Can solar panels generate low level electricity by street light?

[compmad1]

We have just had installed solar panels on our roof, with an Elios4You monitoring system (in combination with a Power Reducer). The Elios4You monitor display says that at night ( no sun whatever) our roof is still generating 10W. We have a powerful LED street lamp outside our house. Could this be causing the power generation, or is the device just faulty? Opinions much appreciated. Thanks.

 

[Worcester]

My calibrated monitoring system says mine is currently generating 3W (It's lying because I haven't updated the software routine to say anything <20W = 0)

Nope, in simple terms the monitoring system isn't that accurate (10W that's 0.043 Amps...) Your inverter won't kick in until it's generating way more than that (100W+). I may be corrected, though I would be surprised if the Elios was more accurate than 1% so on a 3 kW system that would be +/- 30W.

 

[LeeH]

I think you needed sunlight or daylight for solar so I doubt it.

 

[Gavin A]

We have just had installed solar panels on our roof, with an Elios4You monitoring system (in combination with a Power Reducer). The Elios4You monitor display says that at night ( no sun whatever) our roof is still generating 10W. We have a powerful LED street lamp outside our house. Could this be causing the power generation, or is the device just faulty? Opinions much appreciated. Thanks.

either you've accidentally ended up with a perpetual motion machine on your roof, or the elios readout is wrong. Even the best clamps aren't going to be entirely accurate to that degree.

 

[Earthstore]

Maybe it is picking up the current used while the inverter is in sleep mode?
Not sure if your type of moniter reads bydirectional or not.....

 

[jason121]

We have just had installed solar panels on our roof, with an Elios4You monitoring system (in combination with a Power Reducer). The Elios4You monitor display says that at night ( no sun whatever) our roof is still generating 10W. We have a powerful LED street lamp outside our house. Could this be causing the power generation, or is the device just faulty? Opinions much appreciated. Thanks.

That will be the consumption of the elios mine has the same reading

 

[Green]

Amazingly I've lost an installation in the past as a customer was duped by a salesman into thinking they would generate at night due to street lamps - as I was unable to get these special night generation panels the kit I was offering clearly wasn't as good!

 

[telectrix]

these night time solar generation panels are available and have been since 2450. supplies obtainable from starfleet command. mention my name... jean-luc picard.

 

[Worcester]

Apparently there is one guy that backs on to Old Trafford that gets free night time leccy, when it's a home game (Floodlights..)

 

[telectrix]

is that from solar or from a cleverly concealed hook-up?

 

[Worcester]

is that from solar or from a cleverly concealed hook-up?

Allegedly Solar - those floodlights do make it like daylight down on the pitch... (not that half of them can see the ball anyway )

 

[SpitfireW'sale]

Apparently there is one guy that backs on to Old Trafford that gets free night time leccy, when it's a home game (Floodlights..)

I have heard this as well from a system installed next to a Tesco distribution hub - the system generates at night as well. The yard is lit by huge floodlights that are enough to start the system apparently. If it's true I'm still not sure it would be enough to have me living next to a massive Tesco though!

 

[telectrix]

upside would be not having to drive to the offy for beer.

 

[oldsalty]

Interestingly, an old friend of mine has a solar panel on top of his camper van and he always tries to park for the night under a street lamp, especially those that face downwards, because the light on the solar panel charges his batteries overnight.

 

[Gary K]

Interestingly, an old friend of mine has a solar panel on top of his camper van and he always tries to park for the night under a street lamp, especially those that face downwards, because the light on the solar panel charges his batteries overnight.

Doesn't get any sleep because it is too light, but gets a full charge!!!!

 

[oldsalty]

Doesn't get any sleep because it is too light, but gets a full charge!!!!

Still not using curtains in Norwich, then?

 

[series530]

Most clamp based systems or anything which senses a proportion of the current flowing through a cable will struggle with low power. A typical domestic situation will consume anything between zero and 100A and a voltage equivalent of this current needs to be sent to the measuring hardware. The measuring hardware can only sense discrete voltage levels and not an infinite variation of them (AKA codes in the converter) and with a typical system it makes the resolution in the region of 40mA or worse. This means that 41mA of current is measured as 40mA and 79mA is also measured as 40mA while 80mA would be measured as 80mA. All of this equates to a resolution of about 10W in the measurement unit.

In addition to this, low power means low current and low current translates to a low voltage at the sensor. Low voltage often gets swamped by background noise in the system and, unless it is very well designed and specified (and many domestic solutions are not) the noise dominates the measurement at low power and further increases the error.

Finally, some of the circuitry used in the sensors is non linear (often part of the damping and noise suppression) and this also adds to the errors at low power.

If we want super accurate systems we need to pay more for them. More accurate systems require more extensive calibration, require tighter tolerance components and individual characterisation. Domestic users seldom want to pay for this.

The system that I have is accurate to about 1% above about 300W. Below this it gradually drifts away and is as much as 20% off at around 100W. This is after extensive calibration on my part. As our house naturally sits on a standby power drain of at least 300W I see no benefit in trying to tune in more accuracy on either the grid or the solar channels. On the solar side, anything less than 50W of generation is zeroed on my display deliberately. Overall, my system is far more accurate than the Enecsys monitors, albeit taking into account that there is some loss in the cabling between the micro inverters and the sensors that I have added to my system.