What is the thickest gauge wire used on ebikes ?
- Thread starter rumme
- Start date
MadRhino
100 GW
I use 8 ga silicon and keep the wiring as short as possible. Big Anderson silver connectors are crimped, with some solder added to keep water off the cup. I am at the very limit for 8 ga. Many who are feeding the same power are using bigger wiring.
Alan B
100 GW
I've used 6, 8 gauge and pairs of 12 gauge (equivalent to 9 gauge).
Those connections are generally crimped.
I don't generally solder anything heavier than 10 gauge.
8 gauge is rated for 73 amps in open air, best to not exceed chassis wiring ratings and even those are going to get warm.
Those connections are generally crimped.
I don't generally solder anything heavier than 10 gauge.
8 gauge is rated for 73 amps in open air, best to not exceed chassis wiring ratings and even those are going to get warm.
MadRhino
100 GW
Bursts of 150A between my 24s battery and the controller, 24" of 8 ga Turnigy silicon wire.
Bursts of 250A between the controller and motor phases, 28" of the same wire. All wiring is in full air flow.
The wires are hot sometimes, but nothing alarming. I find that bigger than 8 ga, the wiring is getting heavy and I always try to find a fair compromise to save weight.
Genuine Anderson connectors are available locally here. I never had to order some. Chinese copies of Anderson connectors are sh*t, buy the originals, and a crimper for them.
Bursts of 250A between the controller and motor phases, 28" of the same wire. All wiring is in full air flow.
The wires are hot sometimes, but nothing alarming. I find that bigger than 8 ga, the wiring is getting heavy and I always try to find a fair compromise to save weight.
Genuine Anderson connectors are available locally here. I never had to order some. Chinese copies of Anderson connectors are sh*t, buy the originals, and a crimper for them.
liveforphysics
100 TW
My motors phase leads are 00awg to the controller, and battery leads are 0awg (battery side has a much lower average current than phase side).
If there's a place that does UPS (battery backup) or powerchair repair / service near you, they may have a graveyard of dead units. Some of these use some pretty big SB-series connectors. The smallest in the pic below is the SB50 (60A rated). The stack in teh background is a bunch of old 33rpm vinyl records, if you need scale.rumme said:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=67956&p=1024700&hilit=sb50#p1024700
Harvest them with their wires intact and you might get them long enough to use as-is. If not, you can either splice into the existing wires, or get new contacts from Anderson.
Be careful of cheap clones, as the plastic housings may not be made of as good a plastic, and warp under heat, causing contact problems. The springs may not be sufficient force either, and may cause contact problems, which cause higher resistance, which causes heat, which causes other contact problems. The contacts themselves might also not be the same quality, but so far I don't recall any problems with actual contacts without first having had housing or spring problems.
liveforphysics
100 TW
rumme said:
28s, 750amp battery current today..
Lets say you have a certain length of 8 gauge wire and 12 gauge wire and are running a setup of around 50 amps continuous - 80 amp bursts.
Is it best to use the thicker gauge wire :
from the battery to the controller
or
to the controller to the phase wires.
Also, is it best to have a shorter length of wire :
from the battery to the controller
or
from the controller to the phase wires
Is it best to use the thicker gauge wire :
from the battery to the controller
or
to the controller to the phase wires.
Also, is it best to have a shorter length of wire :
from the battery to the controller
or
from the controller to the phase wires
Alan B
100 GW
Heavier motor wires.
Shorter battery to controller wires.
Shorter battery to controller wires.
liveforphysics
100 TW
Alan B said:
+1
MadRhino
100 GW
I use the PP75 Andersons, and I buy them matching colors. Red and black for power. Blue, green, yellow for phases. Just to make sure that kids working for me, don't do stupid things with current when they play with one of my bikes.
I'd say most people use 8-12awg for the higher power wire. That's what I use.
I then also try and use connectors that are either sealed, or are easy to pack with dielectric grease and won't wash out easily. Thats why I like to use bullet connectors, they are also easy to use. Just strip 2-3mm off the end of the wire, tin it (coat in solder), then build up a pool of solder in the cup of the connector, put'em together and let it cool.
Battery to Controller, I use anti-spark connectors like the 7mm AS150 that hobbyking sells.
I then also try and use connectors that are either sealed, or are easy to pack with dielectric grease and won't wash out easily. Thats why I like to use bullet connectors, they are also easy to use. Just strip 2-3mm off the end of the wire, tin it (coat in solder), then build up a pool of solder in the cup of the connector, put'em together and let it cool.
Battery to Controller, I use anti-spark connectors like the 7mm AS150 that hobbyking sells.
liveforphysics
100 TW
atarijedi said:
If you want to leverage the real burst ampacity of the wiring, solder is just not a very good electrical conductor to have in your current path, so heat production is peaked through the soldered area, and the solder melts.
For things you want to hit with big currents, only non-insultated crimp farrels crushed by a tool that can actually cold flow the copper into a continuous path of copper from the wire strands to the terminal in a way that your joints become cold places on a FLIR vs being warm places (if soldered or crimped poorly).
billvon said:
Interesting.
Can you give a link to the connectors/ crimper you use/recommend for attaching connectors to the wire without solder ? Since most people wont be using this method much, is there a inexpensive kit/ setup to do this procedure with 8-12 gauge wire ?
Chalo
100 TW
liveforphysics said:
If seen this advice before. Please explain why having long phase leads is better than having long battery leads, if you get to choose one or the other?
Given that many here use underengineered Chinesium hub motors with flatted axles and through-the-axle wiring, motor leads often can't get much thicker. That's a point in favor of low kV motors-- same torque from less current, so less bottleneck at the motor phase leads.
liveforphysics
100 TW
Chalo said:
That's a great question. The battery itself, by its own current collection foil arrangement happens to be a really amazing capacitor just by virtue of its construction materials and geometry, unrelated to it also having some chemistry on its surfaces making a voltage. Inside your controller are some caps, but they are generally pretty wimpy, and the more ripple current they experience, the more they heat, the more they wear out and climb in impedance (unless they are film caps) and eventually caps become a failure themselves or induce a downstream failure of FETs or control problems from ground references in gate drive circuits bouncing to levels that trigger shoot-through (this is an increasing risk as power levels increase).
The DC input side of any controller connected to the very low ESR/ESL cap bank that happens to be in the battery if it's used or not, enables the controller to survive harsher environments thermally, age better, and for hot rodders pushing the limits it buys voltage stability margin to be as close to the battery as possible.
If the controller happens to be loaded up with an abundance of good film caps and it uses all floating differential based gate drive, you can stick the controller about anywhere and it will only effect efficiency and the controllers run temps slightly. However, most ebike stuff is about as crude as RC stuff and may or may not have meaningful margins left in parts and cheap electrolytic caps are the standard.
liveforphysics said:
I agree that crimping is better for large wires, but I'm only using 8awg or 10awg. Isn't worth it to buy all that stuff for crimping for a single build, versus getting some good 6% silver solder. My burst is really only around 120A from the battery. I've never had heating issues with the wires.
liveforphysics
100 TW
atarijedi said:
Even solder that is 50% silver still conducts like crap vs just copper. If it's big enough cross section for your magnitude of current and duration of current than solder works fine (like RC models). If you have an application with high continuous currents solder becomes more of an issue.
speedmd
10 MW
50% silver is brazing alloy! You are not going to melt it with a dinky iron. Whole other creature my friend. Agree, that a tight mechanical grip (even with common vise, pliers or drift punch) then solder to keep hermetic is a much better setup for any reliable long term high current low resistance connection.
speedmd said:
Very interesting....so everyone agrees, that if you take a connector like a XT-90 and can attach it to the copper wire using a vice/ crimper , under high pressure, that is better then using solder to attach the connector ? Why is solder such a poor conductor but yet the most common method for connecting copper wires and connectors ?
