Sophon

So if you have two strings of PV panels that you want to connect in parallel, which of these connectors would you use?:

5 minutes ago, bjhabal said:

Thank you ubonjoe, but it is not clear when he can apply for the one year ? is it after 45 days of the date or any time before 45 days

It is after 45 days, i.e. during the last 45 days of his 90 day permission to stay.

On 8/7/2022 at 3:02 PM, Encid said:

What if one was to set up 3 strings of panels, say 30% facing east, 30% facing west, and 40% facing south.

 

Could that 6 hour production window be mitigated by such a setup?

I saw a video on YouTube from a guy who had done just that. The conclusion was that the East and West facing panels did produce a little more in the morning/evening than the south facing ones. however, because the sunlight is not strong at that time of day, the extra production early morning/late afternoon far from outweighed the reduced production from the panels during the middle portion of the day. He had better results when turning the panels from East and West to instead pointing South-East and South-West, but even so he didn't increase his total production, he just had a little more power early and late in the day (which was his goal).

 

This was a guy living somewhere in the U.S. with snowy winters, so the results could possibly be different in Thailand. but I think the overall principle stays the same. You get the best production from a stationary panel if it points due South.

On 8/15/2022 at 7:10 PM, PR3 said:

Since I've only recently paid more attention to prices of panels I'm not really certain which way they're likely to go or what they cost before.

The way the world appears to be heading into an inflationary phase so I didn't want to wait any longer. 

In the end I paid 42000 for 10 x 420w mono half cuts.

Inverter, fitting kits, junction box for another 29000.

Hopefully another 9000 will buy the rest, so 80000 plus my labour didn't seem so excessive for a 4.2 system or 3.4ish in reality.

Everything may very well get cheaper in the future but like many things in life it's a gamble I suppose.

I'm sure more experienced members will know more.

Cheers.

PR3.

 

That's a good price for the panels, were they the BQ Solartech from your local shop you talked about?

48 minutes ago, Crossy said:

I'd be more worried that I don't see any setting for lithium batteries (unless I missed it).

There are about 30 different settings, but I have only included the ones that are different between the older and the newer model.

 

It's true that there is not a specific option to select Lithium battery, but the user manual for the newer inverter does say this under features:

 

And under the battery type setting you would then select "User-defined":

 

Since there is not specific Lithium battery setting, this might require you to adjust settings 26, 27 and 29 in order to optimize battery management, but I am hoping that maybe the changes to default settings they have made are partly to address this:

 

For those with inverters with specific Lithium battery settings, what are the values in your inverter for bulk charging voltage, floating charging voltage and low DC cut-off voltage?

So, on to the other changes mainly in the settings and information display software. As I mentioned, the overall impression is that the manufacturer has tried to simplify things by removing settings/options that you would not want to use anyway.

 

Feature	2019 model	2022 model	Verdict (IMO)
Physical differences:
USB communication port	Yes	No	Advantage old model. I don’t know if this is helpful in real life or not.
Battery connection	Screw connector	Ring terminal connector	Advantage new model. I imagine a ring terminal connection is more secure.
On/Off switch	On the side	On the bottom	Advantage old model. Purely objective, but I prefer the on/off switch to be away from all the wire connections.
Inverter settings:
Output source priority	UTI (utility) mode	No UTI mode	Neutral. While it can be argued that having more options is always good, I don’t see ever wanting to use a UTI mode.
Power saving mode	N/A	If no or small load the output of the inverter will be off	Neutral. I don’t see the point and wouldn’t turn it on
Output voltage	220V/230V/240V	N/A	Neutral. I wouldn’t want to change from the default 230V
Charger source priority	CUT (utility first) mode	No CUT mode	Neutral. I would never set the inverter to charge from PEA as first priority
Record fault code	Enabled as default	Disabled as default	Neutral. I can just change the setting
Low DC cut-off voltage	Default 40V	Default 42V	No opinion. I have no idea which is better, but it can be changed.
Battery equalization	Enable/disable plus many sub-menus	N/A	Neutral. As I understand this, it’s only relevant to lead-acid batteries
Information screens:
PV current	Screen shows PV current	N/A	Advantage old model. Could be useful information.
PV power	Screen shows PV power	N/A	Advantage old model. Could be useful information.
Charging current	Screen shows charging current for utility + PVs with diagrams that show if it’s utility or PV charging.	Shows only total MPPT charging current. Only one diagram.	Neutral. I wouldn’t charge from utility anyway.
Charging power	Same as for charging current	Same as for charging current	Neutral.
Load in watt	Screen shows Load plus Battery voltage	Shows Load plus Input voltage	Neutral. The added information is available elsewhere.
Battery voltage plus output voltage	Screen shows these values	N/A	Neutral. These values are already available in (several) other screens.

 

The newer model is a little more expensive, but not enough that it would be a deciding factor.

 

I am leaning towards the newer model, mainly because I get the impression that the manufacturer has made an effort to improve battery management. But I would appreciate input from anyone that actually understands what the changes to the DC cut-off and warning values have actually achieved, and whether the changes are an improvement or not. As mentioned earlier, I would like to believe that the changes are a step in the right direction (why else would they do them), but who knows.

 

So for anyone who have actually made it through both this and my previous post, would you go for the older or the newer model?

 

Edit: I see that the formatting of the table came out a bit wonky, but at least it's readable. 

So I have decided against going for the Powland hybrid On/Off-grid inverter I posted about on the 12th of August. It turned out, that the second manual the seller sent me was for another inverter, and the manual for the Powland inverter is just lacking in details. There is nothing about the different settings, and being new to solar inverters, I don't want to have to guess what the different options in the settings do.

 

The two Inverters I have narrowed it down to (at least for now), are both cheap Chinese hybrid  off-grid inverters.

 

Inverter number one:

 

Inverter number two:

 

The two inverters are basically 95% identical, just different model years with minor updates. The first one (which I believe is the one BritManToo has) is the 2019 model and the second one is the 2022 model.

 

It seems like they have tried to simplify things in the 2022 model, so they have removed settings and information screens, that doesn't necessarily make sense. They have also tried to optimize battery charging (at least that my interpretation of the changes), maybe to make it more compatible with Lithium batteries. Neither model has an option to select Lithium in battery type, but where the older model never mentions Lithium batteries the newer one at least states that it will work with that battery type.

 

In the following I will go through the differences between the two models. The older model is on the left and the newer on the right:

The only difference is under the "Output Short Circuit Protection:

 

 

The new inverter is slightly more efficient.

 

There are also changes to the DC warning and cut-off voltages. I have no way near enough knowledge to determine if these changes are an improvement or not, but one would like to think, that when they make the effort to change things it's for the better. 

 

They have added some additional information for the new model, but the only real change is that max. PV charging current has gone up from 100A to 110A.

 

 

The newer model is a little bigger and heavier, and can apparently work under slightly hotter conditions.

 

So all in all fairly minor changes in the spec. sheets between the two models.

 

Beyond what is mentioned in the specs. there are a few other noteworthy physical changes and quite a few software changes between the two models. But as this post is already quite long, I think I will split those into a separate post.

 

Ignore the below pics. I am unable to delete them.

 

 

 

 

2 hours ago, Crossy said:

 

Sort of.

 

The spec. you show says that if you run your inverter between 110% and 150% full load it will shut down after 10 seconds. Exceed 150% full load and it shuts down after 5 seconds. The idea being that it can support brief overloads such as motor stating surges.

 

What happens between 100% and 110% is indeterminate, it may or may not shut down after 10 seconds, this "gap" is to ensure that it WILL run at 100% indefinitely regardless of manufacturing tolerances.

 

Your 5.5kW unit running at 6kW is running at 109% and is in the "unknown" area, it may run ok, it may shut down after 10 seconds or 10 minutes (more likely on overheat).

 

It is generally accepted as "unwise" to design your system to run the inverter at maximum power regularly or for extended periods anyway.

 

If you actually have the above loading pattern you need a bigger inverter or a gas water heater.

 

 

Our load going over 5.5kW is an unlikely event, but it could theoretically happen in the winter when the water is cold (we live in the north), and if other major loads like a rice cooker is on at the same as we crank up the temperature on the shower heater. At the moment our total load, including all the normal background loads, is around 3.5kW when the shower heater is on. But it will go up somewhat when the water gets colder..

 

It's definitely not something that would be worth upgrading the system over, if it turns out to be a problem, we will just make sure that we don't take warm showers when other big loads are running. I am just trying to understand, what will happen if we do go over the rated power.

 

The inverter in question has this setting:

 

 

If I change that to "Bypass enable", would that mean that the inverter would automatically change to PEA power if overloaded, and would it automatically return to normal mode when the load falls below the rated limit?

When it says this in the specifications for an inverter;

 

does that mean that the inverter can operate at 110% of rated capacity for reasonable periods? So a 5.5kW inverter could operate at 6kW during, for instance a 15 minutes shower, when both pump and shower heater is on?

5 hours ago, Crossy said:

 

I reckon you're good to go, hopefully I've not missed the fatal flaw.

 

It always takes me a few minutes to interpret these "graphical" diagrams, I can interpret an ISO standard drawing quickly but the graphics suffer from "too much information" which confuses my aging and pre-programmed brain.

Because I don't have your knowledge about electrics, I am the opposite. In order for me to visualize how things should be put together, i need to map out the exact connections. Putting pen to paper (or electrons to display) also helps me think through what equipment I will need and where problems may arise.

 

Producing the diagram also gives me confidence that I have thought about everything, and that I will actually be able to do this myself. I think my biggest challenge will not come when putting everything together, but if/when something suddenly goes wrong six months down the road.

 

Thank you for taking the time to review my plans.

Anything I am missing?

On 8/10/2022 at 1:20 PM, 007 RED said:

My 2kW Sofar GTI came with plug-in Wifi module which enables the inverter to send a fairly comprehensive range of performance data to a remote server (in China) via my router.   It appears that the remote server 'calls' for data from the inverter about every 5 minutes.

 

I can access the inverter's data through either an application on my phone or on my PC.  The 2 apps provide slightly different outputs and are very easy to use.  The mobile app is fairly basic, whereas the PC is very comprehensive with a wide range of visual and numerical outputs, some of which can be modified to suite your needs.  The PC version also allows me to download all the system data into an Excel spreadsheet which I can, if required, produce various graphs etc. to meet my needs.

 

FYI... Both apps are recommended by the inverter manufacturer (Sofar).  The PC app = "SOLAMAN" and the mobile app = "SOLAMAN SMART"

 

NOTE:  The monitoring facility does not provide information on the performance of individual panels, it only provides data on the overall output performance of the array.

 

I hope this helps.

I couldn't find any PC or mobile apps named "Solaman", did you mean "Solarman" (which makes more sense)? I can find a "Solarman Smart" app in Google Playstore, but nothing under either name in Microsofts app store.

46 minutes ago, KhunLA said:

Inverter settings will take care of export/import to/from grid.  Just need to pay attention, if export to the grid.   I also have a breaker between the meter and house.  Of course there's the grid supply breaker on the 'breaker box/panel' in the house.

Yes, I understand that but there is always a point where the power from PEA is first connected to your system. If we take my not yet finished plans for my solar installation:

 

There is a MCB breaker on the incoming line from PEA (small blue box). If for instance the surge protector for the grid input blows, I can turn that breaker off to change to a new surge protection device. But if the incoming MCB breaker develops a fault, there is no way to change that breaker without having to work with live wires (other than getting the PEA to pull the wires at the meter). And there is nothing I can do in the inverter settings to change that.  

 

That's why I want to move the MCB to the main box, and install a bulletproof isolation switch at the small box at the power pole. Something like the good old Chang knife switch:

 

But I am open to better suggestions.

So what do you guys use to isolate your system from the grid, so you can work safely without having to have the wires pulled at the meter?

 

I could use a MCB, but then I would have the same problem if the MCB developed a fault, so I would like something bulletproof. The old fashioned Chang knife switch would do the job, but I wouldn't mind something a little less medieval looking.

 

Edit: The knife switch or whatever would be followed by a MCB, so it's not essential to have overcurrent protection in the device.

57 minutes ago, Crossy said:

You could try the manufacturer, many of the Chinese makers actually have pretty good support.

 

Yeah, I already asked the seller by email and just 7 minutes later I received this reply:
 

Quote

Don't worry my dear, these two setting options of the product can solve the problem

 

 

These settings were not in the user manual they sent me, so there must be a second set-up manuel as well. I have asked them to send me that one too.

 

I am pretty sure that I have been communicating with someone in China, and I must say that I am very impressed. They really seem to know what they are talking about and reply very quickly. 

 

I am very tempted to go for this inverter.

 

Update: Just 10 minutes after sending my second email, I received the user manual with the additional settings.

32 minutes ago, Crossy said:

 

Yeah, that's how I would read it too, but it does follow "When solar energy and batteries are insufficient" - zero solar is also "insufficient". Does it allow you to set the maximum grid charge current (set to the minimum)?

 

It might be worth asking the seller if he knows how it behaves at night.

Yes, it does but I don't see how that would help:
 

Quote

Charge current
Total Charge:
(default 60A）setting range is 10A to 90A,
the increment or decrement is 10A per click.
Note:Total Charge=Solar Charging Current+Utility Charging current

 

AC Charge：
( default 30A）setting range is 0A to 60A,
the increment or decrement is 10A per click.
Note: when the AC charging current is set to ‘0A’,if PV,battery and Utility exsist at the same time ,the PV will only charge the battery and the load is powered by
utility and the grid-tie function is not available.

So, if I set the grid charging max. to 0A to prevent PEA from filling up my battery, then my load will be powered by grid power.

 

From reading the description of the different modes, I get the impression that they are going for maximum supply security rather than autonomy and cost savings.

 

I will try to ask the seller, but the English ability of Lazada sellers can be a bit hit and miss and I doubt that the autotranslate will help.

So, the seller was nice enough to email me the manual for the Powland hybrid inverter and it definitely does export to the grid:

 

This is what the manual says about the Inverters different modes:

Quote

Working mode
AC:(default)

AC will provide power to the loads as the first
priority, solar charging the battery. When solar energy is
insufficient, AC and solar energy charge the battery at the
same time. When AC is unavailable, it will be powered by
solar energy or batteries.

 

Solar:

Solar energy provides power to the loads as the
first priority. When the solar energy is sufficient, the extra
energy will charges the battery. When solar energy is
insufficient for load, batteries and solar will supply power
the loads at the same time. When solar energy and
batteries are insufficient or solar energy is unavailable,
AC power to the loads and charge the battery at the
same time.

 

Battery:

Battery provides power to the loads as the first
priority. AC provides power to the loads when battery
voltage drop to low-level warning voltage or setting point,
and the AC power will charge the battery. When
the battery is fully charged, battery provides power to the
loads again.

AC+PV:

Solar energy provides power to the loads as the
first priority. If solar energy is not sufficient to power all
loads, AC energy will supply power to the loads at the
same time.

AC mode (default):

In this mode it sounds like the PVs and battery are only used as a back-up system, and the grid is used day to day to power your load. This would provide very little in the way of savings on your PEA bill.

 

Solar mode:
Sounds like the mode to be in, and it all sounds fine until the last paragraph:
"When solar energy and batteries are insufficient or solar energy is unavailable,
AC power to the loads and charge the battery at the same time."

 

If this is to be taken litterally, then at night or when it's raining your load will be powered by the grid, and the grid will also charge your batteries (if not full). That is not what I would want.

 

In the absence of solar, what I would want is for the load to be powered by the batteries for as long as they hold sufficient charge, and only when the batteries are expended would I want the grid to power my load. And I would also not want the grid to charge the batteries, that would result in them being full when the sun comes up, and there would be nowhere for excess energy from the PV panels to be stored. 

 

Battery mode:
No mention of PV panels in this mode, and I don't really understand the point of this mode.

 

AC+PV mode:

No mention of batteries in this mode. According to the manual, this is the mode you have to be in, if you want to export excess energy to the grid. Sounds like a mode for a system without batteries, where you use the grid for storage. I understand from what I have read that in a utility company authorized system with export to the grid, you will not have power when the grid is down even if your PV panels are producing energy, so maybe it makes sense not to have batteries.

 

Are these modes (especially the Solar mode) normal? The Solar mode doesn't make much sense to me, but maybe something has been lost in translation.

Thanks, so it sounds like even on a fairly bad day I could expect something like 5-6 kWh from my planned 4.1 kW of panels. That's about half of my average daily consumption, so not too bad.

A question for those who already have solar panels.

 

On days like we have had this week, where it is overcast and raining the whole day, do you get any production at all from your panels? If you do, how much compared to the maximum capacity of your panels? 

17 hours ago, Crossy said:

That it has a CT suggests that it can export at least some energy. Could be a good buy at the price.

 

Even though it claims to be an hybrid on-grid (actually off/on-grid) inverter, it doesn't seem to have to load split into essential/non-essential. I can only see one set of out-put ports:

 

 

So it would essentially be wired up like an hybrid off-grid inverter, which is good for me.

Any thoughts on this supposedly Hybrid on-grid inverter:

 

The product description specifically claims that the inverter can export to the grid. I still think that I will probably start out with an off-grid hybrid inverter, but for the price it's tempting.

 

I know the sellers history is questionable, only on Lazada for four months and only a few sales (none of this item). But the same seller has also been on Shopee for 20 months, the description of the inverter is just better on the Lazada link. There are also other sellers on Shopee of the same inverter but under a different brand, such as this one:

16 hours ago, Crossy said:

What's the maximum solar input voltage of your inverter?? Just go over that (there will be internal protection anyway), I expect the 500V unit would do a fine job. 20-40kA would be fine on the panel inputs, it's not like you have massive cable runs picking up the crud.

 

The 15-30% is just a guideline so you don't go too low. MOVs do wear, the trigger voltage gets a little lower each time they fire, so starting too low just means that you'll replace them sooner. 

 

We have 1000V units on our 600V inputs as the 800V units were out of stock.

 

It's always worth installing suppression.

I don't actually have an inverter yet, but the most likely candidates I have been looking at have a max. PV array Voc of 500VDC.

28 minutes ago, Crossy said:

 

You match your DC suppressor voltage to the system voltage. I would go for a suppressor of system maximum voltage +15 to +30%.

 

AC suppressors should be 275V working.

 

Surge suppression is one of those things you don't need, until you do!

 

With a hybrid inverter worth 45k Baht I'm happy spending a few k on surge suppression. And ours have definitely triggered to the point that they wore enough for the inverter to complain about earth leakage.

 

That makes it even harder to find a suitable suppressor. 95% of what I find on AliExpress is rated for 500V plus. With my two strings of six panels the voltage will be in the 230V region. I did find this suppressor:

 

But that is rated for 250V, which would be below your recommended plus 15-30% range. And as most, it's only 20-40KA.

 

How effective (or not) would a 500V rated suppressor be in protecting your solar panels running at around 230V? Would it not be worth it to install it?

On 8/6/2022 at 12:43 PM, Crossy said:

With a 50m gap you can safely run the remote stuff as a TT island with just a local ground rod and no N-E bond.

 

Definitely tie all your structure to the rod, our inverters etc are actually connected to the structure, there is a rod too (also connected to the structural steel) but in reality the structure is already a better ground than the rod.

 

Nice meaty surge arrestors at least 40/80kA preferably 60/100kA and don't forget the DC side if you have string inverters (micro inverters I wouldn't bother with DC arrestors).

 

I have been trawling AliExpress and can find loads of 20KA-40KA DC surge arrestors and some 30KA-60KA but nothing bigger. Do you have any links from earlier purchases to some of the "meatier" ones?

 

Many of the surge arrestors come with different rated voltages 500V/600V/800V/1000V, normally at the same price. Is this one of those situations where bigger is better, or should I buy a smaller one?