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deano9 avatar image
deano9 asked

What size Smartsolar is required for 2 x 250w solar panels

I am installing 2 x 250w solars panels to a caravan with a 12v system. What size controller is recommended. This is the figures on each panel. No sure how accurate the data is, I did think a panel this size would be 200w so the dealer might be overselling the panels capacity. I am installing 2 in parallel. Cheers

Maximum Power(Pmax) 250W
Max Power Current 13.74A
Max Power Voltage 18.2V
Max System Voltage 1000VDC
Tolerance +/- 2%
Short Circuit Current 15.10A
Open-Circuit Voltage 22.3V
Temperature Range -40°C to +85°C
Product Dimension 1580 x 808 x 35mm
Weight 13.38kg (Each panel)
MPPT SmartSolar
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klim8skeptic avatar image klim8skeptic ♦ commented ·

Hi Dean,

Personally I am somewhat cynical regarding claimed panel specs. The dimensions and area of your proposed panels are the same as 72 x 5" celled panels from 15 years ago. I would think you could only count on them to be 200w panels.

The same dimensioned panels from Victron are now rated at 215w. Victron solar panels.

If you only want to run 2 of those panels, a 100/30 Smart solar would be ok. I run 4 x 190w panels flat oriented on a 100/50 without problems.

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deano9 avatar image deano9 klim8skeptic ♦ commented ·

Thanks, yes I am also sceptical of the claimed 250w of the new panels. My old panel of the same size is claimed to be 200w

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4 Answers
Alexandra avatar image
Alexandra answered ·

@Deano9

We would also need to know your system/battery voltage to be able to help. Off hand for two panels usually it's a 100/50 or a 150/35 depending on the battery voltage.

https://www.google.com/url?q=https://www.victronenergy.com/mppt-calculator&sa=U&ved=2ahUKEwjk94rTvLjsAhXNURUIHSbFB4QQFjAAegQIChAB&usg=AOvVaw2xK8dWOhhMPk2v6Pe-atK6

If you use that link you can calculate the correct mppt for your self though.

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deano9 avatar image deano9 commented ·

The system voltage is 12v

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wkirby avatar image
wkirby answered ·

You didn't mention what your battery Voltage is.

For a 12V battery you'd need a SmartSolar MPPT 100/50.

For 24V battery you coiuld use a SmartSolar MPPT 100/20.

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deano9 avatar image deano9 commented ·

Yes I forgot to mention that, it is a 12v system

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wkirby avatar image wkirby ♦♦ deano9 commented ·

@Deano9
Thank you. Also, I edited my answer above because I did not read your question properly.
I originally answered for 1x 250W panel, not 2x 250W panels.

My answer is now correct for 2x 250W panels. stxshadow's answer is also correct.

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deano9 avatar image deano9 wkirby ♦♦ commented ·

Thanks for the reply, the MPPT sizing calculator online comes up with the 150/35 however it makes sense that the 100/50 is suitable. Not sure why they suggest the 150/35

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Meine_Energiewende avatar image
Meine_Energiewende answered ·

You are at roughly 40 Amps at a 12 Volts System .... so a 100/50 should suit your needs.

Jens

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marky01 avatar image
marky01 answered ·

https://www.victronenergy.com/mppt-calculator this Victron calculator will help find the answers. You can try different scenarios for any panel and system voltage

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