Am I correct ? (1 Viewer)

[gus-lopez]

I have 2 x 100watt mono panels & having baffled myself ,easily done, I am proposing to buy a Victron MPPT Blue solar 75A 15V controller. Panels are wired parallel. Would this be sufficient capacity as that is what is being advised?
Or is there a better alternative around the same price?
Thanks in advance.

 

[gus-lopez]

Forgot to put that panel details state;

Pmax =100
Max power voltage=18,29V
Max power current=5.47A
Voltage open circuit=22.8
Short circuit current =5,85A
Max system voltage=DC1000v
Max series fuse =12A
Mono

 

[Leakylunar]

Is it 75v 15amp?

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[Leakylunar]

Website states 220w max for 75/15 unit

 

[Raul]

That would be a match made in heaven. The victron will handle those panels in parallel, also in series 22,8v x 2 = 45,6v voc. that’s under the 75v of the controller limit.
But I would advise to go parallel, you will benefit of a better conversion efficiency, ( batt voltage x 1.5) and better efficiency when partial shading on one panel. The other one will still produce.
Max you will see from the 200w is around 13,8v at 14.4v

 

[gus-lopez]

Is it 75v 15amp?

Yes .On the Victron calculator it shows this model. There isn't much chance of me adding more panels so should be good.

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[Lenny HB]

Sounds good to me.

 

[Red Dragon]

Thats exactly my set-up and works a treat, I also added the bluetooth dongle so I can read the data on the app on my smart phone.

 

[bigtwin]

That would be a match made in heaven. The victron will handle those panels in parallel, also in series 22,8v x 2 = 45,6v voc. that’s under the 75v of the controller limit.
But I would advise to go parallel, you will benefit of a better conversion efficiency, ( batt voltage x 1.5) and better efficiency when partial shading on one panel. The other one will still produce.
Max you will see from the 200w is around 13,8v at 14.4v

But, on the other hand, did I read that series connection was more efficient In low light situations?

Or is that incorrect?

Ian

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[Lenny HB]

But, on the other hand, did I read that series connection was more efficient In low light situations?

Or is that incorrect?

Ian

It is true, but if one panel is in shade you loose your total output, in parallel if one panel is in shade you still get the full output from the other one.

 

[Off da Grid]

I’ve got a Votronic mppt duel battery controller might be worth having a look at.
Photonic universe is a good site to look at for solar stuff.

 

[Podney]

Well,as a well known expert in the field of motorhome electrical matters,not to mention electronic issues,I reckon you’ve got it pretty much dead right.
The only thing that might need checking is your MBBT controller and the OHM loss from the OBD valves.

Let me know if you have any queries about this.

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[Raul]

But, on the other hand, did I read that series connection was more efficient In low light situations?

Or is that incorrect?

Ian

Yes, you will start making power with few mins before and after. That’s all.
The controller will wake up and produce once it detects 5v above the battery voltage. Being in series, that will happen at first light. The caveat is, although you have enough voltage, the insolation is low and no amps or minimal. The min charging I have seen is 5w from a 150v 85A controller Below this I guess it can’t measure current to display. The didly ones will not do very well on high voltage, unless you need to charge a 24v bank. The 18vmp is plenty for the 12v bank. To convert from dc to dc (buck) the most efficient is approx 1,4-1,5 times the battery voltage to be charged. Any higher, the controller will have to work hard and dissipate heat; lost power. No two cases are the same. Everyone’s situation will have its own advantages and disadvantages. In this case the parallel option is best for overall harvest thru out the day. You will gain more energy.