5kwh Battery 100% charged but only used 4 kwh until empty and then back onto grid power. How often are we ment to calibrate the battery, assuming this is the fix? System installed in June. Last calibration was August, it is now September. Any ideas? Thanks
If you look at the spec sheet for your battery, I think you'll find that it doesn't give 100% depth of discharge like the 9.5kw gen 2 battery - only about 80% DOD.
You only get 80% Depth of Discharge with a 5.2kWh battery (https://kb.givenergy.cloud/article.php?id=95&oid=19)
so it looks like it is working correctly.
SJB Thank you for your prompt response, you have saved me from running a recalibration. Now I understand why they all say to get a bigger battery!
JohnSomebody was it installed by Eon ?
simont no, a local company.
JohnSomebody so it is unfortunately working to specification.
Eon sold some 5.2 batteries as 100% depth of discharge and GivEnergy have released a firmware upgrade for those batteries to release the full capacity. The reason the olde4 batteries are only 80% dod is that some capacity is reserved for future battery degradation so over its life you’ll still get the same charge capacity. Some concern with the Eon 5.2’s that they may premature age by being discharged so fully.
Yes, get a bigger or second battery. I bought a 9.5 to go with my original 5.2
You will have to pay VAT on an additional battery unless you are also able to add extra panel(s).
I added a second 9.5kW battery and had to pay the VAT but still glad to have sufficient battery to support house and to be able to play with import/export tariffs
Rogerbu believe you can order just 1 panel, declare it as being floor mounted and get the vat off the battery order?
Stupid government policy should make batteries zero rated as well
geoffreycoan It depends entirely on what your avg use is, the capacity of your panel array... I did the math and based on a 4kw system, that during the summer could achieve a peak of 30kwh generation in a day... and the avg daily use of 16kwh... adding a 9.5kwh or even an 8.2kwh battery to my existing 5.2kwh... simply doesn't make sense.
There would be little to any chance of achieving a full charge on 14.7kwh of battery with my setup... even taking into consideration the 80% DOD on the smaller one... which typically sees me getting in the 4.7kwh charge range anyway.
A larger PV array would make it more viable of course... But in my case, it doesn't... and may not for every one.
It's also worth making sure that people know... that adding to the system incurs VAT when the initial installation of solar+battery does not. Pushing the cost of adding even a 5.2kwh battery to my system up to around £2800 and over £4000 for a larger one.
Anomnomnomaly I agree the economics of adding extra batteries are not great.
I’ve done my own calculations of whether I should add another (3rd) battery to my setup, and I can’t make the math add up with anything like a decent ROI.
I’ve got a large array so can easily charge it in the summer and discharge at Flux peak rates, or import in the winter at overnight rates and save on the import costs (but charge rates and duration of the off peak period become limiting factors), and I still get 5-22 year payback estimates.
I suspect I might have got the same with my original battery purchases, but I’m not going to try that! For me the battery gives a lot of flexibility that I wouldn’t have had before.
The ROI is further impacted by you needing to have a GivEnergy installer plug the battery in, can’t self install as you can with other manufacturers.
Hey ho
geoffreycoan Thank you for this info. Now we are into October with rain and shorter days, I am undecided if a second battery would be financially and environmentally beneficial. I am going to wait a year to get more data, but thanks again for the detail as to why the battery only uses 80%.
I was looking at the figures the installers estimated for generation on my 4kw PV array.
Year one it was 3630kwh, and it was commissioned in mid Jan so we've had a few days over 9 months use out of it so far. We've generated 3753kwh so far this year with 3 months of the year left to go (albeit the shorter days).
In the first half of Oct we've still generated 157kwh so far. Looking at the data for half of Jan, through Feb/March... and I'm estimating over 4000kwh generation for the year based on what we saw in the first part of the year.
I've enquired with the installers about a 2nd battery... I might purchase one direct from a supplier and have them install it... because I can get the battery for less than £1800 and I'm not paying £1000 for a few hrs work to install it.
Installing it now might not be the best time in terms of being able to fully charge it over the winter... But I want it ready for spring and I've saved up the extra money... a load of it from the savings made on the bill this year. Our gas/electric bill for the last 12 months since buying this house 1st Oct 2022 has been £987