Hi guys .... looking for some advice....I'm looking to charge from the grid at night and don't have solar (or though may do in the future, I use 10-12kwh per day and would like to discharge at a fairly decent rate of maybe 5-6 kwh. What kind system would you recommend please?
the 5kw hybrid is only 3.6kw from battery only. So ruled out as you want 5 or 6kw draw
So you are really looking at a dual AC3
which will need 2 batteries matched 2 x 9.5 (19kwh), or 4 x 5.2 (18.7kwh)
Charge time would be around 3Hr 20 min (So within the 4 hour Octopus Go)
Above your likely kwh requirements, the other option would be 1 x 5.2 and a 2.6 paired up (14kwh)
Just be aware that the GE software does not function particularly well, with multiple AC3.0 units. A software update is apparently being worked on, for this configuration, but GE appears to be quite overwhelmed at the moment - so progress/support may be slow.
I have two AC3.0 inverters, each with its own 8.2 battery. You do get the increased power output, and the system works reasonably well, but the numbers you get on the portal/app are often misleading, or grossly wrong. And occasionally one battery will discharge into the other. Also, the batteries do not track each other in terms of SOC (State of Charge), so sometimes you end up with one full battery and one almost empty battery, which limits the rate at which you can charge them up (either from the grid or solar).
Thank you! ... here's another question re. the draw rate. I had convinced myself that I needed 5-6 kw draw as I didn't want to 'underspec' it but having spoken to others I'm now not sure its required. Anyone got any experience on that? I have a 4 bed semi, occupied most of the day and have standard use of TV, cookers, computers, kettles etc. My total usage is around 11 kwh per day which I suppose suggests that 5-6 kw would be too much. Any thoughts on that?
Mongoose I assume you also have an ev (or phev). Without it it will be difficult to the best overnight rates. Depends how honest you are with octopus and how good they are at checking your answers if you don’t!
It really depends on the chances of you having two or more high power items (oven, cooker, microwave, kettle, immersion...) on at the same time.
With the higher power output we have not pulled more than a few units of electricity from the grid, in the last few weeks. If we only had one inverter, our importing would be higher, but not massive. I also wanted some level of parallel redundancy (i.e. if one part of one half went down, we would still have the other half to use).
Remember that with one inverter, you may also be limiting the rate at which you can charge.
Mongoose Every home is different but anyone with lots of "tech" is more likely to have an average baseload demand of 200-800W. Ours is 400W, equating to 9.6kWh/day but from meter readings, I know that we consume 15-18kWh/day on average 365 days of the year. There's very little seasonal variation. The only exception to this is when the house is full of family for a weekend or over Christmas when daily usage increases by 4-5kWh/day.
If you have a smart meter, you can find out your daily consumption from your In Home Display (IHD or CAD). You can also access this data (if you have smart meter), sometimes from your utility provider's web site or from a third party app such as the Bright App. I have no affiliation but do have the Bright app. It's free to access your data but you have to give the company access to your meter readings via your MPAN (again, only if you have a smart meter and it has to be enrolled in the DCC). If you want assurance about your electricity usage, you can buy one of their dongles which connects to your smart meter over zigbee and to their website over wifi and you can get updates every 6 seconds or so on your phone. Data goes back for 13 months and you can download the 30 minute, 1 hour, daily and weekly totals. I'm using this data to work out my Time of Use cost as my smart meter, while enrolled in DCC will not send more than one register. Pitch over.
The benefit of two inverters is that you can supply larger loads such as the kettle or oven from battery and since they ramp up together, the time pulling from grid is less (although there is always some). The downside to two inverters is the cost and whether they will play nicely. AC3s, which are connected over Modbus for control purposes, seem to be bad-tempered siblings and I'm not sure we've heard from anyone with such devices whose system works well. We have two HY5s which know nothing of each other (only being connected at the 240Vac "solar" consumer unit) and perform really well. The battery SoCs is within 4-8% whether charging or discharging and they load share really well, even powering the electric shower on medium, from battery when needed.
If you were to go for a single AC3 with 9.5kWh battery, you would meet most of your needs with probably, quite a low grid import outside off-peak. If you later added PV, you could add a HY5 with 9.5kWh battery and up your maximum supply capability. Alternatively, you could bite the bullet now, install PV/HY5/9.5Batt and add an AC3 or second HY5 later. If/when you do add PV, my suggestion would be to put as many panels onto your roof as you can (given advice from the installer regarding orientation and numbers) as I haven't heard anybody regretting too much PV, only rueing that they hadn't added an extra two or three where there was space in the original installation.
Tim glad it’s not just me with a base load the wrong side of 500w
Mongoose from my perspective I would seriously reconsider what your proposing. If you do this your at the mercy of the energy companies and already Octopus go is only available if you have an EV… who knows what the future will bring? On the other hand if you invest in panels rather than multiple inverters and batteries, they can’t turn the sun off! Also panels are really cheap right now and ultimately battery prices are still falling over the longer term. Personally I would invest in the panels and add the battery later, which is much easier.
As we speak I’m buying in energy from my supplier to sell it back to them at a large profit, but I know they won’t put up with this forever!
Sorry if I seem negative, but I’ve always thought that if it’s too good to be true it will end eventually…
I agree that solar panels would be better than a battery as there is no guarantee that you will be able to profit from buy low sell High strategy.
Also solar provides some degree of independence from the utilities control as long as the sky is bright (we are in Cumbria and still cover our daily use on lots of rainy days as the sky is still bright enough to produce enough for our ongoing use.
Mongoose Given your current daily usage I assume you don’t heat the house with electricity? It that is right then I’d suggest that the 3.6kW output on the latest Givenergy inverters/batteries would pretty much cover things. There will be the odd moment when multiple things kick in at the same time and you have to pull a little from the grid (if you don’t have solar), but to get higher output and faster ramp up speeds you probably have to go for more expensive kit or multiple sets of batteries & inverters - which might not justify the cost. As already suggested getting some solar and some battery storage will get you going in the right direction and you can likely change usage patterns in the house make them work.
Martyn absolutely and I suppose basically with solar the value of what we are producing keeps rising. If I did no more that cover our daily usage I would not really complain, however I’m heading for a 2mWh surplus by end of year largely because I chose 16 panels rather than the 12 originally proposed. Cost of extra 4 panels was around £500 for panels and nothing for fitting because it’s a days work either way. Payoff time less than a year for them at these rates! Good job I don’t listen to sales people…
What is base load? Its all appliance plugged to socket on standby mode?
Is computer computer switch on or TV is included in statistic?
If not what you have that power hungry devices?
Normally as i have it should by less than 200W.
CARLMW We did exactly the same. Installer suggested 12 panels but we installed 16 panels as the incremental cost was marginal as you say.
The end result is that we have quite a surplus over and above our consumption, and we can also generate a higher percentage of our usage on winter days.
Once you are going with solar on your roof it makes sense to install as many panels as will fit.