Idle too low or faulty charging system?

[John Hopkins]

Originally Posted by dluszcz

I have an 86 VT1100 and I'm riding for the 1st time during cold weather. I bought some Gerbings T5 heated gloves and I'm wondering if I'm putting too much strain on my charging system.

I've noticed that at idle, all my lights and gauges dim and then get brighter as I rev up the engine. Battery is 2 months old and is a sealed battery from Advanced Auto. I haven't had a chance to do the tests to measure the volts and will do that this weekend.

I drive 75 miles each way to and from work and I put the battery tender on every night just to make sure that I have a full charge. Is that counter productive?

I've read about the MOSFET R/R and I don't really want to buy it if it is not necessary. But I'm wondering if that is a wise purchase for the sake of piece of mind since I put over 13000 miles on my bike this year. I bought her last year with only 13500 so she's barely broken in.

Any advice is welcome as I'm new to the year round riding and absolutely love it!

To see if the battery is being charged you need to buy a cheap ( around $10 ) digital multimeter set the meter to the 25v dc range and connect the red lead to the + pole on your battery and the black lead to the - pole on your battery..expect about 13v dc..now remove the black lead and place it on the engine fins or any engine bolt..expect exactly the same reading..if the voltage is different you need to run a wire from the - pole of the battery to the frame or engine bolt...

after that start the engine and measure the voltage across the battery again you should still read about 13v dc..

increase the revs up to about 3k or 4k revs and the voltage should increase by at least 0.2 volts and maybe up to 14v dc..if it does your charging system is fine..if the voltage goes over 14.8 volts or under 12volts the charging system is faulty..

Heated gloves or heated anything use a lot of electrical current and as they are designed to keep your hands from freezing they should be switched on when your hands get very cold and switched off again as soon as you feel the warmth coming back to your fingers..you should not leave them switched on so that your hands are very warm all the time..

John.

[dluszcz]

So I did the battery test just now. When the bike is not running, it is around 12-13. My cheap meter has 10 or 50 dc so I set to 50 and measured. When I started the bike, the reading was around the same area. When it was running, it barely moved. If I got it up to 3000-4000 rpms the meter actually drops and then goes back up when it returns to idle. I haven't had the battery minder on since Friday morning and she started up ok.

So, I think that I have no issues and that the extra power draw of the gloves is the reason for the excessively dimming lights at idle.

My heated gloves have a temperature controller and I have never gone over 1/4 and my hands are fine. I don't want them so warm it's uncomfortable. Just enough to counter the cold wind.

If someone spots something amiss with my readings, please chime in. From what I've read, I believe my charging system is ok.

[John Hopkins]

It sounds as if you have a charging problem..search the "three yellow wires" check and after doing that check the voltage again.

John.

[dluszcz]

Well you guessed it right. The 3 yellow wires are fried. So I will repair that, run the volt check again, and then report back the findings.

Thanks for a starting point.

[dluszcz]

So, after putting everything back together and running the bike for a minute, I went up to 3000-4000 rpms and got the meter to read to just below the 15 line. At idle, the meter read just below the 13 line. It is a cheaper Sperry meter but at least the jump in volts appears to be correct. It was kind of bouncing around while I held the 2 probes to the battery while the engine was running but it was consistent when I kept the rpms the same.

I think I may have solved my problem. Now I have 2 reasons to ride tomorrow. Great weather and to make sure that I notice a difference in my charging system and how long it takes to charge up on the trickle charger.

So, did this solve my problem? Does the new test sound about right?

[dluszcz]

Well I've rode her for 300+ miles and it appears that the problem may be solved. However I still see the lights dimming at idle.

The bike starts up quicker than it did before the repair and I used the heated gloves yesterday morning but I didn't notice the lights dimming until it got dark out on the way home, during which I didn't use the heated gloves.

Do I need to invest in a new regulator/rectifier? I really want to add lights to my bike so that I'm more visible on the country roads I ride on once I get outside the urban area.

[taikin]

I worry a lot more about being visible when I'm around more traffic. Critters being visible to me when I'm riding in the countryside.

I run heated gloves and a heated jacket and haven't had any trouble, so I think you could add some lights without any trouble. My jacket and gloves together pull around 100 watts and they haven't caused a weak battery yet.

[John Hopkins]

The real test you need to do is this..

Tools needed..1 x $10 digital multimeter..

set the multimeter to 25v dc.

with the engine switched off measure the battery voltage..on a good battery expect 12.5v to 13v dc..this is reading 1.

Start the engine measure the voltage while the engine is idling expect a slight increase on reading one..this is reading 2.

Increase the revs up to 4k and measure the voltage, this should be an increase on reading 2..this voltage must not exceed 14.8v dc..this is reading 3.

If this is all as above you have no charging problems.

John.

[dluszcz]

Well I finally got a chance to get a digital multimeter. Reading 1 is 12.7. When I start the bike and got it sort of warmed up, I got a reading that was around 13.05.

When I revved it up to around 4000 rpms, I had a reading that was around 14.83. Because I placed the multimeter on the seat, it was kind of hard to keep an eye on the revs to make sure it was at exactly 4000 rpms.

I believe the charging system is ok but since I have the factory r/r, it is a wise decision to still replace the r/r to avoid future issues?

[racerc20]

No leabe it alone and enjoy the ride...my 96 shadow did the same thing 3 days after being the new owner...I found that one of the yellow wires was burned and broke away from the connector...depending upon position and vibration it would sometimes show good and sometimes show bad...as soon as i soldered the three yellows to each other and eliminated the connector all charging/starting problems went away...

At idle after warm up if i have my drving lights on in the dark i notice a little dimming but as soon as i crack the throttle the lights are nice and bright...during the day i ride with the bar off and at night or early morning its on...

I would do what was posted earlier with your gloves...if you can put an on off switch within easy reach and once your hands are warm shut em down...any heated gloves clothing or such items use a resistive coil of wire to generate heat...this causes a super big load/draw on the charging system and as the equipment gets warmer the load/draw gets bigger...

good luck and stay safe...