Help choosing a battery

woolgar.c

\We're looking to get a solar PV & battery install. We're getting some further quotes for the whole system & have had some useful advice already on a range of quotes. 

We want to understand the kit a bit better to help our decision making. We're hoping to make a final decision soon & be done with the research! 

From our calculations we'd like at least a 10kW battery. We plan on a DNO99 application.

Can anyone advise if all the following batteries work well with Octopus Intelligent Flux? 

We'd like one that can be programmed to automatically charge & discharge at set times (without us having to open an app & instruct it to do so each time). An easy to use monitoring app would be helpful. 

Octopus website currently states 'Intelligent Octopus Flux is currently only compatible with GivEnergy batteries. Got a different battery? Tell us which one and we'll let you know when we can connect.' but we've been told that Sunsynk and Tesla work automatically with Octopus. I will be contacting them directly too to see if they can advise. 

If anyone can share what the discharge rates / depth of discharge are that would be great. We've looked on the datasheet but I think we may be getting confused.

Are they all LFP?

Are they all AC?

Tesla Powerwall 3 (13.5kW, discharge rate of 11.2? I think the inverter limit can be set & presume we'd want this to be a little under our array size?)

Givenergy All in One (13.5kW, discharge rate of 6?)

Sunsynk (2x 5.1kW, combined discharge rate of 10? With Sunsynk Ecco Hybrid Inverter limit 5)

Any other recommendations?

It's been suggested that inverters need replacing sooner than panels, not sure in relation to batteries - is it more difficult to replace if it's within the battery like a Powerwall set up?

Screwdriva

There is no battery that can match the Powerwall 3 on capability, features, user friendliness or aftersales support currently in the UK market. 

Reed_Richards

Screwdriva said:

There is no battery that can match the Powerwall 3 on capability, features, user friendliness or aftersales support currently in the UK market. 

And it's made by Tesla, the company run by friend-to-the-UK Elon Musk.

In my case, my battery sits on the DC side of my inverter and I can set the app that controls my inverter to charge and discharge my battery automatically at pre-set times.  It could do this for any battery it recognises, but the Powerwall is not included in the list of recognised batteries.  Probably this is because the Powerwall sits on the AC side and, I think, has its own inverter bult-in.

Best to get your work completed before the C.W. as that is bound to disrupt things.  

charles_b_2

Solaredge 10kwh (9.7kwh useable) is a DC connected battery and octopus/Solar edge have just announced intelligent octopus tariff compatibility coming soon. 
No separate inverter so has no impact on DNO and can charge with clipped energy.  For instance my 6.75kw array with 5Kw inverter can invert 5Kwh but remainder can charge battery directly and is not lost.

Solarchaser

I think it's wise to point out that the inverter is what decides all the terms you are looking at, not the battery,  and there are a range of different inverters and a range of different batteries that can be attached to those inverters.

If money is no object, or you suffer from regular power cuts, id guess the Tesla one would be the one to get, but if you are looking at ROI, you would look far away from the Tesla imo.

Flux is a good tarrif if you don't use alot of electricity, don't have an EV and have alot more solar than you can use.

Intelligent flux is the one that talks to your inverter and essentially let's octopus control it is my understanding, and if that's what you want, all good.

It's not a great tarrif if you do use alot of electricity,  or regularly have to charge an EV as their off peak period is so short.
It would be no good to me personally as I'm a high electric use home.

If you are looking for an inverter which will charge and discharge when you tell it, rather than being controlled by a 3rd party, then basically any modern inverter will be able to do this.

Fogstar do batteries for £1500 which are 15.2kwh with 80% recommended dod, which works out a little over 12kwh, and that would seem to fit with your criteria, you would then need an inverter to match of course.

The Tesla will apparently do 11.5kw of discharge,  and that could be very useful if you have say a 10kw shower, but normal house use rarely goes above 3kw, so I'm not sure how useful that would be, vs how much extra you are paying for the privilege. 

I drive a Tesla, and going by how many times I have to reset it while driving, I'm not sure I'd call it user friendly tbh, it's about 90% great and 10% really frustrating, and the same for their customer service.

Qyburn

Solarchaser said:

I think it's wise to point out that the inverter is what decides all the terms you are looking at, not the battery,  

That's true of a DC coupled battery like our Solaredge.

Not really the case with an AC coupled battery like Tesla. In that case it's the battery that decides when to charge or discharge. I assume the inverter just whacks out it's full power and doesn't know or care whether it's being consumed by house loads or by the battery.

Reed_Richards

I have an DC-coupled battery.  An AC-coupled battery must need a dedicated inverter, so that's one inverter for the solar panels (just DC to AC) and another one for the battery (both ways)?  The inverter may be built-in to the battery but it must be there. 

Solarchaser

Qyburn said:

Solarchaser said:

I think it's wise to point out that the inverter is what decides all the terms you are looking at, not the battery,  

That's true of a DC coupled battery like our Solaredge.

Not really the case with an AC coupled battery like Tesla. In that case it's the battery that decides when to charge or discharge. I assume the inverter just whacks out it's full power and doesn't know or care whether it's being consumed by house loads or by the battery.

Batteries are DC not AC, and so the inverter sets the limits.

My batteries are connected to an AC inverter, the batteries are still DC

thevilla

A quick mention for the Give Energy All in One.  Similar specs to Tesla PW2 but cheaper and assembled in UK.  13.5kwh, 6kw discharge, lfp so 100%.  Gateway gives power cut protection but adds to the price so not the cheapest option.

Edit: a local API too for those looking to tinker with home assistant or similar.

Screwdriva

Sorry to correct a few misconceptions:

- The PW3 is a DC or AC coupled battery. In OP's case, it would be DC coupled as they would use the inbuilt inverter.

- The quotes previously shared by OP highlight that the Tesla PW3 based quote was substantially lower than all others.

- Tesla has been integrated with Octopus's Kraken backend system and will be on the Intelligent Flux tariff soon. Tesla didn't share specific timelines when I asked them in person (just gave us a smirk), but I would expect this to occur within the next 6 months.

The above highlight the fastest ROI of all the options listed above. Then there's the Unbeaten charge/ discharge rates/ app integration/ storm watch/ blackout protection/ longstanding safety & operational record.

I have previously advocated for the All in One battery. While it is still a great option, it has now become a low priced, less capable alternative to the PW3. GivEnergy are scrambling to launch an updated true All in One (with built in inverter) within the next year. 

Reed_Richards

Screwdriva said:

- The PW3 is a DC or AC coupled battery. In OP's case, it would be DC coupled as they would use the inbuilt inverter.

Just to be absolutely clear, "they would use the inbuilt inverter" as the only inverter so serving both the battery and the solar panels?  And what happens if that inverter fails before the battery, as the OP asked?