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Can anyone advise me as to what "round-trip efficiency" I should achieve with two Leoch Lfeli 48100 lithium batteries having a total capacity of 9.6kWh linked to a Victron Multiplus 48/5000/70 inverter having a discharge 4.4 kWh. Is the efficiency affected by the settings of either the inverter or associate equipment – any general advice/help would be gratefully received
Round trip efficiency is a comparison between power out Vs the amount of power it takes to get to fully (balanced) charge.
On the BMV is it easy it is charged energy Vs discharged energy.
The leoch bank I have just looked at is close to 91%
The bank is 700AH, cycled down to about 40% every day.
It can be affected by wiring of the bank and heat heat is loss of energy.
many thanks for your help. if I understand the position correctly the fact that it is taking 10 kilowatt hours to charge the battery which is then only discharging 6.5 kilowatt hours therefore an efficiency of only 65% means that something is wrong or the system is incorrectly configured. Unfortunately I am a layperson with limited understanding the technicalities and the installer seem reluctant to help. I'm very grateful for your input
Chris
You are correct in the understanding.
I would start asking why so inefficient? Those figures are more lead acid realm.
Something doesn't seem right. I am not familiar with your system, but would check wiring and settings.
Check against the manuals for the battery.
How is everything wired? Compare that to the manual as well.
Does your system get hot? Any particular part of it? Is the environment it is in hot as well?
Are you running ESS?
@chris H as a comparison, I have a 5kva 48v MPII unit, with 4 tesla (2S2P) battery modules. I get a charge efficiency of 95-97% and a inverter efficiency of between 85-91%. This makes my round trip efficiency about 80% at worst. My biggest factor affecting my setup efficiency is my DC cable size, battery temperature, and the ambient temperature where I keep my MPII unit.
