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Growatt SPF5000ES Offgrid 9kw DIY Solar Project


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8 minutes ago, Encid said:

The estimate should be based on panel rating x 0.8 x 5 (80% of panel rating over 5 hours), so if you have 20 off 330W panels your average daily production would be 330 x 20 x 0.8 x 5 = 26.4 kW.

Thanks for the input. what i estimated was production/hour ( watthour) to see what would be capacity left for charge batteries.

 

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6 hours ago, BritManToo said:

Doesn't mean anything to me, battery storage is measured in kWhr.

Here is a 48V 8kWhr battery, 35kbht.

https://www.lazada.co.th//products/i2393934477-s8157207174.html

 

80-90% of Lifepo4 batteries are usable, nobody buys lead acid batteries any more.

Small point but the Lazada batteries you mention are not LiFePO4's. They are NMC's same as used in power tools.

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41 minutes ago, Muhendis said:

Small point but the Lazada batteries you mention are not LiFePO4's. They are NMC's same as used in power tools.

Ok

Lithium batteries  .............. can use 80-90%

I didn't look to see what batteries he was putting in that particular pack.

It appears he's mostly using NMC at the moment.

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50 minutes ago, Muhendis said:

And don't forget surge/lightning protection

Unless your home has a history of lightning strikes, why would you need that protection?

IMHO it's nothing but a little extra money in the solar scammers pockets.

(like the 'special' wires they want you to use).

 

Q: How many people have you encountered who had lightning strikes on their solar equipment?

A: None, same as me.

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24 minutes ago, BritManToo said:

Unless your home has a history of lightning strikes, why would you need that protection?

IMHO it's nothing but a little extra money in the solar scammers pockets.

(like the 'special' wires they want you to use).

 

Q: How many people have you encountered who had lightning strikes on their solar equipment?

A: None, same as me.

what wire u suggest for serial string panels?

 

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9 minutes ago, Pink7 said:

what wire u suggest for serial string panels?

 

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I plug all the mc4 connectors in series, then use 2.5mm insulated twin to connect through a double 500V DC breaker to the inverter. 

 

OK, so I should put the exterior twin insulated in an electrical conduit to protect the insulation from uv degradation, but I'm betting it's good for 5 years as is. 

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9 hours ago, BritManToo said:

Unless your home has a history of lightning strikes, why would you need that protection?

IMHO it's nothing but a little extra money in the solar scammers pockets.

(like the 'special' wires they want you to use).

 

Q: How many people have you encountered who had lightning strikes on their solar equipment?

A: None, same as me.

Correct , however , there are lightning strikes on homes every single day , and i do know people who did have it . There was no solar installation there , but that is beside the point i think . Problem with solar is that there are high voltages , and they do keep on generating electricity even when the house is completely on fire ( many times dangerous for firefighters these days , as are the lithium batteries when there is a fire in them ) . Surge protectors are near the cheapest item in a solar installation , only a few 100 baht . For that price , why skip on it ? Taking a 50k to several 100k of installation and then let some extra safety let go for a few 100 baht ...  I am all in for saving some money but for that amount of money , i wouldn't skip it .

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From Inverter manual:

 

WARNING: Because this inverter is non-isolated, only three types of PV modules are acceptable: single crystalline and poly crystalline with class A-rated and CIGS modules. To avoid any malfunction, do not connect any PV modules with possible current leakage to the inverter. For example, grounded PV modules will cause current leakage to the inverter. When using CIGS modules, please be sure NO grounding.

 

Means ?

 

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3 hours ago, Pink7 said:

From Inverter manual:

 

WARNING: Because this inverter is non-isolated, only three types of PV modules are acceptable: single crystalline and poly crystalline with class A-rated and CIGS modules. To avoid any malfunction, do not connect any PV modules with possible current leakage to the inverter. For example, grounded PV modules will cause current leakage to the inverter. When using CIGS modules, please be sure NO grounding.

 

Means ?

 

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It means don't ground the + or - side of the panels, you should still ground the metalwork of course.

 

Also don't ground either pole of your battery, in fact don't gayly scatter grounds around, only ground terminals marked as "ground" or image.png.c6c0e692fae69af1e32fe71eedd86922.png

 

Grounded modules are rare these days anyway, any panel you buy will be just fine.

 

All high-frequency inverters have the same warning hidden somewhere in the dogumentation.

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10 hours ago, Pink7 said:

regarding:  surge/lightning protectionI have 2 serial strings so i guess i need 1 unit per string then?   

solar3.jpg

Are the two serial strings joined into a single feed in a combiner box or are they two separate feeds into the solar inputs of an inverter?

If the former then only one is needed at the combiner output. If the latter then it's one per string.

Also please note that an AC anti surge/lightning protector is different from a DC one so get the right one for the job.

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2 hours ago, Crossy said:

 

It means don't ground the + or - side of the panels, you should still ground the metalwork of course.

 

Also don't ground either pole of your battery, in fact don't gayly scatter grounds around, only ground terminals marked as "ground" or image.png.c6c0e692fae69af1e32fe71eedd86922.png

 

Grounded modules are rare these days anyway, any panel you buy will be just fine.

 

All high-frequency inverters have the same warning hidden somewhere in the dogumentation.

Thanks for that info

 

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1 hour ago, Muhendis said:

Are the two serial strings joined into a single feed in a combiner box or are they two separate feeds into the solar inputs of an inverter?

If the former then only one is needed at the combiner output. If the latter then it's one per string.

Also please note that an AC anti surge/lightning protector is different from a DC one so get the right one for the job.

There is 2 single serial strings who have its own pw port on inverter. So i will use a dc breaker and dc surge/lightning protector between panels and inverter. AC anti surge/lightning protector i should use for grip power before inverter?

 

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2 hours ago, Muhendis said:

Are the two serial strings joined into a single feed in a combiner box or are they two separate feeds into the solar inputs of an inverter?

If the former then only one is needed at the combiner output. If the latter then it's one per string.

Also please note that an AC anti surge/lightning protector is different from a DC one so get the right one for the job.

This one ok for ac?

 

 

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solar4.jpg

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36 minutes ago, 007 RED said:

As has pointed out by @Muhendis and @Crossy, it is wise to have an appropriate breakers and surge suppressors located either side and as close to your inverter as practically possible.  As has been mentioned, it is extremely important to only use a DC breaker on the DC side of the inverter and an AC breaker on the AC side of the inverter.  Big flashes and magic smoke are likely to occur if you use an AC breaker on the DC side of the inverter.

 

The breakers enable you to isolate the inverter from DC and AC supplies, so that you can carry out any maintenance on the panels or remove the inverter if necessary.  The surge suppressors are there to protect your investment (inverter) in the event of a surge arising from a nearby lightening strike or problems with you local PEA supply.

 

The photo below which I provided in an earlier post shows my small scale set up with the Sofar GTI inverter in the centre. 

1275652444_20210926_105915x.jpg.6aec99958942daa886742b36dd658cc6.jpg

 

The cables coming down from the top left of the picture are the DC +/- feeds from the 4 x 415W (connected in series) solar panels mounted directly above on the roof of the car port.  These cables are connected to the DC breaker and and surge suppressor which are housed in my home made 'safety box' (small empty consumer unit box).  From the DC breaker the +/- cables are then connected to the respective input DC sockets on the inverter. 

 

With your proposed setup you would have two feeds coming from your solar panel array, e.g. PV1 and PV2, each of which should be connected to their own DC breakers and surge suppressors before being connected to the inlet connections on the inverter.

 

The large black plug and cable coming out the bottom right of my inverter is the AC cable which is feeding power generated by the inverter to my house consumer unit.  This cable is initially connected to the AC breaker and suppressor, again in a home made 'safety box' before being connected to the consumer unit in the house.

 

FYI.... Both 'safety boxes' and the inverter have separate earth cables which are connected to the metalwork of the car port.  The metalwork inside the main supports of the car port are buried quite deep " meters plus) into the ground, but I have also connected a 2 meter earth rod buried in the soil to the car port metalwork.  'Belt and braces' approach.

 

I hope this helps with your proposed project.

Thanks for the info. Your setup is connected to grid? My manual want breaker and surge protection on the IN power sources, grid and pw.

 

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5 minutes ago, Pink7 said:

Thanks for the info. Your setup is connected to grid? My manual want breaker and surge protection on the IN power sources, grid and pw.

 

It's a grid-tie inverter so there's no "out" connection.

 

Your manual is correct ???? 

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2 hours ago, Pink7 said:

There is 2 single serial strings who have its own pw port on inverter. So i will use a dc breaker and dc surge/lightning protector between panels and inverter. AC anti surge/lightning protector i should use for grip power before inverter?

 

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The incoming AC utility supply will connect to a fused isolator switch with the output from the fused isolator switch going to your inverter. The AC lightning/surge protector connects at the output from the fused isolator switch. The surge protector will go low resistance if there is a spike/surge in the mains voltage. This low resistance will cause a large current to flow through the fused isolator switch which will trip and save all other bits'n pieces  connected to the incoming utility supply.

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3 minutes ago, Muhendis said:

The AC utility input will connect to a fused isolator switch with the output from the fused isolator switch going to your inverter. The AC lightning/surge protector connects at the output from the fused isolator switch. The surge protector will go low resistance if there is a spike/surge in the mains voltage. This low resistance will cause a large current to flow through the fused isolator switch which will trip and save all other bits'n pieces  connected to the incoming utility supply.

Ok, can you show example of what i need to buy for that?

 

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