PV+ - anybody heard of this?

[oldsalty]

Hi,

I am being touted by my local installer to add a module called PV+ to my residential solar array. This module is claimed to effectively improve efficiency of my installation by 20% (thereby increasing my FiT earnings) by balancing out and reducing overvolting, which they tell me cuts out generation for every period of overvolting. Forgive my brief description but that is as I understand what it is supposed to do!

The module costs GBP859.00 (fully installed) so is something worth finding out about before going for it.

Is there anybody who knows this equipment and can comment on the efficacy of the claims. Many thanks.

 

[Deleted member 26818]

I thought PV+ was just a battery or batteries to store excess generated power?
I would expect the inverter to deal with any over voltage?

 

[oldsalty]

I thought PV+ was just a battery or batteries to store excess generated power?
I would expect the inverter to deal with any over voltage?

'Confused!'

 

[SibertSolar]

Is your inverter regularly tripping out due to over voltage?

 

[oldsalty]

Is your inverter regularly tripping out due to over voltage?

Hi Andy,

Not to my knowledge - my Elios4U (and my SolarEdge) don't show any 'gaps' in generation though there are many peaks and troughs.

His ploy is mainly that these overvoltages ARE going to happen and therefore the PV+ module will be working and generating 20% more registered generation, therefore 20% increase in tax free FiT payments. Not, however, prepared to guarantee 20% overall increase so that immediately made me dubious about the whole system.

It is very big in Germany, apparently!

Thanks for your interest.

 

[SibertSolar]

It's a Matt:e product and I'm sure it has its place, but if you're not suffering from regular over voltage trips then I fail to grasp the point....seems like a solution to a problem that shouldn't exist...I've questioned the ER grid-connection compliance/impact of this technology before, but as yet have not been made to understand the nitty gritty of it tbh

 

[TJ Anderson]

Snake oil, steer clear. Your system would have been designed with the Voc of the string within parameters of inverter anyway and its max power point tracking lowers it further anyway. Don't put another fail point in you system, especially a pointless one.

 

[SolarCity]

I've not heard of this before. What is it?

And are we talking about overvoltage on the DC or AC side?

If it's the DC side then the system hasn't been designed correctly. If it's the AC side then you should look at getting the DNO to reduce the voltage.

"generating 20% more registered generation, therefore 20% increase in tax free FiT payments. Not, however, prepared to guarantee 20% overall increase"

I don't even know what that's supposed to mean.

 

[BruceB]

Snake oil by the look of it. I would be happy to be shown some evidence to the contrary, but my feeling is that in domestic circumstances, voltage optimisation is unlikely to produce significant savings given the design of modern appliances and lighting. Even the example they quote of the kettle is wrong:
Voltage Optimisation and Solar PV ? matt:e
A kettle is one example of where being over voltage, boiling more quickly will lose you less heat/energy!

Laws of physics start ringing in my head when claims of an additional 20% of energy are made!

 

[Gavin A]

if they're talking about using the VO unit between the inverter and the grid so the inverter sees the lower voltage, then this is completely against the regs, and would give the DNO the right to disconnect you. IT's bypassing the G83/2 protection settings that are designed to protect the local grid network from over voltage.

I asked ENA about this last year for a different product and they responded by instructing them to change their instructions and write to anyone they'd sold it to to ensure they weren't doing this (not sure the latter bit actually happened).

I'm not clear that this is what this unit does though, in which case it really is just a snake oil salesman who's talked to the OP.

 

[SibertSolar]

Maybe we'll get some input from Matt Hunt on here, I know he's been on before....some explanation/answers would be interesting

 

[Gavin A]

Snake oil by the look of it. I would be happy to be shown some evidence to the contrary, but my feeling is that in domestic circumstances, voltage optimisation is unlikely to produce significant savings given the design of modern appliances and lighting. Even the example they quote of the kettle is wrong:
Voltage Optimisation and Solar PV ? matt:e
A kettle is one example of where being over voltage, boiling more quickly will lose you less heat/energy!

Laws of physics start ringing in my head when claims of an additional 20% of energy are made!

tbf with the kettle example what they mean is that if it's being boiled when solar is generating then a longer boil time and lower consumption levels will result in the solar providing a higher fraction of the total energy used.

Alternatively just buy a lower rated kettle.

We've got a VO unit in at home as a trial, and basically all it seems to do is to make the kettle and toasters take longer which is pretty annoying for someone as impatient as me. It also always seems to be pretty warm, so I have serious doubts that any minor efficiency gains in any pumps etc are enough to offset the losses in the VO unit.

I did one for a customer in an oldish house, and they then had a central heating pump and valve go within a month, which I put down to the reduced voltage not giving the pump enough ooomph to overcome the start up inertia.

 

[snowhead]

It is very big in Germany, apparently!

Something else was big in Germany in the 30's and 40's
That didn't end well.

By the time you find out it doesn't perform as stated, the cowboy has got on his horse and is touting something else.

 

[BruceB]

I am still not convinced Gavin, because although I take your point that certain combinations of generated power, kettle power and voltage could work as you describe, most times when voltage is high will be bright sunshine with good output from the panels that has a good chance of covering the kettle.

 

[SibertSolar]

Guys, don't get sidetracked into the same old VO conversations - I think we all know our opinions on those (at least in a domestic environment anyway), this PV+ unit is pitched as something different....I for one would like to know exactly how this is supposed to differ from VO and how it's compliant to be installed between the SSEG and the grid....I've already decided on its actual value