guage For battery cable

[thehippie]

What’s a good gauge for battery cable to bridge/parallel 2 coach batteries?


There’s 2 guage and 4 guage at pep boys and Walmart Near me

[time2roll]

http://www.genuinedealz.com/custom-cables

Get the exact length, correct lug, pro crimped and sealed up with shrink wrap.
#8 to 4/0 at a good price.

[thehippie]

Thanks for your responses. I ended buying the 1 gauge. So far so good

[Grit_dog]

As long as you're not pulling more than 30A then you're fine, but I bet I could suck alot more than 30A at peak out of my camper batteries without trying too hard. That's a small fuse depending on your setup.

[TBammer]

Interesting topic. 2 or 4 gauge wire, but I am supposed to have a 30 amp fuse in line and the wire attached to the fuse holder is 8 gauge at best.

[Grit_dog]

wa8yxm wrote:
The answer depends on the max Current. For up to 100 amps 4GA is ok, but 2GA is better. if you are planing on drawing 200 amps. Now we are into 0000 land.

What he said^. And at that you could probably get away with 6ga, but I’d have to calc the amp draw, 4 is safe.
2/0 is not even remotely applicable for a couple deep cycle camper batteries unless you’re trying to arc weld with them!

[sbrdude86]

http://www.smartgauge.co.uk/batt_con.html
I have two 12V AGM on my TT
Balance is key to making them last

[wa8yxm]

The answer depends on the max Current. For up to 100 amps 4GA is ok, but 2GA is better. if you are planing on drawing 200 amps. Now we are into 0000 land.

[Optimistic_Para]

I stand corrected. Thank you.

[DrewE]

Optimistic Paranoid wrote:

DrewE wrote:

In theory, the cables between the two batteries only carry half the current that the cables to the inverter would carry (assuming two batteries in parallel) and are short enough that added voltage drop is fairly insignificant.

Well, yes, that's true IF you hook your + and - wires from the inverter up to the SAME battery. Personally, I would hook the + wire to one battery and the - wire to the OTHER battery to keep the load on the two batteries balanced. For that, you want the battery to battery cables to be the same size as the inverter wires.

In that case, it still works out that each interconnect would carry half the current (the half going to or coming from the "other" battery from the connection to the inverter) assuming they are operating in a balanced manner. As I did write, in a fault condition like an open battery, they could have to carry the full current regardless so they should be sized at a minimum to do that safely (without catching fire), but presumably one doesn't care about e.g. voltage drop in a fault condition.

[Optimistic_Para]

thehippie wrote:
putting a heavier gauge is ok?

Sure. Won't hurt a thing. Well, unless you go RIDICULOUSLY overboard, in which case the only thing you're hurting is your wallet . . .

[Optimistic_Para]

DrewE wrote:

In theory, the cables between the two batteries only carry half the current that the cables to the inverter would carry (assuming two batteries in parallel) and are short enough that added voltage drop is fairly insignificant.

Well, yes, that's true IF you hook your + and - wires from the inverter up to the SAME battery. Personally, I would hook the + wire to one battery and the - wire to the OTHER battery to keep the load on the two batteries balanced. For that, you want the battery to battery cables to be the same size as the inverter wires.

But as a practical matter, either way would work.

[thehippie]

DrewE wrote:

Optimistic Paranoid wrote:

thehippie wrote:
What’s a good gauge for battery cable to bridge/parallel 2 coach batteries?

It sort of depends on the loads you're going to put on the battery bank. If you're going to hook a largish inverter up to your battery bank, and use 2/0 gauge cable on it, then the cables between the batteries ALSO need to be 2/0 gauge.

In theory, the cables between the two batteries only carry half the current that the cables to the inverter would carry (assuming two batteries in parallel) and are short enough that added voltage drop is fairly insignificant. I would still size them to be able to safely carry the worst-case current, but not figure any voltage drop considerations for that current. (Under a fault condition, such as an open in one battery, they could carry the full current.) Using the same size wire is perfectly reasonable, though, and any savings from using smaller cables are likely to be insignificant since they are short.

putting a heavier guage is ok?

[DrewE]

Optimistic Paranoid wrote:

thehippie wrote:
What’s a good gauge for battery cable to bridge/parallel 2 coach batteries?

It sort of depends on the loads you're going to put on the battery bank. If you're going to hook a largish inverter up to your battery bank, and use 2/0 gauge cable on it, then the cables between the batteries ALSO need to be 2/0 gauge.

In theory, the cables between the two batteries only carry half the current that the cables to the inverter would carry (assuming two batteries in parallel) and are short enough that added voltage drop is fairly insignificant. I would still size them to be able to safely carry the worst-case current, but not figure any voltage drop considerations for that current. (Under a fault condition, such as an open in one battery, they could carry the full current.) Using the same size wire is perfectly reasonable, though, and any savings from using smaller cables are likely to be insignificant since they are short.

[Optimistic_Para]

thehippie wrote:
What’s a good gauge for battery cable to bridge/parallel 2 coach batteries?

It sort of depends on the loads you're going to put on the battery bank. If you're going to hook a largish inverter up to your battery bank, and use 2/0 gauge cable on it, then the cables between the batteries ALSO need to be 2/0 gauge.