4 ms·

As someone who has acquired rather too much information about solar over the past few years (in preparation for a largish system) I can say this is a good overa

As someone who has acquired rather too much information about solar over the past few years (in preparation for a largish system) I can say this is a good overall primary. One irrelevant detail not mentioned, which I like repeating, is that despite being made to literally sun-bathe all day long, solar panels don't like being hot. (Effeciency drops with heat, gains with cold.) There's not a whole lot you can do about this, except allow for passive air cooling. There are some water cooled panels available, but costs make them uneconomic for now. I was interested to learn though that on a cold summers day, the panel output can exceed the nominal rating got the panel. Something to consider if you are at high altitude.

tibbydudeza 3y ago
Had to get a home PV system out of necessity due to our national power company being up a shitcreek with an aging fleet of badly maintained coal power plants. 3.7 Kw solar panels and 2 x 5KW LifePO batteries and a 5Kw SunSynk inverter tied to the grid - solar geyser and it does not power our electric oven - the only issue is the management system is dumb as bricks - there is no intelligence and difference charge settings or profiles for our cold winters and hot summers or using the weather forecast for the day. It just averages out.
- adql 3y ago
  If it can be controlled via RS485 you might be able to add some smarts to it, like lowering charge level if weather is supposed to be good next few days.
  - tibbydudeza 3y ago
    There are third party solutions running on a Rasberry Pi that connects to WiFi port but it means "hacking" and it bad enough maintaining my own office I.T infrastructure.
darkwater 3y ago
Yep, I live in Southern Europe and my panels have the biggest output end of April/May, while one would expect it to be end of June.
stinos 3y ago
solar panels don't like being hot Indeed, and this touches on the 'Regular cleaning of PV panels is important for ensuring maximum energy production' statement in a funny way. First of all, while the statement is accurate, I'd say is not too important practically depending on where you live. As our isntallation guys also told us. Our panels seem to do just fine with occasional heavy rainfall to clean them and the loss when they're covered in a thin layer of dust is not worth spending time on. On the other hand, the PV cleaning companies will say that it's super important to clean them. So when my mum got her panels cleaned it went like this: sunny day, panels get hot, efficiency drops. Panels were cleaned with water, temperature drops, cleaners told her 'look how much better it is now'. But after they were gone temperature rose again and efficiency was essentially back to where it was before.
hutzlibu 3y ago
"There are some water cooled panels available, but costs make them uneconomic for now." Couldn't you just use that warm water and so make it economic? Are there any combined systems that try this?
- edent 3y ago
  You can, but the problem is that warm water isn't that useful. Unless your system can regularly heat up to >60C to kill legionella then it will need external heating. Secondly, when the external temperatures are high there's very little need for warm water. Perhaps a few dozen litres for washing. No one is taking a hot bath on a summer's day! If you have the space, you can store the hot water underground and then pump it back up in winter for heating. But that's expensive.
  - hutzlibu 3y ago
    "You can, but the problem is that warm water isn't that useful." Depends on your other systems. Dishwater wants hot water(but usually has no input for hot water), washing machine(some do). And if you have a house with 4+ people who like to shower a lot .. it adds up very quickly. And yes, heating. Now are already the days (in europe), with cold nights and mild but sunny days. So .. it makes sense in theory, but not so easy to economically make use of as of now.
- robertlagrant 3y ago
  I'm not sure where you could use it. At least in the UK: - water for heating your home is in a closed loop, and you wouldn't want to add this cooling to that closed loop as it would heat up your solar panels on cold days - water for drinking/washing comes from the same cold feed, and you don't want to heat that up as you can't get cold water then - bisecting the water supply into hot taps and cold taps, and running the hot one under the PV cells could work, but it would only flow the water when something is pulling water, e.g. running a tap, which might be a hindrance to cooling
  - Maakuth 3y ago
RetroTechie 3y ago
> solar panels don't like being hot. For boats there's flexible panels that in many cases you can even walk on. But the sun's power not turned into electricity, heats both panel & roof of the boat (and in turn, its interior). Not something you want on a hot sunny day. A rack-mounted panel otoh, allows for airflow underneath, and -if roof mounted- separates (potentially hot) panel from the boat's roof. So, cool(er) vs. aesthetics. Definitely a pitfall to be aware of for boat owners installing PV.
boredemployee 3y ago
>> solar panels don't like being hot that's why in tropical countries people should aim for photothermical systems instead, collecting sun energy with parabolical mirrors heating up water, moving steam engine thus generating energy
victor106 3y ago
Off-topic: The most practical alternative energy seems to nuclear

tibbydudeza 3y ago

Had to get a home PV system out of necessity due to our national power company being up a shitcreek with an aging fleet of badly maintained coal power plants. 3.7 Kw solar panels and 2 x 5KW LifePO batteries and a 5Kw SunSynk inverter tied to the grid - solar geyser and it does not power our electric oven - the only issue is the management system is dumb as bricks - there is no intelligence and difference charge settings or profiles for our cold winters and hot summers or using the weather forecast for the day. It just averages out.

adql 3y ago
If it can be controlled via RS485 you might be able to add some smarts to it, like lowering charge level if weather is supposed to be good next few days.
- tibbydudeza 3y ago
  There are third party solutions running on a Rasberry Pi that connects to WiFi port but it means "hacking" and it bad enough maintaining my own office I.T infrastructure.

darkwater 3y ago

Yep, I live in Southern Europe and my panels have the biggest output end of April/May, while one would expect it to be end of June.

stinos 3y ago

solar panels don't like being hot Indeed, and this touches on the 'Regular cleaning of PV panels is important for ensuring maximum energy production' statement in a funny way. First of all, while the statement is accurate, I'd say is not too important practically depending on where you live. As our isntallation guys also told us. Our panels seem to do just fine with occasional heavy rainfall to clean them and the loss when they're covered in a thin layer of dust is not worth spending time on. On the other hand, the PV cleaning companies will say that it's super important to clean them. So when my mum got her panels cleaned it went like this: sunny day, panels get hot, efficiency drops. Panels were cleaned with water, temperature drops, cleaners told her 'look how much better it is now'. But after they were gone temperature rose again and efficiency was essentially back to where it was before.

hutzlibu 3y ago

"There are some water cooled panels available, but costs make them uneconomic for now." Couldn't you just use that warm water and so make it economic? Are there any combined systems that try this?

edent 3y ago
You can, but the problem is that warm water isn't that useful. Unless your system can regularly heat up to >60C to kill legionella then it will need external heating. Secondly, when the external temperatures are high there's very little need for warm water. Perhaps a few dozen litres for washing. No one is taking a hot bath on a summer's day! If you have the space, you can store the hot water underground and then pump it back up in winter for heating. But that's expensive.
- hutzlibu 3y ago
  "You can, but the problem is that warm water isn't that useful." Depends on your other systems. Dishwater wants hot water(but usually has no input for hot water), washing machine(some do). And if you have a house with 4+ people who like to shower a lot .. it adds up very quickly. And yes, heating. Now are already the days (in europe), with cold nights and mild but sunny days. So .. it makes sense in theory, but not so easy to economically make use of as of now.
robertlagrant 3y ago
I'm not sure where you could use it. At least in the UK: - water for heating your home is in a closed loop, and you wouldn't want to add this cooling to that closed loop as it would heat up your solar panels on cold days - water for drinking/washing comes from the same cold feed, and you don't want to heat that up as you can't get cold water then - bisecting the water supply into hot taps and cold taps, and running the hot one under the PV cells could work, but it would only flow the water when something is pulling water, e.g. running a tap, which might be a hindrance to cooling
- Maakuth 3y ago

RetroTechie 3y ago

> solar panels don't like being hot. For boats there's flexible panels that in many cases you can even walk on. But the sun's power not turned into electricity, heats both panel & roof of the boat (and in turn, its interior). Not something you want on a hot sunny day. A rack-mounted panel otoh, allows for airflow underneath, and -if roof mounted- separates (potentially hot) panel from the boat's roof. So, cool(er) vs. aesthetics. Definitely a pitfall to be aware of for boat owners installing PV.

boredemployee 3y ago

>> solar panels don't like being hot that's why in tropical countries people should aim for photothermical systems instead, collecting sun energy with parabolical mirrors heating up water, moving steam engine thus generating energy

victor106 3y ago

Off-topic: The most practical alternative energy seems to nuclear