Thread: Triton Dual battery

You do not need anywhere near 70 amps to charge a battery! But yes, your logic is 100% correct. If you put the battery at the back of your caravan and still wanted it to charge...you'd need bigger than 8 B&S. I think I may need a little bit of clarification, and say that 2 B&S is actually a lot bigger than 8 B&S, in spite of the fact that the numbers are ass-about. I think it's a pommy thing . And that, in my previous statement, the first size what's for an auxiliary battery starting the car situation...whereas the second size was for a charging the aux battery and using it...for whatever you planned to use it for other than starting. If you tried to start using 8 B&S I can see fires occurring. If I can digress a little further, without annoying anyone, we take for instance the 8 B&S cabling which has a resistance of 2.4 ohms per kilometer. Now, since we are travelling up to 10m maximum, we have a cabling resistance of 0.024 ohms. We consider that to charge the battery we need 10-15 amps, when battery is fully discharged, so the voltage drop across the cable is 15*0.024 =0.36V! Just acceptable! Naturally, I'm hoping it's a little less than 10m to the tray of the Triton.

i think you guys are referring to 4 guage cable......

Originally Posted by DEFENDERZOOK

i think you guys are referring to 4 guage cable......

Yes I just wanted her to pull her TAFE books out and do her homework

I didn't see did she write the formulae?

Originally Posted by Relay

You do not need anywhere near 70 amps to charge a battery! But yes, your logic is 100% correct. If you put the battery at the back of your caravan and still wanted it to charge...you'd need bigger than 8 B&S. I think I may need a little bit of clarification, and say that 2 B&S is actually a lot bigger than 8 B&S, in spite of the fact that the numbers are ass-about. I think it's a pommy thing . And that, in my previous statement, the first size what's for an auxiliary battery starting the car situation...whereas the second size was for a charging the aux battery and using it...for whatever you planned to use it for other than starting. If you tried to start using 8 B&S I can see fires occurring. If I can digress a little further, without annoying anyone, we take for instance the 8 B&S cabling which has a resistance of 2.4 ohms per kilometer. Now, since we are travelling up to 10m maximum, we have a cabling resistance of 0.024 ohms. We consider that to charge the battery we need 10-15 amps, when battery is fully discharged, so the voltage drop across the cable is 15*0.024 =0.36V! Just acceptable! Naturally, I'm hoping it's a little less than 10m to the tray of the Triton.

Quite a few years ago now, I went to an auction and bought a reel of 20mm. electric welder cable for not very much. I also bought a lot ( auction lot ) of battery terminals that accept this cable. The auction was the receivers sale of a truck manufacturer. Never had a battery cable problem since. Long, thick, and black, the Mother Superior's dream.

*Sighs* I give up! Heh. See I run tycab wiring at work, tycabs sizing is what I know. There isn't really an australian standard, not like the yankees have anyways. The most effective and cross the board way of catagorising (sp?) wiring is by is copper cross sectional area, that way it dont matter how thick the insulation is. And dobbo, if you're not careful, I'll come over there and toss my tafe folders at you! You'd be arms deep in paper! And then you can tell us all the formulae!

Curiously Brian, have you found that getting the welding cable to flex difficult? I would love to acquire some if not, coz auto copper cable is so much more expensive at times!

Check this site out for wire gauge sizes, comparing between AWG/Metric sizes, load carrying capacity etc.
http://www.powerstream.com/Wire_Size.htm

Also check this out for flexible 'power cable' ie welding lead,
http://www.olex.com.au/media/docs/Fl...3dcc1da392.pdf

Welding lead is nice and flexible (depends on size you use)
Always found it hard to remember AWG sizes, cause numbers go smaller for larger cables.
Much prefer metric sizes...
...ok I'm a metric boy!

i think automotive cable has thicker insulation than welding cable.....

Originally Posted by DEFENDERZOOK

i think automotive cable has thicker insulation than welding cable.....

I went down the shed and compared. You seem to be generally right, however there is a good variety of variation in thickness of insulation on the variety of old auto. cables I have stored away "in case of need". I have never had an insulation problem with the welding cable. I usually bung on some Spiwrap anywhere that will rub and possibly wear. I also put on red heatshrink on each end of the positive cable. I used to solder the terminals, but a couple of years made a crimping tool to put under the press.