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Minimum voltage for Solaredge string with optimizers?

DrSmile

Member
Nov 7, 2018
219
138
Northern NJ
I'm coming around rather rapidly to agreeing with the posts stating that optimizers are useless. I was able to clear off only 4 of 9 330 watt panels on one of my 3 strings to my 11.4 KW Solaredge inverter yesterday, completely unobstructed these 4 panels in full sun produced a whopping 8 watts total combined for the day. I believe the problem is that there is a minumum voltage necessary for the inverter to draw power from the string? Does anyone know if this is the case and what those values are? If I shovel off 1 more panel will that fix the problem? The only value in the inverter spec is 400volts nominal.
 
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Vines

Active Member
Jul 20, 2018
1,870
2,185
Silicon Valley, CA
It depends on your optimizer, but the optimizer has a maximum voltage that it can achieve. The residential Solar Edge inverters are all about 400 VDC fixed voltage, so for instance a SE11.4 (400vdc fixed) with P400 optimizers (80v Max) needs 5 modules to barely fire up and likely 6 uncovered to really operate correctly.

Looks like you were just a couple short of making it work.
 
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Ampster

Active Member
Oct 5, 2012
1,749
467
Sonoma, California
The minimum voltage of the inverter does not mean the optimizers are useless. I have a string inverter without optimizers and it doesn't work either before its 250 volt minimum is reached. Under current regulations the optimizers satisfy Rapid Shutdown requirements so some form of device may still be needed depending on code. @Vines explained the details well.
 
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Silicon Desert

Active Member
Oct 1, 2018
3,264
2,968
Sparks Nevada / GF 1
I'm coming around rather rapidly to agreeing with the posts stating that optimizers are useless. I was able to clear off only 4 of 9 330 watt panels on one of my 3 strings to my 11.4 KW Solaredge inverter yesterday, completely unobstructed these 4 panels in full sun produced a whopping 8 watts total combined for the day. I believe the problem is that there is a minumum voltage necessary for the inverter to draw power from the string? Does anyone know if this is the case and what those values are? If I shovel off 1 more panel will that fix the problem? The only value in the inverter spec is 400volts nominal.

USELESS to some people but not to others. It depends on if a portion of the modules are partly shaded during the day due to trees, snow, or other similar reasons. I put optimizers on one home years ago, but not on my latest home just because my new home has perfect orientation of all models and no shading. I didn't want them. But on my other home, it is of great help. Some of the problem can be due to how many modules are in the string that seems not to product power on those 4 modules. I can think of a lot of reasons why you saw that issue. It would help to further describe your system more.
 
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Vines

Active Member
Jul 20, 2018
1,870
2,185
Silicon Valley, CA
I don't think anyone is arguing they are useless.

Optimizers give several advantages. The real question is whether they are worth the price you pay for them over the life of the system.

They do mitigate shade problems, do give good production data, and do satisfy the module level rapid shutdown issues. They also cost a good bit for each module and increase the number of rooftop connections.
 
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Silicon Desert

Active Member
Oct 1, 2018
3,264
2,968
Sparks Nevada / GF 1
Optimizers give several advantages. The real question is whether they are worth the price you pay for them over the life of the system.

They do mitigate shade problems, do give good production data, and do satisfy the module level rapid shutdown issues. They also cost a good bit for each module and increase the number of rooftop connections.
yup, agree with that and in my case, it is worth it.
 

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