I’m just setting up a small 48V system with a 100/20 48V solar charger, cerbo and BMS system. There is also an MP2 3000 with ESS assistant loaded. At the moment, the MPPT is not charging the battery, as the voltage limit appears to be wrong. [console] This shows the charge voltage is set to 52.9…

Thanks, been using Dbus-spy to check on what’s going on… Found where the 52.5V limit is coming from: in DVCCL.py in the folder there is a ‘fix’ for a Pylontech battery - or more properly several fixes. However, the code can only properly differentiate between a 15 and 16 cell Pylontech battery, …

Hub/charge voltage: This appears to be the limit set by the ESS, and it’s not the limit set by the BMS. The reason the/Dc0/ Voltages are the same is cause the battery has stopped charging due to a false limit. [image] found this in d-bus - system: [image] but can’t change the value. further d…

Another possible Bug: I have the system functioning, however, it still seems to want to charge from grid rather than solar, however whilst implementing & Testing the Alarms for the BMS,I found that though the Battery High Voltage & cell High Voltage alarms are set, the Solar charger is not turned of…

Amongst the other documentation I’ve found on the CAN - BMS implementation is this: By way of example, if the BMS sends a CVL of 58V, the MPPT solar charger will add 0.4V to the CVL for a operating charging voltage of 58.4V. At the same time, the inverter/charger will try and hold the voltage dow…

To export an offset of 0.4V is added to solar chargers, over-voltage is the mechanism used for exporting, this only applies when exporting is enabled, not under other conditions. If you enable exporting if it was not previously enabled on a system with a charged battery, there tends to be a short p…

Hi Nick, I disagree with you about disabling the solar charger under alarm conditions. The 0.4 over-volt from the MPPT / solar chargers compared with the inverter is required to make the export work nicely, BUT this should not take the system over the MAX voltage set. So perhaps the inverter ought…

Hi @MikeD Maybe this needs to be addressed this way… All batteries have a range of (safe) voltages for charging. Like Pylontech (15S): 52.5V - 53.5V. So the minimum voltage for which the SOC will be 100% is 52.5V. Also the delta of the (safe) range is 1V in the example above. So, set the chargin…

The system does not sustain the overvoltage. It is drawn down, I presume you aren’t using a “supported” battery? On a 16 cell battery you are talking about 0.02V per cell. I will test again on mine tomorrow and report back.

Hi Alex, that would of course work, but requires manual intervention in capping the DVCC charge voltage limit. My points are: Overvolt alarms should inhibit ALL sources of charging, this is not currenly the case The enable charge flag from the BMS should be implemented in Venus, this is not inhib…

You may be right, because, from my experiences, many, if not all BMSes already send as default CVL the maximum upper limit… So the inverter deducting 0.4V will still be in a good range for 100% charging.

Having tried and failed to get the ESS> External control mode working, I found with External Control mode set, the Solar charger Voltage limit was at 0V this morning, and the inverter set back to 52.5V. I reset to ‘optimised without battery life’ and the solar charger went back to 52.5V also. This …

MPPT getting wrong Charge voltage limit from Cerbo/ESS

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MPPT getting wrong Charge voltage limit from Cerbo/ESS

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