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

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deano9 asked Oct 16, '20

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 ♦ commented · Oct 16, 2020 at 09:07 AM

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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smartsolar-100-30-50.jpg (80.8 KiB)

deano9 klim8skeptic ♦ commented · Oct 16, 2020 at 10:18 PM

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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Modifications Space

Node Red Space

Answer 1 · 2020-10-16T06:25:33Z

Alexandra answered · Oct 16, 2020 at 06:25 AM

@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 commented · Oct 16, 2020 at 06:31 AM

The system voltage is 12v

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Answer 2 · 2020-10-16T06:27:38Z

wkirby answered · Oct 16, 2020 at 06:27 AM

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 commented · Oct 16, 2020 at 06:34 AM

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

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wkirby ♦♦ deano9 commented · Oct 16, 2020 at 08:25 AM

@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 wkirby ♦♦ commented · Oct 16, 2020 at 10:09 PM

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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Answer 3 · 2020-10-16T06:46:43Z

Meine_Energiewende answered · Oct 16, 2020 at 06:46 AM

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

Jens

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Answer 4 · 2020-10-16T18:04:59Z

marky01 answered · Oct 16, 2020 at 06:04 PM

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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