Battery goes low after installing front lights

[sdbagger]

I have a 2003 Vulcan 1500 FI. I recently installed two 4.5" lights (incandescent) and after riding about 70 miles with them on high beam my battery was so low it would not start my bike. I would think that it should be able to keep the battery charged with the extra load. The battery is brand spanking new. I never had any problem before installing the two lights.
I don't know much about the charging system. Does this indicate that something is wrong with my charging system? or is the load too much for it?
Any help is greatly appreciated. Thanks

[mbarr10]

Will the battery charge back up? How old is the battery? Any exposed cells ( Low on Water/ fluid)? Clean and tight terminals? Should help narrow it down some. I see your from San Diego so I'm not thinking you just got it out of storage, that is when I have had issues.
Do you have a shop Manual? I can send you one in .PDF Send me your normal email address in a PM ( the file is to big for this site).
Some one will chime in soon with more information for you.

[recumbentbob]

How did you ground the new lights?
Sounds like a bad ground to me.

[andyvh1959]

Do you have a voltmeter? If so, attach the leads across the battery and start the bike. At idle the voltmeter should read at least 13 volts and go up to about 14.5 volts at 2500 rpm.
If that looks right without the extra lights on, then repeat the steps with the lights on. If the results show much lower voltage it indicates the lights draw way too much for the alternator to keep up at running the bike and the lights.

[radco]

What is the wattage of the lights ?

[Sabre-t]

If the OEM headlights were 1 bulb at 35/50 (low/high) and you install two 80/100s, then you may be outrunning the charging system, especially if you have other accessories adding to the load. What were the OEM watts and how many? What are the new bulb watts?

[Chuck A.]

Originally Posted by Sabre-t

..........you may be outrunning the charging system, especially if you have other accessories adding to the load...…….

My thoughts too.

[DragonLady58]

Ok...what bulbs you have? Halogens? Sealed beams? Replaceable element incandescents?
As you were asked....what wattage?
You have to match the 'pull', powerwise, to what were in the bike.
Thats where LEDs come in, they draw so much less power....

[sdbagger]

Thanks for all the input, really appreciate it. Now i'm pretty sure that I am overloading the system. Found a manual online. It says to not load system with more than 30W. My lightsare 30W each! Thanks everybody for helping.

[ldhthept]

That’s not how it works... 30 watts is the power of the bulb not how much it takes to use it. You want to look at total current or amps used in system.

[Sabre-t]

Originally Posted by sdbagger

Thanks for all the input, really appreciate it. Now i'm pretty sure that I am overloading the system. Found a manual online. It says to not load system with more than 30W. My lightsare 30W each! Thanks everybody for helping.

First, 30W for high beam headlights is pretty low. I don't know about dual headlights, but 55/65 Watts low/high is pretty standard for single bulb headlights. If these lights have high and low beams, there should be 2 different watts listed for the bulbs. Surely you don't have 4 total headlights, 2 for low and 2 for high.

Again, what wattage and how many OEM headlights? The 30W mentioned in the manual is above and beyond the the power needed to run a stock bike. So if you had 2x30W headlights originally, replacing them with 2x30W headlights will not use any extra power.

[Jllm02199]

Sounds like one of your stators may not be putting out.
Measure the voltage at you battery with the bike running Should be 14 volts.

[TX1700]

Originally Posted by sdbagger

I have a 2003 Vulcan 1500 FI. I recently installed two 4.5" lights (incandescent) and after riding about 70 miles with them on high beam my battery was so low it would not start my bike. I would think that it should be able to keep the battery charged with the extra load. The battery is brand spanking new. I never had any problem before installing the two lights.
I don't know much about the charging system. Does this indicate that something is wrong with my charging system? or is the load too much for it?
Any help is greatly appreciated. Thanks

sdbagger, you just added light and still have the main headlights correct?
If so you are over loading your charging system. You can probably just use the headlight on low beam and the auxiliary driving lights and be charging the battery a little more and replace the tail light/brake with an LED and gain 3w/7w, also if you ran to small of wire to the two new lights the small gauge wire with eat up more load.

[Jllm02199]

To follow up: if you system is putting out 14 volts then consider a led headlight and put led lights in the running lights.

[tomm]

That's not the way to look at it.

Think of volts as pressure. The charging system is designed to maintain between about 14.5 and 15.5 volts of pressure when operating normally. The charging system delivers amps or electrical flow. It does not deliver volts. The amount of amps delivered by the charging system is what is required to operate the bike up to the maximum amount that the charging system is capable of producing. It can maintain a pressure of 12 volts and supply 42 amps at about 3500 RPM, if I remember correctly.

Watts is volts times amps. The charging system is capable of supplying 504 watts, which is 12 volts times 42 amps, again if I remember correctly. Try to pull more than 42 amps, and the voltage will start to drop. Draw less than 42 amps, and the voltage regulators will shunt off the excess current to ground to keep the voltage at 14.5 volts so things don't burn out, including the battery.

If your voltage is dropping below 14.5 volts with the engine at 3500 RPM, then you are either drawing more than 42 amps, or something is wrong with your charging system / battery. It is hard to believe that you are drawing more than 42 amps, unless you have an awful lot of accessories. 42 amps is a lot. A single 60 watt headlight draws 5 amps. (5 amps times 12 volts = 60 watts). You could drive eight sixty watt bulbs with a good charging system and still have a little left over (8 bulbs times 5 amps = 40 amps).

Check your voltage at the battery with the bike running at 3500 rpm and everything turned off. Should be 14.5 volts or a little more. Start turning things on. The charging system will supply more and more amps in order to keep the voltage (pressure) at or above 14.5 volts. If a some point, the voltage drops below 14.5 volts, note what has been turned on, and add up the watts for each thing that you have turned on. If you are in the 400 - 500 range, you are getting close to or over-driving your charging system. If it is less than 400, there is something wrong with your charging system or connections.

If over-driving, consider converting some bulbs to LED, manage how and when things are turned on, etc. Also, consider getting one of of those charging monitors (with the little LED's that go from red to yellow to green) to show you the state of your charging system while you are riding. If charging system or battery problem, that is a completely different discussion on how to isolate the problem.