Horn & Battery drain ?

Previously followed the thread on fitting alternative horn. Led to my fitting a very acceptably loud, budget horn. More than once it has gained the attention of myopic, cell phone idiots, so well satisfied. The fitting issue wasn't quite as dramatic as for other guys because due to the Max having a sidecar attached there was a convenient sidecar fitting.

However, following a period of fewer rides, we use another older sidecar rig for our less than reliable UK wintry, wet weather, the previously reliable battery has been draining rather rapidly. It will charge, but loses out fairly rapidly, so as the last electrical amendment was the relay controlled horn, makes me wonder if that could be the culprit.

Any ideas guys, or maybe there could be another reason Max wise that I should be aware of ?:ummm:

I have an after market horn with a relay and have had zero battery issues. It may just be a coincidence and you have a battery that is on its way out. I would disconnect the suspect relay and horn for a few days and compare the measurements. A bad relay could cause a discharge even when it is operating properly and given their low cost you could always swap it with another one. Personally I would remove the addition since that is the only way to confirm if it is the problem and would be the most logical first step in troubleshooting.

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Disconnect one of your battery leads and touch the end of the bulb to the battery post and the wire from bulb to the lead you disconnected. If you have a parasitic drain the bulb will light up. The bulb brightness is related to current draw from what ever it is draining your battery. All of this is done with the ignition off. If the bulb lights up start pulling fuses or disconnecting suspected components.


https://www.youtube.com/watch?v=HBcmoC9h07s

I had a draining battery issue this past summer. It ended up being the voltage r/r. Replaced it with a newer mosfet unit from an FZ6. End of problems, and no more hotstart scenes either

If it is only a small drain then the bulb may not show it up - better to use a multi-meter.
Set it to the highest scale and with the ignition off connect in series between the earth lead and - ve post.

If there isn't any discharge (i.e. a zero reading) then I would suspect your battery is nearing the end of its life.

If you do see a discharge then remove all of the fuses (incl. the main fuse) and check again.
Replace the main fuse first and the remaining ones until you get a reading which is the circuit that you should check.

A better test light will show small drain if you dont want to spend the money on a good volt meter or if you dont know how to use one but a good meter is the way to go.

MaxMidnight said:

If it is only a small drain then the bulb may not show it up - better to use a multi-meter.
Set it to the highest scale and with the ignition off connect in series between the earth lead and - ve post.

If there isn't any discharge (i.e. a zero reading) then I would suspect your battery is nearing the end of its life.

If you do see a discharge then remove all of the fuses (incl. the main fuse) and check again.
Replace the main fuse first and the remaining ones until you get a reading which is the circuit that you should check.

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This forum is the first place I've heard of this method. I believe it was lankee yankee who mentioned it. Helped a friend diagnose a problem with his 05 sportster. Turned out, his whole fuse box was corroded. A little cleaning up and it was all good.

This method definitely works

Disconnecting the cable and checking for drain with a bulb or DVOM is a great idea.

And I agree that a DVOM is a better way to do it as someone mentioned that depending on the wattage of the bulb a very light drain may not light a bulb up.

As far as using the highest scale, just my opinion but if it was me I would start on the highest scale so as not to over range the meter, then start working it down to the lower scales to get more resolution (significant digits) on the amount.

Keep in mind that with a DVOM you need to actually get in series between the battery and the disconnected wire with the meter. I know this might be stating the obvious to most of us but to some it may not be.

And additionally with some meters (Like the Flukes) there may be more than one "lead port" to plug the second lead in to (The other being the COM port) to access the different scales.

Some amount of drain with the key off is normal on cars, all the cars I've ever checked were in the 10-50 milliamp range, but this is on modern cars where the electronics present some amount of load at all times (ECM and Radio memory)

I've never checked the Vmax to know what, if any, amount of drain is normal, although with the systems in place on it if all things are perfect I would expect Zero.

I had never heard of an R/R being the cause of the drain, good to know and makes perfect sense since the R/R has full voltage across it even with the key off, and normal failure mode of a diode is shorted. That being said then when I did the meter check I'd do it from the negative side of the battery so as to make sure the R/R stays in the picture since it may not depending on how or if any "improvements" to the positive side have been executed. On mine the positive side of the battery has at least three cables laid down there, the starter lead, the R/R lead (I think normally the R/R lead is crimped spliced into something before it gets to the batteyr) and the some other stuff I've added as well.

Rusty McNeil said:

As far as using the highest scale, just my opinion but if it was me I would start on the highest scale so as not to over range the meter, then start working it down to the lower scales to get more resolution (significant digits) on the amount.

Keep in mind that with a DVOM you need to actually get in series between the battery and the disconnected wire with the meter.

I've never checked the Vmax to know what, if any, amount of drain is normal, although with the systems in place on it if all things are perfect I would expect Zero.

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That was the point I was making. That said a slow discharge wont be drawing much current but starting with the high scale is a good habit to adopt.

One further point - most multi-meter's are not able to handle high current such as if you are measuring alternator output. So don't try it - you may hear a faint pffft as the circuit board burns through...or a big bang........

I get zero amps when measuring mine.

I had a Odyssey fail on me and want to go through my charging and electrical system before installing a new one.. The bike did have the hot start issue.

Can someone direct me to the best discussion/fix?

I had a similar issued that was caused by a bad RR. Search for "Electrical Gremlins" and you will find two threads started by me. The first one with extensive help from Miles has the information you are look for. After reviewing that and doing a bit of troubleshooting I would encourage you to open up a new thread in the electrical section if more advice is required. That way the real knowledgeable guys like Miles and the many others here can chime in. I hope you resolve it quickly, electrical problems can be quite frustrating.

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rebar said:

I had a Odyssey fail on me and want to go through my charging and electrical system before installing a new one.. The bike did have the hot start issue.

Can someone direct me to the best discussion/fix?

Click to expand...

Work through this.

Thanks guys.. I don't think I have any issues except for slow hot starts.. But I want to check all connections etc before installing a new battery. Old odyssy lasted years.

To bad the Vmax doesn't have a headlight switch..

They don't last forever. I have 6 years on my Odyssey and it was on the bike when I bought it so don't know how old it is. Anything over 6 years is great. More should not be expected.

A way to turn off the headlight so it doesn't come on when you turn on the key and create drain on the battery while starting.

But isnt there an "interrupter" so that when you hit the starter switch.....you headlight goes out to send more voltage to the starter?

m-cman said:

A way to turn off the headlight so it doesn't come on when you turn on the key and create drain on the battery while starting.

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Yup.. My H2-750 had one factory I think. And turning the three way plug 90 degrees on my DRZ gave me high/off.

m-cman said:

A way to turn off the headlight so it doesn't come on when you turn on the key and create drain on the battery while starting.

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All model years are configured so that when the starter motor is energized, the headlight is off.
Check it out yourself. Turn the ignition on - headlamp will light - but as soon as you touch the starter button, it will go off. Remember that the starter switch is a "momentary" design, normally "off"(allows power to go to headlight), when "on" (depressed), power is interrupted to headlight, but goes to starter motor circuitry.
This is accomplished by the configuration of the contacts in the starter switch itself.
Cheers!