Electrical advice sought... - Kawasaki KLR 650 Forum
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

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post #1 of 29 Old 04-24-2011, 03:01 AM Thread Starter
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Electrical advice sought...

I just mounted the rack I built for the trip I'm leaving for on Wednesday. When I bought the bike it came with an extra set of rear turn signals, so I decided to add them as running lights. I wired them into the license plate light so they would be on whenever the ignition is on.

Long story short, I blew the 10amp fuse during wiring (my own fault for shorting the wire while figuring out what went where). I had a 7.5 and a 15 amp fuse handy, so I put the 7.5 in first. Wired everything up and it worked fine. So, I put everything back together and moved on to the next project: heated grips.

The heated grips project was nearly done when the switch I'd bought for the task fell off the bike and broke. I finished the wiring and left everything done up to the switch which I will replace tomorrow.

Problem: After I'd cleaned up and put all of the tools away, I started the bike up to drive it home and had no lights at all. I checked the fuse I'd replaced with a 7.5 amp (which had worked fine earlier) and found it blown. Weird, but not improbable, I thought. So, I stuck the 15 amp in there, but it also blew the moment I turned the key. I'm thinking that when I finalized the wiring for the rear lights after testing them, and tucked everything away, I must have created a new short. Any other possibilities?

Also, as far as the heated grips, I took power for them from the horn. My wiring diagram shows the horn as a separate fuse (although, I can't find it), so I thought it would be a good place to draw power from. It works, but is there any reason I should be concerned? It seemed too easy. Do I need a relay? (what is a relay?)

I'm totally electrically un-savvy, but I'm trying to not let it intimidate me. I'd appreciate any advice written with the assumption that I don't know anything (which isn't far from the truth).

Also, my fuses were not where the manual said they should be. They are spade-type fuses, and they are located on the port side of the bike behind a plastic cover that also covers what looks to be the engine cut-off switch for when the kickstand is down. The book told me they would be under the seat. The book appears to have lied. Is this an aftermarket addition?

Thanks!
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post #2 of 29 Old 04-24-2011, 07:41 AM
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Spade fuses would have been a modification that a previous owner would have done.

A relay is an electrically controlled switch that uses a small amount of current to control a larger amount of current.

Fuses are installed to protect the wiring from the heat that would be created by higher amounts of current flow than the wiring is capable of safely carrying.

Adding additional circuits to existing circuits will increase the amount of current flowing through the fuse for that circuit. A small increase, such as the amount of current needed to operate the control coil of a relay, is usually not an issue. Adding a significant current load to the circuit can cause issues.

In general, it is a bad idea to replace a fuse with another fuse of a higher current rating, as the fuse protects the wiring, not the components of the circuit. A reasonable exception to the rule would be to replace the 15A headlamp fuse with a 20A fuse, as the KLR headlight switch has a tendency to momentarily burn both filiments in the bulb during switching from low to high / high to low which can cause the 15A fuse to fail on a regular basis.

A "short" is a term used to describe an electrical circuit fault where the path of current flow by-passes the electrical load (component) with the result being an over-current condition within the circuit resulting in a failed fuse and/or melted wiring.

Adding excessive current demand to an existing circuit can, and often does, result in fuse failure due to the higher amount of current, a 'fault' has been created, but it is not a "short".

Either your wiring modification has created a "short" - bare wiring contacting ground or inadvertantly by-passing a load, or your modification has increased the demand placed on the circuit for what that circuit's fuse (and wiring) was designed to carry.

As an example, a bulb rated for 35W @ 12V would have a current demand of 2.9Amps at 12 volts. Two bulbs connected in parallel (an example like your turn-signal / running light modification, although the rating of your turn signal bulbs is not what I am arbitrarily using in my example here) would then increase the current load to 5.8A at 12 Volts. Increase the voltage with the engine running to say, 13.6Volts, and your circuit draw will increase to 6.57A.

Pretty safe to say that a circuit protected by a 15A fuse, that most likely protects a circuit that normally flows 7 to 8 Amps is going to have an issue when you add another nearly 7 amps to the mix. It is also necessary to understand that with bulbs, the initial amount of current that flows the instant before the bulb filiments begin to 'burn' will be a significantly higher amount of current flow than what flows once the resistive effect of hot filiments takes over and reduces the current flow to normal operating levels.

It's your motor, and your money. I would not discourage you from learning how, and why electrical circuits behave the way that they do. However, if you want to learn those lessons empirically on your own vehicle, the most important piece of knowege I could pass on to you is that: electricity flows faster that you can say "Oh Shit!".

"If you simply take up the attitude of defending a mistake, there will be no hope of improvement."
Winston Churchill

http://www.ridingwv.com/ (not my site)

Quote:
Originally Posted by Lockjaw View Post
Oh, and I ran two quarts of hot oil through before filling her up cause I'm anal.

Last edited by Some Mook; 04-24-2011 at 07:58 AM.
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post #3 of 29 Old 04-24-2011, 07:49 AM
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If you are blowing the fuse that quickly, you either have a short to ground which is an infinite load in theory, or you have something else pulling a very large amount of current. Disconnect the battery. Take an ohmmeter and hook the ground side to the negative battery connector that is on the bike. (not the neg terminal on the batt) touch the meter's positive probe to the fuse lug on the load side. The meter should be set on the Rx1000 scale. I would bet the meter shows very low resistance. Trace the wire and disconnect the newest connection first. Then hook the meter up as before. Disconnect stuff until the meter shows very high to infinite resistance. (OL) There are other ways to do this type of tracing, and I am sure there are those who will tell you differently. My first instinct is that you either have a pinched wire shorting to ground, or the one of last things you hooked up has a direct short to ground.
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post #4 of 29 Old 04-24-2011, 08:50 AM
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Quote:
Originally Posted by efigalaxie View Post
...a short to ground which is an infinite load in theory..... I am sure there are those who will tell you differently.....
A short to ground is no load at all....

Perhaps you meant to indicate that a short to ground would allow a theoretically unlimited flow of current?

Another method of testing for a "short" would be to place a 12V test lamp in place of the fuse and turn the ignition switch 'ON'. A "dead" short will illuminate the test lamp, then it is just a matter of wiggling wires or disconnecting legs of the circuit until the test lamp ceases to be illuminated to isolate the faulted portion of the circuit.

"If you simply take up the attitude of defending a mistake, there will be no hope of improvement."
Winston Churchill

http://www.ridingwv.com/ (not my site)

Quote:
Originally Posted by Lockjaw View Post
Oh, and I ran two quarts of hot oil through before filling her up cause I'm anal.
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post #5 of 29 Old 04-24-2011, 10:17 AM Thread Starter
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WOW! Thanks for all of the input!

Some Mook, I couldn't have asked for a more intelligible explanation of the basics of 12 volt electrical systems.

I am on my way out the door at the moment, but when I get a chance later I'll get back to work on the bike and let y'all know how it turned out. I feel like I have a much better understanding of what to look for now, and how to solve the problem.

Quick additional question: if it turns out that I am indeed attempting to draw too many Amps with the additional lights on the one system, and the heated grips on the other system, would a solution be to wire them each directly to the battery and instal a relay to keep them from being left on while the ignition is off?
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post #6 of 29 Old 04-24-2011, 11:13 AM
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Installing 30A relays whereby the high-load carrying wires are directly connected to the battery terminals (sufficient sized fuses installed close to the positive battery terminal connections of course) would be one method of providing your accessory load power. Up near the front fairing / front turn signal wiring you will notice some unused factory leads that are for European spec bikes (city lights / front marker lights) that would provide you an ignition switched 12v source to operate the coil side (low current) of the relays.

There are also after-market fuse block power source options available as well.

6 of one, half dozen of the other. What you save in cost one way, you lose in complexity of installation the other.

Wiring in your own relays is low cost, but the wiring can be a little messier to deal with, especially if you are not able to secure dedicated relay harness connectors, and choose to use female spade terminals to attach your wiring to the relays.

"If you simply take up the attitude of defending a mistake, there will be no hope of improvement."
Winston Churchill

http://www.ridingwv.com/ (not my site)

Quote:
Originally Posted by Lockjaw View Post
Oh, and I ran two quarts of hot oil through before filling her up cause I'm anal.

Last edited by Some Mook; 04-26-2011 at 12:52 PM. Reason: spelling like a third grader
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post #7 of 29 Old 04-24-2011, 02:21 PM
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For cheap relays and sockets, go to a salvage yard. Tell them that you would like to scavenge relays and sockets and wire from some vehicles they are ready to crush. Negotiate a 10 or 20 buck deal. Get a bunch of wire, relays, and sockets.

Yes Mook, I meant infinite current flow. My bad.
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post #8 of 29 Old 04-24-2011, 03:48 PM Thread Starter
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I think I'm going to have to tackle my fear and ignorance of 12 volt systems head on. I want to have the knowledge and confidence that you both have about the issue because it bothers me that something on my bike is so overwhelming to me. Maybe I'll find a book on the subject to take with me on my trip.

This morning I had to disconnect my new lights and put a new 10A fuse in to get the lights on for a ride to Easter brunch. I just don't understand how/why when I first wired it all together yesterday, all of the lights worked fine with a 7.5A fuse, and then when I went to leave, the circuit was blowing 15A fuses.

I did notice three spare leads with female connectors on the left side behind the tach. They were all hot though, even without the ignition on, so I didn't want to use them.
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post #9 of 29 Old 04-24-2011, 04:12 PM
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Do you know plumbing? Many water analogies can be applied to electricity. I suggest looking online before buying a book. Yes, online info can be bad, but so can a book. The book I was teaching from this year was a joke. My students and I laughed because we did not go a single week without finding an error in the book.

You are going to want to know about basic electricity. Unless you are getting in to the alternator, you are good concentrating on DC. Let's head off the alternator part. The alternator produces AC, the rectifier changes it to DC, the regulator maintains the amplitude (voltage) at a narrow range. (otherwise, you will see voltage fluctuations that would be unhealthy for 12v stuff. IE: bad voltage regulator in a truck I had let voltage run from 9v to 18v. The battery was ruined and stank to high heaven.) That is all you need to know about the alternator circuit...other than it's carrying capacity. Part of that capacity is used powering the ignition system, maintaining the charge of the battery, powering the lights. On a KLR there is not much extra capacity.

Electricity follows the path of least resistance.
E= I * R
E is potential in Volts. I is current in Amperes. R is resistance in ohms.
This is ohms law.

The next is the power formula.
P = E * I
P is power in Watts. E is potential in Volts. I is current in Amperes.

Via algebraic manipulation, you can get several variations. Such as P = E^2/R

Those are very basics. Now the trick is to apply it.
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post #10 of 29 Old 04-24-2011, 06:54 PM Thread Starter
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It's too bad neither of you are in the Bay Area. I'm nowhere near Virginia, nor heaven - the former literally, and the latter figuratively.

Are there any books you WOULD recommend? Ones with lots of pictures and large fonts?
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