Battery Storage System For Pv(charging From The Grid Off Peak)

[solarhappy]

Looking at getting a system that can charge off peak and then discharge when I need the energy to feed my household loads.

Really with the FIT so low, id be using the solar as a trickle charge rather than income. So would be a small system but a large battery bank.

Anyone any ideas of best and cheapest system out there?

Done some research and reckon economy 7 meter would be best suited for this as cheap rates at night.

I use about 12kwhs per day so seems a good product.

 

[Worcester]

There are a number of us that have been discussing this subject in detail.

EXCLUDING, the costs of equipment to charge the batteries, energy monitoring inverter to discharge the batteries to the house only when needed, installation costs, DNO application costs excluding 20% VAT, and we do need a bit of profit, then the BATTERY ONLY NPV lifetime costs are coming out at around 8p/kWh.

Add in the premium of having economy 7 - you need to be using in the order of 30% of your electricity during the economy 7 hours to even make it economy 7 worthwhile , higher day time rate, plus daily standing charge. And the reasons that you;d do this at this time rather than wait until the technology costs have come down are:

1) Because you always want the latest gizmo.
2) Because you regularly suffer grid brownouts.
3) Because you are doing it as part of an experience gathering / information gathering / costing excercise, that doesn;t depend upon the economic outcome.
4) Pub bragging rights.
5) Because a commission based salesman has blagged you into it.

There are probably other personal reasons you might choose to do it, however at the moment the economic argument doesn't stand up.

 

[rolyberkin]

Tesla unveils a battery to power your home, completely off grid

 

[rolyberkin]

Looking at getting a system that can charge off peak and then discharge when I need the energy to feed my household loads.

Really with the FIT so low, id be using the solar as a trickle charge rather than income. So would be a small system but a large battery bank.

Anyone any ideas of best and cheapest system out there?

Done some research and reckon economy 7 meter would be best suited for this as cheap rates at night.

I use about 12kwhs per day so seems a good product.

Not really viable until the prices of storage systems come down (see my post above), if you want to make the best use of your excess PV energy fit a solar iboost for your hot water immersion if you haven't already got one.

 

[marc8]

Hi just turned on my battery storage system 2 days ago & pleasantly surprised battery stored up over 70% second day of weekend & today was over 80% charged. 5Kw battery system installed.

looking good

 

[t4sltd]

As Worcester says, having done the sums the system is unlikley to pay for itself within the warranty of the batteries.
The 5kWh system described by Marc8 can store 5 kWh of electricity.
If you get this free from PV (very unlikely all year round), saving 15p/kWh import gives 5 x 15p of electricity = 75p.
If you charge it free and discharge it every day for 5 years it would save you nearly £1,400.
5kWh battery storage costs about twice that, plus extra equipment, fitting, VAT and desposing of battery at end of life.

 

[solarfred]

Hi just turned on my battery storage system 2 days ago & pleasantly surprised battery stored up over 70% second day of weekend & today was over 80% charged. 5Kw battery system installed.

looking good

What batteries are you using?

 

[sean_ork]

Hi just turned on my battery storage system 2 days ago & pleasantly surprised battery stored up over 70% second day of weekend & today was over 80% charged. 5Kw battery system installed.

looking good

What size is your array ?

 

[marc8]

Hello Sean_ork & Solarfred

I am using solax inverter with their battery system, I have 4kw system perfect south, Yesterday generated 98% battery charge at end of day, think that there maybe some misconception on the batteries at this time as I was monitoring the battery system yesterday, Battery charges & if the house is demanding more than PV is producing & the battery has charge it starts to discharge.
so in effect the solax interface is constantly monitoring the system always topping up but also discharging when required as i say at end of yesterday I had 98% charge, this is not to mention during the day discharging.
system turned on:

12/02/16 2.45PM - 18th Feb 55.2KWh total
my peak power 3504 Watts

today not so good 7.2KWh generated batteries at 29% at present so I guess only 9% discharge tonight, but I have monitored today & it was charging & discharging all day.

early days but I am going to order another battery at the end of march should my system perform as it has now. my system can handle 4 batteries if required & should they keep going like last 6 days I will fill the rack to full consumption.
hope it helps

Family member has system round the corner just logged into his system tonight although 3.5KWp system today was 4.68KWh
with micro inverters.

 

[sean_ork]

Are you able to look back at historical stats to see how many days of the year you would have been able to fully charge them ?

From the sums I've seen it appears that the assumption is being made that a full charge will be possible (for free) every day of the year.

 

[marc8]

Hello Sean_ork

no you won't get a full load everyday of the year, today as mentioned at one time battery was at 40% in & out so discharging & charging & tonight I have 9% to use.
so it charges & discharges as required you don't need a full charge.

my house is running in the back round at about 420 watts average when I look at the portal, obliviously the wife boils the kettle instead of drinking water & goes to about 4Kw.
we have 1 large fridge, 1 medium freezer, 2 small freezers & pond pump running. LED lights through out though.
so we should have plenty for the batteries.

 

[marc8]

looking at a previous post & going a bit of topic,

had an idea about battery storage for people who don't have PV but do have eco 7 or 10 & the room charge batteries at night & then use an inverter to feed it back during the day. Looked at the you tube video of the guy doing a similar thing with change over switch but I am thinking of using inverter.
this is another reason for me having the system.

 

[marc8]

Batteries charged 100% 18th February by 1pm yesterday & they had been discharging & charging during that period also.
seems to be working fine for me.
12.2KWh for the day.