Wire Gauges and Voltage/Amps coming from Batteries

[Soleadus]

If a battery is rated 14Ah does this mean 14Amps is being pumped constantly or per hour?
Reason for the question is that I'm trying to decide on the wire gauge coming from the battery to devices.

For example, in a 12v 14Ah battery supplying power to devices, the gauge of these wires are determined by what?
And if I go a thicker gauge, besides being an overexpenditure, is it better in terms of safety/performance?

[Sunking]

A batteries AH rating and wire size have little to do with each other.

AH is just a math problem to solve.

Amp Hours = Amps x Hours
Amps = Amp Hours / Hours
Hours = Amp Hours / Amps

See that was fun. So you have a 14 AH battery. All that means is you could apply a load of say 2 amps for 7 hours. Using the math 14 AH / 2 A = 7 H.

The size of the wire is determined by the over current protection device (fuse or breaker). Say a 10 amp fuse would require a minimum 14 AWG wire. 20 amp would be 12 AWG. FWIW on a 14 AH battery a load of 5 amps is too much.

[Audley A]

Think of your battery as a gallon jug of water. If you suck from it with a garden hose, it will empty very quickly. If you use a straw, it will empty more slowly. Now the devices you connect to it could be figuratively sucking power through straws or hoses, depending on their power rating. Your wiring needs to be adequate for the connected devices. (Add the watt rating of each device running at a given time and divide by the volts to get amps.) Normally a heavier gage wire will be more efficient but as you noted, the % improvement in efficiency may not justify the increased cost. There are charts that will give you the recommended size wire for a given amperage. You should use fuses so you will not accidentally go near or beyond the limits of the wiring and maybe cause a fire.

[Soleadus]

A batteries AH rating and wire size have little to do with each other.

AH is just a math problem to solve.

Amp Hours = Amps x Hours
Amps = Amp Hours / Hours
Hours = Amp Hours / Amps

See that was fun. So you have a 14 AH battery. All that means is you could apply a load of say 2 amps for 7 hours. Using the math 14 AH / 2 A = 7 H.

The size of the wire is determined by the over current protection device (fuse or breaker). Say a 10 amp fuse would require a minimum 14 AWG wire. 20 amp would be 12 AWG. FWIW on a 14 AH battery a load of 5 amps is too much.

If I'm charging four phones at the time, each pulling 2Amps(the chargers say 5V and 2A), that would mean I'm trying to pull 8 Amps total from the battery, which would be no good... Right?

If I'm just charging two at the time, meaning 4Amps total, that would mean I need(according to the charts I've seen), around a 14AWG wire from battery to cellphone charging station?

[Soleadus]

Think of your battery as a gallon jug of water. If you suck from it with a garden hose, it will empty very quickly. If you use a straw, it will empty more slowly. Now the devices you connect to it could be figuratively sucking power through straws or hoses, depending on their power rating. Your wiring needs to be adequate for the connected devices. (Add the watt rating of each device running at a given time and divide by the volts to get amps.) Normally a heavier gage wire will be more efficient but as you noted, the % improvement in efficiency may not justify the increased cost. There are charts that will give you the recommended size wire for a given amperage. You should use fuses so you will not accidentally go near or beyond the limits of the wiring and maybe cause a fire.

Check out my response to Sunking.

Regarding your post: Dealing with such low current I didn't think about fuses. I'll have to touch on that later...

[Mike90250]

Fuses are required when the current source (lead-acid battery) can produce enough amps to damage wires likely to be connected to it.

Flashlights with no wires and low amp batteries don't need fuses

But even a low amp car radio has a fuse (because of the big battery at the other end of the wire)

[Soleadus]

Fuses are required when the current source (lead-acid battery) can produce enough amps to damage wires likely to be connected to it.

Flashlights with no wires and low amp batteries don't need fuses

But even a low amp car radio has a fuse (because of the big battery at the other end of the wire)

So a device can only take so much until it burns out, so you get a fuse slightly below the supposed limit to prevent that. That makes sense. But now to the wire from the battery part.

Now, on your first line there, I see "damaging the wires". This means if the amperage is high, and the wire thin(or just thinner than it should be), you get a fuse in(I guess coming out of the battery, before the wire) so when the power spikes(for reasons I not 100% sure, but would like to hear some examples. Could be the draw? The amount of current devices are pulling from the power source) and sends too much current down it burns the wires, unless the fuse is there to blow and save the wire.
Having said that, there can be a wire, say 16AWG, connected to a 225AH battery, and be able to power the charging of one phone, and all be alright, but not forget a fuse because that big of a battery can fry the 16AWG wire if more devices start pulling current through the same line(wire)?

[Audley A]

Yes but more likely could be a short circuit in the wire or connected device which would send a massive amount of 'juice' through the wire with disastrous effects.

[Sunking]

So a device can only take so much until it burns out, so you get a fuse slightly below the supposed limit to prevent that.

No a fuse is not there to protect your equipment. A fuse or breaker only purpose in life is to protect the wire connected to the load side.Otherwise it has no purpose.