25kWh daily output, but I only used to need 10kWh per day.

[Luxpower_Gilbert]

This is their distributors website

Distributors | Sunsynk

www.sunsynk.org

 

[SenileOldGit]

I searched all of those distributors, I couldn't find any that actually have Sunsynk products in stock on their website, available to buy for members of the public. Most of them don't have any mention of 'SunSynk' on their sites at all. Dragons Breath has the 8kW SunSynk Ecco, for way too much for me to consider: £3,488.00 (Exc. VAT) - £4,185.60 - Inc. Vat. And then it says "THIS ITEM IS SUBJECT TO STOCK AVAILABILITY". For that money I would just go for Victron anyway.

 

[rodrick]

Buying local tier 1 equipment with support may lighten the wallet but will lower the blood pressure for sure

 

[SenileOldGit]

I have found a seller on Ebay (in the UK) who has the Deye SUN-8K-SG01LP1-EU for £2,495, and the Growatt SPF5000ES for £1,295. I am going to go for either the Deye, or two Growatts, I think the Victron system is going to be too expensive.
Does anybody here have two Growatts running in parallel, and if so, do you need an RS485/CAN Hub to connect both inverters to your master battery? According to page 9 of v.1.0 of the manual, you need one.
I like the Deye because the touchscreen interface looks really clear and easy to use, and both types of inverter will work with Solar Assistant.
My only concern with the Deye is that it isn't built 'off grid' and uses a CT to prevent sending power back to the grid when in 'off grid' mode. I believe the Growatt is 'off grid' and can't export? That's what I want - no export to the grid.
I also read a thread on here about the Sunsynk where Trebor79 said depending on how you set up the two different load connections (I'm sorry, but I've only just found out about Sunsynk/Deye inverters yesterday and don't quite understand it), your earth connection can be lost if the grid goes down?
https://diysolarforum.com/threads/i-am-the-ceo-sunsynk.36951/page-2#post-584635

 

[timselectric]

I believe the Growatt is 'off grid' and can't export?

Correct

your earth connection can be lost if the grid goes down?

True
If your grids N/G bonding is done at the grid transformer. And not at your building.

 

[SenileOldGit]

Correct

True
If your grids N/G bonding is done at the grid transformer. And not at your building.

Ah, I see. I have a black plastic tube that runs down the wall and into a black box that says something about 'earthing point', to the right of my inverter box. I will ask my electrician about this, he will remember.
I think I will probably go for the Deye inverter, because everything I have seen on Youtube about the Sunsynk and Deye inverters has been good. It's a lot easier looking for a new inverter now, compared to six months ago, when I didn't have a clue about anything!

 

[timselectric]

Ah, I see. I have a black plastic tube that runs down the wall and into a black box that says something about 'earthing point', to the right of my inverter box. I will ask my electrician about this, he will remember.
I think I will probably go for the Deye inverter, because everything I have seen on Youtube about the Sunsynk and Deye inverters has been good. It's a lot easier looking for a new inverter now, compared to six months ago, when I didn't have a clue about anything!

You can't go wrong with those units.
They are very robust and high quality.

 

[SenileOldGit]

The Deye/Sunsynk inverter can also accept an input from a wind turbine - that is pretty amazing, and something I have been thinking about a lot, since I have had so little PV coming into my MPP Solar inverters the last two months. A wind turbine would really help in the Winter months.
I've just looked at the manual, I'm not sure if it can accept a wind turbine AND PV at the same time.

 

[12VoltInstalls]

wind turbine would really help in the Winter months

Maybe. Worldwide, less than 15% optimistically and maybe 5% 100% uptime of the land masses will support adequate wind most of the time. At the cost of a decent small wind turbine I’d just buy more panels- in fact I did. Which is humorous a bit because I’m <1/2mile from a ridge top with like 16 350’ tall wind turbines. That incidentally do not turn a surprising amount of the time while yet being an ‘ideal’ spot.

 

[kitkad]

I searched all of those distributors, I couldn't find any that actually have Sunsynk products in stock on their website, available to buy for members of the public. Most of them don't have any mention of 'SunSynk' on their sites at all. Dragons Breath has the 8kW SunSynk Ecco, for way too much for me to consider: £3,488.00 (Exc. VAT) - £4,185.60 - Inc. Vat. And then it says "THIS ITEM IS SUBJECT TO STOCK AVAILABILITY". For that money I would just go for Victron anyway.

You can get a SunSynk from https://www.tradesparky.com/solarsp...ybrid/sunsynk-36kw-inverter-single-phase-ecco

 

[SenileOldGit]

Thanks for the link, kitkad, but they only do a 3.6kW inverter, I want an 8kW one.

 

[kitkad]

Thanks for the link, kitkad, but they only do a 3.6kW inverter, I want an 8kW one.

Can you use a SunSynk inverter on your system? The Canadian Solar 595W panels have a Short Circuit Current (Isc) of 18.42 A while the SunSynk inverter has a Max. PV Isc of 17 A.

 

[SenileOldGit]

The Deye 8kW inverter I was interested in has a Max. PV Isc of 34A (that's one of the reasons why I can't use a smaller kW version.)

SUN-3.6/5/6/7.6/8K-SG05LP1-EU | 3.6-8kW | Single Phase | 2 MPPT | Hybrid Inverter | LV Battery Supported Inverter Company, Supplier | Deye Inverter Technology

NingBo Deye Inverter Technology Co.,Ltd is China SUN-3.6/5/6/7.6/8K-SG05LP1-EU | 3.6-8kW | Single Phase | 2 MPPT | Hybrid Inverter | LV Battery Supported inverter company and supplier。 SUN 3.6/8K-SG05，hybrid inverter, is suitable for residential and light commercial use, maximizing self-consump...

www.deyeinverter.com

 

[kitkad]

Have you tried this website: https://batteryfactory.co.uk/collec...products/sunsynk-sun-8k-ecco-hybrid-inverter?

 

[SenileOldGit]

Thanks for the link, kitkad, but I've decided against the SunSynk/Deye 8kW inverter - I can only afford one at the moment, and this would mean I would have to get a lot of extra battery cables and busbars to connect my three Pylontech US5000s to it, as I have two inverters at the moment, which are connected one to each end of my three batteries, using 100A cables. I would need to use twice as many 100A Pylontech cables to take the potential 160A of current from my batteries when they are supplying large (over 5kW) loads in my house.
I want to set up a third string of solar panels later this year, but I would need another 8kW SunSynk/Deye inverter at £2,368, to plug them into. If I go with Growatt SPF5000ES inverters, I only need to spend £1,295 to get another one for my third string.

 

[kitkad]

Thanks for the link, kitkad, but I've decided against the SunSynk/Deye 8kW inverter - I can only afford one at the moment, and this would mean I would have to get a lot of extra battery cables and busbars to connect my three Pylontech US5000s to it, as I have two inverters at the moment, which are connected one to each end of my three batteries, using 100A cables. I would need to use twice as many 100A Pylontech cables to take the potential 160A of current from my batteries when they are supplying large (over 5kW) loads in my house.
I want to set up a third string of solar panels later this year, but I would need another 8kW SunSynk/Deye inverter at £2,368, to plug them into. If I go with Growatt SPF5000ES inverters, I only need to spend £1,295 to get another one for my third string.

I am also trying to decide which inverter to install, I ruled out Growatt after I've read so many negative reviews: https://uk.trustpilot.com/review/www.growatt.com

It is down to either Solis or SunSynk.

 

[SenileOldGit]

I have now decided (because I've only just found them) to buy two 5kW Sunsynk inverters, from here:

Sunsynk Sun 5K ECCO Hybrid Inverter

Shop Sunsynk 5kW ECCO hybrid Inverter to manage power flow from multiple sources | Dual MPPT | SolarMan App Compatible | From £1,057 +VAT

batteryfactory.co.uk

(Thank you so much for sending the earlier link to the 8kW SunSynk from the same seller, otherwise I would never have found the 5kW version on there).

They are only £300 more each, than the Growatt SPF5000ES inverters, and I think they will be a much better long term investment, and all the other SunSynk inverters are Type Tested (though I can't find this exact version of their 5kW models on the Type Testing website, I may just have been looking wrong.)

I would take all of those negative reviews about Growatt with a large pinch of salt - the first is complaining about the installers, Growatt are not installers. Then the next one star review says "We waited for 5 months for our growatt system to be installed, we emailed,called and was always told someone would be out next week but nobody ever turned up then we would complain again and still nothing happened." - Growatt are not installers, they manufacture inverters... Then we have "The MPPT (Maximum Power Point Tracker) in the Growatt" - WHICH Growatt inverter? It would help (a lot!) if the reviewer knew what model they had, but I expect they don't, because they paid somebody else to install it all for them. I wouldn't be using Growatt's servers, I would be using Solar Assistant, wired directly to my Raspberry Pi from the Growatts. There are no negative reviews there for the Growatt SPF5000ES, so I wouldn't pay any attention to them at all.

 

[SenileOldGit]

I'm now moving towards getting one 8kW Sunsynk inverter, rather than two 5kW Sunysnk inverters. The 5kW ones can only take 13A of PV, my Canadian Solar 595W panels can output up to 17.2A, the 8kW inverters can take 22A of PV input.

 

[niktak11]

Thanks for the link, kitkad, but I've decided against the SunSynk/Deye 8kW inverter - I can only afford one at the moment, and this would mean I would have to get a lot of extra battery cables and busbars to connect my three Pylontech US5000s to it, as I have two inverters at the moment, which are connected one to each end of my three batteries, using 100A cables. I would need to use twice as many 100A Pylontech cables to take the potential 160A of current from my batteries when they are supplying large (over 5kW) loads in my house.
I want to set up a third string of solar panels later this year, but I would need another 8kW SunSynk/Deye inverter at £2,368, to plug them into. If I go with Growatt SPF5000ES inverters, I only need to spend £1,295 to get another one for my third string.

You need to get busbars. Connect all batteries to the busbars then connect all inverters to the busbars.

 

[SenileOldGit]

This is what the SunSynk manual recommends (the lower right diagram, 'Max 200 Amp') for connecting multiple batteries (I have three 5kWh ones) to the 8kW Sunsynk. I've asked my electrician about it.

 

[niktak11]

View attachment 129133This is what the SunSynk manual recommends (the lower right diagram, 'Max 200 Amp') for connecting multiple batteries (I have three 5kWh ones) to the 8kW Sunsynk. I've asked my electrician about it.

If you want to daisy chain them like that then connect the inverter cables at opposite ends. If you connect to multiple inverters then you'll either have to get creative with your connection points (with two inverters and 3 daisy chained batteries then you can connect one inverter to the top and one to the bottom) or you'll want to add busbars.

 

[HonzaS]

@SenileOldGit Hello,

My opinion how to connect battery in parallel is only this way:


Reason is Ohmic law. Imagine the situation where is your connection. Battery number one have shortest connection such as possible. Next batteries have longer and longer connection. Battery #1 is most exposed by peaks.

My connection sketch comes out from the same length of cables. But this solution still have no optimal impedance for batteries in the center. But for four pieces is enought.

Wire width is so much important. I have seen some "shoelaces" on the pylontech batteries. My recomendation you need use 50mm2 (0 or 00 in AWG) plus wire for 200A peak currents.

When you use thin cables, then voltage drops on the cables will high** and inverter will not be happy.

**High drops I mean 1V+ peak drop on the cables (fuses, switch,..). Everything is important. You need some superconductors for hi currents.

 

[12VoltInstalls]

Ohmic law

What happens to the two middle batteries? Why not balance them?

 

[HonzaS]

@12VoltInstalls Hello,
When You use schematics, which I draw in my previous comment, it will work OK. But two middle batteries will be used with slightly less power due to ohmic law.

I have seen that phenomenon when I formated the LIFEPO Cells for my power plant. I used the same connection, but I used 16 cells. I have seen slightly less voltage on cells connected in middle of the wires.

I made some simulation on LTSPICE. I set every resistors to 1 Ohm for clear result (in reality impedance of battery or cells is many times higher, than wires).

Resistors R1,2,3,4 represent the BATTERY, other resistors is wires.
You can see the voltages measured in schematics.
Again: In reality this phenomenon exist, possible to measure. But it is not critical.
If you want to avoid that phenomenon, you must connect each battery with wire to common node with the exact same cable length.

 

[12VoltInstalls]

When You use schematics, which I draw in my previous comment, it will work OK. But two middle batteries will be used with slightly less power due to ohmic law.

My point was you CAN wire them balanced in two ways I can think of atm. So that’s the way they should be wired- balanced.
Thank you for the diagram. Your diagram, however, is not a balanced arrangement.

have seen slightly less voltage on cells connected in middle of the wires.

Exactly.
So if you balance the cabling such that each battery presents the same load to the SCC and they receive equal discharge (output) when powering a load.

One is to connect equal gage and length cables to a busbar and distribute to the loads and SCC from there.
Second is to cable the batteries alternate offset so that every battery sees the same current.