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16V 32 cells panels valid for 2S setup with grid tied inverter?

Jordi

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Oct 13, 2020
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Greetings solarpeople,

I was designing a small solar system with 2 panels in series to be connected to a MPPT grid tied inverter.

I normally look at cheap 18V 100W panels but recently found the 16V types with 32 cells instead of 36 cells. These 16V panels are 10 euros cheaper each and therefore worth considering; however I am concerned about the lower voltage and possible consequences.

After reading for a while I understood that their lower voltage is meant to partially "self-regulate" the charging of 12V batteries because when the battery is full around 14V, the current naturally decrease due to voltage resistance (so bad to use off-grid in 12V battery system); I also understood they are cheaper to produce (less cells; less material). Since in this case the panels are to be connected in series to an inverter with 22-60VCD range I am expecting that buying 16VDC instead 18VDC won't have any impact on the solar output/production the inverter receives and transforms while I save 20 eur.

Could you please help me confirm this assumption or explain me why 16V panels are a bad idea for this application?

Additional advantage that I see is that given that the inverter has a range of 22-60VDC, a third panel in series might just fit because VOC of 19,2V x3 = 57,6V < 60VDC (Kind of safe) Please alarm me if I am wrong here.
 
No alarm here, but if you were to provide the model of MPPT grid tie inverter and the panels it may help.
 
I would generally confirm your assumption and admire your thriftiness.
I did infer the "16-volt" panels were also rated at 100W.
 
You said you're planning a "grid tie" inverter. Did you really mean that? If so, the paperwork, permits and headaches for installing a grid tie unit would seem to me to be far higher than any possible payback from a very small system like you're proposing.
 
The cheaper I go, the more experiments I can make. I do solar at a hobbye level, so I try to limit costs since I do not have financial returns.
You said you're planning a "grid tie" inverter. Did you really mean that? If so, the paperwork, permits and headaches for installing a grid tie unit would seem to me to be far higher than any possible payback from a very small system like you're proposing.
You are right, only that in the theory, in the Netherlands where I live, I only had to fill in a very short form and the company already started counting the kWh dumped to the grid. Nonetheless, If it does not work, this is a 200W peak installation, so real 140W and where I live 100W in the good days. That is more or less the stand-by consumption.

Purpose is recreational and seeing flexible panels can break in just 2-3 years, I am not aiming payback but I do care about expenditure. I will update you on this in the future. I have already placed the orders.
 
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