
thick walls in a similar way to a wireless router or a cordless phone in your home. 

 

Sounds like it may be OK if there aren't too many walls in the way between the location of the meter and the location of the diverter itself.  I can't see any models that say you can wire the CT up with a longer length of cable, so whether that's an option or not I don't know.  In theory it should be fine, as other kit that uses a CT to sense supply current allow the cable to be extended up to 30m.