Solar power question

[seedy]

If you need 24/7 uninterrupted power, you will also need some way to switch on genset if no one is around.

Auto-start switches are available. Most keep genset running for about 20 minutes or so to ensure battery charging to top up start batteries.

1500w is a sizable amount of panels, and the batteries to offset power surges when starting your load.

[cdmtdm]

seedy , i have staff live here so always someone here , we will restart in stages once we lose power and switch over to genset , i prefer manual changeover ....

[seedy]

seedy , i have staff live here so always someone here , we will restart in stages once we lose power and switch over to genset , i prefer manual changeover ....

OK - should be no problem with genset.

Just ensure that your staff powers up in stages - not one big rush of current turning everything on at once.

This can cause the genset RPM to drop, which drops the frequency, and as Crossy said above this is bad for electric motors.

Maybe divide your loads into different circuits, with a breaker on each circuit, and turn them on one at a time, this will give the genset time to recover.

[ArranP]

Technically yes, you can spin the meter backwards. Legally no.

The official solar rooftop program had a very limited list of approved inverters they'd allow you to use :

https://www.pea.co.th/vspp/Documents/Rooftop/List%20of%20Inverter.pdf

No chance your PEA is going to approve you connecting to the grid in any way unless it's one of these, and highly unlikely they'll sanction you tying to the grid via the existing sell meter....

This system uses an approved inverter, a TranEnergy PVI 5400 inverter. with 20 pv panels it produces approx 5 kWh per hour, therefore with 5 hours of (appropriate) sunlight per day and 30 days per month ( 5 kWh * 5 * 30) it produces 750 kWh per month @ 3.96 baht per kWh, the monthly bill for 750 kWh from the grid would be 3,000 baht per month. It costs 176,000 to install so should pay for itself in 4 to 5 years.

http://www.amornsolar.com/index.php?mo=18&display=view_single&pid=1559236

Whilst the house may use 25 kWh per day this will be mostly within an 18 window (awake time), the array however produces this same energy within 5 hours (appropriate sunlight time). Hence the need to spin the meter backwards and forwards to get then nett reading to 0.

The sell meter you mention I guess spins backwards and forwards. What meters do the PEA sanction for use with grid tie in systems and do they spin backwards as well as forwards ?

Edited October 20, 2014 by ArranP

[IMHO]

Technically yes, you can spin the meter backwards. Legally no.

The official solar rooftop program had a very limited list of approved inverters they'd allow you to use :

https://www.pea.co.th/vspp/Documents/Rooftop/List%20of%20Inverter.pdf

No chance your PEA is going to approve you connecting to the grid in any way unless it's one of these, and highly unlikely they'll sanction you tying to the grid via the existing sell meter....

This system uses an approved inverter, a TranEnergy PVI 5400 inverter. with 20 pv panels it produces approx 5 kWh per hour, therefore with 5 hours of (appropriate) sunlight per day and 30 days per month ( 5 kWh * 5 * 30) it produces 750 kWh per month @ 3.96 baht per kWh, the monthly bill for 750 kWh from the grid would be 3,000 baht per month. It costs 176,000 to install so should pay for itself in 4 to 5 years.

http://www.amornsolar.com/index.php?mo=18&display=view_single&pid=1559236

Whilst the house may use 25 kWh per day this will be mostly within an 18 window (awake time), the array however produces this same energy within 5 hours (appropriate sunlight time). Hence the need to spin the meter backwards and forwards to get then nett reading to 0.

The sell meter you mention I guess spins backwards and forwards. What meters do the PEA sanction for use with grid tie in systems and do they spin backwards as well as forwards ?

In the solar rooftop program, you have 2 meters - one for your incoming mains supply (buy meter), another for what you're feeding back to the grid (sell meter). Both spin only one way. i.e. All of your solar generated power goes through the sell meter, and all of your consumption goes through the buy meter.

[craighj]

So a quick question for you all.

Does anyone have any links for solar system suppliers service Issan, around Khon Kaen or Mukdahan?

Craighj

[IMHO]

So a quick question for you all.

Does anyone have any links for solar system suppliers service Issan, around Khon Kaen or Mukdahan?

Craighj

Amorn have shops all over the country, could be a good place to start: http://www.amornsolar.com/

[craighj]

So a quick question for you all.

Does anyone have any links for solar system suppliers service Issan, around Khon Kaen or Mukdahan?

Craighj

Amorn have shops all over the country, could be a good place to start: http://www.amornsolar.com/

Thanks IMHO!

Craighj

[DrSolar]

As a Solar Professional, I will answer this question for you. First, the PEA is under some confusion as to what to do about Solar. There is a general opinion within the Government to have Solar in Thailand, but they dont want a situation whereby they loose revenue either. In the previous Government there was a push to allow a Buy-Back situation to be promoted. In this current Government, I believe that this project was cancelled...we will have to wait to see the outcome of all this.

Your answer:

As you correctly stated, the best part of a Grid Tie System is that you can use the Power Company as an energy storage system without the use of batteries. To do this, you simply purchase what is called a Buy-Back Meter, which is a special meter that turns backwards when you provide power to it. However, these new meters are Digital (no little wheel turning) and the Meter Man will be quite surprised to see such an advanced meter working on the PEA side of the electrical supply. As you know in Thailand..."If you go ahead and do it, there will be no questions raised". If you ask permission, it will probably be 'Cannot'. Then there is the issue of the Meter Reading. If you put a new meter in without the PEA doing it, then the difference in the Meter Reading from the old meter and the new could be a significant electric bill...its better to have the PEA do it for you to avoid this issue.

Technical:

1. Get a Buy-Back Meter and have the PEA install it for you.
2. Remember, this is a Grid Tie System we are talking about. If the PEA grid goes down (blackout), then you will loose ALL of your power even if there is brilliant sunshine on your Solar Panel Array. If there is no grid, your solar system is 100% lost until the grid is restored.
3. There is a solution to this loss of power without a Grid to ride on, but I dont know if I am allowed to sell things on this Forum, so I wont until I am advised otherwise. Other members of this forum can advise me on this subject.
4. Off-Grid obviously has the disadvantages of the batteries, but a system can be designed that uses minimum batteries because of a technique known as Energy Scheduling whereby certain loads such as Washing Machines are only allowed to be used during the day while others like Air Conditioners can only be used during the night. This technique minimizes the battery requirements, so it is not too bad to have batteries. The BIG advantage is that you are totally independent from everybody...I personally love the idea of this, especially in Thailand.

Any questions regarding Solar from anybody will be promptly answered.

[seedy]

Amorn have shops all over the country, could be a good place to start: http://www.amornsolar.com/

My post #20 prices are from Amorn

[IMHO]

As a Solar Professional, I will answer this question for you. First, the PEA is under some confusion as to what to do about Solar. There is a general opinion within the Government to have Solar in Thailand, but they dont want a situation whereby they loose revenue either. In the previous Government there was a push to allow a Buy-Back situation to be promoted. In this current Government, I believe that this project was cancelled...we will have to wait to see the outcome of all this.

Your answer:

As you correctly stated, the best part of a Grid Tie System is that you can use the Power Company as an energy storage system without the use of batteries. To do this, you simply purchase what is called a Buy-Back Meter, which is a special meter that turns backwards when you provide power to it. However, these new meters are Digital (no little wheel turning) and the Meter Man will be quite surprised to see such an advanced meter working on the PEA side of the electrical supply. As you know in Thailand..."If you go ahead and do it, there will be no questions raised". If you ask permission, it will probably be 'Cannot'. Then there is the issue of the Meter Reading. If you put a new meter in without the PEA doing it, then the difference in the Meter Reading from the old meter and the new could be a significant electric bill...its better to have the PEA do it for you to avoid this issue.

Technical:

1. Get a Buy-Back Meter and have the PEA install it for you.
2. Remember, this is a Grid Tie System we are talking about. If the PEA grid goes down (blackout), then you will loose ALL of your power even if there is brilliant sunshine on your Solar Panel Array. If there is no grid, your solar system is 100% lost until the grid is restored.
3. There is a solution to this loss of power without a Grid to ride on, but I dont know if I am allowed to sell things on this Forum, so I wont until I am advised otherwise. Other members of this forum can advise me on this subject.
4. Off-Grid obviously has the disadvantages of the batteries, but a system can be designed that uses minimum batteries because of a technique known as Energy Scheduling whereby certain loads such as Washing Machines are only allowed to be used during the day while others like Air Conditioners can only be used during the night. This technique minimizes the battery requirements, so it is not too bad to have batteries. The BIG advantage is that you are totally independent from everybody...I personally love the idea of this, especially in Thailand.

Any questions regarding Solar from anybody will be promptly answered.

The program you refer to was called "Solar Rooftop" - it failed to meet it's targets, and ended all by itself. The big problem from my POV was that the contract required you to guarantee 25 years of supply in return for the favorable sell rate, and also was initially limited to a very small range of approved inverters, which while the program was active were inexplicably expensive (I think we all know why that was). Towards the end of the program they expanded the list of approved inverters, but by then you couldn't sign up anymore...

Are you saying that there's actually some other MEA/PEA policy that allows you to buy a 'sell' meter and install it ad-hoc, in the absence of a 'Solar Rooftop' supply contract? And if so, what the sell rate being offered?

[Naam]

DrSolar

Off-Grid obviously has the disadvantages of the batteries, but a system can be designed that uses minimum batteries because of a technique known as Energy Scheduling whereby certain loads such as Washing Machines are only allowed to be used during the day while others like Air Conditioners can only be used during the night. This technique minimizes the battery requirements, so it is not too bad to have batteries. The BIG advantage is that you are totally independent from everybody...I personally love the idea of this, especially in Thailand.

i'm afraid dear Doc you are talking science fiction when mentioning battery stored energy in context with washing machines and airconditioners. i am looking back at 8 years experience with grid charged batteries and inverters to supply essential energy to house water supply, a small microwave, a few ceiling fans, TVs, PCs and their peripheral components plus a minimum of lighting. presently i have 5 systems installed, 3 more planned. i too love being independent even though only for a miniscule part of my regular energy demand which is 100kWh/day ±20% depending on season.

but to cover only 20% of my demand by solar charged batterie banks would require initial capital cost and running maintenance cost far above a diesel generator which would provide nearly 50% of my demand.

times may change and fiction might become a fact. but not in the near future.

here's one of my batterie/inverter sets:

[IMHO]

DrSolar

Off-Grid obviously has the disadvantages of the batteries, but a system can be designed that uses minimum batteries because of a technique known as Energy Scheduling whereby certain loads such as Washing Machines are only allowed to be used during the day while others like Air Conditioners can only be used during the night. This technique minimizes the battery requirements, so it is not too bad to have batteries. The BIG advantage is that you are totally independent from everybody...I personally love the idea of this, especially in Thailand.

i'm afraid dear Doc you are talking science fiction when mentioning battery stored energy in context with washing machines and airconditioners. i am looking back at 8 years experience with grid charged batteries and inverters to supply essential energy to house water supply, a small microwave, a few ceiling fans, TVs, PCs and their peripheral components plus a minimum of lighting. presently i have 5 systems installed, 3 more planned. i too love being independent even though only for a miniscule part of my regular energy demand which is 100kWh/day ±20% depending on season.

but to cover only 20% of my demand by solar charged batterie banks would require initial capital cost and running maintenance cost far above a diesel generator which would provide nearly 50% of my demand.

times may change and fiction might become a fact. but not in the near future.

here's one of my batterie/inverter sets:

100 units per day is serious usage, and way above typical (and you know it)

Anyways, we can still do the math

100kWh * 1.2 (worst case inverter losses) * 5 (80% DOD) * 2 (days of autonomy) = storage requirements of 1,200,000Wh / 48V (4x 12V in series) = 25,000 Ah of 48VDC.

So if using 125Ah batteries, it would only take : 25,000Ah / 125Ah * 4 (for 48V in series) = 800x 12V 125Ah batteries.

Even if dividing by 5 so you're only servicing 20% of your demand, it'd still need 160 batteries. LOL

Of course, that's all theory though, because there's no way you could actually wire up 800 (or 160) batteries to work as a single bank without them killing each other.

So yep, off grid, for normal users is a long, long, long way away......

Edited January 14, 2015 by IMHO

[Naam]

a single bank is not necessarily required IMHO. one could split up whatever sets one needs to service different circuits in the home. moreover, 96V inverters are available and so are 24V batteries. that would reduce the number of batteries considerably.

to set up a "real" system one would also need huge batteries (there was a picture posted by an Australian TV-member which unfortunately i can't find). if i'm not mistaken he uses a dozen batteries who's size i estimate something like 60x60x120cm each. the chap lives in the OZ outback and is completely energy independent.

[IMHO]

a single bank is not necessarily required IMHO. one could split up whatever sets one needs to service different circuits in the home. moreover, 96V inverters are available and so are 24V batteries. that would reduce the number of batteries considerably.

to set up a "real" system one would also need huge batteries (there was a picture posted by an Australian TV-member which unfortunately i can't find). if i'm not mistaken he uses a dozen batteries who's size i estimate something like 60x60x120cm each. the chap lives in the OZ outback and is completely energy independent.

Uh-huh, I was just illustrating the point of just how much total storage is actually needed to support a normal house

In actuality, the only way to get close to it would be by using something like the Trojan 2V/1100Ah batteries so you have more in series and less in parallel - and even then you'd still need to split them into several banks to support a load like yours.

I guess all I was trying to do was reinforce the point you were making - that to do it right, and without adjusting your house and lifestyle for it, the amount of battery reserve required for off-grid is ridiculous and completely uneconomical.

[seedy]

∆ the above Trojan batts were available in Canada at approx $120 each - 3600 baht

Are they available here ?

[IMHO]

∆ the above Trojan batts were available in Canada at approx $120 each - 3600 baht

Are they available here ?

This is the distributor for TH: http://www.gatewayequipment.co.th/productdetail.php?categoryID=56

You can forget those Canadian prices though...

[seedy]

You can forget those Canadian prices though...

Thanks. Did not think for a minute that the prices would carry over !!!

[IMHO]

You can forget those Canadian prices though...

Thanks. Did not think for a minute that the prices would carry over !!!

Knowing that these batteries are in the 20-25K Baht range each in TH, I did some searching, and it seems a good price for them in CA is ~$350?

Edited January 15, 2015 by IMHO

[seedy]

Knowing that these batteries are in the 20-25K Baht range each in TH, I did some searching, and it seems a good price for them in CA is ~$350?

I may have my head inserted ...

Believe that we were buying them in bulk for those prices. Freight would be on top of that, so your figures are good for retail.

And this was before I started coming to LOS, so 11+ years now.

Sorry for the wrong info

[Naam]

You can forget those Canadian prices though...

Thanks. Did not think for a minute that the prices would carry over !!!

Knowing that these batteries are in the 20-25K Baht range each in TH, I did some searching, and it seems a good price for them in CA is ~$350?

are these deep cycle batteries IMHO? if yes, a switch from conventional batteries (which i use) would be of interest in the long run.

[IMHO]

You can forget those Canadian prices though...

Thanks. Did not think for a minute that the prices would carry over !!!

Knowing that these batteries are in the 20-25K Baht range each in TH, I did some searching, and it seems a good price for them in CA is ~$350?

are these deep cycle batteries IMHO? if yes, a switch from conventional batteries (which i use) would be of interest in the long run.

I haven't used them myself, but I've researched a lot, and the Trojan's are easily the most recommended / trusted / used-by-pro's batteries in the solar/off-grid community..

Their online calculator is a handy way to get a handle on the relationship between DOD and lifetime (cycles): http://www.batterysizingcalculator.com/ - Note that it will just say "impossible configuration" on the calcs I did earlier in this thread

Edited January 15, 2015 by IMHO

[Naam]

link doesn't work, please post again.

[IMHO]

link doesn't work, please post again.

Try this: http://goo.gl/ic6CNP

If that doesn't work, it's: www. batterysizingcalculator. com