question

goran avatar image
goran asked

Effectivity with MPPT regulator

Compared to an “ordinary” regulator for solar panels, how much more effective is a MPPT controller?

MPPT Controllers
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3 Answers
wkirby avatar image
wkirby answered ·

There is a good document which explains it all, good bedtime reading.

https://www.victronenergy.com/upload/documents/White-paper-Which-solar-charge-controller-PWM-or-MPPT.pdf

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Victron's Founder Reinout Vader has written a technical white paper here called "Which solar charge controller: PWM or MPPT?" that explores the advantages, increases in efficiency, and theory behind the technology.

There is also a Victron Blog post here by John Rushworth which is a good introduction.

The bottom line for me is, now that Victron MPPT controllers are so cost effective there is no circumstance where I would use a PWM anymore.


Edit: Good Evening WKirby, good to see we are both familiar with the company literature :)

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markus avatar image markus ♦♦ commented ·

But @WKirby is fast typing answering machine. No chance to beat ;o)

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markus avatar image
markus answered ·

@Guy Stewart (Victron Energy Staff) , @WKirby

very off-topic, but just in case it is not known: technical cooking with Reinout Vader. I love this:

But now the theoretical background, which is very simple:
As stated in section 6.3.3, the heat capacity of water is 1.16 Wh per °C. Bringing 1 litre of water of 20 °C to the boil would therefore take 1.16 x (100 – 20) = 93 Wh. In practice it takes more than 100 Wh, depending on the heat capacity of the pan and other losses, which can be reduced by starting with warm water from the boiler instead. So the figure to remember is 100 Wh per litre.

And now the actual cooking:
Today the meal is spaghetti with a home made sauce and a pudding to finish. We are cooking for 4 persons.

For the spaghetti we bring 4 litres of water to the boil, add the spaghetti, bring the pan to the boil again and leave it boiling slowly for 8 minutes. Power consumption: 400 Wh to boil the water, 100 Wh to boil it once more, and 400 W for 8 minutes to keep the spaghetti boiling, total 400 + 100 + 400 x 8 / 60 = 550 Wh.

For the sauce we fry the onions (150 Wh), add the meat and fry again (150 Wh), add fresh tomatoes, herbs, etc and bring the sauce to the boil (1 litre, so 100 Wh) and leave the sauce simmering for 20 minutes
(200 W during 20 minutes), total 150 + 150 + 100 + 200 x 20 / 60 = 470 Wh.

For the desert we heat 2 litres of cold milk right from the refrigerator (300 Wh), plus 3 minutes of simmering (30 Wh), total 300 + 30 = 330 Wh.

Total energy needed: 550 + 470 + 330 = 1350 Wh, or 1350 / 24 = 56 Ah from a 24 V battery.

I have also verified the above in practice and the result is that for most meals with 3 hot courses and intended for 4 persons indeed 1200 to 1400 Wh, or 50 to 60 Ah from a 24 V battery is needed.

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wkirby avatar image wkirby ♦♦ commented ·

That is great!

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