StromTrooper banner

1 - 10 of 10 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #1
Got a power connector for satnav on my 1000. Connected this to the battery, plugged in the satnav unit and, after an initial switch-on of the unit, the whole thing cut out - bike and power to satnav. Satnav is working ok, so thats not knackered thankfully. When I turn on the power, I get nothing, not even the sweep of the dials. And my alarm isnt working now. Checked across the battery terminals and its showing 12v, so thats not knackered. Unfortunately I cant get my fat fingers in to check all the fuses, and cant find suitable pliers for the job so Ive called out the breakdown guys and not admitting to any connector ( I have a comms box attached but this has worked trouble free for the whole time Ive had it, about 2 months).

My question is this. Once I get the bike up and running normally, what can I do to stop this happening again. The connector has a 15a fuse in-line, and is designed for motorbike use. Do I need to put a higher rated fuse somewhere in the fuse box. Or any other advice. Anythin g at all please. Thanks in advance.
 

·
FORUM GODFATHER.....R.I.P. PAT
Joined
·
38,047 Posts
The fuse is there to protect the wiring from going up in smoke. Never replace a fuse with a higher rated one. It can cause a fire. Find the fuse that blew and check the circuits it protects to find out why it blew. When you find out why it blew, fix that.
 

·
Registered
Joined
·
11 Posts
Discussion Starter #3
Sorry, now I re-read it, Ive not worded it very well. What I meant to say, basically, is if anyone has any ideas why it happened. And how I can resolve it. Thanks for the reply anyway.
 

·
Premium Member
Joined
·
3,722 Posts
This is one of the main reasons I much prefer wiring all ancillary devices through a fuse block. If something like this happens you can disconnect the fuse block and go back to "Stock" very easily.

Follow Greywolf's advice. Troubleshooting circuits is usually a trial and error method. I would find and replace the blown fuse, then disconnect everything from the battery except the primary battery cables. If everything works then the problem is in one of your extra device circuits. If not it's something in the factory wiring. Assuming that things work, reconnect your extra devices one at a time and see which one causes the problem, and then hunt through that circuit.

Don't forget the alarm. They are normally tied into several circuits.
 

·
Registered
Joined
·
147 Posts
what size fuses?

what is the rule of thumb for the fuses one would use for certain electronics? I'm not sure how to go about figuring that out.
I wired up my zumo's power cable, and it has an inline 2A fuse in it...
I'm trying to decide which amp of fuses to use in my fuse block though. I have 2 12v outlets and the gps going into the fuseblock, and I also put an inline fuse between the fuseblock and battery, but I'm not sure what size fuses to use.
Can anyone point me in the right direction?
 

·
Premium Member
Joined
·
3,722 Posts
Circuit load, wire size, and fuse ampacity should all be considered. The wire has to be large enough to carry the load of the circuit. The fuse has to be size so that it can carry the ampacity of the wire but not much more. The rule of thumb is 125%. The wire should be sized to cary 125% of the circuit load. The fuse should be chosen based on 125% of the maximum ampacity of the wire, rounded down to the closest standard value.

This table shows the maximum ampacities of standard wire gauges. Use the column for "Free Air" since for this type of wiring the conductors aren't enclosed in a raceway (conduit).

Example: If a circuit load is 5 amps the minimum wire size would be #22, and the maximum ampacity of #22 is 7.0 amps. 7 x 1.25 = 8.75 amps for the fuse. Rounded down to the nearest standard value = 7.5 amp fuse. This way the wire will easily carry the circuit load and the fuse will carry the maximum load that the wire can handle.

Edit ... Forgot to mention that I don't like to use wire smaller than #22. It tends to break or get cut easily, and larger wire is easier to work with. I prefer #18 for most things that are low current.
 

·
Registered
Joined
·
147 Posts
so for something like a 12v outlet that comes with 16awg wire already installed:
22*1.25=27.5, so I'd use a 25A fuse?

I used 10awg wire to wire the fuseblock to the battery:
55*1.25= 68.75, so I'd use ?

this is confusing :???:
 

·
Premium Member
Joined
·
3,722 Posts
so for something like a 12v outlet that comes with 16awg wire already installed:
22*1.25=27.5, so I'd use a 25A fuse?

I used 10awg wire to wire the fuseblock to the battery:
55*1.25= 68.75, so I'd use ?

this is confusing :???:
Yep, that's about right. Most of the 12v outlets are rated at either 20 or 30 amps. It should be molded on it somewhere or in the instructions that came with it.

For the #10 coming from your fuse block I'd probably total up the loads that it's carrying and see if they are lower. If so just fuse it based on the loads. In most cases a 30 amp fuse is sufficient because most of the terminals and other wiring devices are limited to 30 amps or so.

If it's a Blue Seas fuse block I think they are rated at 60 amps or so. For what we usually put on them it would be hard to get that kind of load without sucking the battery dry in a hurry. I wired mine with #10 as well and used a 30 amp main fuse. Haven't had any problems so far.
 

·
Premium Member
Joined
·
3,722 Posts
yes I'm using a bluesea fuseblock as well.
cool, at least I have a formula to go by now. I'm just worried about
reducing my beautiful bike to a pile of ashes.
Thanks a ton for the help.
That's what fuses are meant to prevent. The reason for overcurrent protection is that excess current generates a lot of heat. The formula for power is: Watts = Current (in amps) x Volts. If you use a large fuse with a small wire the wire can get hot enough to melt the insulation before the fuse lets go (been there, done that!).

It isn't uncommon to use larger wire than necessary on circuits and then use a smaller fuse that is rated for the circuit load. For example, if you have a 1 amp GPS you can use something like #18 and fuse it at 2 amps. The important thing is not to use a wire size that is too small for the circuit's current. That comes into play a lot with lighting circuits and circuits for heated gear.

Automotive circuits do that a lot. Seldom do you see anything smaller than #18 on a car electrical circuit. It's just more cost effective for them to use the same wire gauge for everything rather than having to stock all different sizes of wire.
 
1 - 10 of 10 Posts
Top