Well I finally decided to order my fourth battery to take my storage from 15kWh to 20kWh.
It will make no difference to my DNO agreement as I limit my import to 60A and my export is already limited to 36A via the G100 policy setting on the Enphase Gateway.
The extra 5kWh will give me about an extra 2.5 hours on dull/cloudy days, but should save me an additional £1.50 every day, regardless of the weather conditions, so will pay for itself in around 6 years.
Despite the delivery being stated as ‘kerbside only’ I managed to persuade the driver to reverse onto my driveway with the tailgate down so my son and I could lift the battery directly onto the roof and thereby save the additional cost of hiring a Genie lift a second time.
Attaching the battery to the wall was a relatively quick and straight forward process, after all I have done three of these previously and the mounting frame is already in place.
First I drilled the larger holes in the top plate as they are only 6mm and I am using 8mm fixings, then attached the two plates to the Unistrut brackets on the wall.
Next I drilled a hole in the side of the case for the conduit and wires to enter.
I decided to remove a couple of the pieces of Unistrut framing to make it easier to get close to the brackets with the battery.
I also removed the micro-inverters to make it a bit lighter, attached the lifting handles and then with the help of my son lifted it on the brackets.
I then attached the top clamps and the ‘seizmic screws’ to secure it in place before re-installing the micro-inverters.
I then re-attached the pieces of Unistrut and fitted the cover as I will not be wiring it up today.
I can disable these two batteries independently from the other two as they are on a separate isolator in the sub panel.
I didn’t bother taking any pictures of the wiring as it was exactly the same as wiring up the other three.
It took a while to commission the battery as it needed to download and install new firmware and after that the Enphase website went offline for about an hour, after which I find out that one of the micro inverters in the new battery is not responding correctly.
One part of the app says the micro inverter itself is fine, but the battery is reporting that it is not responding.
I did try powering the battery off, removing and re-seating the micro inverter, but it seems to have made no difference.
The batteries usually only use five of their six micro inverters, with the sixth one sitting ‘inactive’ so the battery is still working just fine, hopefully it will sort itself out over the next day or so.
I was slightly lucky today in that when I plugged my car in, Octopus Energy decided to give me a number of charging sessions this afternoon, so I was able to leverage those to charge the new battery from 25% to 68% at the off-peak rate of £0.07/kWh that is available whenever Octopus give me a charging session. It will charge to 100% overnight, again on the cheap rate along with the other three.