Soldato
I appreciate this may not be that relevant, but for what its worth my mobile phone is a Huawei, and its 4 years old and still going strong.
Solar panels and battery - any real world reccomendations?
- Thread starter GinG
- Start date
I appreciate this may not be that relevant, but for what its worth my mobile phone is a Huawei, and its 4 years old and still going strong.
Associate
Ah right, apologies for stupid question, but does this effectively mean that if I had a power cut, the house could only draw a max of 3.6kwh at once?
And I guess in reverse, does that mean I can only charge batteries at max 3.6kwh, even if they're producing 7.2kw of power (ie some is wasted?)
And I guess in reverse, does that mean I can only charge batteries at max 3.6kwh, even if they're producing 7.2kw of power (ie some is wasted?)
Soldato
Not a stupid question at all, a good question and a point a lot of people miss or assume if you have a 5kWh battery for example that you can draw power at 5kW.
Your install will need to be setup to run off grid which a lot aren't, they shut down when there is a power cut to safe guard the dno operators who may be working on the local network.
If you are drawing power from solar and batteries, with that inverter it's combined 5kW, battery only 2.6kW. Battery charging is limited to 2.6kW as well.
Associate
Really helpful, thank you for your patience with me!
Ok, that sounds useful - given we use about 12,000kw per year, we go way past 3.6kwh at various points - think we peak at ~7kwh.
To my point on solar panels, do these have any limits based on inverter size? Ie could I miss out on electricity generation if I had too little?
Ok, that sounds useful - given we use about 12,000kw per year, we go way past 3.6kwh at various points - think we peak at ~7kwh.
To my point on solar panels, do these have any limits based on inverter size? Ie could I miss out on electricity generation if I had too little?
You seem to use similar to me, that's why I've gone with 2 No. 3.6kW inverters each to a battery to maximize my charging and max discharge of 7.2kW
Last edited:
If you have 7kw of solar panels, and they are generating 7kw of power, with a 5kw inverter, the inverter will clip the excess generation to 5kw max (or maybe slightly more than 5kw if your inverter supports oversizing).
There is an interesting video i found here, which compares the Givenergy and Huawei systems which helped make up my mind.
https://www.youtube.com/watch?v=5VqtIoHbbJM
Soldato
The only catch is you can't at the time of the video alter the time the Huawei charges the battery from the grid, which I see as a big benefit to the Powerwall and Givenergy batteries. Is it possible now?
You can't from the app (it seems most solar apps are poor from what i can see). You can by all accounts, using the web interface though.
https://www.youtube.com/watch?v=BPzR3cGbR-4
Be careful with units too. Energy used (such as your annual usage) is in kilowatt-hours (kWh), but instantaneous draw (such as how much an oven draws) is in kilowatts (kW). You need to use instantaneous draw/charge when looking at the inverters and how much power load you have at any one point, but when talking about the amount stored or used over a period of time is the opposite.
So to supply 7kW of power for 1 hour would mean 7kWh usage. Or if you have 3.5kW for 2 hours, that's still 7kWh in total.
Associate
Not seen panels like this before, each one connected has a 5lt water cooler/heater fitted, cools the panels for more energy produced plus heats the water.
Interesting to see how these work out.
Interesting to see how these work out.
Soldato
I could see in the video where you could change the price for the export and import (presumably just for displaying cost info), but didn't see anything relating to telling the battery to charge from the grid at certain times.
Correct! But I have seen it in some video somewhere (I have watched far too many)! It is also listed in the manual
https://midsummerwholesale.co.uk/buy/huawei-storage/huawei-5kw-hv-sun-hybrid
Soldato
I've watched a fair few, and they all end up blending in to one. Looking at the manual it does look to be configurable.
Soldato
Been quoted 7k on the nose, 12 panels for a 4.5kw system, no battery, but a device that flicks the immersion heater on for our hot water tank when excess energy is being generated, (We have oil fired heating with hot water tank) which is effectively acting as a battery and will save us some oil.
It was 10.5k for the same system with battery but the guy was adamant we would be wasting our money getting one, reckons we wouldn't get much use our of it, particularly as we both work from home.
I'm trying to think of any untoward reason why he would try to talk me out of it, and I can't so trust what he's saying about that is genuine.
He reckons it will generate about 4000khw per year, we use about 6000khw a year in total (3500 winter months, 2500 summer) although we've made some changes since that bill, so maybe a bit less.
I think the quote is reasonable and going through this thread, about right, the ONLY thing niggling me is the system is going to be somewhat inefficient during the middle of summer, as it'll be generating far in excess of what we are using even topping up the hot water tank.
We don't have a smart meter and nothing was said setting up a tarriff where we can sell back to the grid.
It was 10.5k for the same system with battery but the guy was adamant we would be wasting our money getting one, reckons we wouldn't get much use our of it, particularly as we both work from home.
I'm trying to think of any untoward reason why he would try to talk me out of it, and I can't so trust what he's saying about that is genuine.
He reckons it will generate about 4000khw per year, we use about 6000khw a year in total (3500 winter months, 2500 summer) although we've made some changes since that bill, so maybe a bit less.
I think the quote is reasonable and going through this thread, about right, the ONLY thing niggling me is the system is going to be somewhat inefficient during the middle of summer, as it'll be generating far in excess of what we are using even topping up the hot water tank.
We don't have a smart meter and nothing was said setting up a tarriff where we can sell back to the grid.
Benefits from the battery aren't just about it being charged from the solar. charging it overnight in the winter months at a reduced rate of 5 to 7.5p per kwh helps bring down your daily cost and also it supplements your solar at times when you're not fully generating so if you whack a kettle on it'll mean you use battery power not pull from the grid on cloudy/lower sun power days.
How much usage do you have through the evening, night and early morning - I'm guessing you will have some and that's where the battery will come on to play.
Also during the winter months, solar generation will be considerably lower and if you have an economy 7 or dual tarrif ( cheap rate) you can charge the battery to supplement it.
As you are working from home, I'm surprised they've not advised one?
Beat me to it!!
Soldato
- Joined
- 19 Oct 2010
- Posts
- 2,559
Do Huawei and Givenergy intelligently charge? My PW hasn't charged over night for a few weeks now as it knows the solar generation expected the following day will cover the usage required.
In february it was more accurate than the actual weather forcast. If it charged i knew the day would be overcast, if I woke up and it was only at 20% I knew it would be a very sunny day.
Soldato
I guess you have to weigh it all up. If you think of the cost of the battery alone, £3.5k, you have to work out if you'll save yourself 3.5k of electricity over the course of the batteries lifetime, maybe 10 years? With just the battery alone. The PV will just run and go (within reason) forever, so you will at some point, make your money back on that, plus the excess going to the hot water is reducing oil use. Again, both of these within reason will go forever.
A battery has a specific life span, if you don't save an additional 3.5k on electric by having it within 10 years you've lost out, or if you only save a little, its a lot more upfront money. I don't know and without having actual use statistics that can never be answered with any accuracy.
In the winter I cant see us generating much over what we will use, particularly if we run the wahsing machine, dishwaher, tumble dryer etc during the day, with the excess going into the hot water, yes during the summer we will generate a whole ton more and that is where it is getting pretty inefficient, but I guess you can only store so much with a battery anyway.