How about a solar car port on a budget?

[007 RED]

My small scale car port system (4 x 415W panels) merrily churned out 217kWh during January, which left me with a massive bill from the PEA of 281THB ????.

 

 

Note:  The dip in production on the 14th, 15th and 16th were due to going to 'NO EXPORT' in anticipation of the meter reader calling on the 15th.  He actually came at 10:00am on the 16th due to a holiday earlier in the week.

 

I've noticed that production has been exceeding my daily target of 7 units per day and reaching as much as 9 units a day on several occasions.  I will need to monitor the system carefully and possibly 'throttle back' to ensure that I don't end up with a 'negative' meter reading, which would definitely not be a good thing.

[Crossy]

Numbers for February, a short and variable month with a low daily production of 15.7kWh and a high of a very satisfactory 43.9kWh. 

 

Total solar for the month is 759kWh whilst we used 228kWh from PEA.

 

[Crossy]

Soooo, this weekend was a spash of re-configuration.

 

A couple of reasons for these activities:-

1. Our Sofar on-grid hybrid has a maximum charge current of 60A (more like 52A in reality), with my planned additional batteries it may not be able to fully charge them from dead in a day.
2. A less known issue is that when paired with lithium batteries with a BMS that has no inverter communications the Sofar only charges to about 53.2V which is only around 80% full, 54V is 99%. Nice for the cells but not for our overnight usage. It seems from posts in dedicated Sofar forums that the inverter software is optimised for lead-acid, Sofar themselves are not really interested in sorting this, they simply recommend getting a compatible BMS.

Anyway, in order to address the lack of charge current I picked up a couple of PowMr 60A MPPT charge controllers, intending to move some panels over to them to bang extra amps into the batteries and, as an extra, top up the packs to 54V when the Sofar had gone to sleep.

 

So I've set up one PowMr on 6 of our panels, we now have something like this:-

 

 

 

The PowMr isn't weather resistant so it got a box to live in, it's really a bit small (it was in stock) but the panels are only about 60% of the maximum so with luck we will be OK without box ventilation.

 

 

Things are spreading sideways, my lack of planning is evident in the somewhat random system evolution

 

 

Testing has been a bit limited so far but it does seem to be achieving the objectives, the Sofar has stopped charging but the PowMr is still banging 10A (500W) or so into the batteries.

 

The acid test will be when the new cells arrive, pretty well doubling our available storage.

 

Watch this space.

[Crossy]

Meanwhile I also had to fix our tumble dryer which we haven't used since we moved into the house in 2012. Madam says it makes the towels nice and fluffy and since the electric is now "free" ...

 

A massive 88 Baht for a motor capacitor (and a YouTube search to see how to get the ruddy thing apart) and she's happy. I'm sure the logs will show increased local consumption on laundry days, there are only two of us, but every day seems to be a washing, drying, ironing day ???? 

 

Love her to bits ????  

[Muhendis]

1 hour ago, Crossy said:

Soooo, this weekend was a spash of re-configuration.

 

A couple of reasons for these activities:-

1. Our Sofar on-grid hybrid has a maximum charge current of 60A (more like 52A in reality), with my planned additional batteries it may not be able to fully charge them from dead in a day.
2. A less known issue is that when paired with lithium batteries with a BMS that has no inverter communications the Sofar only charges to about 53.2V which is only around 80% full, 54V is 99%. Nice for the cells but not for our overnight usage. It seems from posts in dedicated Sofar forums that the inverter software is optimised for lead-acid, sofar themselves are not really interested in sorting this, they simply recommend getting a compatible BMS.

Anyway, in order to address the lack of charge current I picked up a couple of PowMr 60A MPPT charge controllers, intending to move some panels over to them to bang extra amps into the batteries and, as an extra, top up the packs to 54V when the Sofar had gone to sleep.

 

So I've set up one PowMr on 6 of our panels, we now have something like this:-

 

 

 

The PowMr isn't weather resistant so it got a box to live in, it's really a bit small (it was in stock) but the panels are only about 60% of the maximum so with luck we will be OK without box ventilation.

 

 

Things are spreading sideways, my lack of planning is evident in the somewhat random system evolution

 

 

Testing has been a bit limited so far but it does seem to be achieving the objectives, the Sofar has stopped charging but the PowMr is still banging 10A (500W) or so into the batteries.

 

The acid test will be when the new cells arrive, pretty well doubling our available storage.

 

Watch this space.

Won't be long now before you'll be totally independent from PEA.

[KhunLA]

4 minutes ago, Muhendis said:

Won't be long now before you'll be totally independent from PEA.

I can't wait to go solar, and have that 41 baht a month 'connection' bill.  OK, maybe a couple 100 baht now & then, or I'll just get more ESS.

 

Hopefully by Songkran, if the house ever gets done ????

[Muhendis]

2 hours ago, Crossy said:

I picked up a couple of PowMr 60A MPPT charge controllers

I looked at these but decided that the connection terminals were a bit on the minimalistic side.

 

How do they look in real life?

 

If ventilation is called for you might like to consider cutting some good size square holes in top and bottom of your box and fitting some stainless 1mm mesh over the holes. That's what I did for my inverter and the insects hate me for it. Mesh is held in place with construction adhesive, No Nails I think it's called. The mesh I got from Shopee quite inexpensive and still plenty left for the next project.

[Muhendis]

41 minutes ago, KhunLA said:

I can't wait to go solar, and have that 41 baht a month 'connection' bill.  OK, maybe a couple 100 baht now & then, or I'll just get more ESS.

 

Hopefully by Songkran, if the house ever gets done ????

Who will be doing your solar?

 

[Crossy]

10 hours ago, Muhendis said:

I looked at these but decided that the connection terminals were a bit on the minimalistic side.

How do they look in real life?

 

Terminals are certainly "tight" with the recommended 6mm² cable, the alternative 10AWG being slightly smaller (5.2mm²) should fit pretty easily.

 

I ended up using 2x2.5mm² on the panel connections (one per terminal, it has 2 terminals for + and 2 for -) and 4x2.5mm² on the battery side (two per terminal).

 

Connection from the solar MCB to the MC-4 connector is 6mm² and from the battery MCB to the battery is 10mm².

 

All cables are copper VSF which I like because it's reasonably flexible.

 

The SCC is also lifted off the back plate on 12mm stand-offs to allow some air circulation around the back which is where the FETs are mounted, the fan doesn't actually seem to blow air over the heatsink area at all.

[Crossy]

Just a quick update on the re-configured system after a week or so of testing.

 

Adding the PowMr SCC has indeed resulted in the batteries now charging to a more satisfactory 43.8V which equates to around 96% full. I'll go with that.

 

Our "300Ah" pack, which we know is more like 220Ah is storing between 10 and 11kWh for use each night. I can go with that too.

 

I'm currently relying on the inverter "Total Energy Discharged" facility which is pretty carp and only displays to the nearest kWh. A proper coulomb-counter is in the works which uses the BMS's serial outputs to monitor current and voltage (this was spurred on by me finding an Arduino library that talks to the Daly smart BMSs). Watch this space, I'm waiting for a couple of bits from Lazada (coming from China).

 

 

I've also had to update the software in my Solar Data logger https://aseannow.com/topic/1161970-an-internet-enabled-solar-power-monitoring-system-another-project-from-crossy-labs/

 

 

Many things have changed in 4 years and there's now a decent ThingSpeak library which simplifies writing data to the channels and a much better ESP8266 "AT Command" library which makes actually getting the Arduino Mega to connect to the internet a zillion times easier (and it has better error handling too).

 

I had planned on porting the whole thing over to a NodeMCU based device, but the new libraries probably mean that is on hold, at least for now, as I can make the Arduino Mega based unit do everything I had planned without taxing my mind too much (building a web-interface around the AT commands looked daunting).

 

All good fun and keeping the old grey-cells lubricated, or is that a copious supply of Beer Chang doing the lubricating?

 

Madam still suspects thinks knows I'm mad (I don't really look like a typical mad-scientist), but she's most happy with the reduced energy bills (more $$$ for her to spend on plants).

 

Unfortunately the increased battery pack is on temporary hold due to the entertainment system in the car being declared as "Beyond Economical Repair" so shopping at JVC-Kenwood is required (an equivalent unit is a scary 32,000 Baht ???? )

 

[BritManToo]

On 3/7/2022 at 6:43 PM, KhunLA said:

I can't wait to go solar, and have that 41 baht a month 'connection' bill.  OK, maybe a couple 100 baht now & then, or I'll just get more ESS.

Make sure you can get solar panels before anything else.

Impossible to buy at the moment, stores showing stock don't actually have any.

I've had 4 different orders from 4 different suppliers cancelled in the past 2 weeks ..... I only want two!

[Crossy]

9 minutes ago, BritManToo said:

Make sure you can get solar panels before anything else.

Impossible to buy at the moment, stores showing stock don't actually have any.

I've had 4 different orders from 4 different suppliers cancelled in the past 2 weeks ..... I only want two!

 

Check your local Global House they have Sunergy 330W poly panels at 3,590 Baht

https://www.globalhouse.co.th/product/detail/2012110639770 

or Sunergy 410W mono panels at 4,990Baht

https://www.globalhouse.co.th/product/detail/2012110639336

many locations are OOS but you may score.

 

I also saw that Mega Home have 500W mono panels (they are massive, just looking at them gave me a hernia!) at 7,500 Baht a pop, they had a decent size stack in the Rangsit store, no I didn't buy any.

[Crossy]

Here are the numbers for March boosted by a very nice 42 and 41 kWh for the 30th and 31st.

 

We generated a very respectable 905.81 kWh from the solar, meanwhile using 324.5 kWh from PEA, so that means that 73% of our electricity was "free".

 

Very happy with the system as now configured, I might even stop messing about with it for a while and look at some other project.

 

[Crossy]

A minor bump on the road yesterday, the solar was buzzing along at just under 8kW (batteries were full) when the output went to zero!

 

Check the inverters via the App, no grid ???? 

 

Still drawing energy from the grid so the mains was on. Oh well, wait 'til I get home. 

 

The failure was actually on my part. When we expanded the system I didn't replace the 32A MCB on the connection to the car port. Evidently it trips at 34A ???? 

 

Probably lost about 18kWh ???? 

 

40A breaker on order, the cable is already 6mm² so no change needed.

[BritManToo]

1 minute ago, Crossy said:

A minor bump on the road yesterday, the solar was buzzing along at just under 8kW (batteries were full) when the output went to zero!

I also have a minor bump today .........

Torrential rain all night and still going ........ battery ran out at 8am, so on grid now.

Only half the cells for my new 48V 100AH battery have arrived, so nothing I can do but wait.

[Crossy]

3 minutes ago, BritManToo said:

I also have a minor bump today .........

Torrential rain all night and still going ........ battery ran out at 8am, so on grid now.

Only half the cells for my new 48V 100AH battery have arrived, so nothing I can do but wait.

 

If you're not making it you can't store it ???? 

 

The road to energy independance is sometimes a bit rocky.

 

But it keeps the brain cells active.

[Crossy]

Our members may (or may not) be interested in a bit of history, monthly generation and usage since March 2020.

 

 

Significant system expansion points (total installed capacity).

 

March 20 - 2.4kWp

July 20 - 5.7kWp

Jan 21 - 6.3kWp

Oct 21 - 10.6kWp

 

 

[Crossy]

13 minutes ago, BritManToo said:

Only half the cells for my new 48V 100AH battery have arrived, so nothing I can do but wait.

 

Are these cells new? It will be interesting to see how they compare with the used golf-cart cells.

[BritManToo]

15 minutes ago, Crossy said:

Are these cells new? It will be interesting to see how they compare with the used golf-cart cells.

The first 8 (754bht each inc) are second hand (Lazada) and ALL slightly swollen.

The next 8 (690bht each inc) are second hand (Facebook) ..... still to arrive.

All Sinopoly 100Ah green.

 

Already wired and boxed the first 8, waiting on the top row and the Daly BMS.

Given up buying copper bars, 3 loops of 2.5mm (16A x 6= 96A) + a washer are much cheaper

 

Edited April 2, 2022 by BritManToo

[KhunLA]

On 4/2/2022 at 8:53 AM, Crossy said:

Our members may (or may not) be interested in a bit of history, monthly generation and usage since March 2020.

 

 

Significant system expansion points (total installed capacity).

 

March 20 - 2.4kWp

July 20 - 5.7kWp

Jan 21 - 6.3kWp

Oct 21 - 10.6kWp

 

 

How many panels do you have now, and what are they rated at, wattage wise ? Notice you're generating at least 15kWh a day.

[Crossy]

1 hour ago, KhunLA said:

How many panels do you have now, and what are they rated at, wattage wise ? Notice you're generating at least 15kWh a day.

 

We now have (since last October) 32 panels totalling 10.6kWp.

 

Really bad day (18/03) gave us 15.7kWh, best day recently (30/03) gave a very satisfactory 42.8kWh.

 

[Crossy]

Well another month is over so another graph.

 

A couple of bad days were offset by some very good ones and we broke the 1MWh barrier with 1.036MWh from the solar ???? 

 

In the same period we used 0.117 MWh from PEA ???? 

 

 

I've finally got my coulomb-counter doing something sensible so I can better analyse the performance of my used batteries. Watch this space ???? 

 

[carlyai]

Do you still use your origional Arduino designed cct. for checking voltage etc? I was thinking of building it this year before I start my solar build.

[Crossy]

31 minutes ago, carlyai said:

Do you still use your origional Arduino designed cct. for checking voltage etc? I was thinking of building it this year before I start my solar build.

 

This one is still doing it's thing. If I was doing it again I'd go with one of the boards with WiFi integrated, much easier. I did design a replacement using a NodeMCU board but not done much with it.

 

 

 

[Crossy]

Another month breaking the 1MWh barrier, 1,048.9 kWh from solar, 108kWh from PEA.

 

[Crossy]

Well, my shiny new Seplos BMS is installed and working. See this thread https://aseannow.com/topic/1262232-it-is-always-worth-talking-to-the-manufacturer-to-get-a-better-price/

 

To my mild amazement it just worked talking to the Sofar hybrid inverter using the cable that came with the inverter and "General Lithium" as the Battery Type.

 

Even the PC software just worked ???? 

 

It's currently "learning" the battery pack so the active balancer (top left) isn't connected as yet.

 

Whether the new BMS will actually get any better performance from the used cell pack remains to be seen.

 

Next task is to make a cover for the delicate bits.

 

 

[Muhendis]

1 hour ago, Crossy said:

Well, my shiny new Seplos BMS is installed and working. See this thread https://aseannow.com/topic/1262232-it-is-always-worth-talking-to-the-manufacturer-to-get-a-better-price/

 

To my mild amazement it just worked talking to the Sofar hybrid inverter using the cable that came with the inverter and "General Lithium" as the Battery Type.

 

Even the PC software just worked ???? 

 

It's currently "learning" the battery pack so the active balancer (top left) isn't connected as yet.

 

Whether the new BMS will actually get any better performance from the used cell pack remains to be seen.

 

Next task is to make a cover for the delicate bits.

 

 

What information about your battery pack are you getting now?

[Crossy]

Not much to report as it's only been running a few hours, let's give it a chance to do its thing.

 

It is definitely confirming that we have a weak cell at Number 6, but I knew that from the Daly BMS.

 

The inverter is certainly behaving rather differently to when it had no BMS comms so "something" is going on.

 

[Muhendis]

15 hours ago, Crossy said:

"something" is going on.

Scary

 

[Crossy]

The inverter is certainly terminating the charge at a higher voltage than before which was the original intention, so it's having at least some of the desired effect ???? 

 

Just how much "extra" capacity having BMS-Inverter comms actually gives us we shall have to wait and see.

 

There's certainly debate in the solar circles about whether it's actually worth bothering with. I probably wouldn't have done it if the Sofar inverter actually behaved as the manual says when set to "default" battery type rather than seemingly just being fixed as lead-acid.