Solar assistant is saying my load is 448w. production is 468w and battery usage is - 172w. Surley my production + battery should equal my load? 

Edited July 31, 20223 yr by Terminal3k

It should, in an ideal world.
Unfortunately the self consumption of your Inverter is not part of the Load, but that power usage is part of the battery drain. So the difference that you see there is what your solar system consumes internally.
Here is a typical example once solar is zero
Load 359W, Battery 436W. Difference 77W. Typical Inverter usage and other losses.

Edited July 31, 20223 yr by zsde

1 hour ago, Terminal3k said:

Solar assistant is saying my load is 448w. production is 468w and battery usage is - 172w. Surley my production + battery should equal my load? 

Cannot explain the full 172W but I would say about 60-70W of the battery power is to provide for the operation of the inverter. At lower values either measurement could also have a % error.

Sorry @zsde

for posting seconds after you.

Edited July 31, 20223 yr by Scorp007

As mentioned above,there's an inherent leech of inverter on batteries. Also some models of inverters have a PF lower than 1,so 10-20% extra draw from source for providing power

9 minutes ago, PsyWulf said:

As mentioned above,there's an inherent leech of inverter on batteries. Also some models of inverters have a PF lower than 1,so 10-20% extra draw from source for providing power

I have also seen inverters showing the same value for VA than Watts. So driving a inductive load there will be a PF below 1 somewhere in the PV system. Do the inverters calculate it correctly?

1 minute ago, Scorp007 said:

I have also seen inverters showing the same value for VA than Watts. So driving a inductive load there will be a PF below 1 somewhere in the PV system. Do the inverters calculate it correctly?

At low loads they drift apart quite a bit.

20 minutes ago, zsde said:

It should, in an ideal world.
Unfortunately the self consumption of your Inverter is not part of the Load, but that power usage is part of the battery drain. So the difference that you see there is what your solar system consumes internally.
Here is a typical example once solar is zero
Load 359W, Battery 436W. Difference 77W. Typical Inverter usage and other losses.

Your values are reporting the 70W used by the inverter accurately.

15 minutes ago, Scorp007 said:

Your values are reporting the 70W used by the inverter accurately.

It does fluctuate anywhere up to 100W difference. That may well be the update cycle of the two values. The Battery BMS is near real time whilst the inverter always lags a bit.

Thanks all, makes sense.