Gauging the wire....

[GREENReactor]

For my forthcoming dual 6V set-up (replacing the original 12V "dual purpose" battery that came with the RV) I'll need to add the "series" wire connection between the two. Would 4-gauge be big enough for that or should I go with 2 gauge?

[tenbear]

I think your choice of #2 is good. If you have a generator it can draw a very high starting current. With the improvements you are planning, #2 makes a lot of sense.

[fyrflie]

If you prefer DIY check out www.delcity.net.

They have wire, terminals, solder, etc.

When I re-did my boat wiring, I used the solder slugs and terminals from them. No crimping required.
Just a thought.

[MrWizard]

greenracer
do you have an inverter ?
if so what size ? what do you expect to power with the inverter

300w tv etc,, then 4ga will be fine

2000w going to power the MW and/or coffee maker then that connecting wire has to be able to handle a large load, 2ga or even larger
what size wire for the inverter ?

battery connector has to be equal to or larger than inverter wires

[GREENReactor]

Thanx much for all of the helpful tips. My current set-up uses 4 guage, but I was thinking that once I get my GC batteries and the new PD converter in there (when I get back home from this trip) I will start planning for an inverter (maybe a good size one to be ready for some short-term higher-drain use) so I thought that maybe it would be good to plan ahead for occassional higher-amperage load on the batteries. Based on the input here, I'm going for the 2 gauge. With the suggestion above and Amazon Prime I'll have one waiting when I get home Friday with the new batteries...

[time2roll]

IAMICHABOD wrote:
I used This One same as I used to run the batteries in series on the Golf Cart, that is what they recommended for 6 Volt run in series.

3/8" lug hole is large for 5/16" stud on GC2.
No same day shipping but lower price here: $7.75 vs $9.99

http://www.genuinedealz.com/4-awg-custom-battery-cables

[theoldwizard1]

IAMICHABOD wrote:
I used This One same as I used to run the batteries in series on the Golf Cart, that is what they recommended for 6 Volt run in series.

Nice to know that you can buy pre-make battery jumpers for a reasonable price ! For the extra $2, I would go 2 gauge.

[ktmrfs]

donn0128 wrote:
Welding supply stores will sell you any amount of super flex welding cable you need to make up your cables. They also have lugs, so one stop shopping. Welding cable sure would be easier to work with.

that's how I made my battery/inverter wiring up. However, unless you have a quality crimper or good soldering skills, you'll have to have the welding shop crimp on the connectors. many will do that for a very nominal fee and they usually have a crimper that will outdo any other you may have.

[donn0128]

Welding supply stores will sell you any amount of super flex welding cable you need to make up your cables. They also have lugs, so one stop shopping. Welding cable sure would be easier to work with.

[SoundGuy]

corvettekent wrote:
There is no point in going any bigger then your positive and negative wires are, that would be like adding a 2" fire hose to your 5/5" garden hose.

Exactly. And although the OP hasn't indicated at all what gauge cable his trailer mfg used in wiring back from the battery location to the converter chances are it's 6 gauge anyway.

[IAMICHABOD]

I used This One same as I used to run the batteries in series on the Golf Cart, that is what they recommended for 6 Volt run in series.

[time2roll]

Chris Bryant wrote:
Guys, he's adding resistance. Why not minimize that added loss?

One foot # 6 vs #2 is 20 millivolts (0.020) at 40 amps.

[2oldman]

Chris Bryant wrote:
Guys, he's adding resistance. Why not minimize that added loss?

We don't know his usage. If he's adding resistance in that little short wire he's going to have bigger problems on the feed wires.

[DrewE]

Wire size is determined by current carrying requirements (and acceptable voltage drop), regardless of where the wire is. For a short jumper between batteries, the voltage drop is rarely much of a great concern as the length of the wire is short and so the overall resistance low.

If you go with the same size as your power and ground wires, as others have said, you will be fine assuming they have been appropriately sized. If you have more than one of either of them, it's the aggregate cross-sectional area that probably should be considered. Alternately, if you can readily determine the maximum current you'll see, that can also be a good guide. One example of this might be if there's a large fuse or circuit breaker inline with the battery; you can be pretty sure that the maximum current draw will not exceed that fuse or breaker's rating, and size based on that.

If the cost is not excessive and you have the room, there's nothing at all wrong with choosing a larger size than necessary.

[Chris_Bryant]

Guys, he's adding resistance. Why not minimize that added loss?