I have a client buying a Mecer 5kVA / 5kW inverter and a 3.5kW Li-ion battery for a start. 
how many 535W solar panels are needed max? 
can l put 10 that will give me 5350W. 
can the inverter be able to with stand this 5350W? 
it will be 2 in series and then the 5 strings in parallel. 
thanks guys

3 hours ago, 87 Dream said:

The sticker will say along the lines of: Solar DC 4000W 

That usually means the maximum output, and you can safely exceed that by 20%, 25% at a stretch.

So I would use 2S4P (8 panels), unless it's an east-west split, in which case 5P is probably acceptable. Assuming it's a 145V absolute maximum model.

Sometimes the sticker says something like maximum PV array power, in which case you should not exceed that figure at all.

Sometimes the Axpert sticker will also have a maximum input current value. The below pic is an example of the 450vdc solar charge controller on the Axpert, max inpur current 18A. More panels in series is better for this model. 

Edited August 4, 20214 yr by PurePower

On 2021/08/04 at 5:07 AM, Coulomb said:

That usually means the maximum output, and you can safely exceed that by 20%, 25% at a stretch.

So I would use 2S4P (8 panels), unless it's an east-west split, in which case 5P is probably acceptable. Assuming it's a 145V absolute maximum model.

Sometimes the sticker says something like maximum PV array power, in which case you should not exceed that figure at all.

Hi, 

the inverter’s max PV is 4000W.
20% of 4000W is 800W. So l can use (2S4P) ie 8 x 535W mono solar panels to get 4280W, the extra 280W is still safe?MPPT range @ operating voltage is 60v -115V. Max solar charge current is 80A. 

On 2021/08/04 at 3:05 PM, PurePower said:

Sometimes the Axpert sticker will also have a maximum input current value. The below pic is an example of the 450vdc solar charge controller on the Axpert, max inpur current 18A. More panels in series is better for this model. 

57 minutes ago, LeeMun said:

Hi, 

the inverter’s max PV is 4000W.
20% of 4000W is 800W. So l can use (2S4P) ie 8 x 535W mono solar panels to get 4280W, the extra 280W is still safe?MPPT range @ operating voltage is 60v -115V. Max solar charge current is 80A. 

You have the 145vdc version, so 2S is correct with a max of 4P. 4280W is well below the 25%(5000W) threshold. So 2S4P(8 panels) is correct for those size panels.  

On 2021/08/04 at 3:48 PM, 87 Dream said:

So your original question was how many do you need. Simple answer: The MAX PV Array power ÷ solar panel wattage.

So in the above example 4500W ÷ 535W = 8 Panels in series because this is the high Voltage Solar PV limit of 450V (Max Solar Voltage VOC)

 

You can exceed the PV Array power on the Sunsynk's (not sure  how much is safe, I ma sure there is a limit somewhere) , it will however clip the power at the max power so you will never be able to make more than 6500W. It does this by increasing the resistance in the inverter which reduces the amount of power it absorbs. The inverter does the same thing when your battery is full and the power being produced drops. 

You must not however exceed the combined Max Voltage of the panels as voltage cannot be reduced by resistance in the inverter and will result in smoke and fire!!

Max voltage on the 5KW  -  Max V DC input – 370V (100V~500V)

It has two MPPT's so you could do 2 strings of JA Solar Mono's 535W 6-8 per string, max amperage on the panels is 13.79 but the inverter will stop them from producing over 11A so the panels would never be able to produce more than 456W of power per panel and the whole inverter will cap out at 6500W. 

If you can do an East/West split you could have great power for a large portion of the day and start of with 6 panels per string and maybe leave some extra space to slot on 1 or 2 more depending on whether you need it or not

Sorry, thought you had a Sunsynk, see you have a Mecer, not sure on overwatting a Mecer 

 

9 hours ago, 87 Dream said:

The more sun shines on the panels the more voltage is produced.

True, but it's a small effect, perhaps 5-10%. The more solar insolation ("sun power"), the higher the maximum current that can be drawn from the panel, in almost direct linear fashion.

Quote

Seen below here as an example. The sticker of the MKSII above has max input current of 18A. This is the important limit to observe.

This is very true; the MKS IIs are very sensitive to maximum PV-side current. The results when this is exceeded by just 20% is dramatic. But the OP's client doesn't have an MKS II; it's a 145 V max model. These don't seem to have a limit on the PV-side current; it's more about the ability of the control system to cope with panels that respond to a small change in PWM ratio with a large change in current.

2S4P should be fine for this client.

15 hours ago, Coulomb said:

True, but it's a small effect, perhaps 5-10%. The more solar insolation ("sun power"), the higher the maximum current that can be drawn from the panel, in almost direct linear fashion.

This is very true; the MKS IIs are very sensitive to maximum PV-side current. The results when this is exceeded by just 20% is dramatic. But the OP's client doesn't have an MKS II; it's a 145 V max model. These don't seem to have a limit on the PV-side current; it's more about the ability of the control system to cope with panels that respond to a small change in PWM ratio with a large change in current.

2S4P should be fine for this client.

Good day

is there a module that l can link to the Mecer inverter for wifi capability for client to remotely monitor it. 

There is also 

http://www.multisibcontrol.net/

On 2021/08/11 at 5:51 AM, Coulomb said:

True, but it's a small effect, perhaps 5-10%. The more solar insolation ("sun power"), the higher the maximum current that can be drawn from the panel, in almost direct linear fashion.

This is very true; the MKS IIs are very sensitive to maximum PV-side current. The results when this is exceeded by just 20% is dramatic. But the OP's client doesn't have an MKS II; it's a 145 V max model. These don't seem to have a limit on the PV-side current; it's more about the ability of the control system to cope with panels that respond to a small change in PWM ratio with a large change in current.

2S4P should be fine for this client.

Good day to you all 

System installed and up & running. 
8 x 540W mono JA panels 2s4p. Setting 1, l chose SOL but it’s not switching from Grid to Solar until l switch off Grid and then l make Grid ON again. 
2ndly was getting 2kW solar input and it was around midday. Was expecting around 3kW to 4kW. 
We used a US3000 Li-Ion battery. setting 5 - battery type should l select User defined (USE). 
 

thanks guys. 
 

Hi

with 1 Li-ion battery US3000 and axpert Mecer inverter - the cat6 cable, do l need to connect that cable between the battery and inverter? 

thanks 

 

Hi @LeeMun, I have six Ja solar 540 watt panels in series on a Sunsynk, at midday I get about 2.4 kWh , I am based in Cape Town.

4 hours ago, Tariq said:

Hi @LeeMun, I have six Ja solar 540 watt panels in series on a Sunsynk, at midday I get about 2.4 kWh , I am based in Cape Town.

Hi @Tariq that’s like 75%, which l think Is perfect 

17 hours ago, LeeMun said:

with 1 Li-ion battery US3000 and axpert Mecer inverter - the cat6 cable, do l need to connect that cable between the battery and inverter? 

No, your model doesn't have an RS-485 or CAN port to connect to the Pylontech battery. So just leave it with battery type = USE, and use the settings with 52.5 V and 51.8 V (see many posts with those settings).

18 hours ago, LeeMun said:

8 x 540W mono JA panels 2s4p. Setting 1, l chose SOL but it’s not switching from Grid to Solar until l switch off Grid and then l make Grid ON again. 

Check setting 13, back to battery voltage.

18 hours ago, LeeMun said:

2ndly was getting 2kW solar input and it was around midday. Was expecting around 3kW to 4kW. 

Yes, I would expect around 3 kW or a little over near midday of a sunny day, if the panels have good tilt and orientation. 2 kW suggests that something is not optimal. 

On 2021/08/16 at 11:17 PM, LeeMun said:

I have the exact same one. One installer said I can only put 3 x 545w panels because of the 145vdc limit. It doesn't sound right. 

2 hours ago, JonathanLewis said:

I have the exact same one. One installer said I can only put 3 x 545w panels because of the 145vdc limit. It doesn't sound right. 

In series yes. But you can install more in parallel as voltage does not increase then but current (A) will. 

2 hours ago, JonathanLewis said:

I have the exact same one. One installer said I can only put 3 x 545w panels because of the 145vdc limit. It doesn't sound right. 

On the 545W panels I will only connect 2 in Series.

The VOC of the 545W panels are to high and will/can damaged the inverter.

 

If the Voc of each panel is for example 48V then you need only 2 in series. 
Each panel might be around 13A, in series the current remains the same. 
if the maximum solar charger rated current is 80A just make sure your strings don’t exceed 80A.