question

ian0 avatar image
ian0 asked

2 signal BMS

This is probably a really obvious question . . . When triggered by the "battery empty" signal, does the charger always go into bulk? Or does it only go into bulk if the battery voltage is x Volts below the float voltage? (Can't remember what value x is, but I did read it somewhere in this forum)

BMS
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Mike Dorsett avatar image
Mike Dorsett answered ·

Most Victron charge algorithms will start in bulk, then if the Volts are high quickly cycle through absorption to float. As you say, some will check the voltage of the battery. The 2 signal BMS has 2 functions - one is to turn the charger off or to float mode when the battery is full, the other is to turn the inverter OFF when the battery is empty. The inverter voltage settings would normally trigger the gen relay (if configured) to start the gen and to transfer the inverter into charge mode when the AC in is stable and synchronised. In this case, the voltage would be well down, and bulk mode would be initiated.

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Mike Dorsett avatar image Mike Dorsett commented ·
Also you can't use the virtual switch with the 2 signal BMS, so ignore AC in is not an option.
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ian0 avatar image ian0 Mike Dorsett commented ·

. . .but it can be controlled from the general flag, and the general flag controlled from any input using the Relay assistant.

The problem would be running out of inputs, because the float charge must be temperature compensated, so using the temperature input for anything other than temperature is out of the question

However, VE.CAN command 0x0200 can do the same as "ignore AC" by setting "Inverter only" instead of "on".

I'm not sure if "Inverter only" resets the charger to start on bulk, but "OFF" definitely does, although it causes an interruption in power.

I'm learning little by little and still hoping to find a way of getting it into float using the VE.CAN interface and no other connections. I haven't given up yet!

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