Inverter: 6kw or 5kw but with higher battery discharge power

ModelWhy · 24-05-2023 12:03am #1

Hi

My old inverter is gone and I need a new one.

I have 2 options from an installer.

First is a 6kw inverter, an ES:6kW Single Phase with DC Switch & Wifi:

https://www.failtesolar.com/sofar-solar-hybrid/es-6kw-single-phase

I know about the June 1st deadline but installer says they can get it done on time. However the spec sheet says that the battery discharge is limited to 3kw on this.

Alternatively they are giving me the option of a 5kw inverter but one that has a battery max discharge rate of 5kw. This model to be exact:

https://www.ginlong.com/energy_storage_inverter5/3_6k_s5_l_en.html

I have a 5kw battery system and currently a 4.2kw system (10 panels) but I was thinking of adding a few more in a while (maybe in another year or so).

I'm week energia and the sell back rates are €0.18 which aren't great and I try to use my battery the most.

Would I be foolish to not take the opportunity to get a 6kw inverter while I still can, or is the other limitation of the unit something to be concerned about?

Price of the units differ by about €200.

Many thanks

bullit_dodger · 24-05-2023 12:45am

Two additional factors to consider is "how big is your battery?" and "How often (realistically) do you need to discharge more than 3Kw?"

If you have a relatively small battery, or your loads are high enough that your battery is depleted before the swap over to night time rate.....it doesn't matter if your discharging at 3kw or 5kw. Say you are discharging at 3kw and your battery is empty at 9pm. If you were discharing at 5kw, your battery would jsut be empty sooner. Ultimately the question is "can you deplete your battery with 3kw" in the timeframe.

The 2nd question is harder to quantify. Sure, it's nice to be able to cover ALL your load when you switch on the kettle and the oven at the same time, and with a 3kw you won't be able to do that. But then again, is this REALLY a big issue, the kettle will finish in 3 minutes and the your battery is coverring the load again.

I'd go for the 6Kw inverter with 3kw battery discharge, but that's me.

ModelWhy · 24-05-2023 8:49am

Thanks for your reply

Battery size is 5kw.

Might add to it in the future if I add more panels but that's a big maybe.

Most electricity is morning and evening use with some days WFH for 2 adults. Hob is gas so mostly oven, TV, kettle, washing machine, air fryer, dishwasher at evening/night. Morning is kettle, coffee, etc.

We got through our 5kw battery before nights end with old inverter (5kw with 3kw max discharge)

bullit_dodger · 24-05-2023 9:22am

If I'm reading this right ...

We got through our 5kw battery before nights end with old inverter (5kw with 3kw max discharge)

Your saying that your battery was/is depleted before you swap over to night rate? If so then a 5Kw discharge rate won't save you any money. It would be a case of your battery just being depleted sooner. Yes, you would avoid partial importing from the grid at say 8pm, but then you would just be importing full amount sooner when your battery is empty.

I'd go for the 6Kw inverter with 3kw discharge rate.

graememk · 24-05-2023 9:42am

Which ones cheaper?

The solis can only do 5kw for 15 minutes anyway.

ModelWhy · 24-05-2023 9:52am

https://www.boards.ie/discussion/comment/120634473#Comment_120634473

The Solis is €200 cheaper or so upfront

ModelWhy · 24-05-2023 9:55am

https://www.boards.ie/discussion/comment/120634386#Comment_120634386

I was thinking if I added another battery (10kw) next year or so then I could be independent from the grid apart from charging the battery from the grid when the panels don't cover it.

But the revelation of only covering 5kw for a 15 min period makes me think that this won't make much of a difference.

Think I'll go with the 6kw one so. Seems to make more sense from what you're saying. Thanks

unkel · 24-05-2023 9:57am

There are far better hybrid inverters out there like some Sofar models and all Sunsynks. In fact the Sunsynk is officially 5.5kW, so is ok under the new regime. It can charge / discharge at over 5kW continuously for many hours on end (if your battery was big enough LOL)

ModelWhy · 24-05-2023 10:16am

https://www.boards.ie/discussion/comment/120634543#Comment_120634543

Does anyone fit that brand?

I've rang up about 7 different installers and no one ever mentioned Sunsynk

graememk · 24-05-2023 10:30am

https://www.boards.ie/discussion/comment/120634631#Comment_120634631

Not sure but Kellihers Electrical stock them, maybe the installers just haven't heard of them yet.

They are relatively new to the market. They are a rebadged Deye inverter who are a huge manufacturer of inverters.

ModelWhy · 24-05-2023 11:48am

https://www.boards.ie/discussion/comment/120634473#Comment_120634473

Can I ask, where on the spec sheet does it state the 15 min limitation?

I'm glad to know it, thanks, but for my own learning going forwards it'd be great to know that to look for 😀

ModelWhy · 24-05-2023 11:53am

https://www.boards.ie/discussion/comment/120634691#Comment_120634691

I tried their website but no matches for Sunsynk it seems. Might need to ring them, maybe.

https://kellihers.com/?s=Sunsynk

unkel · 24-05-2023 12:00pm

https://www.boards.ie/discussion/comment/120634969#Comment_120634969

It doesn't state it on the spec sheet. That's the problem. Several users in this forum alone have found out it is a limitation in practice, even though the spec sheet promises 100A continuous. And Solis have been lying and cheating about it. They gave some users custom firmware that made it a bit better, but their customer service / support leaves a lot to be desired. New support calls not being answered for several months, etc.

You could wait of course for the next gen 6G Solis models, promising an even better 125A. Probably available before the end of the year. Promises, promises though 😂

graememk · 24-05-2023 12:53pm

https://www.boards.ie/discussion/comment/120634969#Comment_120634969

It's not, but I've experience of it and have the data to back it up.

Yeah give them a ring, a few people here have picked ones up there.

ModelWhy · 24-05-2023 2:07pm

Thank you both so much. Always best to hear from actual people.

Bad customer care in my books is a big red flag (been burned elsewhere by bad customer service).

Definitely a factor in my decision.

ModelWhy · 24-05-2023 9:04pm

Do you mind if I ask you gents if Solis inverters are generally considered good or not?

I've read mixed things from forums about generally all makes of inverters that it's hard to know which brands are generally considered more reliable etc.

Thanks

unkel · 24-05-2023 9:08pm

Solis are sound. It's just their hybrid inverters of the last generation simply don't live up to their specs. Which is quite well known now, so will affect resale value too. If you want a conventional inverter, by all means go Solis. If you want a hybrid, I'd look elsewhere. And try found out from current owners if the inverter performs to spec.

ModelWhy · 24-05-2023 9:36pm

Yeah is looking at the spec sheet of the S6 vs S5 and the funny thing is that on the S6 a lot of the specs are slightly lower than the S5.

I imagine though that they are more honest for the S6.

Spec of S6 here: https://www.ginlong.com/solarinverter2/2500_6000w_s6_en.html

ModelWhy · 24-05-2023 10:03pm

On my original dilemma, I think I'll go back to the 5kw as the battery that installer is offering me is much better.

Given my house and neighbours and trees etc around it in parts, I'm going to be doing most of my savings via battery then directly from the sun (also due to usage lpatterns) so I think I'll get more impact from them.

It's a Solis S5 EH1P work a Puredrive 5kw battery. This one: https://puredrive-energy.co.uk/purestorage-ll-battery/

Alternative is a 6kw ES:6kw Single Phase with I think a Dyness BX551100 battery. This battery: https://www.failtesolar.com/dyness/5-1kwh-lpf-battery-bx51100

I think the ES is older tech though as it's spec sheet is almost the same as the Solis. Same input max etc. Only advantage I can see is an extra 500VA (0.5kVA) ability going back to grid.

PV panels are identically between both (10-12 panels maybe depending on what fits).

Thoughts welcome

graememk · 25-05-2023 12:55am

https://www.boards.ie/discussion/comment/120637399#Comment_120637399

Ah I didn't click the link in your original post.

The 6kw is a sofar! Hyd6000es.

If you get the sofar hyd6000ep it can do 5kw from battery all day long. @irishchris has one.

irishchris · 25-05-2023 8:01am

https://www.boards.ie/discussion/comment/120637399#Comment_120637399

After using several solis inverter (3kw standard upgraded to 3.6 hybrid upgraded to 6kw hybrid) they are an ok inverter. But would I recommend their S5 hybrid. Absolutely not.

The advertised 100amp charge discharge is the reason majority like me purchased one and it simply doesn't do it, instead only holding high charge for max of 15 mins. Their customer support were adamant that all inverters do this but the truth is they don't.

As people get moved to short smart meter charging windows the max charge starts to be more important than ever, never mind the short spurts of sunshine in winter that you try to store. Obviously the 5kw discharge is just as important.

Wouldn't recommend the sofar hyd-ES models either as their max charge/discharge is 3kw whereas for practically same price from same supplier failte solar you can get the 6kw hyd-EP model which comfortably does 5kw charge and discharge without any restrictions. Also with the massive heatsink runs cool under big loads compared to the Solis. Best decision I did was getting the sofar and when you are doing the install now may as well get it done right than regretting it few months later.

unkel · 25-05-2023 8:35am

That Sofar is a very good hybrid by all means. The Sunsynk is a decent alternative if you'd like more features, like built in generator feed in and (immersion) diversion, always on emergency supply output for when the grid is down - this works like a UPS function too, touchscreen colour screen, etc., even better performance (about 110A continuous charging and discharging) and a several hundred euro cheaper price. Bit more of an enthusiasts choice of inverter though.

ModelWhy · 25-05-2023 12:48pm

I'll ask about the EP model over the ES.

What about the battery type though? Didn'ty that make an (arguably) bigger difference as no matter what spec inverter, if the BMS says no, then that's it!

irishchris · 25-05-2023 11:22pm

https://www.boards.ie/discussion/comment/120639082#Comment_120639082

Yes the battery needs to allow charging discharging up to 5kw too avail if it. But if it doesn't still best with having an inverter capable as leaves it as an easy fix at later stage for adding second battery to the setup

ModelWhy · 30-05-2023 2:25pm

UPDATE: I can either get a Sofar EP: 5kw or a Solis S5-EH1P6K-L hybrid inverter.

Should I go for the 6kw for last chance to get future proofing? Or the Sofar for a better all round unit (from what I'm reading here)?

Thanks

ELM327 · 30-05-2023 2:40pm

dont get the solis

regards

solis owner

bullit_dodger · 30-05-2023 3:00pm

https://www.boards.ie/discussion/comment/120658421#Comment_120658421

LOL at that.

ModelWhy · 30-05-2023 3:06pm

Could I get the 6kw solis now to get in before the cut off, then replace it with a better 6kw inverter in a few years?

graememk · 30-05-2023 5:43pm

I'd be going for the sofar without a doubt

ModelWhy · 30-05-2023 6:37pm

https://www.boards.ie/discussion/comment/120659162#Comment_120659162

Do you mind me asking... Any particular reason why? What specifically about the Solis is so bad?

My installer swears by them and it's my only chance of getting a 6kw inverter and the future proofing they gives.

Thanks 😀

graememk · 30-05-2023 7:26pm

https://www.boards.ie/discussion/comment/120659349#Comment_120659349

5kw from batteries for 15 minutes.

If you will only ever have a small battery, solis is fine, as that is your limiting factor. If you are thinking of getting a big battery then having high output for a prolonged time is more beneficial.

Also think the sofar does a better job at balancing the grid. I don't have experience of a sofar hybrid but the me3000 is much better at keeping a neutral grid balance.

ModelWhy · 30-05-2023 9:50pm

https://www.boards.ie/discussion/comment/120659557#Comment_120659557

Thanks so much. I'm going for a 5kw battery and will be keen to see what the data says my usage is (I have a fair idea but I like to see the numbers).

I might go to 10kw battery in the future but not for a good while given the cost of them.

Inverter: 6kw or 5kw but with higher battery discharge power

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