Solar Panels

[misterangry]

Since my retirement and spending more time at home during the day, have thought of Solar Panels to help reduce the cost of running the swimming pool pump and aircons in the house.

Seems 10kw going back to your meter when not using is a good idea?, quote around 200,000 baht.

Any helpful thoughts or ideas would be very welcome.

[Heppinger]

Are you in Thailand? As i thought Thai power companies do not pay produces of solar power any money or even credit on your account when putting power back into the grid.  If this is the case than 10kw is overkill,  depending on how many air cons your running, a 5 or 6kw system would be enough.

[BritManToo]

1 hour ago, misterangry said:

Seems 10kw going back to your meter when not using is a good idea?, quote around 200,000 baht.

Any helpful thoughts or ideas would be very welcome.

You'd need to tell us what you were thinking of buying.

10kw doesn't mean anything  ...........

10kw of panels? (30x 330w panels)

10Kw of batteries?

10kwh of generation per day/week/month/year?

 

I'm about to add another 3x 330w panels to my garden with a 1000w Grid Tie inverter.

Power generation around 3 units per day (90 units a month).

Total cost around 13,000bht.

[jacko45k]

Not sure you can pump power back without getting permission (running the meter backwards). Certainly requires extra controls.

It may prove a good saving if it takes on the load though, or a good part of it. The usual issue is the expense of all the hardware, and it would take a long time to recover that based on reduced bills. 

You need to talk to someone who has done this themselves.... I recall someone at the Expats Club talking of the idea once 

[BritManToo]

Just now, jacko45k said:

The usual issue is the expense of all the hardware, and it would take a long time to recover that based on reduced bills. 

Long time = 3 years at current prices (no COVID discounts).

[jacko45k]

7 minutes ago, BritManToo said:

Long time = 3 years at current prices (no COVID discounts).

At my place, even if it took on the full load, 200.000 baht would take 5 years as my average monthly bill is 3000 baht. 

I presume the above price included sufficient batteries to do this.

[BritManToo]

9 minutes ago, jacko45k said:

At my place, even if it took on the full load, 200.000 baht would take 5 years as my average bill is 3000 baht. 

Lemme see 3,000bht/month = 750 units of electricity/month = 25 units/day.

24x 330w panels at 3,000bht/panel + 8x 1000w gtis at 4,000bht = 100,000bht 

You'd need a lot of space to put the panels!

 

Assuming the leccy people don't notice the meter running back.

Safer to just generate 25%-50% of your total usage, it's not quite so obvious.

[Crossy]

Since this isn't directly Pattaya related let's move it to Electrical for more directed input.

 

[Crossy]

Do you intend DIYing this or getting an installer to do it? Global House do a 10kW on-grid system for 330k installed https://www.globalhouse.co.th/product/detail/9229052020106

 

You can likely do it for less than half that if you DIY. 

https://forum.thaivisa.com/topic/1120934-how-about-a-solar-car-port-on-a-budget/

 

Either way net-metering (spinning the meter backwards) is not permitted, this despite the fact that there are thousands of systems in Thailand (including ours) merrily spinning backwards when exporting. The authorities are certainly clamping down and a number of members have had no-reverse meters installed, much to their annoyance. You need to ensure you never go net-export and that you're not exporting when the meter reader calls.

 

 

[sungod]

Interested in this, from a money saving, fun and green perspective. But I am also interested from a back up side. What size of batteries would i need to keep a Tv, router, a few ceiling fans, limited lighting and a largish fridge freezer running overnight if there was a blackout say.

[BritManToo]

3 hours ago, sungod said:

Interested in this, from a money saving, fun and green perspective. But I am also interested from a back up side. What size of batteries would i need to keep a Tv, router, a few ceiling fans, limited lighting and a largish fridge freezer running overnight if there was a blackout say.

Easiest way is inverter + battery.

Like this one, 1000w inverter 4kbht, 100AH battery 5kbht.

(Next step up 3kva hybrid inverter 8kbht, needs at least 2 batteries)

No need for solar (better without IMHO), this will keep my TV/NAS/router/computer (330w) going for 2-3hours and switches itself when the power goes off ....... computer doesn't blink. Needs to be outside (watertight shed) really as it has a fan you can hear on all the time. Every extra battery gets me another 2-3hrs.

 

 

For what you suggested doing, 3kva hybrid inverter (8kbht) + 4x 100AH batteries (20kbht).

Plus 4 x 330w solar cells (12kbht) if you want it to work off solar.

You might get away with 1/2 the cells and batteries.

Cheaper to buy a petrol generator IMHO.

[sungod]

35 minutes ago, BritManToo said:

Easiest way is inverter + battery.

Like this one, 1000w inverter 4kbht, 100AH battery 5kbht.

(Next step up 3kva hybrid inverter 8kbht, needs at least 2 batteries)

No need for solar (better without IMHO), this will keep my TV/NAS/router/computer (330w) going for 2-3hours and switches itself when the power goes off ....... computer doesn't blink. Needs to be outside (watertight shed) really as it has a fan you can hear on all the time. Every extra battery gets me another 2-3hrs.

 

 

For what you suggested doing, 3kva hybrid inverter (8kbht) + 4x 100AH batteries (20kbht).

Plus 4 x 330w solar cells (12kbht) if you want it to work off solar.

You might get away with 1/2 the cells and batteries.

Cheaper to buy a petrol generator IMHO.

 

Thanks, was actually looking at the price of a gennie, not that expensive in comparison and think you may be right. Just thought it may be a bit more fun, and would be totally no reliant on anything (fuel etc) .

[Metropolitian]

8 hours ago, BritManToo said:

I'm about to add another 3x 330w panels to my garden with a 1000w Grid Tie inverter.

Power generation around 3 units per day (90 units a month).

Total cost around 13,000bht.

That's or an error or an very good deal on the grid tie inverter !

3x3500 (for the panels) = 10500 that leaves out 2500 for the 1K GT inverter.

 

 

 

7 hours ago, Crossy said:

and a number of members have had no-reverse meters installed, much to their annoyance.

Metro is one of them...

 

Now working on an automatic switch to a array of chargers for the battery pack (for modified UPS, lights and 12V equipment on nights) and a signal lamp (for the missus; that she doing the laundry).

Turns on when the consumed energy going to drop below zero.

 

Sensors and process flow working already, smart switch turns on the table light.

Later this smart switch will be modified to drive a contactor/relays for starting the chargers

 

 

If I still had the old spinning wheel then I this was no issue BUT only if the generated power that day is used the -same day- , before 22.00 ,  as we are on a Time-Of-Use contract.

 

Anyone else, on a regular contract with spinning disc meter, make sure that on (and around) the day of netmetering the wheel is NOT spinning back.

 

 

 

So, to the OP; which meter and what contract are you on?

 

[misterangry]

I found the info out on the net, like others on here just looking at it for now, am I permitted to put the website of the company I found on the net, or would that be deemed to promoting them, (I do not know if they are good or bad).

But the info received so far on here has really opened my eyes, thank you all so much.

I live on the "darkside" in Pattaya and my 3 phase meter is around 12 years old.

Frankly just to run an aircon or two, the pool pump, water heater, washing machine would be brilliant, the back into the meter thing is not an issue.

If anybody runs a company or philanthropically would offer assistance, I would be very happy.

Again thank you all so much

[BritManToo]

7 hours ago, Metropolitian said:

That's or an error or an very good deal on the grid tie inverter !

3x3500 (for the panels) = 10500 that leaves out 2500 for the 1K GT inverter.

I've just ordered 3x 340w poly solar panels for 8,650bht inc delivery from Lazada.

Prices are very up and down at the moment.

[Crossy]

I have one of these chaps on order https://www.aliexpress.com/item/4000227401890.html 

 

Link it with 20 x 340W panels in two strings and you'll make 25-30 units per day (very dependent upon the weather of course). So that's going to be about 3,300 to 4,000 Baht off your power bill each month.

 

These units have a handy facility that allows you to limit the power exported, not sure yet if it can be time related but it's simple to disable the current transformer that it uses as the sensor for "export ok" days. Any excess generation is just thrown away (not actually generated).

 

There's a rather cleverer (and a lot more expensive) version which dumps excess power into batteries and then discharges the batteries when the solar isn't enough, generally it aims to keep the grid power zero.

 

 

 

 

[Metropolitian]

2 hours ago, Crossy said:

I have one of these chaps on order https://www.aliexpress.com/item/4000227401890.html 

Looks good except for the 30 euro just only for the CT ????

This inverter has the wifi and rs485 separate which is a plus.

Mine has all datacommunication trough one D-sub connector port.

In order to use the modbus data I would have to give up the wifi option.

Not giving up, trying to decode the data from the wifi to the cloud and writing a code to scrape.

Last resort is to daisychain the rs485 or Y-split the wiring, not sure which lines the wifi is using but I suspect it's just a serial to wifi gateway with a small webserver and api to upload to the cloud.

 

2 hours ago, Crossy said:

Link it with 20 x 340W panels in two strings and you'll make 25-30 units per day (very dependent upon the weather of course). So that's going to be about 3,300 to 4,000 Baht off your power bill each month.

*drooling*

 

 

2 hours ago, Crossy said:

These units have a handy facility that allows you to limit the power exported, not sure yet if it can be time related but it's simple to disable the current transformer that it uses as the sensor for "export ok" days. Any excess generation is just thrown away (not actually generated).

Yea.. that's good for who not want to export a nanowatt. For the time being I just let it export and have the electric company keep the 'waste'. And I can still monitor the 'wasted power' by checking at the meter outside.

 

But..

2 hours ago, Crossy said:

There's a rather cleverer (and a lot more expensive) version which dumps excess power into batteries and then discharges the batteries when the solar isn't enough, generally it aims to keep the grid power zero.

That's what I will let it do here when the power goes below zero it will turn on loads. Better a nutty load then a dummy load

 

 

 

[Crossy]

8 minutes ago, Metropolitian said:

Yea.. that's good for who not want to export a nanowatt. For the time being I just let it export and have the electric company keep the 'waste'. And I can still monitor the 'wasted power' by checking at the meter outside.

 

Yup, for us it's a case of not letting the meter reader see it going backwards, so the "do not export" facility will only be enabled during the meter reading period (he's pretty consistent).

[Metropolitian]

3 hours ago, Crossy said:

version which dumps excess power into batteries and then discharges the batteries when the solar isn't enough, generally it aims to keep the grid power zero.

Any ideas on DIY-ing this?

 

With TOU; Time isn't a big issue but utilizing it before 22.00 would be a better idea, IF there is any 'usage' indoors.

 

Things to consider are the  discharge rates and 'repeating'.           (price, leave that aside in the calculation/consideration as it's an external factor)

 

For a lot of repeating and short intervals high capacitors could be an option.. (?)

 

For daily buffers at and after sunset, pack of lifepo4 (or whatever the future brings us) and a hybrid-without-solar grid tie inverter which kicks in.

 

A flywheel, in the attic ?  55555

 

[Crossy]

1 hour ago, Metropolitian said:

Any ideas on DIY-ing this?

 

Thinking about it ????

 

I've got a 5kW dummy load that's controlled by an Arduino (light dimmer type phase control) which works pretty well although not needed any longer. It shouldn't be rocket science to make a variable battery charger on a similar principle, or even just PWM the DC side to keep the net grid power at zero. Going to need over-charge protection etc.

 

I've not seen a battery only grid tie inverter so it might be better to just use a normal inverter and switch the normal load (lighting, TV etc etc) over en-mass and run off the batteries until they reach the low point and then flip back to mains power. This would also have the advantage of giving a UPS-like system to keep the lights on even with the mains off.

 

Going grid tie for this would be more elegant, need to source an inverter. Maybe look at inverters intended for wind?

 

EDIT This chap looks promising, grid tie that can run battery only. It has RS-485 too although it's intended to run with a dedicated sensor. https://www.aliexpress.com/item/4001054628033.html

 

 

 

[Metropolitian]

17 hours ago, Crossy said:

Going grid tie for this would be more elegant, need to source an inverter. Maybe look at inverters intended for wind?

https://www.aliexpress.com/item/32868854419.html?spm=a2g0o.productlist.0.0.c5787534MfanfJ&algo_pvid=acf3a0bf-6108-4dbd-a831-0e0eb05f27c4&algo_expid=acf3a0bf-6108-4dbd-a831-0e0eb05f27c4-11&btsid=0ab6d69f15914272031672452e3ef8&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

 

This one seems to do the trick.

 

Some research on the web (people already tried those methods) tells me that using an 'normal' GT inverter which is only meant for solar panels would work, but on a lower efficiency.

Batteries are voltage sources and the mppt function in the inverter is for current sources like the panels.

But when the battery voltage was close to the optimal voltage for the inverter they were able to get efficiency of 80%, and some did hook up the batteries for a long time without the inverter going poof.

 

Even the cheaper inverters (with new firmware ?) , like this one
https://www.ebay.com/itm/600W-MPPT-Grid-Tie-Inverter-230V-for-12V-PV-Panel-24V-Battery-Solar-Microinverte/174201705696?hash=item288f3b14e0:g:aLwAAOSw6-5eVOEg  would accept batteries according the description.

 

[Metropolitian]

17 hours ago, Crossy said:

 

Thinking about it ????

 

I've got a 5kW dummy load that's controlled by an Arduino (light dimmer type phase control) which works pretty well although not needed any longer. It shouldn't be rocket science to make a variable battery charger on a similar principle, or even just PWM the DC side to keep the net grid power at zero. Going to need over-charge protection etc.

Sounds like a plan for one of the boards here ???? do you have an article on this?

 

17 hours ago, Crossy said:

I've not seen a battery only grid tie inverter so it might be better to just use a normal inverter and switch the normal load (lighting, TV etc etc) over en-mass and run off the batteries until they reach the low point and then flip back to mains power. This would also have the advantage of giving a UPS-like system to keep the lights on even with the mains off.

For a reason that I have an 4P ATS on my shelf.

 

Using the other 2-3 for opening/closing the batteries and switching between charger and inverter. Only the L1 port (and N) is connected to the circuit inside.

Method that I was thinking was like this: the sensor that detects when the power usage (almost) going the other way it will de-energize the L1 (using smart switch) and the ATS changes over and at the same time connects the batteries to a offgrid inverter which feeds a low-power group like lights and tv.

The sunny side with this method is that with power cuts the batteries would kick in too.

 

Then I would have to ponder about how to hook the on grid inverter in the same group, and the offgrid inverter would give the 50hz to the group but the load in the group need to be higher than the generated power by the ongrid inverter otherwise the offgrid inverter gets the magic smoke. (Ask me how do I know )

 

And then came along the idea for a ongrid inverter on batteries instead ????

 

 

 

17 hours ago, Crossy said:

EDIT This chap looks promising, grid tie that can run battery only. It has RS-485 too although it's intended to run with a dedicated sensor. https://www.aliexpress.com/item/4001054628033.html

 

 

I have seen something like that yesterday, but a slightly different diagram. 

Wonder if the mppt controller and inverter are happy working together and with the DC pulsating like an half AC.   (Here around 47khz)

By the way isn't a hybrid inverter just like B and C together? And C alone seems likely to work on batteries alone.

 

 

The reason for the invention of the no-power-to-the-grid inverters was simply because there are digital meters on the world which has no sense of direction of the flow.

The consumer would then pay for imported+exported power.

Smart-meters now really don't need those. 

Spinning wheel meters, in Thailand, no exporting as we all know on metering days and having the luck your meter to be the only one on the pole ????

 

[Metropolitian]

18 hours ago, Crossy said:

EDIT This chap looks promising, grid tie that can run battery only. It has RS-485 too although it's intended to run with a dedicated sensor. https://www.aliexpress.com/item/4001054628033.html

 

 

 

Spot on ????

 

Just checked the manual; the inverter (C) can work in two modes (mode setting via display). 

 

PV and BAT,  on which the PV mode use the built in MPPT method and BAT mode locks on the voltage according the type of the GTI.

 

The MPPT controller (B) is needed IF you want to use both solar and batteries.

The GTI (C) need then be set on BAT-mode.

 

Edit:

'Connection method (optional):

4. B+C

5. A+B+C

6. A+C

7. A+B

 

I like mehod 5 and a cloud in my brain says with a modified system; a current resistor in series between device B and C and a contactor between the battery and an extra battery bank (nutty 'dummy' load) when the primary bank is full. In normal mode the contactor (NC) shorts the current resistor and when the power usage is low energize the contactor, the current resistors clamps the flow going to the GTI, current goes to the banks. 

Most MPPT controllers want to have a battery bank connected, permanently.

The extra battery bank can connect automatically when the primary runs out.

I need a drawer for those plans, missus has other plans for me to do ????

 

[Crossy]

The current plan of action, once the new 6kW inverter arrives is:-

• Fully populate the car-port roof with panels, there's room for 18, so two strings of 9.
• Store the existing GTIs for later.
• Sort out how the do-not export function works and if it can be controlled via the app.
• Assuming not then link a relay across the CT controlled from my solar monitor to enable the function (disable export) on and around meter day.
• Add an extension to the car-port roof for 6 more panels 4 of which can run with the existing micro-inverters and cover the base load, add the other two to the 6kW beastie which would put it at capacity.

Hope we don't get sussed by PEA  

 

But assuming we will eventually end up with an electronic / no-reverse meter look at adding batteries and a controllable charger to store excess power for use later via a GTI like the one linked above.

 

Oh, and keep going to work to pay for it all ????

 

That should keep the mind active for a while ????

 

[davemos]

Plenty of info from Australia that shows the cost of solar is not just in the initial  installation but in maintenance .This makes the savings marginal or non existent. A small efficient generator on back up would do the trick for a fraction of the price.

[Laza 45]

This popped up on my FB.. I don't know how available these systems are.. or how good but I thought it is interesting.. https://sunshine.en.made-in-china.com/product/YNrQVPuyClhs/China-Pure-Solar-Powered-Air-Conditioner-DC48V-12000BTU-Easy-Installation-Solar-Air-Conditioner.html?utm_source=facebook&utm_medium=cpc&utm_campaign=01-pc-feed1-old&utm_content=01-pc-feed1-retargetdev-stheast-3c&fbclid=IwAR1UllH0qrioaP764L05VlCdEi8J-kIlgb6oXGZ91indgKmNFfNca2bV1xs

 

[BritManToo]

1 hour ago, davemos said:

Plenty of info from Australia that shows the cost of solar is not just in the initial  installation but in maintenance .This makes the savings marginal or non existent. A small efficient generator on back up would do the trick for a fraction of the price.

What maintenance?

My panels have been in since last July, apart from wiping the panels once a month, what else could I do?

[Fruit Trader]

36 minutes ago, BritManToo said:

What maintenance?

My panels have been in since last July, apart from wiping the panels once a month, what else could I do?

Not everyone has panels lashed to the fence.

 

QUOTE :-

Homeowners spend an average of $150 to have their solar panels cleaned. Depending on factors such as roof slant, home height and system size, companies charge between $3 and $10 per panel. Some charge a flat rate within a range of $150 to $350. Annual inspections are typically $150 before the cost of cleaning.

[Andrew Dwyer]

Here’s another option for you budding “ solar junkies “.

 

[BritManToo]

1 hour ago, Fruit Trader said:

QUOTE :-

Homeowners spend an average of $150 to have their solar panels cleaned. Depending on factors such as roof slant, home height and system size, companies charge between $3 and $10 per panel. Some charge a flat rate within a range of $150 to $350. Annual inspections are typically $150 before the cost of cleaning.

Did everyone not realise they'd have to clean them?

One of my first considerations when looking to place mine, have to be easy to clean.

I guess you can't fix stupid!