(1)Drawing's of the electrical system in progress. I am a plumber by trade and this electrical has been kicking my but. I chose the Growatt 24v 3000w

Tbj35j

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(1)Drawing's of the electrical system in progress.
I am a plumber by trade and this electrical has been kicking my but.
I chose the Growatt 24v 3000w after watching Will P.
I'm putting 6 320w Renergy panels in the system
4 12/300 LIP batteries in S then P =24/600
Now to finishing is getting the wire/fuse size correct on the battery side of this.
Bluetti AC200p DC 4 now.

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Supervstech

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Nicely drawn out. I don’t see anything that immediately jumps out as an issue yet.
 

740GLE

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DWV a house and plumbing a full bath is just like wiring and electricity, you got this!
 

Pappion

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More fuses. 1 for 24 to 12v inverter input (because electronics short out), 1 for inverter output (protect wiring at source). 1 for 24v service. That 200A battery fuse will not protect smaller wires. You don't want wires turning into glowing cigarette lighters.
Grow Watt 24v output will also need a fuse, unless it has one or circuit breaker internally.
 
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HRTKD

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If you want 24v, then why not buy the 24v batteries from Ampere Time?

I'm not a fan of putting BMS-based batteries in series. Hence, my suggestion to go with a 24v battery from the start.

I have no experience with Ampere Time batteries. Please don't take this as an endorsement of their 24v batteries.
 

Tbj35j

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As for ampertime I'm not sure yet.
But there 24v battery is only 100ah
 

Tbj35j

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More fuses. 1 for 24 to 12v inverter input (because electronics short out), 1 for inverter output (protect wiring at source). 1 for 24v service. That 200A battery fuse will not protect smaller wires. You don't want wires turning into glowing cigarette lighters.
Grow Watt 24v output will also need a fuse, unless it has one or circuit breaker internally.
The issue I have is knowing what size wires and the fusing.
I agree I need more fuses/breakers
 

Pappion

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The charts are from Blue Sea Systems. Of course they are near the end.
Fuses at the source should protect the wire from over heating. The assumption is that a short could happen any where along the line.
Fuses at the destination protects the internals and assumes the source fuse might be too large.
Sometimes the source fuse is sized to protect the destination. Such as 1A for propane detector.

DIY Resource Fuse/Breaker Sizing
 

HRTKD

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As for ampertime I'm not sure yet.
But there 24v battery is only 100ah

A 200 Ah 12v battery has the same watt hours as a 100 Ah 24v battery. At the higher voltage you need fewer amps.

Two 12v batteries with 200 amp output rating, wired in series, is still only 200 amp output.

Four of those 12v 300 Ah batteries is going to consume a lot of space. Do you have that much open cabinet/storage area?

You're going to spend around $5200 for 600 Ah of battery capacity. If you're feeling adventurous, you could build your own batteries for a lot less money. I built 560Ah of LiFePO4 for around $1200 last summer. This was two 12v 280Ah batteries that I wired in parallel. The same set of cells could have been configured for 24v 280Ah for about $1100. If I had gone 24v and wanted to keep to 560Ah, the cost would have been $2400.

It looks like this will be going in a motorhome. What is the 12v item with highest amp draw?

You don't have to use a 6 port combiner box. If you run three panels in series and then another three panels in series, you can then parallel those two strings. No combiner box needed at all. Just a Y connector. However, the limiting factor here is the Max PV Input on your Growatt.
 

Tbj35j

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Thank for the input.
Trying to get my head tied around this electrical is taxing.
 

Pappion

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Generally 40A at 12v is enough. Many converters are 35-55A.
Caveat: Slide out hydraulic pump motors, may need peak power from a battery.
My slide with the 2 in wall motors has a 20A self resetting circuit breaker. I bet 10A is enough.
Other slides are motor driven from underneath. What's their fuse rating?

Other people have done energy audits for their 12v systems. Search for postings.
 

Tbj35j

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The charts are from Blue Sea Systems. Of course they are near the end.
Fuses at the source should protect the wire from over heating. The assumption is that a short could happen any where along the line.
Fuses at the destination protects the internals and assumes the source fuse might be too large.
Sometimes the source fuse is sized to protect the destination. Such as 1A for propane detector.

DIY Resource Fuse/Breaker Sizing
Thank you.
 

Jimmynik1

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A 200 Ah 12v battery has the same watt hours as a 100 Ah 24v battery. At the higher voltage you need fewer amps.

Two 12v batteries with 200 amp output rating, wired in series, is still only 200 amp output.

Four of those 12v 300 Ah batteries is going to consume a lot of space. Do you have that much open cabinet/storage area?

You're going to spend around $5200 for 600 Ah of battery capacity. If you're feeling adventurous, you could build your own batteries for a lot less money. I built 560Ah of LiFePO4 for around $1200 last summer. This was two 12v 280Ah batteries that I wired in parallel. The same set of cells could have been configured for 24v 280Ah for about $1100. If I had gone 24v and wanted to keep to 560Ah, the cost would have been $2400.

It looks like this will be going in a motorhome. What is the 12v item with highest amp draw?

You don't have to use a 6 port combiner box. If you run three panels in series and then another three panels in series, you can then parallel those two strings. No combiner box needed at all. Just a Y connector. However, the limiting factor here is the Max PV Input on your Growatt.
What size breaker would you recommend going from a 24v 620ah bank to my growatt 3k? I was thinking 120a to keep it on the lower side of the units max rating to be safe.
 

HRTKD

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What size breaker would you recommend going from a 24v 620ah bank to my growatt 3k? I was thinking 120a to keep it on the lower side of the units max rating to be safe.

I think that would be an undersized breaker.

3000 watts / 24v / .85 (inverter efficiency) * 1.25 (fudge factor to avoid nuisance trips) = 183 amps. I would probably go 200 amps.

However, if you know that you're never going to put more than a 2000 watt load on the inverter, you can adjust down the circuit breaker rating. I would probably play it safe and stick with 200 amps.
 

Jimmynik1

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Ok thanks for the reply
Ok awesome thanks. I was initially thinking 150a.
On my crude drawing below, I have my 2 separate 8s packs that will join together at 2 3 post bus bars.
The wire off my daly bms is 6ga which will have to be spliced or connected to whatever size wire I use to lengthen it so it can reach the bars. Is 2ga wire sufficient for that extension to the bus bars, the the proper size for the main run between the bars and the inverter. Trying to size my stuff accordingly on paper before I get the wrong stuff and waste time.

 

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HRTKD

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Your BMS is going to limit the amp charge/discharge amount. I would use the wire gauge calculator below to figure out what you need. I can't answer your question because I don't know your inputs needed for the calculator.

 

Jimmynik1

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Your BMS is going to limit the amp charge/discharge amount. I would use the wire gauge calculator below to figure out what you need. I can't answer your question because I don't know your inputs needed for the calculator.

Yea good point I didnt think about that. Now that you mentioned it the charge is 75a and discharge is 150a. So if 2ga wire is good for 205a, as long as windy nations chart is correct, 2 should be fine to extend the bms - wire to my buss bar, the from bars to inverter?
 

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HRTKD

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That chart doesn't take into account the length of YOUR wire. It's possible that the gauge you need is actually lower. Use the calculator I suggested and see what the answer is.

Are you going to cut the BMS wire and splice on your own? Or are you going to run the BMS wires to a bus bar and then go from there? Using the bus bar is easier. Splicing different size gauges is a little difficult. Most butt connectors are the same gauge on both ends. You can double up the 6 gauge to take up the space when using a 2 gauge butt connector. That may work. I had to connect 10 gauge to 6 gauge and used that technique. If I were you, I would go the bus bar route since you need to combine the output of two BMS.

A switch on the positive side of the BMS is recommended so you can turn off each battery independently and continue to use the other one.
 

Jimmynik1

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That chart doesn't take into account the length of YOUR wire. It's possible that the gauge you need is actually lower. Use the calculator I suggested and see what the answer is.

Are you going to cut the BMS wire and splice on your own? Or are you going to run the BMS wires to a bus bar and then go from there? Using the bus bar is easier. Splicing different size gauges is a little difficult. Most butt connectors are the same gauge on both ends. You can double up the 6 gauge to take up the space when using a 2 gauge butt connector. That may work. I had to connect 10 gauge to 6 gauge and used that technique. If I were you, I would go the bus bar route since you need to combine the output of two BMS.

A switch on the positive side of the BMS is recommended so you can turn off each battery independently and continue to use the other one.
Ok yea forgot about drop over length, nevertheless I only need about 3 feet, I put 5 to be safe and still only had a drop of .25 when calculating 150a @ 24v over 5' which I think is decent based on the chart results.
I was planning on splicing the 6 wire to 2 wire since the wire off the bms's are so damn short, 6" they say and I haven't built my box yet but I don't anticipate being able to have a bar that close, but I do see what you're saying about splicing two different sizes. Crude as it may be, but the factory ring terminal on the bms is a m8, and I plan to use all 1/4 rings as the growatt is 1/4 and they're fairly common for 2 awg. m8 being equal to .315 and 1/4 being .25, what if I just nut and bolted the two rings together and heat shrinked it.
 
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