House battery cable size?

[grantgoold]

I am ready to connect the house batteries. I have 1100 amp hours total (5 X 220 ah per battery) I have a 3000 watt inverter and the longest distance will be between the battery switch/300 amp inline fuse and the inverter about 6 feet.

Any suggestions on the size or awg of the wire. Would a 4 awg be sufficient?

Thanks in advance.

Grant
Sacramento

[gr8njt]

I do not know if this will make sense but I just got delivery of my Xantrex SW4024 and I was reading the owner's manual.
On page 131 of the manual, Table 11, a Minimum Recommended Battery Cable vs Cable Length table indicates that for the model SW2512 (I'm guessing this is 2500 watts/12 volts which is close enough for your 3K inverter for comparison), lengths of 1ft to 3ft or 3ft to 5ft cable runs should use #4/0 AWG and not recommended to run the power cable over 5 feet.
On the other hand, the 24 volt models can run the #4/0 AWG up to 10 feet.
I am not so sure if the 4 AWG you are thinking of using is the same as 4/0 AWG.
Hope this helps.

[Dallas]

4 AWG is Definately NOT the same as 4/0!

This is not a good mistake to make. You might end up letting the smoke out of things.

Dallas

[gr8njt]

4 AWG is Definately NOT the same as 4/0!
This is not a good mistake to make. You might end up letting the smoke out of things.
Dallas

I was hoping it was just a "typo" and he really meant 4/0 AWG.

[Dallas]

I wanted to make clear the difference. I had a friend with a Bounder S&S that installed a big inverter using 4 AWG ..... it didn't take long for him to open all the doors and windows as soon as he got the fire out. Burning insulation really smells bad and leaves a lasting aroma!

I didn't want anything to happen to Grant & Company or his pride and joy!

[grantgoold]

Thanks Dallas for the concern. I think that I can use 2/0 awg for the system and be just fine. I may go with 1/0 awg if the material becomes available soon.

Thanks

Grant

[JackConrad]

1/0 is smaller than 2/0. When you get into the wire sizes that include 0, the larger the number, the larger the wire. Wire gauges (Small to Large) are 8, 6, 4, 2, 0 (AKA 1/0), 00(AKA 2/0), 000 (AKA 3/0), and 0000 (AKA 4/0).  Remember, bigger is better.  Hope this helps, Jack

[belfert]

I'm assuming 12 volt so you will almost certainly want 4/0 cable.  4/0 isn't going to break the bank for 12 feet total.  The worst thing to do to an inverter is to have a voltage drop due to undersized cables.

Brian Elfert

[H3Jim]

Here is a copy of a worksheet done by Jock, who has since passed.  its in excel, although this is just a copy of the values for 50 amps.  For DC power, voltage drop tends to be more critrical for wire size than the safe size for a given amp flow.  Generally bigger is better for wire size.

I used 0000 (thats 4/0) for all my connections.   I have 6, 200 amp hour, 12volt gel cell batteries, wired in series / parallel for 600 amp hour capacity at 24 volts. The large wire size might be considered overkill, but I will obtain greater efficieincy for the life of my system.  Just that much less current goes to heat than with a smaller wire.  I have a 4024 Trace inverter, and and all electric coach.



Voltage drop worksheet               Jock Fugitt Revised November 13,2002 c            
                              
   Insert Current,      then read voltage drop for size & run                           
   Run length Feet (2 way) vs Voltage drop For Current of ...........                     50   Amps   
                              
      <<<<   <<<<      run length      >>>>   >>>>   >>>>   
AWG      5   10   15   20   30   50   100   200   Ohm /1000
14      0.65   1.29   1.94   2.58   3.87   6.45   12.90   25.80   2.58
12      0.41   0.81   1.22   1.62   2.43   4.05   8.10   16.20   1.62
10      0.26   0.51   0.77   1.02   1.53   2.55   5.10   10.20   1.02
8      0.16   0.32   0.48   0.64   0.96   1.60   3.20   6.40   0.64
6      0.10   0.20   0.30   0.40   0.60   1.01   2.02   4.03   0.40
4      0.06   0.13   0.19   0.25   0.38   0.63   1.25   2.50   0.25
2      0.04   0.08   0.12   0.16   0.24   0.40   0.80   1.60   0.16
1      0.03   0.06   0.09   0.13   0.19   0.32   0.63   1.26   0.13
0      0.03   0.05   0.08   0.10   0.15   0.25   0.50   1.00   0.10
00      0.02   0.04   0.06   0.08   0.12   0.20   0.40   0.79   0.08
000      0.02   0.03   0.05   0.06   0.09   0.16   0.32   0.63   0.06
0000      0.01   0.03   0.04   0.05   0.08   0.13   0.25   0.50   0.05

[niles500]

Grant - you probably know this, but just in case to avoid confusion - when ordering the wire it is verbally refered to as "aught" when you get to 0,00,000.etc

Another words 2/0 or 00 is "double aught" - HTH

[ChuckMC8]

I used 4/0 (0000) for all my house bank, including the jumpers on the golf cart batteries.
  Here's a tip that could save some $$$, if you need big cable, try going to your closest big scrap yard (not a car yard, go to one that buys metal from the public) and tell them that you need some new scraps of 4/0 with the insulation still on it.........they will usually sell it for what it would bring them if it were stripped. (and then they dont have to strip it) The peice may be 20' long and still considered a scrap peice
  Copper is baadddd expensive now..................glad I dont need any............