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Help me understand the solar panel numbers

Jason Dunkin

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Nov 19, 2021
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As a solar noob I'm trying to understand the Voc and Isc numbers and how its related to the number of panels. As an example of numbers between Renogy and Ecoflow.

Renogy 450 Watts
Voc 41.25V
Isc 13.89 A

Ecoflow 100 Watts
Voc 20.3V (Vmp 17.1V)
Isc 6.3A

If I string 2 Renogy Panels in Series technically its 900W and if I string 10 100Watt panels I'm at 1000W.

Going by the voc and isc numbers for each.
For Renogy 2 panels in series is it 41.25Vx2 = 82.5V with 13.89A and with Ecoflow 10 panels in series is it 20.3V*10 = 203V with 6.3A ?
So if the above the correct in theory, the Renogy has lower volts but higher amps and the Ecoflow has high volts but lower amps ?
Am I understanding this correctly ?
 
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Yep, that's right. I think you made a typo though:
Ecoflow 10 panels in series is 203V.
 
If connecting in series, is it better to go with a bit higher volts and lower amps or high amps and lower volts or does is matter ?
 
Depends on your purpose and the MPPT/inverter/charge controller you'll be using. Can you provide more detail about your intended setup?
 
Keeping it simple, planning to get the Ecoflow Delta Pro (max 150v solar input). Trying to decide to get 10 100W panels or 2 450W .
 
I like that the ecoflow delta pro has the mppt inverter + charge ctrl + battery builtin with 4 120V ac output.
 
Delta Pro - 11-150 volts and under 15 amps. These numbers are from their specs on the website. So both ways Im under the specs.
 
Delta Pro - 11-150 volts and under 15 amps. These numbers are from their specs on the website.
What is the max power for the solar input? 1600W?
Are you going to use all 12 panels (2 Renogy, 10 Eclflow)?
What are the Vmp and Imp of the Renogy and the Ecoflow panels?
Vmp x imp = panel power rating
 
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Not sure what you mean by max power for solar input. The specs for the Delta pro just says 11-150Volts and under 15amps for solar input.

Renogy
Vmp 34.67V
Imp 12.98A
34.67V × 12.98A = 450.01W

Ecoflow
Vmp 17.1V
Imp 5.9A
17.1V × 5.A9 = 100.89 W
 
Either configuration would work.
It'll be easier and cheaper to mount two panels rather than ten. Would you want to expand the system in future?
 
These panels would be ground mount so its easier either way. I'm thinking going with 10 100W, if there is damage to one panel then I can just replace one. In case of a damage to the 450W, then more money to replace it.
I dont have plans to expand anytime soon.

Being that 450W panel pushing more amps is preferred over the 100W pushing smaller amps, no ?
 
Just realize that the strings' (panels in a single series) voltage has to be under your charge controllers intended voltage. If you're cc only handles 150v, like a Midnite Solar Classic 150, you can't (safely) go over 150 per string. But you can parallel smaller strings together, as long as you're under your cc's specs.
 
These panels would be ground mount so its easier either way. I'm thinking going with 10 100W, if there is damage to one panel then I can just replace one. In case of a damage to the 450W, then more money to replace it.
I dont have plans to expand anytime soon.

Being that 450W panel pushing more amps is preferred over the 100W pushing smaller amps, no ?
Voc should not exceed the max PV input rating of the EcoFlow, the Voc also goes up in cold weather, I suggest to limit the Voc to be about 85% of the max PV input rating of the charge controller.
If you are going to use Ten 100W panels, then the arrangement will be 5s2p that will give Voc of 20.3Voc x 5 = 101.5V which safe for the ECoflow, the current will be 5.9 Imp x 2 = 11.8A, so it will be below input current limit.
For the two 450W, you can just string them together in series, Voc = 41.25Voc x 2 = 82.5V, the Imp = 12.98A so it will be below input current limit.

The input current limit spec of the Ecoflow (or other solar generator) has quite an effect on power you will get from your panels, for example:
Having the two 450W panels in parallel, the Imp will be 12.98A x 2 = 25.96A, the Vmp is 34.67V, since the EcoFlow limits the input current to 15A that means you will only get 34.67V x 15A = 520W of power, the EcoFlow will not try to draw more than 15A from the panels.
 
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"then the arrangement will be 5s2p that will give Voc of 20.3Voc x 5 = 101.5V"
Oh good catch, thanks.
 
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