Page 1 of 2
Thin main feed from battery
Posted: Sun Dec 29, 2019 5:47 pm
by Gunnar
Hi all! I ride a Classic 2010 (EFI). Has anyone had any thoughts about the main feeder cable from battery to the fuse box? The cable from the battery to the starter relay is reasonably dimensioned, but the spliced cable that goes from the relay and is the main feed for the complete bike is ridiculously thin (in my opinion). On the other hand, it is only max 20 cm long, so in theory it can perhaps still manage (well, it obviously has managed so far any way). I am about redoing this part of the wiring but it would be interesting to hear your view. Any thoughts anyone?
Best regards,
Gunnar
Re: Thin main feed from battery
Posted: Sun Dec 29, 2019 10:54 pm
by stinkwheel
Modern thinwall cable seems incredibly flimsy but is rated to carry high currents. I find I have to buy cable double or more the thickness it actually needs to be in order to get the crimp terminals to grip it sufficiently.
2mm square thinwall cable is rated at at 25 amp. Roughly half the cross section of "standard" cable. A standard crimp connector will struggle to get hold of it. To put it another way, you could comfortably power 5 standard headlamp bulbs through a piece of 2mm square thinwall cable without overloading it.
Assuming that is, they used thinwall and didn't just cheap out...
Re: Thin main feed from battery
Posted: Sun Dec 29, 2019 11:04 pm
by Wheaters
On my jobs list for my 350 Bullet is to replace the battery wiring. The weak points on mine are the ring terminals to the battery terminals. These are very flimsy.
Re: Thin main feed from battery
Posted: Mon Dec 30, 2019 8:01 am
by Leon Novello
If you have a ratchet crimper, they will do the job, no matter how thin the wire.
<a href="
https://imgbb.com/"><img src="
https://i.ibb.co/tQFPhyq/untitled-png-r ... rimper.png" alt="untitled-png-ratchet-crimper" border="0"></a>
Re: Thin main feed from battery
Posted: Mon Dec 30, 2019 8:07 am
by Leon Novello
And again, with imgbb full linked SIGH!

Re: Thin main feed from battery
Posted: Mon Dec 30, 2019 8:10 am
by Boxerman
Leon Novello wrote: ↑Mon Dec 30, 2019 8:01 am
If you have a ratchet crimper, they will do the job, no matter how thin the wire
I have one of those and have experienced the same problems that Stinkwheel has.
Frank
Re: Thin main feed from battery
Posted: Mon Dec 30, 2019 9:16 am
by stinkwheel
I use a proper crimping die, and it will grip 2mm sq cable, but only just. The thing is, I only really need 1mm sq for the wiring on a classic engine bullet without electric start (up to 16A). If you put a crimp on this, it doesn't grip the cable properly meaning you have to move to the next size smaller die to get it to grab hold and then the insulation crimp gets folded too far and tends to snap a "leg" off. That, or you land up soldering it which is not ideal on a mobile joint.
The solution is to use thicker cable than necessary or avoid thinwall but it seems inelegant and the insulation on thinwall is more resistant to UV damage.
Not so relevant to the OPs problem though. I suppose the answer is, if you aren't happy with it, change it, a thicker cable is not inappropriate, it's only going to conduct better. That notwithstanding, I bet it attaches to a ludicrously thin and flimsy wire at the other end where it goes into the ignition switch.
Re: Thin main feed from battery
Posted: Mon Dec 30, 2019 9:44 am
by Wheaters
I find it's better to fit a thicker cable where it will need to be be disturbed; just because it's physically stronger. I also prefer to solder essential joints, rather than just crimping them (or even do both).

Re: Thin main feed from battery
Posted: Mon Dec 30, 2019 12:04 pm
by Gunnar
Hi and thank you for your comments. What made me look into this in the first place was in fact the ring terminals for the battery. I have two "add-ons" on my bike: a fixed installed charging connector for a Ctek charger and a separate feed for two extra lights that are driven via a relay placed in the fuse box. This means that I have three wires with ring terminals on each that are attached to the battery pluspole. Not good, since the area is very tight and the battery cable is something you might want to disconnect for different purposes every now and then. What I want is to have one robust ring terminal that attaches to the battery and connect my two "add-ons" to either a splice on the battery cable or to splices inside the fuse box. The ideal solution would be to use the empty extra fuses that are available in the fuse box for the charger resp the extra lights.
I then realized two things: first, the cable shoe for the battery terminal is impossible to find as spare anywhere and second, the cables are molded where they enter the starter relay. In other words: difficult to replace. I am considering replacing the starter relay with the older variant with bolt on terminals but haven´t decided that yet. With that arrangement I could do my own standard, industrial grade battery cable from the battery to the relay and then feed the fuse box from the relay with whatever cable arrangement I choose. The drawback with this would possibly be that the two bolted terminals on the relay need to be protected against shortcut. Some kind of plastic hood perhaps?
Re: Thin main feed from battery
Posted: Mon Dec 30, 2019 4:25 pm
by stinkwheel
I put a relay controlled accessory fuse-box on the wifes CBR600 recently. Takes a single feed from the battery and uses a branch of the rear brake switch as a switched live to trigger the relay. It has slots for 3 fuses. One for her heated grips, one for her heated vest and one for a USB socket.
https://www.vehiclewiringproducts.co.uk ... lay-socket