question

Kevin Windrem avatar image

Battery upgrade?

I have an existing system that consists of:

  • 1 Multiplus Compact 12/2000/120
  • 1 BlueSolar MPPT 100/30
  • SmartShunt
  • 2 Battle Born GC2 100 AH batteries (parallel connected)
  • Raspberry PI running Venus OS
  • custom, manual inverter pre-charge circuit

I'm wondering if there is any advantage to replacing the batteries with Victron Smart Lithiums, and if so which BMS would be appropriate.

I've read that the VE.Bus BMS prevents inverter control from Venus. Is the same true with the Lynx BMS?

I believe the VE.Bus BMS will shut down the Multi (charge and inverter) but I believe it will NOT shut down the MPPT. Correct? So that means I'd need a battery protect for both load and the MPPT. Correct?

Lynx BMS documentation hints that it will control both the Multi and MPPT and can disconnect the loads so no battery protects would be needed. Correct?

Lithium battery Smartbattery bms
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1 Answer
Stefanie avatar image
Stefanie answered ·

Hi @Kevin Windrem,

yes it's true. You can't control Inverter state from within Venus OS when a VE.Bus BMS is connected.

In my old system I had a VE.Bus BMS. MPPTs were controlled by the BMS (Load Disconnect, Charge Disconnect) Battery Protect. I haven't tested this down to the limit, but it worked just fine.

Now with the Lynx Smart BMS it is not advised and no longer necessary to control your MPPT via a Battery Protect. MPPTs and Multiplus are controlled by the BMS through your GX device directly. No further devices or wiring required.

Yes, the Lynx Smart BMS has a contactor, which can switch off all your loads. I'm still using a 220A Battery Protect in between the load side of the BMS and the loads, just as a precaution and because I still have different load branches.

And I should add that the Lynx Smart BMS has a built in pre-charge circuit, which runs automatically at start up.

Not sure about your battery upgrade. If your old batteries reached end of life and you always was thinking of replacing them with lithiums, then do it. I don't regret going this route, even with the higher priced Victron Smart Lithiums. Now with the Lynx Smart BMS it all comes together, kinda like the cherry on the cake.

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