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mr-jeff avatar image
mr-jeff asked

Minimum Solar Panel to be used for Victron MPPT 150/60

Hello,

I am planning to build my solar power system, And I will start with Victron MPPT 150/60 and a Trina Solar 550 Watts Voc 49.8 Imp 14, and 24v 100 ah battery as a starter project and soon upgrade little by little, my question is, will the Victron MPPT 150/60 work with 550 watts panel.

Thankyou

MPPT ControllersSolar Panel
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3 Answers
mr-jeff avatar image
mr-jeff answered ·

@AHTrimble Thank you very for your answer and idea.

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ahtrimble avatar image ahtrimble commented ·
No problem, I hope I helped a bit. If you have any other questions just ask away. I actually love building systems for folks...and sometimes helping folks rebuild/redesign a system that doesn't work out like they had hoped. Now that I am retired...nice little hobby of mine ;)

Expanding and upgrading my own system this winter...I fell in love with POWER!!

AH


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Alexandra avatar image
Alexandra answered ·

@Mr. Jeff

For the mppt to do any kind of charging the voltage from the pv side [under load] needs to be at least 5v above battery voltage.

So it should be ok.


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mr-jeff avatar image mr-jeff commented ·

@Alexandra Thank you very much for the clear and straight forward answer.

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ahtrimble avatar image
ahtrimble answered ·

Are you referring to their RSM550-144HC, the specs are as follows: MaxPwr = 550w, Open Circuit Voltage = 49.9, Maximum Power Voltage = 41.96, Short Circuit Current = 14a, Maximum Power Current = 13.11?

You might want to consider more closely matching the power of the PV to the MPPT rating in light of future expansion. Meaning, think if you would put your panels in Series or Parallel. I have found that the higher the PV voltage input into the MPPT the more efficient charging...staying within the MPPT max voltage rating. Remember, you may exceed the PV "standard test condition" and pump too much voltage into the MPPT...and that isn't efficient, so leve a nice safety margin.

Then there is the consideration of cost vs benefit. Have you considered lower cost per watt used PVs such as those available from Santan? I have purchased 24 PVs from them, and spent as little as 22cents per watt for Canadian Solar PVs. That's hard to beat, and the PVs are still under warranty and have performed with zero issues.

As far as the 150/60 MPPT...does that meet your ultimate goal for your system when the system is complete? Going with the 250/60 would give you the ability to string 4 of the 550 PVs together in series with a nice safety margin. The 150/60 is running about $540 right now, the 250/60 is less than $100 more.

Consider your options...but remember to define your ultimate system goal before you do anything. "What is it you want the system to do when it is completed?"

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kevgermany avatar image kevgermany ♦♦ commented ·

If PV voltage exceeds the MPPT rated input voltage, the MPPT will be destroyed. It's not an efficiency issue.

Given the system is going to be upgraded, putting in a large expensive MPPT may be false economy. If the same panels can't be found at upgrade time, it's probably better to add another MPPT than put mismatched panels on the large MPPT.

Setting up and running a high voltage system may legally require professional installation, depending on where the op is located, even if not, better to keep the voltage down for safety in a home installation.

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ahtrimble avatar image ahtrimble kevgermany ♦♦ commented ·

For clarification I stated "staying within the MPPT max voltage rating". However, I should have made it more clear at the end of that paragraph and chosen my words better.

Also, you don't have to worry about always using the same matched PVs. It has been proven many times that you can mix and match PVs and still greet great performance. Adding a second MPPT can be beneficial under some circumstances. In the stated situation, a cost savings of $440 would be realized with a single higher voltage MPPT.

And you are spot on about the "legal" issues...one must always comply for sure.

As for "keeping voltage down"...I do not agree. I use 48v batteries, not 12v. A 48v system is much more efficient and more cost effective. And using higher voltage on the PV side is virtually the same. Otherwise, no one would ever wire PVs in series.

Overall, I am aware that there are different opinions on solar systems. You and I have somewhat differing views. As long as the system works as efficiently as possible for the best cost/benefit ratio...then all is good...as long as it is safe!

Thank you for your input and sharing your views.

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kevgermany avatar image kevgermany ♦♦ ahtrimble commented ·
Please don't confuse 24/48V batteries with dangerously high voltages on the PV side.
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ahtrimble avatar image ahtrimble kevgermany ♦♦ commented ·

Amen! Two entirely separate issues...but the concept of effciency in relative voltages is the same...as is wiring them in Series and Parallel. 48v system on the battery side makes sense...way more sense than 12v or 24v. And PV strings/arrays at higher voltages can be perfectly safe if a person simply follows basic safety precautions. And the higher PV voltages can increase efficiency to a significant degree...just as a 48v battery vs a 12v battery system.

Good to hear your caution...but I didn't think anyone was confusing the two. It was a dicussion on relative efficiencies. Enjoy your week!

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kevgermany avatar image kevgermany ♦♦ ahtrimble commented ·
Also bear in mind the skill of the builder as well as electrical regulations.
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Related Resources

MPPT Product Page

MPPT Error codes

MPPT 150/60 up to 250/70 Manual

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