I am considering to purchase an EasySolar II GX for building a domestic ESS system. Have studied the manual - looks really nice. My question concerns the built-in battery monitor: is that the one inside the Multiplus ? If so, then it would not measure charge current from the MPPT.
I would expect that the battery monitor provides an overall measurement of all charge and discharge currents flowing into/out the battery, but cannot find it with so many words in the manual. Can someone confirm that this is indeed correct ?
The easysolar is a standard Multiplus with a GX board and Mppt in one housing.
The MP GX does not offer all the connections of a Cerbo GX. In particular, it only has one CAN connection for the a managed battery and NO additional CAN port for a CAN bus solar charge controller, only one USB port and one VE.direct interface.
The MultiPlus implements a “software battery-monitor”. Also known as “built-in battery monitor“.
The Venus OS software running on the GX card includes the option to send “corrections” to compensate for MPPT current charging the battery.
The setting is called “Use solar charger current to improve VE.Bus SoC“
But, as you probably realize, the accuracy is not great.
For the best accuracy, install an external battery monitor (BMV-712 or SmartShunt) and connect it via VE.Direct to the GX card.
Most managed Lithium batteries also measure the SoC and if it’s connected to the CAN port of the GX card, then the system will use the SoC reported by the BMS.
For cheap Chinese batteries with cheap BMS, the SoC accuracy is terrible and I strongly recommend a Victron SmartShunt.
Thank you for the clear answer !
I think it would be a great addition to the “all-in-one” easysolar if Victron would include a built-in smartshunt which measures the overall current flow from/to the batteries.
But until then I agree it’s better to add the shunt yourself and not rely on the calculation by the GX device.
Most managed Lithium batteries are connected with CAN bus, so a additional shunt isn´t nessary
Easysolar and MP GX are entry-level models for customers who do not want to assemble the system themselves.