question

pieterwm avatar image
pieterwm asked

Lithium Superpack connected to MPPT and/or PWM solar charger

Setup is simple: 1 Solar panel connected to solar charger and to the lithium superpack.

The inbuilt BMS with disconnect will disconnect the battery internally from the connected cables (in this case the load and MPPT/PWM solar charger) This is fine to protect the battery. With the load we have no problem but what happens with the solar chargers. (specially low voltages cut out)

In the manuals they say first connect the battery. When there is a battery disconnect and the next morning the the solar charger will start again what will happen. There is no reference voltage from the battery. With the auto select function from the solar chargers we don't known what it will choose or how it will act. A far as i know newer MPPT will only select ones (first it is connected) and/or you program it. With PWM I don't known.

I found some comments about problems and destroying the solarcharger when the battery was disconnected with the solar panels where connected.

Question:

Is it safe and without destroying the solar charger (MPPT / PWM) to connect the solar charger to a lithium superpack


Pieter


MPPT ControllersLithium Battery
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1 Answer
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @PieterWM

The chargers start up fine without the battery connected, you have to program the correct voltages anyway before you leave things connected.

But....
The disconnect function of the battery needs to be seen as a safety feature, normally you:

-shouldn't charge above recommended charge voltage

-shouldn't discharge below recommended discharge voltage.

Nothing is hurt with a disconnect sometimes, but this shouldn't be 'normal practice'

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