question

drtpotter avatar image
drtpotter asked

MPPT controller upstream of a PWM

Hi, I have a power bank with an inbuilt PWM controller. The solar panel I use has an open circuit voltage that is too high for the internal PWM, so I’ve had to cover parts of the solar panel to reduce the Voltage to a safe level for the PWM to operate. I am considering buying an MPPT controller to reduce the Voltage and increase the Amps from the panel before sending the power on to the PWM and power bank. If I can get the MPPT battery charge profile right, would this scenario work?

MPPT SmartSolar
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2 Answers
JohnC avatar image
JohnC answered ·

Hi @drtpotter

I'm not sure, but I think the mppt would object to being 'pulsed'.

Why wouldn't you just flick the pwm and go direct with the mppt?

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drtpotter avatar image drtpotter commented ·

Indeed, but the PWM is "inside" the sealed powerbank unit. Flicking the PWM means opening things and voiding warranties.

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JohnC avatar image JohnC ♦ drtpotter commented ·

@drtpotter

Yeh ok. What is this 'powerbank'?

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JohnC avatar image JohnC ♦ drtpotter commented ·

@drtpotter

I'm sorry, I don't know. Maybe someone else has tried this and can comment..

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drtpotter avatar image drtpotter JohnC ♦ commented ·

No problem, I've since given up on looking for a solution and gone with a different solar panel. If there was a Victron product (dcdc converter or mppt controller that is ok with pulses) that could have solved the problem I likely would have bought it. Perhaps there is space here for a future Victron product if it doesn't already exist.

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DeVo Tyler avatar image DeVo Tyler drtpotter commented ·

The only way I could see a work around is if you get a new solar set up and charge it from the inverter as it can charge via wall outlet but the cost and efficiency just won't be there the PWM inside of it kinda screws ya.

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Paul B avatar image
Paul B answered ·

Hi if you put the MPPT unit directly to the panels then the output of the MPPT direct to your PWM

and as long as the output from the MPPT does NOT exceed the PWMs limits amps wise then I see no problem it doing the above as the PWM would only see the 13-14v output from the MPPT unit or what ever the voltage was, especially if you set the MPPT slightly lower than the PWMs voltage limit as well

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