Every night I get a couple of spikes of spurious house load and corresponding grid supply generally about 2.4kW, if the battery still has capacity, it shows as discharge. There are no loads (over the general background 3-400W) on at these times.
Has anyone else noticed or seen a solution?
Thanks
Steve
It will probably be something like the fridge or freezer kicking in and be the startup spike that happens to coincide with the data log. The battery just can't react to take it up.
Anglefire, thanks for the reply, although I doubt the fridge start up would be 2.4kW. The chance of it occurring on the 5 minute cycle 2 - 3 times every night also seems unlikely. It only started on 3rd June so it would seem to be related to a change that happen then. It is now happening every night
I'd agree that it's unlikely to be a household appliance (unless you're sleepwalking and having a cup of tea!)
Those numbers look more like an immersion popping on briefly but you'd expect that to be a consistent load for some time whilst it does its job.
The only similar thing I've seen on my kit is when the battery itself suffers a low voltage alert and does a spot charge off the grid to get back up to a comfortable minimum voltage. It's possible I guess that the data might show a discharge at the same time as a mains import if the battery did a rapid charge/discharge within the sampling time of the inverter.
MRich mine will do that but only if the battery is flat and below 47v (might be 48) then it will through 1kwh in the rebalance the cells.
MRich I've just looked at my load power for last night and I get a regular spike always just before a change in load, but not all the time. The only thing I can think if is a motor - so compressor on the freezer probably. The large continuous "spike" is the dishwasher. The spikes are not as big as yours - about 800-1100w - but does show that spikes do exist. Immersion heater would be a longer load. Unless there is an issue with the stat.
anglefire I was going to say a larger freezer could create this.
So, OP do you have one?
Or an aircon unit?
If it’s daily, and at the same time, it’s definitely something in your home. Hot water maybe? On a schedule to heat a tank overnight?
I have a system that does a weekly heat and hold to 60°C for hygiene reasons so perhaps something similar? I have no user control over when mine happens. It’s fixed at 02:00 Saturdays.
anglefire That graph looks pretty familiar, although I don't get as much of a clear spike as the three smaller ones you do (probably the sample time missing the motors starting up). The load looks similar though except we run our dishwasher earlier in the evening (when we're still generating enough to run most of the cycle).
2.4kw definitely seems too much still - my guess would be an immersion heater or an aircon (I'd imagine a really chunky heat pump might spike that high but the time of year makes that less likely anyway). Given the confusion from the OP I'm guessing though that anything obvious like that would have already been noticed.
If anyone has more experience with appliances, would an older fridge/freezer (one which might be in need of replacement) use more power trying to cool? I'm wondering if wear and tear might account for a higher spike load. I'm thinking a problem analogous to needing to re-gas the aircon in a car due to failing performance.
MRich peak starting current of a motor is typically stated as 7x running current. So for 2.4kw spike that is only a 340w motor load. Easily possible especially if it is a bit older.