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Panel Test Why is this?

JoeSTP

New Member
Joined
Aug 3, 2020
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18
Hi all,
I tied two 390watt together for sreies test, the output 88.0 volts each panel outputs 44.5 or so and each outputs 8.6 amps. But on the series test the amps output was 15.8 is this normal, everyone says in series volts add and amps will not, I'm confused!
 
Panels should be tested individually to establish that they meet specs. If you test two in series or parallel, you can't establish if they both are performing as they should.
 
Snooble, What do you think this is as I stated in the post "and each outputs 8.6 amps" did you not understand each is out putting 8.5 or so, but in a series its 15.8!
 
Did the voltage change? Power is the relevant measurement of panel output. A MMPT controller will change both voltage and current to optimize power output. Your first post was confusing. It described a series voltage then a parallel current result.
 
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Ampster, This is at the Aray (5) 390 watt panels: specs. are as fellows model sx390m-144, Open circuit 48.48, Short circuit current (A) 10.14. Ok I installed these on my box truck and I tested each one of them the output is 44.5 volts and 8.6 amps, so I then put panel 1 and 2 in series, the reading on that test for output is 88.5 volts and 15.5 amps. this has nothing to with the MPPT and I have been using meters for many years. Could it be the way the panel is built or wired?
 
this has nothing to with the MPPT and I have been using meters for many years. Could it be the way the panel is built or wired?
I only mentioned MPPT to illustrate why power was the important measure of output. Were your measurements all under the same relative load? Was the insolation exactly the same. Unless you are able to duplicate Standard Test Conditions (STC) there are too many variables in the equation. Yes, that could include wiring and panel construction. The resistance of the diodes could be a factor. I am just guessing, but if it were me I would not be concerned unless I could eliminate other variables.
 
Does not compute.
If you can figure out how you accomplished that, I suggest you don't disclose until you've filed for a patent.

You're correct that in series voltage adds and current doesn't.
In parallel current adds and voltage doesn't.

Two, 44.5V 8.6A panels can't be connected to produce 88V and 15.8A.
(Although, with the addition of electronics, any individual voltage and current values could be generated; I think I saw someone with a fraudulent business offering that once - they claimed 3kW from a single panel.)

As Snoobler said, user or instrument error. If you connected four panels 2s2p it would be close.
 
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