Excess generation not always going into the battery?

Our 3 AC couple systems were installed in the middle of September with 4x 8.2kw batteries going in with them. As many of you did, the first few weeks I was checking it daily, getting all excited when I saw nice blue sky in the morning and the sun beaming down.

While looking at the charts I kept noticing this happening. We'd have excess generation, minimal usage, but the battery isn't charging at those times. Naturally I wonder if this appearance is just due to the 5 minute updates, or if it is representative of what is actually happening.

Looking at the only data I have which is the still standard 5 minute (ish, kind of) it looks like yes, the inverter isn't sucking down juice at those times or even between those data points, leading to excess power going to the grid. Is this something anyone else sees? is it normal, expected, accepted even?
Note, this image is just from one system, not all 3 combined.

Please could you email us at support@givenergy.co.uk and we will take a look into this for you, I will need the serial number of the three devices in the email - thanks.

Thanks Adam. Rhys is currently looking into a battery oddity for me and as soon as I'm happy that one is done I'll get a separate email chain open with the serial numbers and a smattering of examples of this happening.

dbt85 It could easily be down to the 5 minute snapshot as it is literally as things stand at that second in time, not an average of those 5 minutes - which would be more helpful in your case. You could export the data, pop it in a spreadsheet and use the "totals" to compare each hour of PV gen/consumption/charging etc. Might give you a better idea of what is happening.

Looking at the meter data it does appear that the totals for PV generation, export and charge are all following the same path. But I am not sure why the snapshot for those times would still show 3500w being exported and 0w going to the inverter and then 5 minutes later the snapshot showing 3000w being exported and 0w going to the inverter.

Realistically what are the odds of it happening to take a snapshot at the exact time in a 5 minute window when the inverter is idle and all the excess is going to the grid and then do the same thing 5 minutes later, yet the system data shows (in that same 5 min window) PVGen going up 0.4kwh, consumption going up 0.3kwh, Export going up 0.1kwh and bat charge going up 0.1kwh.

Maybe I do need to put the effort in to trying to grasp the local data collection to be able to see with more confidence what the system is up to as at times like this the 5 minute interval is not nearly enough.

I don't think I'm seeing what you report, most of the excess solar seems to be being pulled into the battery (until it reaches 100%). Mine is a smaller system (AC inverter and 2x5.2KwH). The graph below is based on data from 2 current clamps on the grid and the battery supply, sampled approximately every 2 secs, and updates every 5 minutes from my solar inverter.

Graph

I think I may have the same, or a similar, situation. It's a new battery install (16/12/21) and a much older PV.
For years now the smart meter display shows a lot of excess PV being exported to the grid (when the sun shines). This is what prompted me to get a battery. I would rather store and later use that excess than export it and then import it. However, on the few sunny days since the battery was installed the smart meter still shows PV being exported. The inverter also reports the PV generated but it doesn't use it to recharge the battery. In fact it appears to think it's extra demand! It's only a small system but I'm not getting the use of my excess PV. Any ideas?

Nev Young You might want to get the installers back to review the cabling - I wonder if one or more current clamps may be back-to-front, or on the wrong cable.

Hi - first really sunny day and I appear to be having the same problem. The solar panels are generating electricity and for much of the morning, they have been charging the battery (from 4% to 41%). They are still generating a large amount, but rather than continuing to charge the battery, the excess is being exported.
Would include a picture of the graph, but cannot seem to do that!

Chanced How much is it exporting - the inverters have a battery charge limit lower than 5KW on the 5KW hybrid so can only charge the battery at 2.5KW - it will export the rest (production above charging + home consumption)

I don't know how to insert the image of usage, but....

From 10:00 my solar generation rose to about 3Kw at 11:30 and stayed that way through to 14:00. Consumption stayed around 500W and during this time, the battery was charging at around 2Kw (from 4% to 41%). At approx 13:30 the battery charge dropped to zero and I started to export the 2Kw to the grid. The export has continued in line with the solar generation and no further charging of the battery has taken place. Interestingly, any excess solar power since 13:30 has been exported and not sent to the battery.

BTW - Thank you for responding, being new to solar means not knowing if this is how it works or if it is an issue, so all help is really appreciated.

Chanced if you can, be good to see the summary graph from the beta portal page. (use a service like this: https://imgbb.com/, to create a link to add the image to a post)

Here's an example:

You can see my battery charged from 82% to 100%. Why your battery would stop at 41% I'm not sure. (you won't see much grid export on my graph as after the battery reached 100% the hot water diverter kicked instead)

Thank you for the instructions. See below:
https://ibb.co/h8X5ph3

Chanced You haven't showed the battery SOC in the screenshot, but if it really only got to 41% it is indeed a bit odd - looks like it's just hit a charge limit and stopped. Has it ever charged to 100%? It might need recalibrating.

Chanced suggest you add the battery SOC % to the graph. As suggested above, it does sound like the inverter thinks the batteries are full or hitting some configuration limit. I can see in the graph the battery charging stop at around 13:30.

Is the inverter set to "Eco" ?

Thank you all for your help. It appears talking to GivEnergy that the battery 'tripped' the circuit breaker between it and the inverter - that was why the sudden stop in charging and the export of excess electricity. Something I'll need to keep an eye on (I didn't know that there was a breaker in the circuit!)

Chanced I've had that on mine a couple of times - I found the insulation on the outgoing (To inverter!) red cable was pinched in the terminal. Its actually something mentioned in the commissioning manual to look out for for exactly this issue. I sorted it myself (I'm qualified electrically) but if you aren't get the installer back to check it.

Thank you - I didn’t get a chance to talk through the installation with the team when it was done so I’m just learning what I have and what to look out for

To be fair to the guys that did my install, it was dark when they finished, so couldn't test it in use.

andrew_bond

Got tired of waiting for a call back from the installer so I looked at it myself.
Sure enough the black clamp that should go between the henley block and the supply meter was on the consumer unit feed. As a result the inverter saw the PV (from the blue CT clamp) but not that it was being exported. Good job I checked it too! As I had to re-route the black and white cables out of the consumer unit I found one had been over tightened and the tail had broken off at the EM115. All done now and it's a nice sunny day and the battery is charging nicely.

Nev Young The connection of the black and white wires from the mains CT to the EM1155 seems to be a weak point as there is a mismatch between the small diameter of the wires and the size of the clamping block/screws on the EM115. My installer spent over an hour trying to trace a commissioning error which he was convinced was the mains CT clamp intermittently failing to communicate with the EM115. No amount of removing the CT wires and refitting them or tightening the clamping screws made any difference. In the end he crimped metal sleeves over the ends of the bare wires and tightened the clamping screws against these. Problem solved. It seems that the diameter of the CT wires is just too small to allow the EM115 clamping screws to get a reliable grip, even when tightened as hard as you dare.

Solved my problem with some help - one of the wires in the breaker had been clamped with its sleeve in the connector and this was burning when I hit a certain power from the inverter to the battery. After I fixed this (with remote help from a new installer) the next sunny day, the battery now charged to 100%