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I am looking for an off grid system for a three bedroom house in the countryside. We have five A/C units so will need a lot of panels and batteries.

Although we have three phase mains electricity it often goes off.

For full off-grid solar, you realistically need to work on about 1000 Baht per unit. e.g. if your monthly usage is 1,000 units, budget around 1,000,000 Baht for the system - and that's just the initial setup - batteries will need to be replaced as they become unserviceable.

For on-grid solar, work on about 50 Baht per kWh as a starting price (50-70 typical).

(Note that both are priced using different measures)

Off-grid is still too expensive for normal houses - people doing this need to be serious energy savers to keep the usage and costs down.

On-grid doesn't give you the backup power you need.

Your best options, in cheapest to most expensive order are:

1. A generator

2. A UPS (mains charged is cheaper than solar charged)

3. A hybrid solar system (uses solar for charging, has limited backup power ability, and send excess solar production to the grid).

All 3 require you to spec out how much backup power you actually need, before you can understand their basic costs...

When the mains goes out:

1. What system load needs to be supported (how many watts)?

2. How long of an outage does it need to support (how many hours)?

3. How frequently does it need to do this (twice daily, daily, every x days, weekly etc)?

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I am considering solar, grid connected, as well for lets say 5 kW, but I am struggle to find a relaible company in Pattaya area, which can provide all out of one hand including registration at PEA.

Any known contacts?

cheers.

No idea in the Pattaya area - most are based in greater BKK but will travel though.

This poster bought his equipment through Amorn and had Baan Solar do the installation and commissioning: http://www.thaivisa.com/forum/topic/837457-solar-installation/

Here's some others found on Google:

http://www.xn--42c5a8aa0a4fc5l8ao.com/

http://solarcellcenter.com/en/

http://www.solarmaster-thailand.com/

http://www.thaisolarfuture.com/

http://www.tgs.co.th/photovoltaicmain.html

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Actually, payback of an on-grid system comes out nearer 7 years. Got a zero misplaced somewhere CM?

An off-grid system may never break even if you consider battery replacement sad.png

Right - grid tie can break even reasonably quickly... even more quickly if you can predict how electricity costs are going to rise...

Off grid needs substantially cheaper batteries and/or much longer cyclic lifespans than what we have today to ever have a hope of competing with grid prices.

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Off grid needs substantially cheaper batteries and/or much longer cyclic lifespans than what we have today to ever have a hope of competing with grid prices.

If the Tesla mega-battery plant can get the price/performance of their Li-ion and Li-po batteries down into the same ball park as lead-acid that will be a game changer for off-grid solar power.

We shall have to see what happens.

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Thanks IMHO,

I know that it is not possible to "break even" on this system, even though my electricity bill is around 6500 baht/month. I want to instal the system mainly to be "independent" of the mains electricity supply. Do you know of a reliable supplier/installer in Thailand (we live near Hua Hin) who perhaps speaks a little English ?

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Thanks IMHO,

I know that it is not possible to "break even" on this system, even though my electricity bill is around 6500 baht/month. I want to instal the system mainly to be "independent" of the mains electricity supply. Do you know of a reliable supplier/installer in Thailand (we live near Hua Hin) who perhaps speaks a little English ?

The biggest challenge with your system is the batteries.... my 1000 Baht/unit price point assumes using relatively cheap domestic batteries (which cost 3.5-3.7 Baht/Wh) - but there's just no way to configure them for the size of load you'd have.

Let's say you build a system that can support 50 units/day, in order to give you a little headroom. Based on a 70% depth-of-discharge (to maximize battery life) and figuring 20% charging loss and 10% inverter loss, you're going to need 192,000 Wh of battery bank. And that's assuming only 1 day of autonomy (better not have too many cloudy days in a row).

The problem is, just how to make a battery bank with that kind of capacity, without it trying to kill itself... In reality, you can only go so far with the number of batteries you have in series (the smallest voltage battery is 2V - so max. of 24 batts in series for 48V), and again there's real world limits on how many strings you can wire in parallel (generally speaking, 4 parallel strings is the accepted max. before small differences in resistance becomes a big issue).

The only way I could see it working is by using the super pricey Trojan 2V 1,100Ah cells - which with 4x parallel strings of 24 batteries, would give you 211,200 Wh.

The problem is, the Trojan's cost closer to 10 Baht/Wh - so in this example, that's 96x batteries that cost 20K Baht each... which equals 1,920,000 Baht just for the batteries alone.

Still interested? tongue.png

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For some context, arguably the best (economically and scalability speaking) domestic battery for off-grid usage is the NC 6V 225Ah - which costs around 5K Baht/ea,

In a 48V system, the biggest safe configuration you could make would be 4 parallel strings of 8 batteries (32 batts total = 160K baht), which is 43,200 Wh - but that's still less than 1/4 of what you'd need.

My suggestion? If you're really serious about getting some grid independence, lower your aim down to a hybrid system, where you can afford to have less battery capacity, possibly target much deeper depth of discharges, and offset your mains bill with some grid-tie.

In order to do any math on that, I'd need you to answer those 3 questions I asked before.

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Thanks again IMHO. I am impressed by your knowledge of the subject. I can't answer those three questions precisely at the moment as I need to do some investigation and am currently out of the country. I never realised that the batteries arrangement would be the biggest problem. Perhaps I will aim for a smaller system just to act as a back up for when the power goes off. It usually goes off on average once a day for about 30 mins. which can be a bummer if you are in the shower or watching a good movie in the evening. Although we have 5 A/C units we generally only use two at the same time. Do you know a good supplier/installer ?

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This is why we have Thaivisa smile.png

To be honest, if you have mains available then a decent 1,500 RPM diesel set with auto start and small UPS's to keep your PC and TVs alive whilst it starts is going to be your most cost-effective solution. That's pretty well what we have although our genset is petrol and only 6kVA (no aircon or water heaters).

The money you save on batteries would pay for the diesel set plus an on-grid solar system to reduce your overall power bill.

EDIT and of course the backup time is limited only by the size of your diesel tank :)

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This is why we have Thaivisa smile.png

To be honest, if you have mains available then a decent 1,500 RPM diesel set with auto start and small UPS's to keep your PC and TVs alive whilst it starts is going to be your most cost-effective solution. That's pretty well what we have although our genset is petrol and only 6kVA (no aircon or water heaters).

The money you save on batteries would pay for the diesel set plus an on-grid solar system to reduce your overall power bill.

EDIT and of course the backup time is limited only by the size of your diesel tank smile.png

Thanks Crossy that is a good option to consider

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OK, let's make a hypothetical hybrid system :)

Avg total mains usage: 50 units/day (a little more than your bill)

Max. load at any one time:10kW (hot water, pump, some lights and a few AC's running).

Backup period needed: 2 hours

Outage frequency: 2 times per week

Based on this, we'd need a battery bank that could give us 20,000 Wh of usable capacity. Seeing as we'll only be cycling the batteries ~100 times per year, we can afford to push them to 50% depth-of-discharge - that pushes it up to 40,000Wh needed - but now we also need to add 10% to cover inverter losses - so we're up to 44,000 Wh.

Amazingly, my hypothetical scenario is a perfect fit for low-cost domestically made batteries :P So we know we're going to need 32x 6V 225Ah batteries at a cost of 160K Baht.

Next comes the inverter. >=10kW over 3 phases needed. Then we need a way to charge the batteries too. Based on our 2 hours @ 10kWh of usage, and providing for 20% charging loss, we're going to need: 24,000w / 48v = 500 amps of charge current - divided over say 10 hours (overnight on mains, 2 days on PV), that's 50A of charge current needed.

Shopping list:

>= 10kW 48VDC to 220VAC 3 phase inverter

>= 50A 48V battery charger

Assuming you might also want to go solar charging, and possibly even send excess solar to the grid, the best choice is probably going to be 3 of these (giving you both plenty of capacity, plus 3-phase support):

http://www.ebay.com/itm/Parallel-5kva-4000w-48v-pure-sine-wave-off-grid-solar-inverter-MPPT-60A-charger-/131134588867?hash=item1e883b07c3

Which in reality are going to cost you about 40K baht each, landed.

Add in some money for wiring, connectors, AC/DC switches and protection, and you're probably up to about 300K Baht now.

You can stop here and have a UPS, or keep going if you want solar charging....

As we can see from the spec sheet, the maximum charge rate is 60A @ 48VDC = 2,880 Watts. PV Panels will never achieve their rated output in Thailand due to the heat, and they lose capacity as they age, so let's just assume that an extra 30% PV makes sense - that's 3744 watts. So, 15x 250W panels will do the trick for recharging the batteries. They cost about 30 Baht/Wh so that's another 112,500 Baht.

On top of that, you'll need to allow ~40K Baht for PV mounting accessories, cables, connectors, control box and installation.

Total system cost: Just over 450K Baht.

On days when the batteries are full, we can also expect it to generate at least 12 units/day on average. At current prices (approx 4.5 Baht/unit) that means it's reducing the electric bill by about 1,000 Baht/month (8 days/month goes to charging the batts remember) - so over 12 years payback on the PV side of it.

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OK, let's make a hypothetical hybrid system smile.png

Avg total mains usage: 50 units/day (a little more than your bill)

Max. load at any one time:10kW (hot water, pump, some lights and a few AC's running).

Backup period needed: 2 hours

Outage frequency: 2 times per week

Based on this, we'd need a battery bank that could give us 20,000 Wh of usable capacity. Seeing as we'll only be cycling the batteries ~100 times per year, we can afford to push them to 50% depth-of-discharge - that pushes it up to 40,000Wh needed - but now we also need to add 10% to cover inverter losses - so we're up to 44,000 Wh.

Amazingly, my hypothetical scenario is a perfect fit for low-cost domestically made batteries tongue.png So we know we're going to need 32x 6V 225Ah batteries at a cost of 160K Baht.

Next comes the inverter. >=10kW over 3 phases needed. Then we need a way to charge the batteries too. Based on our 2 hours @ 10kWh of usage, and providing for 20% charging loss, we're going to need: 24,000w / 48v = 500 amps of charge current - divided over say 10 hours (overnight on mains, 2 days on PV), that's 50A of charge current needed.

Shopping list:

>= 10kW 48VDC to 220VAC 3 phase inverter

>= 50A 48V battery charger

Assuming you might also want to go solar charging, and possibly even send excess solar to the grid, the best choice is probably going to be 3 of these (giving you both plenty of capacity, plus 3-phase support):

http://www.ebay.com/itm/Parallel-5kva-4000w-48v-pure-sine-wave-off-grid-solar-inverter-MPPT-60A-charger-/131134588867?hash=item1e883b07c3

Which in reality are going to cost you about 40K baht each, landed.

Add in some money for wiring, connectors, AC/DC switches and protection, and you're probably up to about 300K Baht now.

You can stop here and have a UPS, or keep going if you want solar charging....

As we can see from the spec sheet, the maximum charge rate is 60A @ 48VDC = 2,880 Watts. PV Panels will never achieve their rated output in Thailand due to the heat, and they lose capacity as they age, so let's just assume that an extra 30% PV makes sense - that's 3744 watts. So, 15x 250W panels will do the trick for recharging the batteries. They cost about 30 Baht/Wh so that's another 112,500 Baht.

On top of that, you'll need to allow ~40K Baht for PV mounting accessories, cables, connectors, control box and installation.

Total system cost: Just over 450K Baht.

On days when the batteries are full, we can also expect it to generate at least 12 units/day on average. At current prices (approx 4.5 Baht/unit) that means it's reducing the electric bill by about 1,000 Baht/month (8 days/month goes to charging the batts remember) - so over 12 years payback on the PV side of it.

Thanks for all the calculations IMHO. I am prepared to pay that amount.

Lastly can you recommend a company in Thailand that could provide and instal all the above ?

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OK, let's make a hypothetical hybrid system smile.png

Avg total mains usage: 50 units/day (a little more than your bill)

Max. load at any one time:10kW (hot water, pump, some lights and a few AC's running).

Backup period needed: 2 hours

Outage frequency: 2 times per week

Based on this, we'd need a battery bank that could give us 20,000 Wh of usable capacity. Seeing as we'll only be cycling the batteries ~100 times per year, we can afford to push them to 50% depth-of-discharge - that pushes it up to 40,000Wh needed - but now we also need to add 10% to cover inverter losses - so we're up to 44,000 Wh.

Amazingly, my hypothetical scenario is a perfect fit for low-cost domestically made batteries tongue.png So we know we're going to need 32x 6V 225Ah batteries at a cost of 160K Baht.

Next comes the inverter. >=10kW over 3 phases needed. Then we need a way to charge the batteries too. Based on our 2 hours @ 10kWh of usage, and providing for 20% charging loss, we're going to need: 24,000w / 48v = 500 amps of charge current - divided over say 10 hours (overnight on mains, 2 days on PV), that's 50A of charge current needed.

Shopping list:

>= 10kW 48VDC to 220VAC 3 phase inverter

>= 50A 48V battery charger

Assuming you might also want to go solar charging, and possibly even send excess solar to the grid, the best choice is probably going to be 3 of these (giving you both plenty of capacity, plus 3-phase support):

http://www.ebay.com/itm/Parallel-5kva-4000w-48v-pure-sine-wave-off-grid-solar-inverter-MPPT-60A-charger-/131134588867?hash=item1e883b07c3

Which in reality are going to cost you about 40K baht each, landed.

Add in some money for wiring, connectors, AC/DC switches and protection, and you're probably up to about 300K Baht now.

You can stop here and have a UPS, or keep going if you want solar charging....

As we can see from the spec sheet, the maximum charge rate is 60A @ 48VDC = 2,880 Watts. PV Panels will never achieve their rated output in Thailand due to the heat, and they lose capacity as they age, so let's just assume that an extra 30% PV makes sense - that's 3744 watts. So, 15x 250W panels will do the trick for recharging the batteries. They cost about 30 Baht/Wh so that's another 112,500 Baht.

On top of that, you'll need to allow ~40K Baht for PV mounting accessories, cables, connectors, control box and installation.

Total system cost: Just over 450K Baht.

On days when the batteries are full, we can also expect it to generate at least 12 units/day on average. At current prices (approx 4.5 Baht/unit) that means it's reducing the electric bill by about 1,000 Baht/month (8 days/month goes to charging the batts remember) - so over 12 years payback on the PV side of it.

Thanks for all the calculations IMHO. I am prepared to pay that amount.

Lastly can you recommend a company in Thailand that could provide and instal all the above ?

I can't personally recommend any, no.

Those links I posted earlier are a good place to start - they've all been in my bookmarks for a few years now, and they look to still be in business, when many others don't seem to be now...

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This unit, or a similar one, gives the best of both worlds and is highly configurable http://www.wholesalesolar.com/2550154/outback-power/inverters/gs4048a

Note that the specific unit linked to is US standard so is not directly suitable for Thailand sad.png

In outline it provides:-

  • Grid-tie capability when the mains is on and the batteries are full reducing your utility bill.
  • UPS functionality to power your loads from the batteries / solar when the mains is off.
  • Charges the batteries from the solar (or mains if you wish).
  • Can accept and control a genset input if the batteries are depleted and there's no/insufficient solar.
  • Several units can be connected in parallel for extra oomph.

Dead clever eh smile.png

Have a look at the downloadable manual for full capabilities.

Under 3 Grand for the 4kW inverter.

EDIT a cheaper but less configurable unit http://www.alibaba.com/product-detail/hybrid-power-inverter-3kw-hybrid-solar_1852692727.html?spm=a2700.7724857.35.1.Mtjp1R&s=p

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  • 2 weeks later...

W-FIN SOLAR CELL COMPANY LIMITED

23/77 Moo1 Nongprue Bangramung

Chonburi 20150

Tel. 038-051-245 ,090-404-1138

This is a recently opened solar shop on the Crocodile Farm Road opposite the big market. Don't know if their any good, the girl spoke a little English and was very helpfull.

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  • 3 weeks later...

Have been in the shop opposite Nongprue market on Chiapornvitee road, which careybruce1 mentioned.

They told me again and again the panels should be mounted at an angle of 45 degree, no 3 line inverters available and after I asked them if they can do the registering at the PEA with all needed approvals I was told that all that is no problem.

When I asked that I would have the last payment related to the registering they kind a blocked.

Their main business is garden lights and hot water but I am certain not grid tied solar systems.

If I am wrong and somebody else made a different experience I am happy to hear about it and visit them again.

Cheers, Charly

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Thanks IMHO,

I know that it is not possible to "break even" on this system, even though my electricity bill is around 6500 baht/month. I want to instal the system mainly to be "independent" of the mains electricity supply. Do you know of a reliable supplier/installer in Thailand (we live near Hua Hin) who perhaps speaks a little English ?

The biggest challenge with your system is the batteries.... my 1000 Baht/unit price point assumes using relatively cheap domestic batteries (which cost 3.5-3.7 Baht/Wh) - but there's just no way to configure them for the size of load you'd have.

Let's say you build a system that can support 50 units/day, in order to give you a little headroom. Based on a 70% depth-of-discharge (to maximize battery life) and figuring 20% charging loss and 10% inverter loss, you're going to need 192,000 Wh of battery bank. And that's assuming only 1 day of autonomy (better not have too many cloudy days in a row).

The problem is, just how to make a battery bank with that kind of capacity, without it trying to kill itself... In reality, you can only go so far with the number of batteries you have in series (the smallest voltage battery is 2V - so max. of 24 batts in series for 48V), and again there's real world limits on how many strings you can wire in parallel (generally speaking, 4 parallel strings is the accepted max. before small differences in resistance becomes a big issue).

The only way I could see it working is by using the super pricey Trojan 2V 1,100Ah cells - which with 4x parallel strings of 24 batteries, would give you 211,200 Wh.

The problem is, the Trojan's cost closer to 10 Baht/Wh - so in this example, that's 96x batteries that cost 20K Baht each... which equals 1,920,000 Baht just for the batteries alone.

Still interested? tongue.png

What about Vanadium batteries? You can make them in any size you want and they last forever.

https://en.wikipedia.org/wiki/Vanadium_redox_battery

A Thai company is offering them: http://www.vanadiumbattery.com/

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Thanks IMHO,

I know that it is not possible to "break even" on this system, even though my electricity bill is around 6500 baht/month. I want to instal the system mainly to be "independent" of the mains electricity supply. Do you know of a reliable supplier/installer in Thailand (we live near Hua Hin) who perhaps speaks a little English ?

The biggest challenge with your system is the batteries.... my 1000 Baht/unit price point assumes using relatively cheap domestic batteries (which cost 3.5-3.7 Baht/Wh) - but there's just no way to configure them for the size of load you'd have.

Let's say you build a system that can support 50 units/day, in order to give you a little headroom. Based on a 70% depth-of-discharge (to maximize battery life) and figuring 20% charging loss and 10% inverter loss, you're going to need 192,000 Wh of battery bank. And that's assuming only 1 day of autonomy (better not have too many cloudy days in a row).

The problem is, just how to make a battery bank with that kind of capacity, without it trying to kill itself... In reality, you can only go so far with the number of batteries you have in series (the smallest voltage battery is 2V - so max. of 24 batts in series for 48V), and again there's real world limits on how many strings you can wire in parallel (generally speaking, 4 parallel strings is the accepted max. before small differences in resistance becomes a big issue).

The only way I could see it working is by using the super pricey Trojan 2V 1,100Ah cells - which with 4x parallel strings of 24 batteries, would give you 211,200 Wh.

The problem is, the Trojan's cost closer to 10 Baht/Wh - so in this example, that's 96x batteries that cost 20K Baht each... which equals 1,920,000 Baht just for the batteries alone.

Still interested? tongue.png

What about Vanadium batteries? You can make them in any size you want and they last forever.

https://en.wikipedia.org/wiki/Vanadium_redox_battery

A Thai company is offering them: http://www.vanadiumbattery.com/

Got any pricing?

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