question

Miro Vidos avatar image
Miro Vidos asked

BlueSolar PWM or MPPT with battery disconnected

I am considering using BlueSolar PWM with 20W total in PV panels on a small boat. We are talking 5m boat.

I would be connecting it to starter battery in order to keep it charged during long periods of not using the boat. On that battery there are some small loads as well, like radio, echo, lightning. We are talking about 12V/50Ah battery.

I would move those loads on a load connection available on pwm, engine directly to the battery and of course pwm directly to the battery.

There is a safety switch on board that is suppose to cut the battery off from the grid completely.

I am wondering if I would be cutting a battery away from BlueSolar PWM, how would that unit take that action and what would happen with power to connected loads (in case there is a full PV activity)?

MPPT Controllers
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4 Answers
JohnC avatar image
JohnC answered ·

Hi Miro. Not sure all are on the same page here, so to prompt further discussion..

Batteries should always have an isolator (and ideally a fuse too). Opening that isolator will just shut everything down. Closing it should just start it all up again. PWM or MPPT, no matter. That's your 'safety switch' that you have already.

You could separate them, say if you wanted to isolate loads and leave the cc up, but it doesn't really matter. Convenience issue there.

Victron kit eats that sort of treatment. That said, I haven't managed to kill cheap Chinee either..



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bluepowershop avatar image
bluepowershop answered ·

Disconnecting the battery can lead into a switch of the controller into 24V modus.
All your equipment will be fried.

So, no disconnecting the battery when the panels als connected!

Regards,

Mark

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Miro Vidos avatar image
Miro Vidos answered ·

That is what I was afraid of as well and that was the main reason I have posted this question. I was hoping that PWM would shut off completely, but guess not :(

Thank you for your fast answer and help

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Miro Vidos answered ·

John we are completely in line here!

Thank you Gents for your help

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