Battery Systems - size is everything

I have been asked to share my experience with storage batterie. We have only been using them fully for 3 months but it became obvious that generating more electricity that we could use in the summer daytime even with an EV car that paying full rate of just less than 30p made no sense when being paid only 4p by SEG system. I first bought a GivEnergy 8.5 battery and that was too small so we bought a 9.25 KWh as well couples with the 8.5 KWh so we had 17.75 KWh battery storage to see us through the night and fun our jacuzzi, pond lights, pond pumps , fridges etc.

We now use OVO anytime which charges our EV at 10p per kWh. If our batteries are full then they charge the car at 0p per kWh.

winter will be different but there are many bright days and today in the cloud we were generating 1.9kWh.

I hope this is useful info.

Hi,

Just like to say I have solar with a GivEnergy 2x8kw battery system and 5kw inverter and it has been very reliable, easy to use and so far made quite a chunk of return on investment. What a great bit of kit!

How did you get Anytime? ive been told I cant have it as I have Solar panels

You can use Charge Anytime with an Indra charger. 

Hello Chris78,

I have solar panels and have used charge anytime since its inception but do have an Indra Smart pro charger. I am a private individual retired and have no connection with OVO.

Hope that gives you an independent view.

Thanks for confirming, @Jequinlan.

If anyone lands on this topic and has a similar set up we’d love to hear from you. 

How was the installation, how is the performance and are you seeing any savings that would allow a reasonable return on investment? 

Very interesting advice, @BPLightlog.

Would it be up to the occupier to calculate and decide on the appropriate storage size? In my mind a battery supplier would always advocate as big a battery as they think they can get away with recommending. I supposed the main limitations are size and cost?

Perhaps it’s decisions like this that make independent advice from other people such as yourself on this forum so helpful, and also OVO’s energy expert visits:

A supplier would always make suggestions .. cost, size and location are key factors of course. One thing most suppliers don’t ascertain is the typical high point of usage - and to be frank, many users wouldn’t know. This part of the calculation is critical to my mind  .. without it, the user could still draw from the grid even with a near full battery. This often leads to frustration as they expect the system to cope.

From what I’ve experienced over the years, many suppliers are not that good at useful advice, mainly because they seem to specialise in one aspect of the system rather than having a full understanding of all the relevant parts.

Absolutely agree. The supplier didn't really ask the appropriate questions. His calculation suggested 3 x 2.4kWh batteries but there was s supply hold-up (confirmed with other suppliers). When the supply eased, we actually chose to have 4. More than enough for summer. We've just added a fifth!  It allows us in winter to top up overnight (economy 7) and run on batteries until the following night.

They also don't tell you that the system is designed to prevent the batteries from discharge below 10%, so your stated capacity is not usable. 

Our power move challenge targets are always 0.1 kWh - what happens when even a kettle is switched on before the system reacts and allows more to flow from the batteries. The monthly % for peak tea time usage is not a problem. 

@BPLightlog @EverythingNeedsAUserName Very timely comment bringing this thread bubbling to the surface !

I’ve been on Octopus’s Cosy tariff which gives two cheap sessions of 3 hours 4-7am and 1-4pm, followed by an expensive 3 hours 4-7pm. I’ve read that charging a battery during the cheap times effectively doubles the size of the battery, assuming it can be completely filled within the three hours. The Cosy tariff is aimed at heat pump owners with a view to heat up the house during the 3 cheap rate afternoon hours, then setting back for the next peak rate 3 hours (I think). This hasn’t worked for me as the fabric of the house hasn’t held the heat that long, and the heat pump has used a load of power when fired up again after the peak time is over.

I don’t have the PV and battery yet but I do have records of how much electricity I’m using during the peak time now. How do I work out how much battery ?! and what about the inverter ? Does that have a size too ?!