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wire size for 7k lithium pak


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Well. I have ordered my battery pak. It is 3/ 7k paks. So I will have 3 sets of cables to the bussbars. Magnum calls for #2 cable to inverter, 4400 hybird. So what yall think is needed from each battery pak to bussbars.

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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Do you mean 3, 7,000W battery packs?  I would trust this website's calculations over what someone told me on the internet.https://www.altestore.com/howto/wire-sizing-tool-for-12-24-and-48-volt-dc-systems-a106/

Edited by Ray,IN

 

2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country.  John F. Kennedy 20 Jan 1961

 

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 I'm running W10 home version on a HP desktop, firefox 69.0.2 browser. I don't know what to say.

 

2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country.  John F. Kennedy 20 Jan 1961

 

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It's not really a calculator, as far as I can see. Here's the text:

STEP 1: Calculate the Following:

VDI = (AMPS x FEET)/(%VOLT DROP x VOLTAGE)

VDI = Voltage Drop Index (a reference number based on resistance of wire)
FEET = ONE-WAY wiring distance (1 meter = 3.28 feet)
%VOLT DROP = Your choice of acceptable voltage drop (example: use 3 for 3%)

STEP 2: Determine Appropriate Wire Size from Chart

Compare your calculate VDI with VDI in the chart to determine the closest wire size. Amps must not exceed the AMPACITY indicated for the wire size.

Wire Size Area mm2 COPPER ALUMINUM
AWG VDI Ampacity VDI Ampacity
16 1.31 1 10 Not Recommended
14 2.08 2 15
12 3.31 3 20
10 5.26 5 30
8 8.37 8 55
6 13.3 12 75
4 21.1 20 95
2 33.6 31 130 20 100
0 53.5 49 170 31 132
00 67.4 62 195 39 150
000 85.0 78 225 49 175
0000 107 99 260 62 205

 

Metric Size
by cross-sectional area
COPPER
(VDI x 1.1 = mm2)
ALUMINUM
(VDI x 1.7 = mm2)
Available Sizes: 1 1.5 2.5 4 6 10 16 25 35 50 70 95 120 mm2

 

EXAMPLE:
20 Amp load at 24V over a distance of 100 feet with 3% max. voltage drop
VDI = (20x100)/(3x24) = 27.78

For copper wire, the nearest VDI=31.
This indicates #2 AWG wire or 35mm2

I have been wrong before, I'll probably be wrong again. 

2000 Kenworth T 2000 w/N-14 and 10 speed Gen1 Autoshift, deck built by Star Fabrication
2006 smart fourtwo cdi cabriolet
2007 32.5' Fleetwood Quantum


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Looks like a max of 148 amps at 48 volts per pack

http://www.freesunpower.com/wire_calc.php#startGrn 

Calculator only goes to 100 amps, but pulling more than 100 amps from each bank is not likely. but would go one wire size bigger anyway.

Edited by jcussen

Foretravel 40ft tag 500hp Cummins ISM  1455 watts on the roof, 600 a/h's lithium in the basement.

 

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Glenn, If you're talking 7000 Watts at 48 Volts ???????? that's 145 Amps. You have three banks ??? Wooooooo Hooooooooooo. If a load was drawing 145  Amps and I was sizing the cable, Id opt for No 1 even if 2 suffices per Magnum (If the Blue Sea DC Systems chart is accurate ???? no guarantee) but, of course, that all depends on current and wire size and length and acceptable % drop, so I cant say from here exactly. If you have three such banks can I camp next to you and plug to your Inverter lol.

https://www.bluesea.com/resources/1437

Of course bigger wire = less line voltage drop and less I Squared R heat losses so bigger is better but the current and wire length are required to compute voltage drop. Its just in my DNA as an engineer to be on the conservative side and over engineer a bit, so if Magnum says No 2 Id still opt for No 1, still subject to actual current, wire length and acceptable % voltage drop 

John T    

Edited by oldjohnt
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Length will be short. Building a wall in generator area. Batteries at door, two on floor, one above the other. Inverters, master box, solar controller, bussbars, disconnects, etc all go on this wall. I have some #2, plenty actually left over from my factory installed inverter. Not welding cable though. If not too hard to work will utilize it. On second thought, I will get #1. It is very short run and not costly. Or double up the #2?. Hate to throw it away

Edited by GlennWest

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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To begin with I will be purchasing 2 Magnums  MS4448PAE. IMarine has them for $1800 each. They will work as one master and other slave. They are each 60amp chargers. Will be purchasing the Magnum Panel also. Simplify wiring. I know everyone wants the Victon equipment now, but I am rather old school and simple.  I plan to eventually put solar on but no real rush on this.Get this up and running good and then solar. Solar be simple after all this. Weather is cooling off now and allowing me to do this. With my work it will be slow going though. I intend to do away with the subpanel and wire directly into breaker box. Need to do this in the short fall we have here. ACs be off while doing this. Don't want DW upset!!!! I considering getting a simple fast charger, guy getting batteries from has one for $150. Putting DC side online first. That is why I was asking about a DC/DC converter in my other post.

Edited by GlennWest

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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12 hours ago, Darryl&Rita said:

It's not really a calculator, as far as I can see. Here's the text:

STEP 1: Calculate the Following:

VDI = (AMPS x FEET)/(%VOLT DROP x VOLTAGE)

VDI = Voltage Drop Index (a reference number based on resistance of wire)
FEET = ONE-WAY wiring distance (1 meter = 3.28 feet)
%VOLT DROP = Your choice of acceptable voltage drop (example: use 3 for 3%)

STEP 2: Determine Appropriate Wire Size from Chart

Compare your calculate VDI with VDI in the chart to determine the closest wire size. Amps must not exceed the AMPACITY indicated for the wire size.

Wire Size Area mm2 COPPER ALUMINUM
AWG VDI Ampacity VDI Ampacity
16 1.31 1 10 Not Recommended
14 2.08 2 15
12 3.31 3 20
10 5.26 5 30
8 8.37 8 55
6 13.3 12 75
4 21.1 20 95
2 33.6 31 130 20 100
0 53.5 49 170 31 132
00 67.4 62 195 39 150
000 85.0 78 225 49 175
0000 107 99 260 62 205

 

Metric Size
by cross-sectional area
COPPER
(VDI x 1.1 = mm2)
ALUMINUM
(VDI x 1.7 = mm2)
Available Sizes: 1 1.5 2.5 4 6 10 16 25 35 50 70 95 120 mm2

 

EXAMPLE:
20 Amp load at 24V over a distance of 100 feet with 3% max. voltage drop
VDI = (20x100)/(3x24) = 27.78

For copper wire, the nearest VDI=31.
This indicates #2 AWG wire or 35mm2

I was clicking on link for easy caculator. I was making that hard. I just needed to look at amp rating for wire. 

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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36v minimum, 50.4 max. Open for conments. I am thinking maybe 48-49v max charge, start at around 40. Know one doesn't want full charge or too low charge. I will talk with him more on this. My hearing is poor, too much construction noise. In person I do good. One can charge with high amps. It doesn't hurt them. That is the big adavtage for lithium. This will be a slow project. I have a total of 4 days off a month and that is subject to change depending on progress at work.Although, it is rumored I will be getting a upper supervisor position soon. Be lot easier  on me and feel more like doing this on my days off. Also be getting vaction time paid. We will see.

Edited by GlennWest

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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Ray was asking about current that you can charge at. Without bringing out the slide rule, 100 amps should be reasonable.

ETA: The vendor should have a spec sheet available for both the battery packs and the BMS he's supplying. Get all your charge parameters from there, don't depend on internet info for settings this important.

Edited by Darryl&Rita

I have been wrong before, I'll probably be wrong again. 

2000 Kenworth T 2000 w/N-14 and 10 speed Gen1 Autoshift, deck built by Star Fabrication
2006 smart fourtwo cdi cabriolet
2007 32.5' Fleetwood Quantum


Please e-mail us here.

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You will need to research your charging rate. Tesla's will take 2 times the charging rate. i.e. a 75 kw battery can be charged at 150 kw, but they are water cooled to remove the heat produced by charging . BattleBorn's have no cooling and will accept a 1 C charge, 100 amps into a 100 amp hour battery.

Looks like your inverters will charge at 60 amps each. So charging a 400+ amp battery bank should not be a problem, but do double check with the seller.

Foretravel 40ft tag 500hp Cummins ISM  1455 watts on the roof, 600 a/h's lithium in the basement.

 

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I will. He was trying to tell me some on phone but my hearing no good on phone. He said he would supply all that with batteries. The reason I went with 21k is due to the nature of these batteries. Need to done in 14 module pairs.  18k doesn't work. He stated amps would be lower that I could draw from them. Needed to go 14k or 21k. Stated I could pull these down in the 20vish. Not that i want to though. I will get all this info correct when I get them and share with everyone. 

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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Charge at bulk and float at 57v.. Disable asbord.  Can charge at max 200amps. 40v-58v is operating range. His quotes. He is suppling a charge displaly unit.He also texted me that with the 2 magnum 4400 hybrid I would only be pulling 60 amps from each battery. #4 battery cable plenty. 

Edited by GlennWest

2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1

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WOW Glenn, that's one nice system you're building. Unless I missed it, I'm curious, can you tell us the "ENERGY STORAGE Capacity" in Watt Hours or Amp Hours of those batteries ???

You mention having plenty of #2 Cable which it appears can "work" (even if I would use #1) and, of course, you could parallel a couple of them given proper connectors even if such isn't quite as professional looking. As you mentioned since it's a short run a few feet of No 1 isn't all that expensive. I like fine stranded Marine Grade cable for its improved flexibility and ability to withstand vibration. Regular old Welding Cable is fine stranded, flexible and has high quality insulation. Even if it takes more length I also like using a vibration/flex coil if possible.

Were having fun spending your money lol 

Keep us posted of your progress and choices, I'm enjoying this thread.

John T

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30 minutes ago, hemsteadc said:

As I read  it, 7k means 7,000 watts.  At 48v nominal that would be about 140ah each.

 

Indeed "POWER" in Watts = Volt x Amps, so 7000 "Watts" at 48 Volts, (7000/48)  =  145.83   "AMPS"   

However, that's NOT "Amp Hours"  which is what I was asking Glenn about, I asked if he knew the batteries "Energy Storage" Capacity which is typically listed in "Watt HOURS" or "Amp HOURS", let me elaborate.

His post just stated 7K !!!! Is that POWER in "Watts" or "Watt Hours" of ENERGY ?? To me the term 7000 Battery "Watts" alone doesn't mean as much, its how many "Watt Hours" I want to know, and for sure 7000 "Watt Hours"  would be a good number if that's what was meant ????? Perhaps it is, but I have to ask....

Instantaneous POWER in Watts = Volts x Amps. ENERGY, which is what the electric utility charges you for, is Volts x Amps x Time. You are billed for how many KiloWattHours of Energy you used.  Often an RV or Golf Cart or similar Deep Cycle battery (an electrochemical energy storage device) is labeled in "Amp Hours" which is a measure of the available useful ENERGY it can store.

So Glenn, I was wondering if you know the "Energy Storage" capacity (in Amp HOURS or Watt HOURS) of those batteries ???

1) Maybe they aren't labeled as such and you don't know ??

2) Perhaps that  7K "Watts" you posted is really 7000 "Watt Hours" ??

 I'm just curious....

John T     

 

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