# 2/0 vs 4/0 effects on range



## F16bmathis (Jun 6, 2008)

I have a 144V, Warp 9, Curtis 1231C Chevy S10. It gets 15 miles if I coast alot. My last truck had 4/0 cables, this one has 2/0 all around. The weather is warming up, but the range is still limited, to the point that when I had my Zilla installed, I removed it and went back to the Curtis, thinking the Zilla was pulling too much. I also changed rear end gears from 3.73 to 3.08. Now I get a severe vibration when accelerating above 40mph. I'm going back to the Zilla, and ordered 4/0 cable and lugs for the whole thing. I may even throw the 3.73 back in till I figure out what the vibration is all about...

I did feel one of the main 144V cables going to the front was warmer than the rest of the battery cables, thats where I've decided to go with 4/0.

Any other ideas?

www.evalbum.com/1752


----------



## Zemmo (Sep 13, 2007)

I've got 4/0 on my Fiero and I haven't ever had any warm wires. I have been told that it was overkill but it can't hurt! I also have the LPT (Low Profile Terminals, the bolt terminal you have) on my Trojans and I actually like those. Easy to torque down to the right specs and easy to hookup.


----------



## F16bmathis (Jun 6, 2008)

I'm going to drive it around some and see if I can find more wires that warm up. 

I also made a water heat sink for the Curtis out of aluminum. I'm waiting for the water pump to show up.


----------



## peggus (Feb 18, 2008)

2/0 = 0.077 Ohms/1000 ft
4/0 = 0.050 Ohms/1000 ft

Presuming wiring lenth to be 20ft:
resistance for 2/0 = 1.54mOhms
resistance for 4/0 = 1mOhms

Cruising at 100 amp the cabling losses are I^2*R
15.4W & 10W respectively out of 14.4kW, or 0.1% & 0.069%

So changing from 2/0 to 4/0 will gain you 0.031% more range.

Your problem is most likely elsewhere. Check your alignment and brake drag for starters. Are you sure you're charging you're batteries properly?

The zilla doesn't draw more juice than the curtis unless you're flooring it. The Zilla is actually more efficient than the curtis.


----------



## rfengineers (Jun 2, 2008)

F16bmathis said:


> I have a 144V, Warp 9, Curtis 1231C Chevy S10. It gets 15 miles if I coast alot. My last truck had 4/0 cables, this one has 2/0 all around. The weather is warming up, but the range is still limited, to the point that when I had my Zilla installed, I removed it and went back to the Curtis, thinking the Zilla was pulling too much. I also changed rear end gears from 3.73 to 3.08. Now I get a severe vibration when accelerating above 40mph. I'm going back to the Zilla, and ordered 4/0 cable and lugs for the whole thing. I may even throw the 3.73 back in till I figure out what the vibration is all about...
> 
> I did feel one of the main 144V cables going to the front was warmer than the rest of the battery cables, thats where I've decided to go with 4/0.
> 
> ...


I agree with Peggus, you have a problem elsewhere. Your T-105s should be giving you about 20kWhr of usable power, so 15 miles of range means you are averaging 1300 Whr per mile! That's way too much.

Can you do a rolling resistance test? find a straight, flat stretch of road where you can get up to 40 or 50 mph and then time yourself as you coast down to 15 or 20 mph. Do two or three passes in each direction. THEN repeat the test in your other S10 and see how they compare.

Joe


----------



## F16bmathis (Jun 6, 2008)

I did take it for a ride last night. Checked wires for heat and found one of the controllers cables going to the motor warm. The rest were cold. So maybe just size that one up. A 2/0 cable that gets warm means something. Might look at motor resistance.

The Zilla is going back in.

The rolling of the truck appears to be the same as the last truck. The last truck was sold. I have hills and can coast 0.3 miles before even using any juice.

Charging of batteries... Maybe..., When I got the Manzanita it said to have the batteries fully charged, but I had used them allready. I charge it based on my last truck where a fully charged battery read 6.47- 6.50V. Also, one of my batteries I wasn't using this winter froze a cell and it expended the side of the case. I turned it in for a new one, but I wonder...If they can mess up one cell in one battery by not adding acid???, can they have not added enough acid to all the other batteries? So I bought a "acid thingy" (gravity) tester and tested it after a drive, it was low, have not tested it with batteries full yet.


----------



## peggus (Feb 18, 2008)

If it's just one cable it is likely that that one cable has bad crimps or corroded lugs. All the cables in the motor loop sees the same current and so should be equally warm. The same applies for the battery loop.

That said, the motor wiring sees much higher current during takeoff than the battery wiring so there's more benefit to upsizing the motor loop wiring to 4/0.

Is 6.5V your end of charge voltage or resting voltage?


----------



## F16bmathis (Jun 6, 2008)

All the wires being the same temperature on the motor loop makes sense. I didn't really check all the cables, just found one, and with the rain, didn't want to get on the ground and get wet.

I found the batteries were only being charged to 6.25V instead of 6.5, so I did a equalization charge and reset the charger. I'll check it tomorrow. Also, I did get 22 miles yeserday, and could have gone a little further, but it was starting to go below 126V if I really got on it.

I'm still going with 4/0 all around, allready order cable and lugs.


----------

