question

ralphd avatar image
ralphd asked

Setting battery capacity

Hi, I just changed my AGM house battery bank in my boat to a LiFePo4 bank consisting of three LiTime batteries. My system consists of a Multiplus II, Smart Shunt, Cerbo GX and three MPPTs. I have the smart shunt set as the battery monitor.

My question is how to I set the new battery capacity so that the Cerbo GX will display the remaining capacity / run time correctly?

The system has a capacity of 10.7kwh. I ran a test and with the system at 99.9% and drawing 129 watts the "time to go" was displayed at 32.83h - this would mean the system thinks the capacity is:

32.83*129=4235 wh.

Any help would be greatly appreciated.

cerbo gxbattery capacity
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

2 Answers
pwfarnell avatar image
pwfarnell answered ·

To connect to the SmartShunt by Bluetooth you need Victron Connect app on a Smartphone. Instructions are in the SmartShunt and Victron Connect manuals. Access the Shunt, go to settings, battery and input the Ah capacity of your batteries. The time to go calculate the time to go until the discharge floor setting is reached, which may be set at 50% or 60% for AGM which is why it tells you you can only use 4kWh. For lithium set the discharge floor to 10 or 20% depending how low you want to go. Also set the Peukert constant to 1.05 and charge efficiency to 0.99 and tail current to perhaps 5%.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

ralphd avatar image
ralphd answered ·

Thank you!!


2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

Related Resources

Additional resources still need to be added for this topic

Cerbo GX product page

GX family product range

Cerbo GX & GX Touch datasheet

Cerbo GX Manual

Venus root access document