Do Bigger Wires Mean Better Performance?

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mikejuv
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Do Bigger Wires Mean Better Performance?

I have a Z20, and would like to know if there are any benefits to increasing the size of wiring used for the batteries or other components. I went through previous posts and came away with conflicting answers.

Is there a performance improvement if I go from 8AWG to 6AWG? I still have to wire the bike for bank charing and install the PakTracker - so it would make sense to upgrade the wiring at the same time. Is it worth the extra effort?

My Z20A came with 8 gauge stranded wire, they don't use solid lugs but flimsier ring type connectors. I haven't ridden the bike yet, so I don't know if the wires get warm.

If a wiring upgrade is recommended here are a couple follow-up questions:
- What gauge wire is recommended?
- Does using a cheap ring connector versus a real lug matter [copper ($2/pair) or tin plated copper ($6/pair)]?
- Do all wires between batteries need to be the same length to keep resistance equal between batteries?
- Do the wires going to the controller and motor also have to be upgraded to see a performance gain?

Since the bike is new and folks are finding flaws in other areas of wiring configuration, here is my attempt at providing a representation of the Z20a's battery wiring scheme. I've seen references that say even the wiring configuration matters to equally load the batteries, so confirmation that it was correctly done at the factory would be reassuring.

Battery View (Z20A)
Z20_BatteryConfig01.jpg

Battery Config - Side View
BattConfigDraw_SideView.jpg

Battery Connection Config
BattConfigDraw_TopView.jpg

astar
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Re: Do Bigger Wires Mean Better Performance?

The reference you site is for batteries in parallel, and will produce 12 volts. They do it this way to increase the potential amperage. The batteries on the Z20, and most scooters, are in series. This means you add the voltages together for 60v on the Z. Your batteries are wired the same way mine are. However, they are normally numbered from the minus side of the string to the plus side; your numberings are based on the battery position. It should be:

1 5
2
4 3

Sorry, my diagram is not as pretty as yours. :)

I'm not an expert here, but I would upgrade the wiring where it's easy to do. For me this meant the battery wires, including to the breaker (positive side) and to the terminal block (negative side. Replacing the wires into the controller would be close to impossible since the case is made to be opened. Ditto on the motor wires. So I left the motor and controller wires as is, and did the rest. My thinking is that you are still removing resistance from the system. The "bottleneck" is most likely moved into other wires, and/or the motor/controller. The controller is . . . ummmm . . . undersized, so that's probably where the real bottle neck is. So is it worth the effort? Not sure. If I had it to do over again, I would just buy some #6 wire and connectors from EV source. They have everything you need, including new boots to go over the connectors. Trying to round up all that from auto parts stores and Home Depot, etc. is difficult or impossible. I would use AWG 6 or even AWG 4, but you should know that AWG 4 will no go through the PakTrakr current sensor.

ZEV 7100 Alpine
Fort Collins, CO

jdh2550_1
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Re: Do Bigger Wires Mean Better Performance?

If you're going to replace the wire then you need to do the complete "high power" circuit for it to have any affect on performance. That means all the wiring between the batteries and from the battery to controller and the wires from the controller to the motor. One of those circuits must also contain the breaker and thus would be rewired.

Note that if you do go to AWG 4 then PakTrakr sell a bus bar that you can put through your current sensor. http://www.paktrakr.com/Shopping.html

John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.

pchilds
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Re: Do Bigger Wires Mean Better Performance?

If you're going to replace the wire then you need to do the complete "high power" circuit for it to have any affect on performance.

The facts disagree with this, anywhere you can lower the resistance will help. Using better connectors, fewer connections or bigger wire will all help. If you have 12 feet of #10 at 60 amps, has a voltage drop of .732 volts and .0122 ohms of resistance. If you have 10 feet of #6 and 2 feet of #10 you will have a voltage drop of .36 volts and .006 ohms of resistance. You will have cut the wire voltage drop in half.

Philip

Philip
2011 Nissan Leaf SL

chas_stevenson
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Re: Do Bigger Wires Mean Better Performance?

Philip,

You are correct when it comes to theory, however I am answering from experience on this one. I had an EV which used everything from a 14 to 10 gage wire. I replaced all of the smaller power wires, about 8 feet, with 8 gage and it made only a minor difference. I then replaced the remaining wires, about 3 feet, with the same 8 gage wire. I could then feel the difference in both acceleration and hill pulling power. I think I would replace all of the main power wires.

IMO,
Chas S.

pchilds
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Re: Do Bigger Wires Mean Better Performance?

You probable had a bad crimp or other high resistance connection in that 3 foot of wire, just my guess.

Philip, Z20bs owner.

Philip
2011 Nissan Leaf SL

jdh2550_1
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Re: Do Bigger Wires Mean Better Performance?

OK, change "have any affect" to "have most affect". I thought that the performance would be determined by the smallest wire in the circuit - but you're right it's additive.

However, if you're going to go to the effort of replacing the wires then why would you leave a couple of "weak links" in place? Of course, feel free to do half the job and get half the results (or less).

John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.

astar
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Re: Do Bigger Wires Mean Better Performance?

Note that if you do go to AWG 4 then PakTrakr sell a bus bar that you can put through your current sensor.

Yes, I thought about using the bus bar. But I don't like the idea of a bare 60v bar, and it means 2 more lug connections. And is the bar just rattling around? Maybe if you could put heat shrink tubing around the whole thing while it's through the sensor. Using a bus bar in an EV car may be OK if protected from the weather, but on the scooter? Not something I would want to try. I have two paralleled 8's though there on mine.

Replacing the wires into the controller would be close to impossible since the case is made to be opened.

Typo - case and motor are NOT made to be opened. So I think on a ZR20, it means replacing the motor and controller if you want the bigger wires throughout. The controller should be replaced anyway for other reasons. Not sure about the motor yet.

So much to replace, so little (riding) time! :(

ZEV 7100 Alpine
Fort Collins, CO

chas_stevenson
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Re: Do Bigger Wires Mean Better Performance?

Philip,

Good point, there were some crimp connections on the bike but now there are NON. I don't believe in using them, I solder all my connections then cover with shrink wrap. The only connector on the bike, in the main power wires, is an Anderson Power Pole (Sermos) connector that allows me to remove the battery pack for charging. I even removed the motor connector and connected the wires directly to the controller.

sermos_connector.gif
Anderson Power Pole

Chas S.

andrew
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Re: Do Bigger Wires Mean Better Performance?

mikejuv,
I think the increase in performance will be marginal. But, from the looks of it, there are some poor quality points in the wiring system. Such as insufficient terminal ring connectors. I'd suggest pulling hard on all the crimped connectors to make sure the crimp is good, than replacing the terminal ring connectors that are bent over, or look like they will fatigue crack in time due to vibration.

Overall, I think what's most important is fixing the weak points that could cause shorting and fires. All wires should be routed to be protected in a position that will not cause abrasion to the insulation. In some parts it may be good insurance or necessary to use spiral wire wrap. Definitely check the tightness of all of the connection bolts, including on the batteries. Correct for inconsistencies. It looks like some wire may be smaller than 8 AWG, and this should be replaced in the high-power circuit.

Other than that, I wouldn't strain yourself to do a complete wire overhaul unless you are really eager to do it. Take a look at my 900 watt scooter wiring. That handles 140 amps, albeit for a very short period.

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri

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