Gen 1 Inverter efficiency query

Hi, For about 5 years, I have been running a Gen 1 5KW Hybrid Inverter with 3 x Gen 1 5.2KWh batteries.
The system has always been a bit "flaky", so I control it programmatically using GivTCP. Recently since joining up with Axle energy I have found it hard to export any more than about 1.8KW from the batteries.
Tests have shown that When converting Solar to AC, the Inverter is around 97.6% efficient, but when there is no Solar in the equation, exporting just from the batteries, efficiently falls to around 80%.
I wondered if others have found this, perhaps because Low Voltages Batteries are the reason, or perhaps I have an issue my particular installation?

If your data comes from the GE app it isn't objective as what is reported isn't necessarily what is being measured. You may need an independent bidirectional current clamp on the AC feed to the inverter to see what is going into and out of the batteries. This is quite difficult to measure with a Hybrid as you have both solar and battery going through the same wires.

With my AC 3.0 Gen1 (not a Hybrid), I measure the currents with an Emporia system which is telling me that each day I lose around 2kWh of energy charging and discharging my 2x Gen1 5.2kWh batteries. This is for an average 8kWh charge/discharge cycle per day so around 80% efficient (10kWh in 8kWh out). This is the figure I have used in my round trip efficiency calculations. My GE spreadsheets has it at around 90% efficient using the GE counters figures.

In your case 97.6% charge efficiency may be right as it is all on the DC side. But 80% efficiency does seem a bit low for taking power out of the batteries which involves inverting DC to AC.

Windy Miller
Thanks for your comments and point taken about the GE Current measurements. I'm happy with the AC side of things because that checks out against other measuring methods, but I am relying on the GE internals for the DC measurements.
I'm thinking that the losses are down to using low voltage batteries. I just use the ratio of Battery Power : Inverter Power and find the following:
Charging Batteries from AC (Grid at night with no PV) gives around 97% efficiency
Charging Batteries from PV (280V DC) gives 97%
Discharging Batteries from their 52V gives 60% - 70% (depending on discharge current)

GeorgeLawrence The battery is 96% round trip efficiency - that's the chemistry losses.

The inverter <-> battery round trip efficiency is dependent on load and source.

If you search for a user called Hoggy then have a browse through his posts you'll see how it works.