Hi there,
When I'm running from my batteries (80kw) on the 3x MP2 10kva (3 phase) - I'm getting power overload warnings on my system at around 6kw draw on a single phase.
However if I turn on the grid, I don't get any kind of warnings and the system is happy running upto 18kw for awhile.
Can anyone explain the issue or point me to the specification sheet which shows this limit on the battery power.
There can be a few reasons.
Heat causes derating.
Battery voltage sag under load, increases the amperage drawn from the battery, so can do that as well. So look at the power being drawn from there rather than the AC load figure.
Or a combination of the two.
it is just a warning not an alarm, so it really is just letting you know you are approaching the limits
You seem to be conflating kW(inverter) and kWh(battery).
The capacity of the batteries (kWh) is irrelevant in this case, it is the discharge limit (DCL) that is relevant.
You have 30kVA of inverter, your pack needs to be able to deliver up to 600A to deal with that.
What are the battery specs?
When there is grid, the inverter can lean on that to compensate for tranisents. Without grid, the battery has to deal with it.
Some loads will also surge on start and can be many multiples of the nominal power, can be various causes.
6kW isn't that far from the 8kW limit, readings can be delayed or normalised and might not show you the actual peak, which may be higher. Grafana is better for charting these things when more detail is required.
Hello
Thanks for your messages.
So my discharge limit is 1250amps, I have 16x UC5000 pylontec batteries, arranged in banks of 2x.
The batteries voltages are stable, and temps never get above 26c.
The issue is if I don’t intervene, the system will completely shutdown, and I loose all the data on the charts.
I’ll upload some charts so you can see what it being reported.
Here are the screenshots from the last warning.
How is the DC wiring done?
A good sized battery bank and inverter system can be crippled by undersized cabling fusing bus bar and bank set up.
Why I ask is the DC voltage takes a dive when the load comes on. It is possible you are dipping down lower. With 60 second logging the real low might possibly be missed. You will have to check it in realtime.
What is the easiest why to setup better charting or collection of the data? But I do agree with you it seems like something is take a big hit suddenly. The only thing to say differently is actually what happens at the time.
For example, if I turn on 2x ovens in the house they will draw a constant 4-5kw each whilst they heat up that rating is stable from what I can see from my separate energy monitor (which reports every second).
The DC wiring, is all oversize using tri-rated cables.
Inverter to Power Distros: 2x95mm (run length 3.6 meters)
Power Distros to battery: 35mm (run length 1 meter) going to isolators then battery cables which are around 25cm.
Solar charges to Distros: 70mm (run length 2 meters)
All cable lengths are perfectly measured and match across all batteries and inverters; everything has been kept to the same length. 
If you want higher resolution charting:
https://github.com/victronenergy/venus-docker-grafana">https://github.com/victronenergy/venus-docker-grafana
