Hybrid Solar Inverters In Thailand

[Crossy]

Probably a bit of a long shot, but worth asking anyway.

I'm looking for a hybrid inverter, 2-3kVA rating, something along the lines of the illustration:-

The system provides the following:-

1. UPS function - When the mains is off the inverter powers protected devices either from the array or from the batteries.
   
2. Battery charger - During the day the solar array charges the batteries.
   
3. Grid-tie export - When the batteries are charged and the mains is on excess solar power is exported to the grid (spins the meter backwards).
   

I've spoken to a couple of the major solar suppliers who (if they knew what I was talking about) did not have and were unwilling to get said item.

Before I bite the bullet and import a unit (with associated taxes etc.) has anyone seen anything like this in sunny Thailand.

For my application it is the ideal solution.

[aarn]

Very interesting - I lived for years on solar in the boonies in aussie, first on 12V DC with very inefficient inverter to 240V AC. Later got a bigger 24V DC solar collector array, more batteries, bigger inverter. Needless to say the batts need constant monitoring or you end up fawked...

Haven't seen solar feeding back into the grid in LOS, and generating credits and/or winding the meter backwards. Good luck!

What you want ie.

<UPS function - When the mains is off the inverter powers protected devices either from the array or from the batteries.

Battery charger - During the day the solar array charges the batteries.

Grid-tie export - When the batteries are charged and the mains is on excess solar power is exported to the grid (spins the meter backwards).>

should be do-able with a couple of small units searchable on, say, dicksmith.com.au. Shouldn't have to buy some massive, overpriced unit.

There is a chainstore ground level Tesco building in Chumphon (sorry can't remember the name) which had a lot of solar and electronic stuff.

Maybe some kind thaivisa soul can be prompted to go out there and get the name - the chainstore would have a www. presence for sure.

Building solar systems is on a par with learning linux - entails a lot of swearing to get the job done. Cheers, AA

[Crossy]

I suspect the in-store outlet was Amorn (amornsolar), they don't appear to have grid-tie let alone hybrid.

Whilst PEA don't yet have any form of domestic level feed-in tariff I don't want paying for over-generation, just generate excess during the day, use more at night, as an overall net-consumer there should be no issues with the supply authority.

I'm quite capable of designing and implementing such a system using commercially available inverters and charge controllers, but why re-invent the wheel?

Two-three days work at my full time job will pay for a unit from China (without panels, I don't earn that much), it would take longer than that to design, build and debug a DIY system.

[Crossy]

Just for comparison a few www prices for components parts to build a system:-

2500 VA grid-tie inverter = 30,000 Baht

2500 VA UPS/charger = 8,000 Baht

100A solar charge controller (assuming a 24V battery system) = 6,000 Baht or so

Say 44000 Baht for the basic big units, plus a bunch of bits and bobs to hang it all together.

The hybrids I've seen from China are about 35,000 - 50,000 Baht (plus shipping and import duties) for an integrated and adjustable unit that will probably do the job much better than anything I could build.

[SpaceKadet]

Crossy, do you have any links for the Chinese stuff?

I definitely would be interested setting something up for my house in the boonies.

The electric always goes when I'm soaped up in the shower...

[Crossy]

SK, if you're going to want to run the water pump and shower heater you'll need a BIG inverter, I suggest an auto-start genset would be better value or even a manual start provided the neighbours won't get scared by a soapy farang running around starting the generator .

I'm talking to these chaps http://www.alibaba.com/product-gs/630829634/Grid_Tie_Inverters_For_Sale_on.html for a hybrid inverter, but it won't run the A/C or water heaters. We already have a dual fuel (petrol / LPG) genset, but Wifey (yes my Thai wife) wants solar to be green.

[SpaceKadet]

Thanks for the link. I was thinking of a gennie but would prefer solar, even if it's more expensive. Problem is that electric can be out for hours, especially if it happens on a Sunday. Maybe a genset as a backup for the solar....

Don't have A/Cs, but water pump, fridge, TV/Sat and a fan is a minimum to power. 5KVA might just do it. Have to do some load calculations.

[Crossy]

There's lots on the web about on and off grid solar, a lot of reading is a smart move

The problem with any UPS system, whether the batteries are charged by solar or off the mains is that once the batteries are dead you have no power. When a generator runs out of fuel, you just fill it up and off you go again.

We have a 2kVA UPS that runs some outlets and the indoor lighting, it keeps the PCs, TVs, fans, fish tanks and lights on when the power goes off. Our battery bank is good for about 30-40 mins on full-load giving ample time to start (or refuel) the genset. I usually wait for about 15 minutes in case the power comes back before firing up the gennie.

During the floods we had no mains power for 6 months. We survived by running the genset from noon to 10PM, charging the batteries and running the fridge then going onto the UPS to run a fan and the TV. By limiting our battery usage we could usually stretch it out until we ran the genset again, it got a little boost in the morning because we ran the generator to brew tea and make toast. We also have a fast-charger so we could get a full charge in only 6 hours, but it's not good for the batteries.

After that abuse our batteries are now shot and awaiting replacement, which is of course another problem with UPS systems.

It's amazing how little power you need to survive, but no power at all makes life very difficult.

[SpaceKadet]

Definitely agree with your last statement. You don't need much, but none at all is a real bummer...

Thanks for sharing your flooding experiences. I might re-evaluate my approach. Good batteries are expensive and don't last that long. Perhaps only a generator would be enough for my needs. The neighbours are not that close, and we are all walled in, so no problems running outside all soaped up... We are going off topic here, but out of interest, what size is your gennie, and why did you prefer gasoline/lpg to diesel?

[Crossy]

We have a locally made Kwai Thong 5kVA beast.

As they say beggars can't be choosers, it's petrol because that's what was available at the time when our little Honda 2kVA died.

Also at the time we lived on the 10th floor of a condo and getting the chaps to carry a diesel set up the stairs may have been problematic.

If we need to replace it any time a diesel set with full auto-start would be the preferred option, subject to funds being available.

[balderdash]

I was interested in a system with the requirements that Crossy mentioned above and searched around for a solition. There are inverters from Outback and others that meet the requirements but are very expensiive relative to the Chinese unit mentioned above. Upon further investiigation with the company linked (post #6) I found that...

1) it is not actually a UPS because it doesn't have an ATS (automatic transfer switch). You would need to cut the mains yourself and then hit a switch on the back of the inverter. Then the inverter will take the input DC source from the battery bank rather than from the solar input as per the diagram above. Thus, any computers that were downstream of the unit would shutdown until you manually switch over the device. The Outback inverters have actual ATS switches in them and will switch like an UPS to cut the link to the grid and take over powering the home.

2) When the inverter is set in the non-GT configuration, it only takes input DC from the battery input, not from the solar MPPT input. Thus the solar MPPT logic in the device is useless when not grid-tied.

3) It doesnt have a battery charger. Therefore you would need take one of two options

a) have a seperate AC/DC charger for the battery bank (I could not find anything suitablle for the array V/A required by the inverter. Of course this would mean that you would be wasting power from the solar panels during

any grid downtime.

or

buy a solar MPPT charge controller and connect that to the solar array and the battery bank. Therefore the

solar MPPT input of the inverter would be wasted/unused. Unfortunately, again, I could not find a controller that fit

this systems volts/amps required for the battery input.

I don't mind that the system has no ATS because I am okay with having a small standard UPS on my critical devices (computers, etc), which would give me a few minutes to get up and change over the inverter to battery power.

But not having a battery charger is a big problem.

If anybody finds an inverter from a Chinese company that actually has an ATS and battery charger please let us know... at least I'd be interested. Or at least at battery charger build in, and the inverter can take DC power from both the battery and the solar array at the same time.

[Crossy]

At least you got a response BD, they didn't bother replying to me

[balderdash]

Crossy, if you (or others) are interested in the Foshan literature I received I can forward it on to you. PM me your email. I haven't found any other information on the company so I have no idea about their quality. My house here isn't built yet so I still have plenty of time to think about this.

[balderdash]

This unit seems to fit the bill...

http://www.alibaba.com/product-gs/535813146/On_Off_grid_solar_inverter_for.html

[Crossy]

It does indeed, PM sent regarding literature.

Any indication of pricing??

[Crossy]

I've got some details from Sunfine http://www.sunfinepower.com/ , quote attached.

quotation_SMS_series__1.xls

SMS的特色1.pdf

SUNFINE_grid_tie_and_Off_Grid_PV_Inverter_SMS_series1.pdf

No quantity discount for OEM, no shipping costs