Non-DIY Solar installation

[BasketCase]

I’m thinking about adding solar to my house. I live out near Lake Maprahchan in Banglamung Chonburi. I’ve got 4 inverter aircon units, and my PEA bill is usually ~6K baht per month. Plenty of roof area and unobstructed sun exposure. 
 

while I appreciate all of the DIY info and ideas on this forum, I know full well that I do not have the skills to undertake such a project on my own. 
 

I’m probably looking at a hybrid system with at least enough battery to get me thru the usual power outages, if not take me off the grid 90% of the time. I have a digital meter, sadly, so no expectation I will be a position to sell power back to the utility. 
 

Any recommendations for contractors?  Any particularly useful websites for me to guesstimate sizing?  Any particular equipment types/brands to look for or avoid?

 

thanks!!

[Muhendis]

2 hours ago, BasketCase said:

Any particularly useful websites for me to guesstimate sizing?

Sizing is easy to do for yourself.

• Think about what appliances might all be on at the same time.
• Have a look at the rating plate on each of those appliances*
• The power for each is added plus 20% for future expansion.

That will be a guide to the size of the inverter(s) you will need

* The rating plate is a small usually rectangular metal plate attached to the appliance often on the back or side where you can't quite see it.

Information on this plate will be voltage, frequency and power in watts. That power in watts is the relevant number you want.

 

Example I worked out that I should have a 12kW inverter but in reality 8kW is more than enough.

Incidentally I use 36kWh battery pack which discharges down to about 70% each night.

I am completely off grid but have an ATS (Automatic Transfer Switch) so that I can use PEA electrickery, which just happens to come into my house, if necessary.

[KhunLA]

Sizing is simple, as your PEA bill will have your units/kWh used on all bills, along with 6 month history down the bottom.   Pick your highest usage, add 20%, and I'd price a system to handle that amount.

 

It's going to be a large, expensive system, if running all those ACs in the non sun/solar producing hours.   That's about 14 hrs overnight, 1800 to 0800 hrs

 

There's only 2 of us, and we only run 1 (13k BTU) overnight, and have 20kWh of ESS/battery.  Use 40% of that most nights, and our system cost ฿445k.  If we were running the other AC (24K BTU), then TBH, our system wouldn't really be enough.  

 

I wouldn't want to take the ESS down to 30% or less every night.

 

How many people in the house, during daytime and or nighttime, along with running the ACs.

 

We can use 1000kWh during March, April, May, and that's just 2 of us, and just those two ACs (13&24k BTU).  Bedroom on 24 hrs, and larger one on, only 10 hrs, if that.

 

We have BEVs, but our local driving is minimal, and not that much of a drain keeping them charged up.  Plenty of excess to keep them charged.

 

Along with more than a few days, where the solar is barely enough to supply the house, and recharge the batteries for overnight.

 

~40% of our system cost, was the ESS/battery, 20kWh @ ฿185k of that ฿445k.

 

 

[Muhendis]

17 hours ago, KhunLA said:

Sizing is simple, as your PEA bill will have your units/kWh used on all bills, along with 6 month history down the bottom.   Pick your highest usage, add 20%, and I'd price a system to handle that amount.

It is misleading to use the kWh of your electricity bill to estimate the power output of your inverter. 

For example:

Shower heater at 4kW will use 18A @ 220v lets say for 5 minutes or 1/12^th of an hour.

That's 333Wh. 

But you would still need to have an inverter with enough power to deliver 18A or 4kW for 5 minutes.

[KhunLA]

Just now, Muhendis said:

It is misleading to use the kWh of your electricity bill to estimate the power output of your inverter. 

For example:

Shower heater at 4kW will use 18A @ 220v lets say for 5 minutes or 1/12^th of an hour.

That's 333Wh. 

But you would still need to have an inverter with enough power to deliver 18A or 4kW for 5 minutes.

That's how I sized mine, and it was almost perfect.   Why I suggested adding 20%, as there are a few days, I wish I had a bit more.

 

Though I also didn't have 3 BEVs when sizing the system, or as many electric appliances.  Made sense for more electric powered crap, after having solar.

[Njoku]

I had a 5.4 kw system with 10kw battery back in Melbourne Australia, the battery part would be beneficial here but double the size min if running aircons in evenings (not all night) other wise just cooking and lighting and a fan or two 1 10kw battery and youre likely to never pay much for electricity again, if you have a pool and just want to cut the bill a 3 kw system will do it, if no pool and dont care to much 3 kw again, they over kill the sizing here I noticed but anyway Home Pro and Mega Homes same company have solar systems installed, 3kw for around 155,000 think the 5kw around 210,000...checked with 2 local solar installers here in the Pattaya area pricing was similar of course you may add to the cost if roof needs attention for panels here they run rafter spacings a lot further apart here, battern spacings could be a problem too.

 

Then the sales guys try and sell you the Rolls Royce systems in the end you cant believe a word they say because we dont know what there flogging us so I will just go cheapest, but do youre homework on inverters as thats important, well its all important but again you are relying on them to tell you the truth..

 

Footnote, unless you are using aircons during the day most electrical consumption is in the evenings, if running aircons evenings one 10/12 kw battery wont be enough, will need 2 to make a significant dent then 5.4 kw should do it most of the time in charging up batteries here in Thailand, back in Melbourne in summer my 10kw battery was full by 11 am.