Solar panels and "add on" devices

tunnel

Hi all,

As its a nice sunny day and my 2 sets of panels are furiously generating I got to wondering!!

Having 2 systems that total 4kWp rather than 1 single system, I currently don't possess any type of add on

Has anyone got any ideas on what would be available, i'm quite interested in a wattson but would have to buy extra kit as my 2 systems are more than 15 metres apart. With a potential 3rd system on the cards in the coming months how can I utilise something like a wattson without it costing the earth with the extra pieces of equipment needed.

I currently implement the Eric look out the window system to use my generation to its best potential but would like to use something a little more scientific.

How about you Mart with your 3 systems, do you use anything to "help" make the most of the generation?

EricMears

As I'm sure you've read here, I have a Wattson meter read by Holmes on a nearly permanently running PC.

It gives a rough idea of what is going on but isn't altogether reliable. I often see the message "out of range" on the Wattson. That's supposed to mean that the radio signal from detectors to meter isn't strong enough but it happens without me moving either end of the kit (and both ends are supplied by mains transformers rather than batteries which might go low and cause same message). I've also had the odd generation 'spike' during the hours of darkness. If I could persuade the SPs to generate when a brief gap in the clouds exposes them to starlight I'd be well chuffed:j

There are apparently other systems which work on similar principles to Wattson/Holmes but I have no experience of them.

I have just bought all (I hope) the bits I require to build a much more reliable system based on counting flashes from my TGM & my import meter. Total cost around £25. I may well extend that system to read a (proposed new purchase of) meter recording total usage (or the majority thereof since I intend to fit it between the permanent side of my split load consumer unit and the RCD protected side (the same lead that Wattson uses to measure consumption). If it all works out I'll have a secondhand Wattson system for sale - but I don't advise you to hold your breath : it's not top of my to do list yet.

tunnel

That's one of the reasons Eric that I've held off from buying such a device and now hearing that you occasionally lose signal from 1 transmitter and I may need potentially 3 transmitters to do the same job, doesn't fill me with confidence. guess that's one of the pitfalls of multiple systems.

I've contemplated installing a hot water tank too but again I believe i'd need more transmitters for the immersun(or similar).

Hopefully someone may have another solution.

Martyn1981

Hiya T Man. I'm pretty low tech, relying mostly on the MkI Eyeball.

Ok, to be fair, eyeball, plus weather forecast, plus two ENViR energy monitors .... but apart from that! Hopefully all PV'ers with a few months under their belts will know that very little effort is required once you get into a pattern of checking the weather forecast, then glancing out the window at the level of clouds, and the reading(s) from the energy monitor(s). It all gets rather automatic after a while.

Although I have 3 systems, the two ESE's wire into a small CU before the TGM so really only 2 systems to monitor. Both TGM's have Optismart's reading the LED flashes and reporting to the ENViR's.

As you probably know, you could have all your systems running through the same TGM (or should that be 'could have had') but differing tariffs and orientations mean that this needs careful consideration. It wouldn't have worked for me, nor for you if I remember correctly. And if you do add a partially 'N' system, then you'll need a third TGM to prevent generation being apportioned on a kWp:kWp basis - especially given your current tariff rates.

Now for the assumption part - I don't have any diversionary device, but wouldn't the sensor be placed on the mains cable on the supply side of the CU to monitor the amount of export, so whether you have 1, or 20 systems, there will still only be one reading that is the net of all generation minus demand. That reading is then used to decide if/how much to divert.

I have pondered a diversionary switch coupled with a storage heater (I don't have a water tank), but I'm not happy that this would be particularly green, so holding off and still looking into the small ASHP (A/C unit) idea for the shoulder months (Mch/Apr & Sept/Oct), but if this ever happens, it'll probably be operate via the Mk1 Eyeball again.

Mart.

tunnel

Martyn1981 wrote: »

Hiya T Man. I'm pretty low tech, relying mostly on the MkI Eyeball.

Ok, to be fair, eyeball, plus weather forecast, plus two ENViR energy monitors .... but apart from that! Hopefully all PV'ers with a few months under their belts will know that very little effort is required once you get into a pattern of checking the weather forecast, then glancing out the window at the level of clouds, and the reading(s) from the energy monitor(s). It all gets rather automatic after a while.

Although I have 3 systems, the two ESE's wire into a small CU before the TGM so really only 2 systems to monitor. Both TGM's have Optismart's reading the LED flashes and reporting to the ENViR's.


Mart.

I've looked into the Optismart too mate but the write ups say they are not any good for PV systems, something to do with the red light being on constant during non generation spells. Then again on the electricians forum I read that while generating they're pretty damn accurate. So confusing:mad:

Martyn1981

tunnel wrote: »

I've looked into the Optismart too mate but the write ups say they are not any good for PV systems, something to do with the red light being on constant during non generation spells. Then again on the electricians forum I read that while generating they're pretty damn accurate. So confusing:mad:

I bought my first Optismart just before they put the warning on their web-site, (late 2011) but it worked fine. I then mentioned on a forum that I couldn't get a second for my WNW TGM as it had a constant red light when no generation. But I was told it would be fine, so I swopped the original over to the new TGM and it worked perfectly fine, and carried on the next day, despite a night of red light. So I bought a second one.

No idea what CC are worried about in their warnings, I can only guess that they found a possible problem, so added a warning, but they seem to work fine ....... famous last words ..... don't blame me!

As to accuracy, they are spot on, since they report the actual reading from the TGM by measuring the time gap between flashes, of course that assumes that the TGM is accurate, but TGM's (import meters) have pretty tight performance requirements.

For cheap monitors, try fleabay, and search for Eon energy monitor, but get your eye in first on CC's website to make sure you get an ENViR, as they are better than the ENVi or earlier models. They have different looking fronts. Keep shopping till you get one for around £15 all in. I got lucky and bought one that didn't have a transmitter unit (the Optismart does that bit), nobody else was interested, so it was about £5 all in.

Should add, that whilst I don't know anything about them, I'm quite curious, even jealous about what the other boys and girls have been saying on the generation thread about the Holmes & Wattson kit. And the use of opti-plugs to switch things on. :cool:

Mart.