Small Offgrid DIY system

DIY
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1

Hello,

Apologies in advance if this is a dumb question so please bear with me.

My Offgrid system consists of :

  1. MultiPlus 2 48/5000/70 (230V)
  2. SmartSolar CC MPPT 250/100 VE.Can
  3. Smartshunt 500A/50mV
  4. Cerbo Gx
  5. Lynx Power In
  6. Solar Panels 450Wp in 4S2P configuration (3600Wp)
  7. Diy EVE LF280K (14.4KwH) LiFePo4 battery with JK BMS PB2A16S15P .

Wish to know how to make DVCC ON in such a way that, system wide

  1. Voltage and Current parameters should be from Smartshunt
  2. Temperature parameter from BMS
  3. Limit max charge voltage and current to be set manually (55.36V and 40A)

Have read the DVCC manual, but confused with SVS, SCS and STS enable/disable settings for non Victron managed battery.

Appreciate all the help

Thanks

Aananda

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AanandaOffgridSystem (1)
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2

Just swtich on DVCC and leave SVS, SCS and STS off.
Some BMS, like pylontech even force those settings.

with DVCC swtiched on and the BMS selected as battery manager, the Cerbo GX will instruct you MP2 and your two MPPTs to apply the correct charge voltage.
MP2 and MPPT must be connected to to Cerbo GX via Ve.bus (MP29 or VE.can (MPPT).
Instead of JK BMS you can also use SmartShunt but than you might loose alarms from JK BMS.
I have no experience with the SmartShunt for batteries.

BTW: you can show data from several battery monotors. Just enable them in GUI v2 → settings → battery → battery monitor

3

Thank you very much for the suggestions.

Yes all components are connected using VE cables.

  1. MP 2 to Cerbo Gx VE Bus port using RJ45 cable
  2. SmartSolar CC to Cerbo Gx VE CAN port using RJ45 cable and terminated at both ends
  3. Smartshunt to Cerbo Gx using VE Direct cable
  4. JK BMS to Cerbo Gx BMS CAN using BMS Type A RJ45 cable and terminated at Cerbo Gx end only

Also

  1. SmartSolar CC is the (only one) charger in the system as am not using Grid and disabled MP 2 charger in settings.
  2. Have selected Smartshunt as Battery Monitor in Settings/System Setup/Battery Monitor

All communications are good and reported to VRM.

Currently the AC load is less and battery gets fully charged by afternoon.

Wish to charge the battery slowly so as to make it fully charged by evening and hence thought of DVCC to limit charge current.

Will enable DVCC On and keep SVS, SCS and STS Off and observe

Thanks again

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4

Hi, you can set the JK BMS to be the controlling device not the smart shunt. The benefits here are the voltage measured at the battery are little more accurate, the current isnot as accurate in the JK compared to the shunt, you will get a SOC imbalance between the two (BMS and Smart Shunt) over time when the battery doesnt get back to 100%. But if you regularly get back to 100% its not an issue. Even if you dont you may see a 10% difference in SOC values. My system runs this way using the JK as the source for battery voltage and charge current. I use the smart shunt just as a backup monitor. But ultimately in my view, it should be the battery BMS telling the charging system what to do, as its job is protecting the battery form over current etc. Because you are cycling the battery quiet a bit, there is some belief that 2 batteries is better, this would reduce the cycling on the battery, thus greatly increasing the battery life. I have subscribed to this theory, but I am not convinced these batteries have been around long enough to actually have the evidence to back it up. But I feel that gentle approach is better as it must chemically be better for the battery. So when the 48/5000 draws max amps for an hour (110A) its shared across 2 batteries at more like 0.25c rather than closer to 0.5c Your charge rates are low enough to not require any changes as this meets the 0.2c or 57amps suggested charge normal limit of the Eve LF280k batteries.