I’m having an issue with my Victron setup and I hope someone can help me understand what’s going on. I will attach a short video to illustrate the behaviour I’m seeing.
System configuration:
MPPT SmartSolar 250/100
MultiPlus inverter/charger
Lithium battery: 4 x Tensite 48V TS-L5000/LV, connected via BMS
Cerbo GX for system management
ESS mode: Optimized (without BatteryLife)
Problem:
When the battery reaches 100% and solar production is still available, the system enables grid feed-in, but instead of sending the excess to the grid, the MPPTs suddenly stop producing. At the same time, the battery experiences sudden charge and discharge cycles, with high current peaks.
This behaviour leads to overstress on the batteries, and I’ve had to set a voltage limit of 51.6 V (low V batteries) to avoid overvoltage conditions. That reduces the voltage peaks, but the core problem remains: the MPPTs continue to cut off, even when there is solar energy available and loads or feed-in possible.
Interestingly, when I disable grid feed-in entirely, the behaviour becomes normal. The MPPT output follows the consumption smoothly, the battery stays close to idle once full, and no erratic cycling occurs.
I enclose a video with the behaviour (without voltage limitation).
My questions:
-Why are the MPPTs cutting off when the battery reaches 100% with feed-in allowed?
-Is this a misconfiguration, or is it a known issue with the Tensite BMS or MPPT-Cerbo interaction?
-Is there a way to force the MPPTs to continue production towards feed-in or loads, without cycling through battery charge/discharge?
-Could this be solved through custom DVCC settings or feed-in limits?
These aren’t supported (tested) batteries. It may well be the bms is having an issue with the overvoltage that exporting needs to get going.
Post your bms linits (ccl,dcl,cvl) chart from VRM advanced here. It will help show what the bms is coping with.
That is also one very hot battery, I would try improve airflow for that system.
Do you have access to the battery logs to see if it is reporting an issue?
The BMS isn’t changing limits from the image supplied, assuming the chart covers the tests you have showed above.
Have you checked the voltage readings with a meter at the battery and the inverter/mppt battery terminals to confirm they all agree?
Maybe post your remote configuration file.
Had the same weeks ago out of nowhere and the only thing that works was to change the ESS-Mode to “optimized (with battery life)” and after that back to “optimized (without battery life)”.
That’s what I thought was happening but the previous limits chart didn’t show any drop.
When it blocks charge you will have problems. That is the BMS being unhappy, explains why lowering the charge voltage helps, prevents the BMS cutting out.
I think the battery manufacturer needs to adjust their firmware a bit.
Yes, the previous chart was taken during discharging.
The manufacturer stated that the battery is 100% compatible with Victron and even provides configuration guidelines in their manuals.
Is there anything else I can try?
Manufacturers always say that. And when it doesn’t go as planned are nowhere to be found.
Part of certification and testing is working with the 0.4V overvoltage that is triggered for exporting.
All you can do is tune down the CVL in DVCC, which isn’t supposed to be used for this purpose nor indefinitely.
The battery manufacturer really needs to improve their BMS parameters and behaviour.
instead of sending the excess to the grid, the MPPTs suddenly stop producing
I’ve seen this and wondered the same. Had this happen both on its own when batteries are full just like you described and also when I turn off the inverter due to no need but batteries are low and could be charged directly. Sometimes both scenarios work as expected, but sometimes production just stops and I don’t know why.
