Adding Solar Batteries to existing PV system

Jase1975

Hi I have had a quote to add solar batteries to are existing 4KV solar PV array system. The price to add a 4.8KVh battery plus new inverter is £4,000. I currently drive a full EV car that I am charging at night using my economy 7 rate (13.3p KWh). We are a lively household 2 working parents, 3 kids all using numerous electronic devices when they arrive back from school. In my head it makes sense to add the battery with current energy rates etc.. and the fact we are out of the house 8-4 Monday to Friday , however before I make the jump I thought I’d ask for some advice. Best Regards Jason 

QrizB

That's a high price for a battery that size.

If you manage to catch and use an extra 1000kWh per year with your battery, and electricity remains at the current high price of 28p/kWh, you'll save £280/yr and it will take 15 years to recover the cost.

That seems a long time.

[Deleted User]

You will also be very disappointed with such a small battery UNLESS your home consumption is less than 4.8 -10%(transmission loss) kWh/day. I have a 13.5kWh battery and an EV. As I am on Octopus Go, I can recharge my battery when the sun doesn’t shine at 7.5p/kWh. The battery meets our needs even on a dank Winter’s Day. 

Have a look at GivEnergy’s products.

All batteries need the prior approval of your DNO as they are potential generators. The DNO may impose a revised export limit. Some DNO’s work more quickly than others (my DNO took over 3 months), and there will be a bill.

Phlik

[Deleted User] said:

You will also be very disappointed with such a small battery UNLESS your home consumption is less than 4.8 -10%(transmission loss) kWh/day. I have a 13.5kWh battery and an EV. As I am on Octopus Go, I can recharge my battery when the sun doesn’t shine at 7.5p/kWh. The battery meets our needs even on a dank Winter’s Day. 

Have a look at GivEnergy’s products.

All batteries need the prior approval of your DNO as they are potential generators. The DNO may impose a revised export limit. Some DNO’s work more quickly than others (my DNO took over 3 months), and there will be a bill.

I thought you only need to get the dno involved if you're storage system has islanding capability? Purely adding storage doesn't affect the amount you can generate it just allows you to time shift the use of the power generated by your panels.

bobbybuttons

My circumstances are very much like yours Jase1975 . I run an electric car and have 3 kids using devices etc same sort of times after school . We are using around 750kwh a month 9000kwh a year I'm just wondering if you are using about the same ??
We think ours is very high but it's hard to compare against when people don't have an electric car. We are seriously considering having solar panels and a battery too but trying to work out if it'll cover the majority of our electric use ?

MWT

Phlik said:

[Deleted User] said:

You will also be very disappointed with such a small battery UNLESS your home consumption is less than 4.8 -10%(transmission loss) kWh/day. I have a 13.5kWh battery and an EV. As I am on Octopus Go, I can recharge my battery when the sun doesn’t shine at 7.5p/kWh. The battery meets our needs even on a dank Winter’s Day. 

Have a look at GivEnergy’s products.

All batteries need the prior approval of your DNO as they are potential generators. The DNO may impose a revised export limit. Some DNO’s work more quickly than others (my DNO took over 3 months), and there will be a bill.

 Purely adding storage doesn't affect the amount you can generate it just allows you to time shift the use of the power generated by your panels.

My DNO export approval is comprised of the solar output + the output of the battery.

If you have a battery capable of exporting to the grid then it needs approval...

Adding more capacity without changing power output wouldn't be a problem though.

[Deleted User]

bobbybuttons said:

My circumstances are very much like yours Jase1975 . I run an electric car and have 3 kids using devices etc same sort of times after school . We are using around 750kwh a month 9000kwh a year I'm just wondering if you are using about the same ??
We think ours is very high but it's hard to compare against when people don't have an electric car. We are seriously considering having solar panels and a battery too but trying to work out if it'll cover the majority of our electric use ?

It will not. I have a 6.55kWp array. My total output last December was 87.7kWh. My worst day was 300Wh. Even with a battery, it is difficult to use 75% of the total solar output.

markin

bobbybuttons said:

My circumstances are very much like yours Jase1975 . I run an electric car and have 3 kids using devices etc same sort of times after school . We are using around 750kwh a month 9000kwh a year I'm just wondering if you are using about the same ??
We think ours is very high but it's hard to compare against when people don't have an electric car. We are seriously considering having solar panels and a battery too but trying to work out if it'll cover the majority of our electric use ?

The car should tell you how many kw its taken on a charge, just keep track of it for a month.

Jase1975

markin said:

bobbybuttons said:

My circumstances are very much like yours Jase1975 . I run an electric car and have 3 kids using devices etc same sort of times after school . We are using around 750kwh a month 9000kwh a year I'm just wondering if you are using about the same ??
We think ours is very high but it's hard to compare against when people don't have an electric car. We are seriously considering having solar panels and a battery too but trying to work out if it'll cover the majority of our electric use ?

The car should tell you how many kw its taken on a charge, just keep track of it for a month.

Thanks all for responding. Hi Bobby are current annual estimated is 9800kwh. The breakdown in that is 6300 for day and 3500 for night which is when I mainly charge the EV. From the posts I get the feeling my quote was quite high and also that I need to be looking at a minimum of 8kw battery. Does anyone recommend a specific solar battery installer/provider? 

Thanks again Jason