Solar Power

[tjo o tjim]

16 hours ago, ArranP said:

 

One per shower room.

You might be light on collectors, unless you have a reflective roof behind them.  Too late now, but in general you are better off with a single bigger unit with more storage to take advantage of diversity between bathrooms. 

 

Optimistically though you should get a 10 minute shower from each, and they will pay for themselves in a year or two with good utilization. 

[maxpower]

55 minutes ago, Crossy said:

OK, time for action on my part.

 

I'm going to bung a couple of 600W micro-inverters (two panels each) on the car port and see where we go from there.

 

They should cover our standing load from the pool and koi pond without actually exporting.

 

Please correct me if wrong but does having two panels per inverter not make the installation a regular string setup. I see a micro inverter installations as having a single inverter for each panel to avoid string effects and provide optimization for each individual panel.

Joining two identical adjacent panels together in theory should be no different to using one panel of equal capacity but some seem to see this as a no no in micro inverter installations? 

[Crossy]

@maxpower the 600W inverters I have ordered have connectors for two 300W panels (4 connectors). They are tagged as "micro inverters" along with the 300W single panel and 1200W 4 panel units (the 1200W unit has 8 connectors).

 

My only reason for going for the 600W unit is that it was cheaper than 2 x 300W ????

 

No idea how the panels are connected internally or how any MPP tracking handles the two. One could reasonably assume that it's a two panel string but wouldn't the manufacturer wan to save the cost of two connectors?

 

I shall exert my curiosity when they arrive.

 

 

[maxpower]

15 minutes ago, Crossy said:

@maxpower the 600W inverters I have ordered have connectors for two 300W panels (4 connectors). They are tagged as "micro inverters" along with the 300W single panel and 1200W 4 panel units (the 1200W unit has 8 connectors).

 

My only reason for going for the 600W unit is that it was cheaper than 2 x 300W ????

 

No idea how the panels are connected internally or how any MPP tracking handles the two. One could reasonably assume that it's a two panel string but wouldn't the manufacturer wan to save the cost of two connectors?

 

I shall exert my curiosity when they arrive.

 

 

I guess the mppt control of these multi panel micro inverters provide individual channels for each panel then combine output into a common inverter.

[Crossy]

11 minutes ago, maxpower said:

I guess the mppt control of these multi panel micro inverters provide individual channels for each panel then combine output into a common inverter.

 

There's a teardown of the 1200W version here:-

 

 

Certainly looks like a per-panel MPPT ????

 

 

[jvs]

2 hours ago, Crossy said:

They should cover our standing load from the pool and koi pond without actually exporting.

You know a lot more about electricity than i do but if you just need to run a pump for lets say a pool you could just go DC?

No need for converters and the DC pump does not stop when the sun disappears behind a cloud,it just runs a little slower.I have a DC setup for irrigation and i am very pleased with it.

No switches no batteries just a pump that runs when it is light out.

[Crossy]

5 minutes ago, jvs said:

You know a lot more about electricity than i do but if you just need to run a pump for lets say a pool you could just go DC?

No need for converters and the DC pump does not stop when the sun disappears behind a cloud,it just runs a little slower.I have a DC setup for irrigation and i am very pleased with it.

No switches no batteries just a pump that runs when it is light out.

 

If I was going from scratch then yes, that would be the best way. But we already have all the pond and pool kit installed and working. We also need to run the koi pumps at night or they stop swimming and start floating.

 

[maxpower]

42 minutes ago, Crossy said:

There's a teardown of the 1200W version here:-

Certainly looks like a per-panel MPPT ????

Interesting video thanks for sharing.

 

One controller handling the optimal power point of four separate channels. I wonder how much protection has been provided against lightning induced spikes as this guy has found faults on the DC side of all channels.

[KhaoYai]

7 hours ago, BritManToo said:

I lived in a house on Brighton beach, in 1956.

The house is still there and the waterline is still in the same place 64 years later.

Same for my pal's house on Shoreham beach, zero detectable change in sea level.

You might be able to push an argument for 1-2cm sea level change in 100 years, but 30cm is just BS.

 

Anyway if you really cared about the environment you wouldn't be building houses, or flying back and forth to Thailand. If climate change was real, the first preventative step should be to ban all recreational flights.

Unfounded and unreasonable statements.

 

Firstly, I feel extremely guilty about flying 'back and forth' to Thailand. That has been a result of being thwarted in my efforts to move in 2008 by the world recession and now Brexit - believe me, I really don't want to be flying 'back and forth'.

 

I have though, done what I can to try and offset that and I believe that is significantly more then most people have done - I have halved my car usage for example and I have always made cars last - my current drive is 13 years old. I believe that its not only the fuel that we burn that has caused problems, its the constant demands on resources. As for building houses, terribly sorry but I need somewhere to live - whatever country that may be in.  The house I will be building next year is a replacement for one that is occupied by a family and they will live in the new one when its built. The old house is not at all evironmentally friendly and is in poor state.  There is no prospect of repairing it - its too far gone.  Should that family live in a tent then?

 

As for rising sea level, your claims are against all the evidence.

 

I could post hundreds of references but please argue with the findings of this UN report if you can.

 

https://www.un.org/en/sections/issues-depth/climate-change/

 

I think you might take a different view if you lived in the Maldives or the Marshall Islands.

 

Whilst Thailand is not doing enough (much the same as many other countries) to combat climate change. Do you think the Thai government is taking steps costing billions of baht to defend Bangkok for nothing?

 

Fight or flight in South East Asia and the South Pacific

South East Asian cities are busily building defences against sea level rise. For example, Jakarta is building a massive sea wall with Dutch support, and is planning to relocate 400,000 people from threatened riverbanks and reservoirs. Critics, however, fear that the city is not doing enough to address groundwater issues that are causing the city to sink. Bangkok, which faces similar challenges to Jakarta, has also laid out a 2,600km canal network and central park with a capacity to drain 4 million litres into underground containers.

Some Thai parliamentarians fear that the only way forward is a managed retreat, moving the capital further inland. Singapore, too, is adopting myriad mitigation strategies including land reclamation schemes and embankments across 70% of its coastal areas.

 

https://www.weforum.org/agenda/2019/01/the-world-s-coastal-cities-are-going-under-here-is-how-some-are-fighting-back/

 

Its time that you stopped denying climate change/sea level rises - unless you know more than the experts?

[BritManToo]

4 minutes ago, KhaoYai said:

Its time that you stopped denying climate change/sea level rises - unless you know more than the experts?

You're absolutely right, my childhood home (and my pals) must really be underwater.

PS,

Bangkok was built on a swamp, and they keep pumping out the groundwater, same in New Orleans, don't know about Jakata. Still I've got my panel up and working, while you're only talking about it.

[KhaoYai]

7 hours ago, beddhist said:

That is all true, but to keep things in perspective think about how the fuel in your car gets there and how each step damages the environment. Most EV manufacturers offer battery warranties around 8 years now and Nissan recently stated that they expect the battery to outlast the car in the new Leaf. After that the batteries have a second life for energy storage (another 10 years), after which they can be recycled. I find this Youtube channel an entertaining source of information.

 

I really tried hard to replace the family's old car with an EV, but in Thailand, outside of big cities we will have to wait a little while longer.

I agree that battery technology is advancing and its good that batteries will be recycled.  I know little of the disposal of new style batteries but old lead/acid ones were particularly bad to deal with.  Ultimately though, the new style batteries will need disposing of. My point was that at the moment, electric vehicles are not quite panacea that some people seem to think they are - mainly because of the fuels used to generate the power to charge them.  People seem to think that just because their EV itself has no emmissions - it doesn't create them. It does.

 

I'm more interested in hydrogen powered cars.  The technology doesn't seem to be there yet although Hyundai recently released a hydrogen model.  If the car manufacturers can make hydrogen work, I believe its a better alternative. No large battery pack to dispose of and the only emmissions from the power plant is water. There will no doubt be an environmental cost to produce the power cells though.

[KhaoYai]

22 minutes ago, BritManToo said:

You're absolutely right, my childhood home (and my pals) must really be underwater.

Sarcasm is the lowest form of wit - this is a serious issue.

 

https://www.climatechangepost.com/united-kingdom/coastal-floods/

 

22 minutes ago, BritManToo said:

Still I've got my panel up and working, while you're only talking about it.

I can hardly do any different when there's no house to put it on.

 

I'm fully aware that Bangkok is built on a swamp - that doesn't stop it being under threat from rising seal levels.

[Crossy]

Whilst the Climate Change stuff is interesting I really must ask that we stick to the subject in hand which is Solar Power.

[Crossy]

1 hour ago, maxpower said:

Interesting video thanks for sharing.

 

One controller handling the optimal power point of four separate channels. I wonder how much protection has been provided against lightning induced spikes as this guy has found faults on the DC side of all channels.

 

Could be time for a bag of these https://www.aliexpress.com/item/33047402955.html

 

Possibly need the 48V version (inverter max input V is 50V).

 

EDIT I note from the video that there are a few smallish MOVs in the unit. I'm probably going to add some more externally.

 

[KhaoYai]

Are the batteries used on off grid systems purely for back up or do they somehow help to stabilise output?  When the batteries are being used as the power source, what voltage do they supply?

[Crossy]

18 minutes ago, KhaoYai said:

Are the batteries used on off grid systems purely for back up or do they somehow help to stabilise output?  When the batteries are being used as the power source, what voltage do they supply?

 

An off-grid system uses the batteries to supply load when the solar input is less than the demanded power (when you put the kettle on or at night). Most use 48V battery supplies, low enough to be safe, high enough that the currents are manageable.

 

An on-grid system has no batteries, any net imbalance between the solar supply and the load is made up by using grid power (or exporting power to the grid if solar is greater than load).

 

There are also hybrid systems which combine the two functionalities either with or without the ability to export to the grid.

 

[KhaoYai]

44 minutes ago, Crossy said:

Most use 48V battery supplies, low enough to be safe, high enough that the currents are manageable

Several batteries wired in series to produce 220v or thereabouts?

 

I might be waiting a while for the kettle to boil at 48v ????

[Crossy]

6 minutes ago, KhaoYai said:

Several batteries wired in series to produce 220v or thereabouts?

I might be waiting a while for the kettle to boil at 48v ????

 

Nope, usually 4 x 12V batteries (maybe with several parallel groups to provide sufficient current or storage capacity). The inverter creates 220V AC from the 48V DC.

 

[KhaoYai]

6 minutes ago, Crossy said:

 

Nope, usually 4 x 12V batteries (maybe with several parallel groups to provide sufficient current or storage capacity). The inverter creates 220V AC from the 48V DC.

 

Ah yes, sorry, I was forgetting about the inverter.

[BritManToo]

4 hours ago, Crossy said:

 

There's a teardown of the 1200W version here:-

 

Will you have to pay duty on that?

5k5bht is a reasonable price on AliExpress, but they're 9k5bht on Lazada.

[KhaoYai]

Well thanks to everyone for their contributions - I think I've got enough information for now.  The prices have really surprised me. I'd heard some very high prices previously - probably from people who'd had a system supplied and fully installed by a dedicated solar energy company. I had at one time thought it could cost as much as 500,000 baht.

 

Incidentally, I e-mailed one such company in Thailand who have a glossy website in perfect English as I wanted a qoute to compare semi DIY against professional installation. Having seen a lot of Thai company websites, I thought the standard of the website might indicate foreign ownership.  However, having received no reply, I now believe the company is Thai????.  In the past I've found that Thai companies rarely reply to e-mails but I really thought that might have changed by now. One day they'll wake up.

[Crossy]

9 hours ago, BritManToo said:

Will you have to pay duty on that?

5k5bht is a reasonable price on AliExpress, but they're 9k5bht on Lazada.

 

Probably 10% + VAT @ 7% (both on CIF cost).

 

So 5,500 Baht (including shipping) + 10% duty 550 Baht + 7% VAT 424 Baht

Total = 6,474 

 

EDIT https://www.simplyduty.com/import-calculator/ calculates a total cost of 6,155 THB (6.67% duty - General WTO rate)

 

We shall see what is actually charged when the stuff arrives. Being shipped FedEx IP so hopefully won't get gouged. Yes I know the general advice on using courier services but if given the correct customs code they usually work ok.

 

[beddhist]

Here is what we paid on an invoice of US$ 440 (= 13767.6 THB at the time):

Duty & Tax  6,446  THB ~ 46.82%
EMS Delivery 25 Kg. 2 boxes  is  1,084  THB
Customs agent 400 THB
Total : 7,930  THB

[Crossy]

7 minutes ago, beddhist said:

Here is what we paid on an invoice of US$ 440 (= 13767.6 THB at the time):

Duty & Tax  6,446  THB ~ 46.82%
EMS Delivery 25 Kg. 2 boxes  is  1,084  THB
Customs agent 400 THB
Total : 7,930  THB

 

Seems excessive! What was the contents of the shipment?

 

[beddhist]

2 identical boxes with inverter and parallel board. On the invoice inverter and "accessories". The agent did not produce a breakdown of the charges. Perhaps I should have asked for one?

 

Your calculator uses a duty rate of 6.67% and this works out to 1915 B. Can't be right.

[Crossy]

Hmmm, the (very slow) Thai customs tariff database 

http://itd.customs.go.th/igtf/th/main_frame.jsp 

has "inverters" as 8504.40.40 the ceiling rate is 35% but there are several reduced rates.

 

The "General Rate" is 10% but there are other rates available down to exempt. The whole customs game is so fuzzy it's not true.

 

[beddhist]

I had looked at this db, but could not make any sense of it. I figured the rate would be about 35% and by the time you add VAT it's about right. I have no idea how you would go about getting better rates.

[Crossy]

Just now, beddhist said:

I had looked at this db, but could not make any sense of it. I figured the rate would be about 35% and by the time you add VAT it's about right. I have no idea how you would go about getting better rates.

 

Sadly "we" don't, that's what your agent is supposed to do.

 

We shall see what FedEx gouge on this initial small order, I've had good luck in the past (with DHL) charging the "General Rate" on a lathe.

 

[sometimewoodworker]

5 hours ago, Crossy said:

We shall see what is actually charged when the stuff arrives. Being shipped FedEx IP so hopefully won't get gouged.

Humm it looks as if you have missed the FedEx charge for customs clearance. I have often seen something in the region of 6,000 for the "service" I hope you will be lucky.

[Crossy]

3 minutes ago, sometimewoodworker said:

I hope you will be lucky.

 

So do I. IIRC DHL charged about 1k Baht clearing fee on a $1000 order, that I could accept.

 

If FedEx gouge then I'll have to find an alternative, all the other shipping methods from the seller were significantly more expensive (like double).

 

I don't mind paying, duty or VAT (not that I actually like paying of course) but if someone is asking 6k for clearing then they don't get a second chance.