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I'm So Confused !*#?

Eric in TN

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Joined
May 23, 2022
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I am trying to put together my first solar system to prepare for possible long-term power outages at our home. We are on a tight budget so I'm trying to not waste money on my DIY mistakes. I've been watching Will's videos but a lot of this is just over my head and I'm having a hard time with figuring out how to size the wiring. Based on Will's reviews, I think I want to go with an MPP Solar LV6548 all-in-one with 2 SOK 100Ah 48v batteries to get started. I can get a good price on 250w Canadian used solar panels (model CSP-250PX). Would someone be so kind as to tell me how many panels this would support and also what wiring I would need to run 100' to the panel array, what size from battery to battery, and what size from the batteries to the LV6548? When I've read the replies on many of the other threads, I get lost when the answer includes a lot of abbreviations and technical jargon is used. Please try to dumb it down for me because I don't think I'm quite as sharp as I used to be.
 
I used 2/0 wire from inverter to buss bar and 4/0 from buss bar to battery bank, also use a T fuse
I used some 250w panels I got used in a 6s2p configuation giving 3kw to each mppt on my lv6548
I used 10 awg pv wire to the array
I have 2 of the lv6548 and 2 arrays at 6kw each
the 250w panels is a pretty good choice for this inverter as its limited to 250v voc and 18 amp
so 6s2p works pretty good and 250w panels are dirt cheap
 
I understand most of what you said, thank you. Is the buss bar just a way of connecting multiple batteries to a junction so 1 cable can be run to the LV6548 for whatever batteries are connected? How long is your wire from the array to the LV? Do you think 10awg will be good for my 100' length?
 
I need a buss bar because I have 2 inverters that need the wires combined before going to the battery. If you will never expand to be able to use 240v using 2 inverters then you dont need a buss bar and you could probably use 2/0 wire between inverter and battery with a T fuse inbetween
my pv wire is 100 ft to 1 array and 150 ft to the other array
 
The calculation for wire size is pretty easy. You look at the manufacturer's ratings for the Maximum input DC current and Maximum output AC current. You multiply the Amps X 1.25 and that gives you the Ampacity of the wire required. Then use a THWN-2 wire in conduit, or Silicone high-temperature wire that meets that minimum ampacity calculation.
 
I am trying to put together my first solar system to prepare for possible long-term power outages at our home. We are on a tight budget so I'm trying to not waste money on my DIY mistakes. I've been watching Will's videos but a lot of this is just over my head and I'm having a hard time with figuring out how to size the wiring. Based on Will's reviews, I think I want to go with an MPP Solar LV6548 all-in-one with 2 SOK 100Ah 48v batteries to get started. I can get a good price on 250w Canadian used solar panels (model CSP-250PX). Would someone be so kind as to tell me how many panels this would support and also what wiring I would need to run 100' to the panel array, what size from battery to battery, and what size from the batteries to the LV6548? When I've read the replies on many of the other threads, I get lost when the answer includes a lot of abbreviations and technical jargon is used. Please try to dumb it down for me because I don't think I'm quite as sharp as I used to be.
Did you see our new inverter? Will did a video on it - saves a few hundred dollars over the 6548. It supports up to 500VOC per MPPT so depending on your panels you could do 15ish of the ones you listed above (and up to 4 strings to easily hit your total wattage limit). Shoot me a PM and I can have someone from my design team contact you.

Also I've met @Texican in person and he doesn't lead many people astray.
 
my battery rack has its own buss bar to connect multiple batts together, I have 6 eg4 batts
Great explanation, even I understand it! I want to make sure I am understanding the 6s2p array. Does that mean you have 2 sets of 6 panels connected in series and then you join those sets together positive to positive and negative to negative to run to the inverter? Thank you Texican for your help. This info is going to make all the difference for me to go forward.
 
The calculation for wire size is pretty easy. You look at the manufacturer's ratings for the Maximum input DC current and Maximum output AC current. You multiply the Amps X 1.25 and that gives you the Ampacity of the wire required. Then use a THWN-2 wire in conduit, or Silicone high-temperature wire that meets that minimum ampacity calculation.
Thank you for that. Does the length of the run make any difference in the calculation?
 
Great explanation, even I understand it! I want to make sure I am understanding the 6s2p array. Does that mean you have 2 sets of 6 panels connected in series and then you join those sets together positive to positive and negative to negative to run to the inverter? Thank you Texican for your help. This info is going to make all the difference for me to go forward.

connect 6 panels like the picture..pos on first panel to neg on the next panel til all 6 are connected, you will end up with a free pos wire on 1 end and a free neg wire on the other side of the 6 panels. That is 6s, then get a Y connector and connect 2 rows of 6 panels with the Y at each end, that is the parellel connection, now you are 6s2p

feel free to ask more questions, its really not rocket science

scroll down the image to see the wiring
1653441521317.png
 
connect 6 panels like the picture..pos on first panel to neg on the next panel til all 6 are connected, you will end up with a free pos wire on 1 end and a free neg wire on the other side of the 6 panels. That is 6s, then get a Y connector and connect 2 rows of 6 panels with the Y at each end, that is the parellel connection, now you are 6s2p

feel free to ask more questions, its really not rocket science

scroll down the image to see the wiring
View attachment 95719
So the Y connects the + and + together and the other Y connects the - and - together, correct? I'd rather ask what might be ignorant questions than think I understand it all and ruin something because I was a little embarrassed to ask. :)
 
So the Y connects the + and + together and the other Y connects the - and - together, correct? I'd rather ask what might be ignorant questions than think I understand it all and ruin something because I was a little embarrassed to ask. :)
yes, thats right
 
I would seriously look at the EG4 video will just put out the other day, their standard 48v battery (not the pro) is priced better than the others and that new UL listed 6548 they have is the best one out there and $200 cheaper than the LV6548. Good luck on your build!
 
So the Y connects the + and + together and the other Y connects the - and - together, correct? I'd rather ask what might be ignorant questions than think I understand it all and ruin something because I was a little embarrassed to ask. :)

yes, thats right
Thank you so much! I really appreciate all of your help. If I have other questions, it's nice to know that you are willing to lead me through them.
 
their standard 48v battery (not the pro) is priced better than the others a
Did Signature Solar ever get the battery UL approved? I think that’s the hold up for many of us. I know SOK was in the process and was due sometime around September 22.
 
Did Signature Solar ever get the battery UL approved? I think that’s the hold up for many of us. I know SOK was in the process and was due sometime around September 22.
Yes, they announced it about a week ago
 
Yes, they announced it about a week ago
Link? I know they’re using UL prismatic cells but the whole battery itself wasn’t UL approved. I can’t find anything on their we’ve only that regards.
 
here is the email I got from eg4

Message from EG4​

"EG4 Electronics is excited to announce that it has received it’s first fully UL listed battery - the EG4 Lifepower4 48V 100AH rack style battery!
This unit is highly regarded as one of the top quality batteries on the market, and previously only the cells themselves were UL listed, which meant a lot of people were unable to use them in their system if it required every component to be UL listed.

The UL listing is for the entire unit - and it’s important to note that we were required to implement no changes to our current units to achieve this listing. We have been working behind the scenes for a while now to get this listing for the entire battery as a full unit after the feedback we have received on the forums and directly through our conversations with the DIY community as a whole.
We think this is a great first step forward and are also working on obtaining UL Listed status on other products on our line sheet. This includes the rest of the batteries (this is just the first to be fully listed, more will come!), and our inverter line that we have recently been rolling out."
 
here is the email I got from eg4

Message from EG4​

"EG4 Electronics is excited to announce that it has received it’s first fully UL listed battery - the EG4 Lifepower4 48V 100AH rack style battery!
This unit is highly regarded as one of the top quality batteries on the market, and previously only the cells themselves were UL listed, which meant a lot of people were unable to use them in their system if it required every component to be UL listed.

The UL listing is for the entire unit - and it’s important to note that we were required to implement no changes to our current units to achieve this listing. We have been working behind the scenes for a while now to get this listing for the entire battery as a full unit after the feedback we have received on the forums and directly through our conversations with the DIY community as a whole.
We think this is a great first step forward and are also working on obtaining UL Listed status on other products on our line sheet. This includes the rest of the batteries (this is just the first to be fully listed, more will come!), and our inverter line that we have recently been rolling out."
Thanks! I was originally looking at the EG4-LL battery for the UL listing. Your email helped identify it for the LifePower version and I was able to find the certificate on the website. Thanks again!
 
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