The Numbers Don't Add Up - #1 Battery

I have eight 440W solar panels, a “GivEnergy Hybrid Gen 3 3.6” inverter and a “GivEnergy Giv Bat 5.12” battery. The system has been up and running since the middle of July (2025), and I’m using the Web Portal to get my data.

While the system seems to be working well, I have come to the conclusion that I don’t trust the accuracy of most (perhaps all) of the data that I’m getting from the Portal, including Solar, Batteries, Import & Export. Either the portal data is inconsistent with itself, or it is inconsistent with data from other sources.

Is this just a issue with my system, is it an issue that other people have (or am I analysing things incorrectly)?

There’s far too much to put in one thread – I’m going to start with observations on my Battery.

Definitions:
Power data found in the My Inverter/System Data table
Energy data found in the My Inverter/Inverter Data/Meter Data table

A) Charge & Discharge

Here (hopefully) is a graph of the cumulative energy used to charge my battery (blue line) and the cumulative energy discharged from my battery (orange line), calculated from the Energy Data table.

I was expecting to lose perhaps 10-20% of the energy between the charge and discharge cycles (see various other posts).

But that’s not what I’ve found – over the course of 3 months I have used a total of 260.5kWh to charge my battery and have got out a total of 300.9kWh when discharging it! Overall, it has discharged 13.5% more energy that has been used to charge it, a gain of about 0.4kWh per day!

Great – free energy (probably from dark matter)!

Unfortunately, I’m pretty sure that’s not possible according to modern science.

Either the charge is being understated, the discharge is being overstated, or both.

B) Discharge when at 100%

In the summer, on sunny days, when my battery reached 100% charge, the portal reported a discharge rate of about 30W (from the Power Data table), and the battery discharge value (from the Energy Data table) rose slowly.

However, the Battery Charge percentage never dropped below 100% (and it never switched from discharging to charging), even after many hours, making me think it wasn’t really discharging.

Could this actually explain the above problem?

If the meter measuring the discharge continuously reads about 30W more than the true value, then over 24 hours, would produce a fictitious discharge of about 0.7kWh.

This would mean that the above 0.4kWh daily gain from (A), would actually be about a 0.3kWh loss, which would make sense.

Questions

Has anyone else found their battery seems to discharge more than it charges?

Has anyone else noticed this small (potentially fictitious) discharge when their battery is at 100%?

MFW My inverter (Gen 1) doesn’t report charge and discharge total to the portal, only total battery throughput which is pretty useless. But looking at the inverter data in Home Assistant, my charge total is 5918 and the discharge total 5183, so about 13% difference which is within the 10-20% range others have quoted.

I know there are some differences in the way the charge and discharge energy is measured, one is AC and one is DC before conversion, so that might explain the difference for you. I also know the today figures are less accurate because they assume that the charge and discharge will be constant between each 5 minute data collection, and of course varying solar and varying house load means it isn’t.

Plenty of other people have reported all sorts of data discrepancies in the past so to be honest I only use the portal data as a guide as to what is going on.

my gen 2 9.5 battery is hovering around the 95% mark.

Hi
Thanks for your replies.
Both of you have results that make sense - your charge total is bigger than your discharge total.
Mine is the wrong way round - my discharge total is bigger than my charge total.

Mine is the same I just don't worry about it 😟

Well, it's nice to know I'm not alone with this issue.
It's just really disappointing, because if this data is inaccurate then the chances are the rest of it isn't any better.

geoffreycoan My inverter (Gen 1) doesn’t report charge and discharge total to the portal, only total battery throughput which is pretty useless.

They used to then GE broke that functionality - probably March/April this year where charge/discharge figures started randomly being reset to zero by something on their side.

Various other reporting functions got screwed at the same time.

No surprise really, just glad I don't have to use the portal....

Vestas No surprise really, just glad I don't have to use the portal....

likewise, I don’t use the portal either. With two inverters the graphs are even more screwed up, but from what I hear there are lots of discrepancies in the portal

geoffreycoan Its mainly OK for PV generation figures and where that's going (reports) which I use occasionally. The rest of the report is less accurate but in the ball park.

Oh and remote control of course to sanity check things 😉

I used to check the system inputs & outputs when I first got my system installed back in 2020 and the numbers never added up, so I don't bother nowadays. I've got 2 x 8.2kWh batteries and the % charged is totally inaccurate, for example right now one battery is at 87% and the other at 52%. Recently I've had the problem that the App shows the battery charge at 100% even though the individual battery %'s are much lower. It stays jammed at 100% for a day or two then seems to reset itself at approx 2am.
At this time of year when solar PV has dried up, make sure you are on a cheap rate tariff overnight so that you can fully charge you battery with cheap rate electricity. This will last you for much of the day plus a little solar PV.