Relocating house batterys advice needed

[bigdale]

I have an older 91 sportcoach p30. I am replacing house batteries with 4 6 volt golf cart batteries. I do not want new batteries in the front where the old 12 volts where. I want to put them in the basement, the closest door is 10 ft away from where the original 12 volts where hooked up.
I feel I need to get the battery wired to the original place the old 12 volts where hooked up in the front by the fuse panels. In order for everything to work out right. I do not really know what size wire I should use for the 10 ft run. I have been reading a lot but cannot seem to figure this out. I already have a new 3 stage converter. Any advice would be nice.

[wa8yxm]

So long as you do NOT have an inverter... Just use battery cable from Auto Zone. to Extend it out.

NOTE: Batteries, epically flooded wet cells like the GC-2 six volters MUST BE IN A VENTED COMPARTMENT!

[dgapilot]

Simple answer for any DC circuit, the biggest wire you can a. work with comfortably, + b. afford, will give the best performance. A lot depends on what draw you will have on the system. The farther you run the wires the more the resistance, and associated loss of efficiency.. Another issue is the connections between the batteries. If you are makingg a 12 volt bank using the 4 6 volt bateries, you will have two pairs of batteries in series and then the two series sets in paralell. Each of the cables between the batteries should be the same gage, and the same length so the loss in ieach is the same. If in the future you plan on installing an inverter, the inverter should be as close to the batteries as possible. For future planning, make sure the battery location will allow sufficient room for that upgrade.

Battery venting is an important issue. The compartment does need to be vented, and it would be a good idea not to have items that would be affected by battery acid anywhere near this compatment. Paint the interior of the compartment with acid proof paint.

Have you figured out what the change in load(weight) distribution will do? Moving the batteries may change the loading on your axles where you could exceed a loading recommendation if you were close to the limit already. Likewise if the old set up had the batteries evenly distributed left and right, and you load them all on one side, you could impact handeling. Just some other things to think about with a change like this.

[Gary RVRoamer]

Agree - the bigger diameter the cable, the better!

[historyljc]

Consider spending the extra money and get AGM batteries and then you can put them anywhere and not worry about gases or venting. They're not cheap but to me have been worth the cost in not having to fool with the regular batteries and cleaning up after them.

[deblas]

For the cable size, do not go any smaller than what is existing for sure! For a 10ft run, I would be inclined to go one gauge bigger to minimize voltage drop and vent that compartment.

[Dave78Chief]

The owners manual for you rig indicates you have a AUX Start switch on the left side of your dash. When used, the starter can draw upwards of 400 amps for a short period. If you wish to retain this feature, then you will need to use 2 or 4 gauge stranded battery cable from the coach battery back to the isolator solinoid. Bottom of page 2 http://www.generalcable.com/NR/rdonl...tterySS_FA.pdf

If you intend on eliminating the isolator relay option and wire directly to the DC fuse panel, then you will only be pulling a max of 40-50 amps. 10 gauge stranded automotive wire will work for that. If your new 3-stage converter is larger than 45 amps then select wire size appropriate for the converter size vs cable length from the following table:
http://www.sherco-auto.com/wirespec.htm

If you are adding an inverter, then size of the inverter needs to be known first.

Dave

[JimM68]

I'd run 2 gauge wire back to the original battery connections, or directly to the isolator solenoids if possible.

[Old Bounder]

Originally Posted by Dave78Chief

The owners manual for you rig indicates you have a AUX Start switch on the left side of your dash. When used, the starter can draw upwards of 400 amps for a short period. If you wish to retain this feature, then you will need to use 2 or 4 gauge stranded battery cable from the coach battery back to the isolator solinoid. Bottom of page 2 http://www.generalcable.com/NR/rdonl...tterySS_FA.pdf

If you intend on eliminating the isolator relay option and wire directly to the DC fuse panel, then you will only be pulling a max of 40-50 amps. 10 gauge stranded automotive wire will work for that. If your new 3-stage converter is larger than 45 amps then select wire size appropriate for the converter size vs cable length from the following table:
Automotive Wiring Specification Chart - Length vs. Size

If you are adding an inverter, then size of the inverter needs to be known first.

Dave

It would take far more than 2 or 4 gauge wire to connect into the existing battery wiring and maintain all functions such as aux/start. I think you meant to say 2/0 or 4/0 cable. That would be the minimum i would consider using.

[Dave78Chief]

I did not just pull the information off the top of my head. Look at the bottom of page 2 of the general cable site doc I linked to.
For 500 amp max load (starter is around 400 amps), cable size for a given length is:

4 guage = 10ft
2 gauge = 15ft
1 gauge = 19ft
1/0 guage = 24ft
2/0 gauge = 31ft
3/0 gauge = 39ft
4/0 guage = 49ft

Can you go bigger? Why sure you can. But it is not required.

Dave

[Ed-Sommers]

If the distance is physically 10 feet away, then the distance used for planning cable size is TWENTY FEET!

Ed

[bigdale]

Thanks all of you. I knew I would get the help I needed in this forum. This site is the best.

[Always-RVing]

There are several web pointers that have formula charts to calculate the minimum wire size. Copper? Aluminum? Length? Voltage? Amps?

Wire Size Calculator

Cable Gauge Chart