Minimum number of panels needed?

[Pho3nix]

Hi all,

Looking for different perspectives here. Have a 5kW Deye Inverter and looking to off-set some power costs (not go completely off-grid) and charge the battery for daylight load-shedding sessions.

Quoted on a 5x470W Jinko panels and worried this might be too much for my daily current idle load of 400kw throughout the day/night BUT was told it's the minimum the inverter needs and panels around 550w won't be ideal.

Thoughts and suggestions? Looking for as few panels that will allow the Inverter to do what it has to.

 

[Fcon_Vpro]

Hi all,

Looking for different perspectives here. Have a 5kW Deye Inverter and looking to off-set some power costs (not go completely off-grid) and charge the battery for daylight load-shedding sessions.

Quoted on a 5x470W Jinko panels and worried this might be too much for my daily current idle load of 400kw throughout the day/night BUT was told it's the minimum the inverter needs and panels around 550w won't be ideal.

Thoughts and suggestions? Looking for as few panels that will allow the Inverter to do what it has to.

You could probably go with 4 of them minimum.
150v required for startup, and the 470w panels are 43v each, so 4 in series is over 150v.

The 550w panels won't hit their maximum wattage as they will clip at 11amps(mppt max). But will provide slightly less max power than the 470w panels.
If I take the Canadian solar 550w panels, they 41.7v and 13.2a.
So the 550w panels will produce: 11ax41.7=458.7w
The 470w panels will produce 470w because they 43.28x10.86a (10 is less than 11)

So you still need 4x 550w panels minimum to produce less max power and you will pay more for it.
The 550w will only be better in lower light situations.
I have these 470w jinkos with a sunsynk 5kw and they work great.

This advice is only to give you the minimum panels required to start up. I don't know your max loads, etc or your battery size to say if 4 is enough.

 

[Mike Hoxbig]

Quoted on a 5x470W Jinko panels and worried this might be too much for my daily current idle load of 400kw throughout the day/night BUT was told it's the minimum the inverter needs and panels around 550w won't be ideal.

Thoughts and suggestions? Looking for as few panels that will allow the Inverter to do what it has to.

Wtf is idling at 400 kW?

 

[Pho3nix]

Wtf is idling at 400 kW?

You know my Engrish is no good. House seems to have a constant 0.4kW draw throughout the day.

 

[Pho3nix]

You could probably go with 4 of them minimum.
150v required for startup, and the 470w panels are 43v each, so 4 in series is over 150v.

The 550w panels won't hit their maximum wattage as they will clip at 11amps(mppt max). But will provide slightly less max power than the 470w panels.
If I take the Canadian solar 550w panels, they 41.7v and 13.2a.
So the 550w panels will produce: 11ax41.7=458.7w
The 470w panels will produce 470w because they 43.28x10.86a (10 is less than 11)

So you still need 4x 550w panels minimum to produce less max power and you will pay more for it.
The 550w will only be better in lower light situations.
I have these 470w jinkos with a sunsynk 5kw and they work great.

This advice is only to give you the minimum panels required to start up. I don't know your max loads, etc or your battery size to say if 4 is enough.

Thanks for this feedback. Wonder why they say minimum 5 then over your 4.

Could you share your production values from your panels?

 

[Fcon_Vpro]

Thanks for this feedback. Wonder why they say minimum 5 then over your 4.

Could you share your production values from your panels?

Perhaps their 5 recommendation is to give you extra power to charge or run during lower light conditions. When you go for minimums then the calcs get tricky.

Don't know if mine will help because I have 14 panels but make of them what you will. This is for December including yesterday being a constant change between rainy sunny rainy sunny rainy, etc.
Sunday was 26.2kwh day for me and was very sunny with the odd clouds.
My base load is about 600w but during the day I run my 4kw geyser and 1.1kw pool motor from 9am to 4pm.
Sunday was first day I ran my aircon at the same time so I think that's why my values increased a bit.
My plan was be gridtied but maximize power from solar panels so I only have to install once and then I don't struggle to find panels when I want to expand in the future.
The sunsynk 5kw with ac pass-through meets my needs perfectly so won't need a bigger inverter for the future.
I only have 1x 5kwh battery that I need to last me for loadshedding periods at night.
I rarely hear of issues with solar panels and they have the longest warranty.
Batteries are a big cost and seem to provide the most issues so I wasn't willing to risk a lot of money on it quite yet. Although with my December bonus I'm probably going to get another 5kwh battery to cover me for extended loadshedding periods.

 

[Mike Hoxbig]

Thanks for this feedback. Wonder why they say minimum 5 then over your 4.

Could you share your production values from your panels?

For margin of error. Voltage will vary depending on light and temperature.

I wouldn't even consider 5. Probably 6-8 x 500+ W. Then you can run your geyser during the day for even more savings...

 

[Pho3nix]

For margin of error. Voltage will vary depending on light and temperature.

I wouldn't even consider 5. Probably 6-8 x 500+ W. Then you can run your geyser during the day for even more savings...

Looking at some starter panels and hopefully more come bonus season. Depending if I still live here as well :/

 

[PsyWulf]

I started the same,initially we were installing 4 to just scrape by the minimum startup voltage,then it became 6,then 8 on the day

 

[Koosvanwyk]

Thanks for this feedback. Wonder why they say minimum 5 then over your 4.

Could you share your production values from your panels?

4 is not enough, it will dip under and over the minimum start up voltage which will cause issues with PV production and might not even hit the start up voltage on cloudy days.

If it was me, 8 minimum (8x 470w)

 

[B-1]

You get high voltage solar panels as well. These are just the first to pop up in a search but 3 of these will work just fine.

I'm not sure its very cost effective though as you need to buy the PV combiner box, cabling, mounting hardware and labour for 3 panels. More panels will probably just add the cost of the panels.

Enersol 395HV 395W High Voltage Solar Panel

General characteristics Cell Orientation (Connections): 144(6*24)). Panel Dimensions: 1980mm x 1002mm x 30 mm. Weight: 22kg. Output Cable: 1100mm ,4mm2 Junction Box: IP65, 1 bypass-diodes Frame: Anodized aluminium Electric performance at STC * Maximum Power: 395 Wp. Maximum Power Voltage: 81.04...

www.sustainable.co.za

 

[rh1]

I have 10 460w panels. The way my roof is orientated, means that I mainly have 5 panels working in the morning and the other 5 in the afternoon. Around noon, for a short while, all 10 are producing. I have a 8kWh Sunsynk inverter.

Dont know much about the technicalities. Just giving my experience.

 

[HowTo]

You need to get over 150V DC, requirement of inverter.
VOC are all in line with +/- 49V. Four panels will bring you close to 200V.
Best to go with 5 panels minimum.
All my strings consist of 6 panels each.

 

[1am7h30n3]

I'm running 4x 490W canadian solar panels on 5kW sunsynk. I don't seem to have issues reaching the minimum MPPT startup voltage, for example this morning my inverter graphs show that I started producing power (only 10W, but still) at 4.45am.

 

[Lupus]

I'm running 4x 490W canadian solar panels on 5kW sunsynk. I don't seem to have issues reaching the minimum MPPT startup voltage, for example this morning my inverter graphs show that I started producing power (only 10W, but still) at 4.45am.

You're lucky, normally I also start producing at that time, but this morning we were in a massive storm. Put the kettle on and it switched to Eskom

 

[1am7h30n3]

You're lucky, normally I also start producing at that time, but this morning we were in a massive storm. Put the kettle on and it switched to Eskom

Yup, massive storm this side at the office in Randburg and not looking good for solar production at home in Centurion side either! My batteries are at 38% though, I should be able to pull through until we get some decent solar production.

 

[spiff]

If I may jump in here with a similar question. I have a 3kw / battery inverter setup which has being working fine now for 3yrs using eskom for charging but now it's time to go for solar charging.

I'm using 2 x 12vdc 105amp batteries in series giving me 24vdc 105amps, my house hold power needs are small since I use solar for hot water / gas for cooking - what size panels / what configuration would I need to ensure the batteries are fully charged during the day?

 

[SauRoNZA]

Yeah erm sticking to the bare minimum isn’t going to work.

Install as much as you possibly can and compensate for the low days which you’ll see are shockingly low.

Minimums really only apply to peak days and every other day with the slightest drop of rain or cloud cover will be a massive margin less than that.

I have a base load of about 400W-500W as well and still 14,4kWh of batteries and 6.3kWp of panels still sees me using about R500 in winter on Eskom every month.

 

[B-1]

If I may jump in here with a similar question. I have a 3kw / battery inverter setup which has being working fine now for 3yrs using eskom for charging but now it's time to go for solar charging.

I'm using 2 x 12vdc 105amp batteries in series giving me 24vdc 105amps, my house hold power needs are small since I use solar for hot water / gas for cooking - what size panels / what configuration would I need to ensure the batteries are fully charged during the day?

Thats roughly 1.2 KWh of usable battery. So theoretically 1.2KW of panels will charge the battery in 1 hour. A 300W panel will charge it in 4 hours.

You will need to provide the actual make and model of the inverter though as its more complicated than just the pure power generation of the panels.

 

[Lupus]

Yup, massive storm this side at the office in Randburg and not looking good for solar production at home in Centurion side either! My batteries are at 38% though, I should be able to pull through until we get some decent solar production.

Luckily mine is drawing from Eskom, as we are shed at 8am and I'm getting about 80w from the panels right now