2 Gauge or 4 Gauge

davlan88

2012 EzGo RXV, 6 inch lift, 23 inch tires, Danaher controller, not sure of any other mods. In replacing the batteries and figured I might as well get a good cable set too. Any experienced suggestions? And are there forum sponsors that sell them?

BGW

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teecro

4 gauge is generally considered more than big enough... But 2 gauge is only a couple of bucks more extra and is more than enough for a 6 or 7 hundred amp built up cart...

http://www.cartsunlimited.net/battery-cables.html

cgtech

Your cart has a 235a controller, 4g cables will be great.

BobBoyce

Please keep in mind that a 235 Amp rating for a 3 phase AC controller is 235 Amps per phase, multiplied by 3 phases. To generate that can require over 500 Amps from an RXVs battey pack. Since the RXV controllers are extremely current limited for safety, they can never really put out the full rated power. In actual use, they will rarely put out even 150 Amps peak per phase. Most are limiting at under 100 Amps per phase unless you are climbing a hill. Part of that is parameter limitation, part is due to the current limitation of the factory battery wires limiting current draw from the battery bank, and part is from the internal resistance of the batteries themselves. With a good set of batteries and 2 guage battery wires, I have been able to measure peaks of 225 Amps per phase with a stock Curtis RXV controller, once the higher level parameters have been tweaked. I really don't know what the Danaher controllers are capable of being tweaked to, since I don't yet have a higher level programmer developed for the Danaher controllers that I have here to work with.

Bob

davlan88

I'm not ready to pull the trigger on a new controller, I just lit $230 on fire by buying an HD Electric Brake that I cant use. What would be a good drop in controller? How much? And what will I gain?

Also, I didn't see where cartsunlimited had a 2 gauge wire set for an RXV, just TXT.

JohnnieB

FWIW: The numbers in the highlighted sentences don't add up because the 3 phases are 120° apart, so when one is drawing 235A, the other two are drawing less than 235A, so only drawing 500A from the battery pack rather than 705A (235A X 3) is a reasonable expectation.

BobBoyce

Correct on the phase angle, however it is a Delta configuration 3 phase, not a Wye with a high leg. The voltage and current on all 3 legs should be equal and balanced for the most part, minor impedance differences between windings aside. While the total of 3 phases could be added up to 705 Amps at max rating, it is not the same as 705 Amps at DC or Split Phase AC.

davlan88: There is no reason to change your controller if it is working for you. I was just describing the differences between what we can do with the Curtis vs the Danaher controllers. Upgrading the battery cables will help both. I've always made my own out of welding cable and lugs. Crimped, soldered, then heat shrinked.

JohnnieB

It has been many moons since I messed with any 3-Phase AC in theory or reality, so I stand corrected.

davlan88

I guess I should have been a little more detailed, 2012 Ezgo RXV Freedom, 4 x 12v Trojan T1275s. I didn't see a 2 gauge cable package, may be I need to make my own.

bronsonj

It is not difficult to make your own cables if you have access to a proper crimper.

I was lucky as a friend of a friend had one to lend. Then it's just a matter of getting welding cable, good terminals, crimp, solder.

You could start a whole thread on how to prevent corrosion. But from what I've seen people either leave the cable as-is. Some people slather grease on the bare copper where it goes into the lug (after crimping and soldering). Some people use specially lined heat shrink. I used grease where the cable meets the lugs (one time application) then red spray on terminal protectant where the lugs meet the batteries (once every month or three).