48v solar build questions

[yves demers]

Hello all, thanks for the add!

I'm wanting to build a off grid 48v solar system for full-time living. Pannls will be mounted either on the roof or I'll build a ground rail where they get the most light per day. I'm using just under 10kwh a day. The fridge and microwave being the big users.
Wanting to buy 8-New Trina 400w 144 half cell mono pannls, or 10- Canadian solar bifacial 500w momo 72 split pannls, 2 Epever 40amp charge controllers, I'll get 2- 100ah battle born batteries for now but will have 4 total. I'm not sure what inverter.. So many out there I've read so much in the last month my head is going to explode.. I need a little help and guidance just making sure I'm going down the right path. I've already waisted 4 weeks by trying to figure it out on my on and missed some smoking deals.. So many people buying right now it's gone if you fool Around and don't buy right then.. New pannls vs used sunpower.. Battle born vs other lithium batteries... Etc. It sucks not being able to just call and talk for a few minutes.. Lol

i m a beginner myself and you are first person i m writing to; i must admit; i m a bit scared because of the present situation which might just collapse like a house of card and i m not ready yet; i moved from canada to australia to be self sufficient ; i know a bit of electricty and basic principles but want to spend all my money on tools and equipment as i believe all central banks will collapse; anyways; doesnt one need like dozens and dozens of 100 amp batteries to run normal access to household consumption? not 4 batteries like you mention?

 

[Oldtimmer69]

i m a beginner myself and you are first person i m writing to; i must admit; i m a bit scared because of the present situation which might just collapse like a house of card and i m not ready yet; i moved from canada to australia to be self sufficient ; i know a bit of electricty and basic principles but want to spend all my money on tools and equipment as i believe all central banks will collapse; anyways; doesnt one need like dozens and dozens of 100 amp batteries to run normal access to household consumption? not 4 batteries like you mention?

I have seen 18650 cells made into some big batteries. These are the ones Im getting

 

[yves demers]

Thanks Oldtimmer69 for the input; i ll check it out.

 

[Oldtimmer69]

Thanks Oldtimmer69 for the input; i ll check it out.

No problem, good luck my friend!

 

[JoeHam]

I have seen 18650 cells made into some big batteries. These are the ones Im getting

I’m getting one also. The latest I have heard is that the batteries should get to Texas on September 27 after multiple delays.

What have you heard about delivery date?

 

[Oldtimmer69]

I’m getting one also. The latest I have heard is that the batteries should get to Texas on September 27 after multiple delays.

What have you heard about delivery date?

He told me Fri the samething 27th.. Got held up in customs...

 

[JoeHam]

He told me Fri the samething 27th.. Got held up in customs...

Now held up again, pulling into port tomorrow.

Then I think to Texas and then mine should ship to Ohio.

I forgot how impatient I am

 

[Oldtimmer69]

Now held up again, pulling into port tomorrow.

Then I think to Texas and then mine should ship to Ohio.

I forgot how impatient I am

I did get my two.. I need some time off work so I can set it all up did yours come in?

 

[JoeHam]

I did get my two.. I need some time off work so I can set it all up did yours come in?

Yessir, battery is installed. I had some cosmetic damage as you can see in post #12 here:

100 Ah LiFePO4 @ $1250 usd. 48v nominal

Let me start by saying that I have an affliction where I read almost every post on this forum. I then wander down various paths following up on what I find interesting. I recently came across this company on one of my rabbit hole trips and I cannot remember the thread where I found this...

diysolarforum.com

But it works fine.

 

[Oldtimmer69]

I was able to worked on this a little today.. I really wanted a single 4" post but I didn't want to spend that much money.... So I used 2.5" galvanized scheduled 40 pipe 10' long, I put 4' in the ground with 5 - 80lb bags of concrete In Each hole.after getting it all together.. I need to move the whole rack down one more foot so it will be 70% at the bottom and 30% on top. I think it will be more stable like that when I run a brace from the bottom of the post to the bottom outside corner on Each side. Right now it's set to 50 degrees at solar south and I'll have to ability to adjust tilt a couple of times a year. That should help with efficiency. I'll try to keep on this as time permits and I'll update. Let me know Whatcha think.

 

[Oldtimmer69]

Couple more pictures

 

[Oldtimmer69]

2nd array up and waiting on concrete to dry for #3 hope to have them all done by next weekend. Have some help coming to give me some guidance on the wiring

 

[JoeHam]

Nice work!

 

[Oldtimmer69]

Nice work!

Thanks, a little slower than I'd like, but steady is what counts.

 

[Oldtimmer69]

3 done 1 more left.

 

[Oldtimmer69]

Ok ordering 2 of these midnight solar PNVP-6 combiner boxes with 4 - 15a breakers. I'm going to run 3 pannls in series and 4 parallel into each box. ( 12 panels) Then 4 - 10g wires 2 from each box into inverter. Sound right?

 

[Hedges]

Ok ordering 2 of these midnight solar PNVP-6 combiner boxes with 4 - 15a breakers. I'm going to run 3 pannls in series and 4 parallel into each box. ( 12 panels) Then 4 - 10g wires 2 from each box into inverter. Sound right?

Is that one inverter, one MPPT input, fed from two separate combiner boxes with breakers?
The vendor may say to do that, but I would say do NOT. I do not believe polarized breakers (which can only interrupt current in one direction without arcing and burning up) can protect against backfeed into a damaged PV string from the other PV strings.

If each combiner box feeds a separate MPPT input, that is a step in the right direction.
Is it possible to gang all breakers in the box by slipping a wire through a hole in the handle of each one? If so, that would resolve my concern.

Or, put an anti-backfeed diode in series with each string. Then two boxes into one MPPT would be OK.

Or, get a combiner box with a touch-safe fuse holder for each PV string, and a single breaker as disconnect. That would be good with up to two combiner boxes wired to a single MPPT input even if the breaker is polarized.

 

[Oldtimmer69]

Pannls up, and I'll start the wiring. That's exciting

 

[Oldtimmer69]

Is that one inverter, one MPPT input, fed from two separate combiner boxes with breakers?
The vendor may say to do that, but I would say do NOT. I do not believe polarized breakers (which can only interrupt current in one direction without arcing and burning up) can protect against backfeed into a damaged PV string from the other PV strings.

If each combiner box feeds a separate MPPT input, that is a step in the right direction.
Is it possible to gang all breakers in the box by slipping a wire through a hole in the handle of each one? If so, that would resolve my concern.

Or, put an anti-backfeed diode in series with each string. Then two boxes into one MPPT would be OK.

Or, get a combiner box with a touch-safe fuse holder for each PV string, and a single breaker as disconnect. That would be good with up to two combiner boxes wired to a single MPPT input even if the breaker is polarized.

I have a 12k split phase inverter all in one with two inputs so I was going to split the pannls up. Seems like two combiner boxers were cheaper that one big one.. I would like to run all four wires through one piece of conduit into the house though.

 

[Oldtimmer69]

I'll take a picture of it tom

Is that one inverter, one MPPT input, fed from two separate combiner boxes with breakers?
The vendor may say to do that, but I would say do NOT. I do not believe polarized breakers (which can only interrupt current in one direction without arcing and burning up) can protect against backfeed into a damaged PV string from the other PV strings.

If each combiner box feeds a separate MPPT input, that is a step in the right direction.
Is it possible to gang all breakers in the box by slipping a wire through a hole in the handle of each one? If so, that would resolve my concern.

Or, put an anti-backfeed diode in series with each string. Then two boxes into one MPPT would be OK.

Or, get a combiner box with a touch-safe fuse holder for each PV string, and a single breaker as disconnect. That would be good with up to two combiner boxes wired to a single MPPT input even if the breaker is polarized.

I'll take a picture of the Inputs tomorrow just to make sure.