# Max and Continuous Amps for 1/0 and 2/0 connectors.



## rwaudio (May 22, 2008)

tennisthehilife said:


> Hi, I would like to know how much continuous and max amps 1/0 cable can take and for 2/0 also.
> 
> Please and thank you.


I like this site:
http://www.powerstream.com/Wire_Size.htm

The tool at the bottom is handy for estimating voltage drop at a certain current level etc.

No idea if it's accurate or not but I use it as a rough guide. At the top I would use the "chassis wiring" section as long as your runs are fairly short in the car.


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## major (Apr 4, 2008)

tennisthehilife said:


> Hi, I would like to know how much continuous and max amps 1/0 cable can take and for 2/0 also.


Hi tenni,

rw posted a nice chart. I have been using a chart published by Anderson Power Products. It corresponds pretty well. 265A for 2/0 and 230A for 1/0, single conductor, 75°C, Copper (NFPA). These current ratings are for continuous, or average. Peak currents can be higher, much higher and for how long, depends on an I²T calculation.

In most cases, for EV cars and EV motorcycles, if your average current is within cable rating, you don't have a worry about peak currents. A good way to judge this is by the ratings of the rest of the power system, like motor, controller and batteries. If you have a 200 Ah battery and run your EV for an hour to drain that battery, then your average current is 200 Amps.

Also be advised that motor current is likely to be higher than battery current. So motor cables might be sized a gauge bigger.

I think often DIYers oversize cables. They try to size to max amps, and that is really not needed. Oversize cable does not hurt the electric circuit, in fact it helps by having less resistance and therefore less wasted energy, but this is typically a very small value. Oversize cables do hurt your pocketbook, vehicle mass and ease of routing. But that is all part of the glory of the DIY EV experience. 

Regards, 

major


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## lockduke (Dec 25, 2009)

been a long time reader to this site and a lot of info learned for my current project this is one of those time's that I need to ask a question if higher gauge wire is better just in case but weight is also a factor why not use aluminum wire in place of copper. just a thought there is probably a good reason not to such as the problem's with heat expansion and loosening of terminal connections. but just a thought. thanks for any info along these line's. Duke


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## DavidDymaxion (Dec 1, 2008)

Here's a couple of additional thoughts: 4/0 is about 1 lb/foot, and 2/0 about 0.5 lb/foot -- so the weight difference is about 20 pounds. It seems there are many folks that have melted posts off of batteries. I figured the bigger cable would act as a heat sink and help keep the battery posts cool.

I like how Mike Willmon has little heat sinks for all his battery posts on the Crazy Horse Pinto.


major said:


> ... I think often DIYers oversize cables. They try to size to max amps, and that is really not needed. Oversize cable does not hurt the electric circuit, in fact it helps by having less resistance and therefore less wasted energy, but this is typically a very small value. Oversize cables do hurt your pocketbook, vehicle mass and ease of routing. But that is all part of the glory of the DIY EV experience.  ...


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## major (Apr 4, 2008)

lockduke said:


> why not use aluminum wire in place of copper.


Hi duke,

I know we've covered this a number of times. Use the search feature to find previous discussion on aluminum cable. In short, it will work, but is more trouble than it is worth. Aluminum is tough to work with (stiffer) and, if you can find them, terminations (lugs and clamps) are expensive and troublesome. Aluminum corrodes immediately upon contact with air and the corrosion is nonconductive. Special measures need be used. Aluminum work hardens and will fatigue with vibration.

Have you seen any of the major players (GM, Nissan, Toyota, etc) using aluminum wire? Wonder why 

Regards,

major


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