gordonpascoe avatar image
gordonpascoe asked

DVCC & Constant Low Battery Warnings

I am experiencing low battery problems at our regular home (48v) and at our off-the-grid bungalow in the bush (24v) with my Victron system (i.e. "low battery" was coming on far too soon and battery never seemed to fully charge). This is one reply I received from my battery supplier after my installer pointed to a problem with the battery BMS at our lodge (48v also in the bush);

"Your assessment is completely incorrect in this regard. Your installer set the solar charger to charge to 56.2V and it only charged to 55.9V. This can be verified by a multi-meter. He then had to increase the setting on the solar charger to 56.7V to get it to charge to 56.4V. You can see this on the recorded data. We have a special instruction in our manual to ALWAYS verify that the chargers charge to the correct set point as we’ve seen some of them not to do so. The Victron system has a function called DVCC (Distributed Voltage and Current Control) which allows the battery to control the voltage set-point. This is not enabled on your 8kWh battery.

Your belief that the BMS is unable to communicate with the Victron system is unfounded. I have investigated each and every parameter between the battery and the CCGX and these are communicated correctly."

As you can see our installer fiddled with the Victron charger to get the system to work at the lodge. I really don't understand what DVCC means and whether or not it is wise to use this setting, or whether it will even solve the problem. Any advice will be highly appreciated. I am now experiencing the same problems at my home and our bush bungalow having just bought new lithium batteries (interestingly we did not have any such problems with our lead-acid batteries).

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
ejrossouw avatar image
ejrossouw answered ·

Hello @Gordon.Pascoe. Firstly, which brand batteries are you using and have you checked compatibility with Victron equipment? Secondly, DVCC should be enabled to allow the battery's more accurate internal BMS readings to be used by the CGX / Venus. SVS and STS should however be turned off. This would put the charge controller under BMS control. Have a look here as you will find configuration information specific to certified Victron batteries.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

gordonpascoe avatar image
gordonpascoe answered ·

Thanks @ejrossouw. I have BlueNova batteries installed at all three sites.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

James Verster avatar image
James Verster answered ·

Hi All.
We are aware of Mr. Pascoe's issues. He has 2 issues:
1. Battery doesn't charge to 100%. This was due to that fact that the MPPTs would not charge to the 56.2V setpoint. The installer had to adjust the MPPT setpoint to 56.6V to achieve to ensure that the battery is charged to 56.2V. The installer did not activate DVCC as I suspect that it had just been released a month or so before the installation and he didn't know about it. BlueNova batteries are fully compatible with the DVCC function.

2. "Low Battery" is displayed on the CCGX when the battery protection circuit activities the main DC battery isolator and then disconnects the battery from the DC bus. There are various reasons for this. There had been a BMS failure which caused the battery to disconnect. In another case the battery was over-discharged and disconnected because no grid or generator could support the load at that stage.

James Verster

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Related Resources