need help making sure not over powering growatt 3k tl lvm-48 145voc unit with panels I have planned to purchase

motomarc

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I have been researching and asking questions & think I have come down to this setup, if it is all good in power and output please let me know.

1 Growatt 3k tl- lvm 48v, 145dc voc pv input ,
panels Newpowa 240watt voc 27.08 vmp23.32 in 2 strings of 5 VOC is 135.4v & 116.6VMP
the manual says PV Array MPPT Voltage Range is 60~115Vdc .
if I hit VMP of 116.6 will it still charge and produce power output??
I know VMP doesn't happen often with flat panels on top of a rv unless in the desert sun @ high noon then combine possible shading from AC units etc.
I do plan on making tilt system for them as well to help output.

thank you everyone have a great day.
 

Cory V

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It’s most important to not go over Voc limits as the inverter isn’t controlling how much voltage panels push before the charge controller starts pulling power, and going over that limit can fry things. You are under that limit now, but do you need headroom for the cold? Voc starts to climb the colder the panels get. AFAIK, the charge controller just won’t sweep the voltage high enough to hit the panels actual Vmp, so you would just be clipping some of the peak production off in those rare scenarios.
 

timselectric

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VOC is too close for my comfort.
Just depends on the climate, in your area.
Otherwise, looks good.
 

motomarc

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VOC is too close for my comfort.
Just depends on the climate, in your area.
Otherwise, looks good.
I am located in Oklahoma but plan on taking the 5th wheel all over the country.
so conditions will change on a regular basis when traveling. with the 5% added 142.17 VOC would be total on string of 5, yes extremely close to the 145 voc.
I just don't see it ever hitting that high most panels never do what advertised from what I have read and watched VMP is more avg and sometimes better but never close to VOC output.
I can always cover/disconnect or shade 2 panels to drop voltage if needed.

If I am wrong please correct me on that and link it for me. as I am a newbie

thank you MM
 

timselectric

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5% is a very modest figure.
As far as covering some panels. That would have to be done, ahead of time. Once the VOC goes over, the damage is already done.
I live in Kentucky, and had to figure in 14%.
While it's a rare occasion, it only has to fry the SCC once. To make me wish that I had planned better.
 

motomarc

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5% is a very modest figure.
As far as covering some panels. That would have to be done, ahead of time. Once the VOC goes over, the damage is already done.
I live in Kentucky, and had to figure in 14%.
While it's a rare occasion, it only has to fry the SCC once. To make me wish that I had planned better.
Well crap I need keepnthe dcv high enough for a 3k inverter. Maybe the 250v es unit and all 10 panels or 11 panels will work.
 

motomarc

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I don't understand this statement.

If you take one panel off each string you should be fine no matter where in North America you travel.
27x4=108 voc < 145 max.
23x4=92 vmp is between 60-115.
but then I am out 480 watts of power that won't cut it for me I would rather take the risk of frying a AIO then not getting my wattage of 2400.
I am trying to run air conditioner on my solar power. need at least 2k watts.

if I got with the ES model it has 250v max but starts at 120v but will prouse took 160v to get it to come on, so I am screwed either way.
my other choice is go with rich solar 24v panels 45.5voc & 37.6 vmp & get the EG4 AIO 500v but it has 40watt + standby power use so wasteful vs 5 watts on a Growatt unit.
this will also cost me another 2 panels at $259 each to get the 2400 watts I am wanting, as well more room on the roof of trailer not Bueno.

so frigging frustrating . thought I had a good system but now I am screwed according to you guys.

any help or suggestion I am open. just let me know.
need panels under 36 inches wide in order to fit beside AC units on the roof.
these are only 2, 200 plus watt units I could locate in weeks of searching the internet .
would be great if you could search panels by dimensions but that would make way to much sense for the solar community.

thank you MM
 

TomC4306

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Or a second standalone charge controller for the balance of your panels.
Certainly cheaper than replacing a fried AIO.
 

motomarc

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Or a second standalone charge controller for the balance of your panels.
Certainly cheaper than replacing a fried AIO.
that's a added $400 for a 200v controller, on top of the AIO I am not liking this situation at all, there has to be a easier way to make this work.

a better AIO unit or something.
there new 6.5 egs AIO comes on at 60v not 120 v like the 3k unit WTH signature solar how about a consistent mppt start up point.
1 would think smaller 3k ES unit would start mppt at 60v not 120v.

someone tag Richard from signature Solar on this one please. what is the true mppt start value on a 3k ES Growatt unit???

thank you MM
 

Cory V

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Did I miss something or are you trying to go batteryless? AIOs start up on battery/AC power just fine. If you’re trying to get one to start up on ONLY solar then you will have an issue with the unit starting up unless you have a high enough voltage coming through the PV input, and this is due to the inherent limitations of using an inverter to supply steady power on unpredictable PV power without anything to buffer.
 

motomarc

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Did I miss something or are you trying to go batteryless? AIOs start up on battery/AC power just fine. If you’re trying to get one to start up on ONLY solar then you will have an issue with the unit starting up unless you have a high enough voltage coming through the PV input, and this is due to the inherent limitations of using an inverter to supply steady power on unpredictable PV power without anything to buffer.
No I'll have eg4 100ah rack unit and then add 1 or 2 more as $$ allows. Made the decision for eg4 Aio and battery to make easy all in series on panels so no issues on dcv. Just not happy with the standby use 70 watts maybe 40 if lucky.
Going drive and get it's cheaper then shipping even with tax at 15mpg in the dually 😁.
 

Cory V

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Yeah, standby consumption on all of the less expensive AIOs is rough, pretty much need to dedicate an extra panel or 2 just to that. There are units with better standby consumption but they are very cost prohibitive, ie Victron. Typically the recommendation is to spend the money on the extra panels unless you don’t physically have the space for them, like in your case.
 

timselectric

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Put a couple panels on your neighbors house, and run an extension cord from your house to his TV.
Problem solved
 
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