Home Storage Battery

[Deleted member 2439]

Watching the EV Puzzle provides a lot of good background information - I'm considering a solar diverter for hot water such as an Eddi or Solar iBoost to supplement/replace my gas system boiler heating my hot water tank - his latest video on vertically placed panels facing East was really interesting in this respect.

I agree, a solar diverter was the step I took before even considering a battery system. Again, a word of caution as many immersion heaters are quite short and only designed to heat up the top 30cm or so of the tank to give enough for a quick shower! My tank only had one of these and lacked the lower heater found in many newer tanks. The solution was to buy a much longer heater which heats all the water in the tank. Also, you must buy a rugged heater element which is designed to be switched on & off a lot - many cheaper ones aren’t and will fail prematurely in such an application. Mine has been working for 9 years.

My diverter is a home made one from a magazine article back in 2013 and works well. I have a remote display of the water temp in the tank which is helpful. My gas boiler is still there but only used when there is a shortage of sunlight or stored power to operate the immersion. I can manually operate the immersion by voice control with an Alexa operated switch which turns on for an hour - this is enough to go from a cold tank to a tank full of hot water. Be careful though as many of these type of switches aren’t upto the job of switching high current loads - I’ve used an intermediate relay which the Wi-Fi switch then operates, in turn switching the immersion load.

 

[jem111111]

I paid £6200 for the Solar+4.8kWh battery storage setup. I've been quoted £1000 for an additional 2.4kWh battery. Hope this helps!

That seems a good price , who did you go with/
Another question if i may , i have attempted to understand all this PV and battery storage and invert stuff and need to ask a question concerning the inverter.
If its a 3.6kw inverter , it appears this is the max the solar /battery can feed into the 240v house supply. Is this a correct understanding? So if you peak at 4.6 kw does this mean the battery etc will supply 3.6kw and the grid 1kw?

thanks

 

[Deleted member 2439]

That seems a good price , who did you go with/
Another question if i may , i have attempted to understand all this PV and battery storage and invert stuff and need to ask a question concerning the inverter.
If its a 3.6kw inverter , it appears this is the max the solar /battery can feed into the 240v house supply. Is this a correct understanding? So if you peak at 4.6 kw does this mean the battery etc will supply 3.6kw and the grid 1kw?

thanks

Yes, spot on.

 

[jem111111]

Hi Robert thanks for answering.
So basically 3.6kw is putting the kettle on (LOL), so if you have other items on ( eg microwave / Electric oven etc) then it does no matter if the sun is shining , or the size of the battery , you will be taking power off the grid when you turn the kettle on.
So really I would need a + 5kw inverter , to cover the peaks in the day e.g microwave / oven on, then putting the kettle on to make a cup of tea , so its actually covered by solar / battery.
Thanks

 

[Deleted member 2439]

Hi Robert thanks for answering.
So basically 3.6kw is putting the kettle on (LOL), so if you have other items on ( eg microwave / Electric oven etc) then it does no matter if the sun is shining , or the size of the battery , you will be taking power off the grid when you turn the kettle on.
So really I would need a + 5kw inverter , to cover the peaks in the day e.g microwave / oven on, then putting the kettle on to make a cup of tea , so its actually covered by solar / battery.
Thanks

The Lux power ACS3600 can operate as a pair, giving 7.2kW instead of the 3.6. Twice the price though ….. I thought it would be an issue, but has proven not really to be in practice. You are 100% correct, but I think this is a classic example of the 80/20 rule

 

[Mihir]

That seems a good price , who did you go with/
Another question if i may , i have attempted to understand all this PV and battery storage and invert stuff and need to ask a question concerning the inverter.
If its a 3.6kw inverter , it appears this is the max the solar /battery can feed into the 240v house supply. Is this a correct understanding? So if you peak at 4.6 kw does this mean the battery etc will supply 3.6kw and the grid 1kw?

thanks

@Lincs Robert has answered your question. I went with a Luton based company called SSU Renewables. Really good chaps, knew what they were doing. Great customer service and still support me for any questions, concerns or doubts I may have.

 

[jem111111]

Hi Robert , i might be silly here , but im not quite understanding what you mean by the 80/20 rule .
Is it possible you can explain , then for me to say "oh that 80/20 rule" lol .

Thanks also Mihir for responding

 

[Coulomb]

Does anyone have solar panels and a home storage battery?...

Does anyone have any experience on if savings are possible and how much bills can be reduced by.

In my case, I have a home made battery system and FIT (Feed In Tariff) system, and my bills are literally reduced to zero. I haven't had a refund cheque yet.

But I'm in Queensland Australia (the Sunshine State), so things are likely very different where you are.

 

[PAULinTHAILAND]

I don't have a Feed In Tariff so went for off-grid and maximizing my self-consumption. I have 20kW of solar PV; 27kWh of LiFePO4 batteries. The savings on household electricity and not having to put petrol in my car means a payback of 5 years on my solar components.

 

[Alb]

Hi Robert , i might be silly here , but im not quite understanding what you mean by the 80/20 rule .
Is it possible you can explain , then for me to say "oh that 80/20 rule" lol .

Do a Google search on the Pareto Principle

 

[Deleted member 2439]

Hi Robert , i might be silly here , but im not quite understanding what you mean by the 80/20 rule .
Is it possible you can explain , then for me to say "oh that 80/20 rule" lol .

Thanks also Mihir for responding

I think this has been answered- but a Google search will also answer & clarify

 

[BarryH]

For the benefit of everyone, adding a screenshot of what I've been charged for 1 week of electricity which includes normal day to day use + one EV charge from 65% - 100% with my current setup in the last 1 week :
View attachment 6836

I'm checking this out as an alternative to Solar plus Storage as the system and particularly the Uhome Batteries are interesting to me as they operate down to 0C whereas the Pyontech (which look very much like Uhome externally) drop off below 10C. My roof is a little tricky and shade issues could seriously drop Solar generation for about 4 months of the year. A 9.6 kWh Squirrel Pod storage only, is about £3k less expensive than a 3.45 kWp Solar generating about 2900 kWh in ideal conditions with 9.6 kWh storage. So over ten years 29,000 kWh (ignoring degradation) costs me £3,000 up front which is 10.3p per kWh for adding solar to the mix. Currently OctopEnergy is 35p for all of the day with only 10 to 12 time dropping below the cap and then in carrent 24 hours never below 32p. I'm on Octopus Go and in December 2021 got fixed price of 5p and 24.5p, but currently Oct'GO is 7.5p and 30p. This makes Solar attractive though since the Oct'Go EV charging rate has surly to rise to 10p+ by the end of this year. Price shock is that i was building up a Credit suplus on £100 Direct Debit up untilOctober 2021, but todays Octopus bill in my email was £102 Electricity and £108 Gas and I can tell you I'm being careful. That's in effect a 100% increase!

 

[BarryH]

Yes, no problem. Each battery can only charge, or discharge at a certain rate. A single battery can only charge/discharge @ 1.2kW. Adding another battery increases the charge rate by 1.2 to 2.4kW so the inverter is being “restricted“ by the capacity of the batteries. Adding another battery means that the batteries charge/discharge capacity is the same as the Lux unit (3.6kW). A fourth battery being added still sees the Lux unit operate at 3.6max, but the power is spread over 4 batteries rather than 3. Having 8 batteries means that the individual battery charge/discharge rates are proportionally less than a system having 3, or less, batteries. As each of the n batteries in the system is connected in parallel with the other batteries and Lux unit, the current in or out of all the batteries will be the same for each one. Hopefully that clarifids things?

Lux do an upgrade where adding a second unit gives a 7kW max charge/discharge rate.

A video introduction to LuxPower

 

[Happy Zappy]

Getting seriously interested in the whole PV / battery situation and hope to be having some discussions at Fully Charged in a couple of months.

Quick question for those in the know. Does the equipment have to be sited indoors? Can it be mounted outside or in the loft?

 

[Mihir]

Getting seriously interested in the whole PV / battery situation and hope to be having some discussions at Fully Charged in a couple of months.

Quick question for those in the know. Does the equipment have to be sited indoors? Can it be mounted outside or in the loft?

I have the inverter and batteries in the loft. Right below the panels. Some of them prefer having it in the understairs storage too but closer the units are to the panels, the better IMO. Reduces the minor dissipiation. Not sure if anyone would fancy having the inverter and batteries outdoors though.

 

[Happy Zappy]

I was mainly concerned about the temperature variations of mounting either in the loft, or outside. I’m aware that PVs don’t work that well in a loft,!!

 

[Alb]

Don't forget that the loft and anything in it is likely to suffer an extreme range of temperature so any equipment mounted therein would need to be very tolerant of this.

 

[Gadget Geek]

Some systems are designed to be sited outdoors. You probably need to check with the manufacturer. Tesla Powerwall can be mounted outside.

 

[seye]

I have the inverter and batteries in the loft. Right below the panels. Some of them prefer having it in the understairs storage too but closer the units are to the panels, the better IMO. Reduces the minor dissipiation. Not sure if anyone would fancy having the inverter and batteries outdoors though.

some are rated for outdoor use. I have GivEnergy system. They are, but mine is installed in the garage

 

[BarryH]

I have the inverter and batteries in the loft. Right below the panels. Some of them prefer having it in the understairs storage too but closer the units are to the panels, the better IMO. Reduces the minor dissipiation. Not sure if anyone would fancy having the inverter and batteries outdoors though.

Personally, I wouldn't have batteries in the loft the temp extremes aren't good for the battery chemistry no matter what it says on the label. I had my first PV system installed in 2011 and had an SMA 4 kW inverter in my large very spacious loft and it struggled in the summer and it ramped down of output in summer as the loft temp went up was the limiting factor in solar generation. Had I installed the inverter in my garage I would have lost 1% to 1.5% in DC Volt drop for sure but the inverter wouldn't have been throttling back and losing 10% to 15% output. I'm looking at a new system now (I moved 3 years ago) and the DC runs would be longer this time than at my previous house and I'm seeing spec sheets for inverters that say 0C to +60C but then saying throttling from +45C and summer temp's are often above that in my loft. As for batteries, they are really fan cooled as the majority of inverters would be and rely on passive cooling. They generate heat don't forget when charging and discharging and Lithium (found in both LEP and Lion batteries) doesn't like heat but also doesn't like the cold either. The ideal temp for batteries is 25C to 35C in most cases. Pylontech for instance has reduced charge and discharge rates below 8C-10C and can't deliver the specified 1.2 kW whereas the Uhome battery (used by LuxPower) has the advantage over Pylontech in that it can deliver down to 0C.

Tesla Powerwall says it has an operation range down to -20C but what they don't explain is that for the Lion cells to deliver that they need to be heated just as you might precondition your EV battery before a charge in winter or if you want to get full power when driving.

All of this makes a garage if you have one the better place to install battery storage or PV Inverter. I used to sell, survey and design PV systems and I know I made a mistake in my early days in the industry in putting my inverter in the loft but I soon gathered the evidence that this was a mistake. The companies I worked for liked putting inverters in the loft as it was easier to route a single AC 240v armoured cable from loft space, down an outside wall and into the location of the Consumer Unit and meter than to route 2 or 4 individual DC lines. However, the performance and the longevity of the inverter suggests that was not an ideal solution.

Having weighed up the options, I'm pretty certain that I'll be just going with the storage only option this time around and sticking with Octopus Energy. I'm on Go now and when the market stabilises and is a little less crazy I'll switch to Octopus Agile. For the price difference between Solar PV + Storage and just Storage, I could significantly increase the storage to more than I need. Then When Agile starts to have credible plunge pricing I'll switch to that and buy low and export when its peak time and export rates are high.

If you want to be ready for that switch to Octopus Go as there are still very attractive EV nighttime charging rates and it would be great if you used my referral code and share £100 with me (50:50) go to: share.octopus.energy/zappy-guppy-175