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vassilis-bourdakis asked

Q: how to set Charge Current Limit on Multi2/MPPT/BMS system with DC loads?

I've read previous discussions on the issue, not quite the same (or 2yrs old) so I'd like to have another go at clarifying my thoughts!

24V system on a boat, Multiplus2 3000/24 handles the 230V loads, 600W solar via MPPT100/30, BMV700 and rpi3B connecting all 3 together.

About to add a BMS LifePO4 circa 7kWh battery with canbus connection to the system. Easy to enable DVCC and set a CCL, fine. BMS is diyBMS, with passive balancing that will run fine at 1.5A on latest custom boards. Just finished testing it at home.

Now thinking of typical scenarios:

early afternoon, bank about to start balancing, no consumption from 230V (so Multi2 is idle), enough solar. Result, diyBMS asks for CCL of 1.5A, Venus obliges, asks MPPT to only sent 1.5A. Fine!

A large 230V consumption is requested (watermaker, coffee machine whatever) Venus talks with Multi2, notices this consumption and "allows" MPPT to pump more amps (assuming they are there!). Fine.

Now, third scenario, large 24V consumption crops up (pressurised pump, el. toilet, air compressor, etc) This doesn't go via the Multi2 obviously, but straight through the battery bank.

Am I right in thinking that the BMV700 reports that Amps going out instead of in to the bank and Venus allows MPPT to pump more to the mix until the 1.5A is reached?

Or put it differently, is BMV700 interrogated constantly to make sure that right amount of current reaches/leaves the battery bank?

Hoping the answer is a straight yes :-)


MPPT ControllersMultiPlus Quattro Inverter Chargercharge current limit
2 |3000

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