Battery/Charging Voltage

[XJ Rob]

I recently bought a new battery for my XJ. I went through the whole "Before You Use" instructions. Filled, charged and installed. I repaired my alternator wires a couple weeks ago and everything seems ok. The problem I'm having might just be my DMM. After sitting for more than an hour I check the voltage at the battery and it reads 12.9V. At idle it reads about 14.2 V. At 2500 rpm's it reads about around 14.9 - 15.3V. I've checked and cleaned all connections, so i'm wondering if my DMM is the real problem with the high reading. Any help would be great.

[CatatonicBug]

Not sure what the problem is...What you are describing sounds like a perfectly healthy, productive battery and charging system. I'd say, stand back and smile, then get on and ride!

[XJ Rob]

I was just concerned about over charging at 15+ volts is all. I don't want to burn up a new battery or anything else.

[Geezer]

Yes, your bike is over charging and could lead to early battery failure. Until you fix this, check and top up the battery level often.

The problem is caused by resistance losses in the connections. The way it works is the rectifier output is on the red wire but the voltage regulator senses power on the brown wire. So if there is a resistance loss on the red to brown connection (ignition switch and other places) the regulator will boost charging to get what it's set to produce.

I'd start by cleaning or replacing the connection at the ignition switch first. On my bike I had to replace the plug on the switch and the harness as well as disassemble and clean up the contacts in the switch.

Geezer

[CatatonicBug]

I'd start by cleaning or replacing the connection at the ignition switch first. On my bike I had to replace the plug on the switch and the harness as well as disassemble and clean up the contacts in the switch.

I just discovered how easy this actually is! Took a max of 1 hour to slowly take the switch out, disassemble and clean it, and put it back together and install it. Only takes a regular #2 philips and a flat screwdriver.

[XJ Rob]

Ok so I went out yesterday and pulled the ign switch apart. Everything looked sparkling clean. Terminals included. To make sure, I used a small piece of sandpaper and small picks to scape and clean what I might not be able to see. I cleaned every connection from the switch back to the voltage regulator. Battery cables. All terminals, grounding points ect... Still have 14.9 volts at 2500 RPMs. Just for S&Gs I put my DMM on my truck to see what kind of reading I had thinking maybe my cheap meter was giving me false readings. Nope 14.5 volts max.
So is it possible that the problem is with the voltage regulator. Or possibly resistance where the wires are crimped to the terminal connector inside the plastic housing of the plug?
Is there a way to check the voltage regulator to rule it out?
It's getting pretty frustrating and I don't want to just start installing parts I don't need.

TIA

[BigRed]

Does the voltage go higher than 15 at higher RPM? If it never goes much above 15, I'd leave it, and just check your battery fluid once a month or so. The voltage gauge I installed on my CX500 doesn't indicate an over voltage condition until 15.25V (It's the single LED voltmeter shown here:http://www.customdynamics.com/LED_battery_gauge.htm http://www.customdynamics.com/LED_battery_gauge.htm).

I had a faulty regulator/rectifier and when I revved the engine, it would spike up over 17V IIRC.

[XJ Rob]

Thanks BigRed,
How how does it get mounted on the bike?

[BigRed]

I'm not sure how I'd mount it on an XS11. The box has a peel and stick back, so you could mount it under the gas tank someplace, but I'm not sure where I'd put the LED.

On my CX500, there's a headlight cowl and dash, so I mounted the box inside the headlight cowl, and drilled a hole to flush-mount the LED in the dash.

[BigRed]

Just checked out your photos -- nice ride!

Looks like you could mount the box right under your gauge cluster and put the LED in some of the plastic either beside your ignition switch, or between your idiot lights and your tach. I've got photos of the installation at home; I can post them later if you're interested.

The only thing I don't like about having the voltmeter is that is shows low voltage at stop lights because I've got headlight, brake light, grip heaters, and sometimes a turn signal running, and the bike's stator (Honda CX500) doesn't produce enough voltage at idle to power all that stuff, so the voltage drops to around 11.5. Doesn't bother me, but now when I go to sell the bike, I've got to tell the potential buyer to "ignore that flasing light... everthing's fiiiiine." However, if this is a bike that you're going to keep for the rest of its life, then that little LED will be a gread heads up for any potential electrical problems.

[XJ Rob]

Thanks BigRed
Yes I plan on riding it to the "Pearly Gates"
Maybe something like this. No flashing lights. Just a display. I was looking for a clock for the bike one day and came across it.Of course it doesn't solve the problem. If there is one. But it would be good to know if It does start charging over 15V.

http://cgi.ebay.com/ebaymotors/DIGIT...item5d28764214

[BigRed]

That looks like a slick set-up. I've been looking for something like that with a nice low profile. So many of those combo clock/temp/volt gauges have huge displays. You're better off with numbers than the flashy lights anyways. I only get a flashy red light for anything below 12V, so I don't know if I'm getting 11.5V or just 5V until I go home and hook up my dmm.

You're right though, it doesn't solve your problem if there is one. I'm not an expert by any means, but I wouldn't worry about an extra half or three quarters of a volt if that's as bad as it gets.

Good luck!

[TopCatGr58]

I cleaned every connection from the switch back to the voltage regulator. Battery cables. All terminals, grounding points ect... Still have 14.9 volts at 2500 RPMs. Just for S&Gs I put my DMM on my truck to see what kind of reading I had thinking maybe my cheap meter was giving me false readings. Nope 14.5 volts max.
So is it possible that the problem is with the voltage regulator. Or possibly resistance where the wires are crimped to the terminal connector inside the plastic housing of the plug?
Is there a way to check the voltage regulator to rule it out?
It's getting pretty frustrating and I don't want to just start installing parts I don't need.

TIA

Hey Rob,

Did you pull the Voltage REG/RECT unit OFF the frame, and clean the casing/frame contacts, as well as where the bolts hold it down, the wires connected to those bolts!?

Geezer is one of our electrical gurus, he sells a Reg/Rect that provides much more charging power as lower rpms vs. OEM. Also, the XJ has a stronger charging sytem than the XS, XJ using brushes. Perhaps others can chime in with what their IDLE charging rate is on their XJ...perhaps being at 14 volts is close to normal for the XJ, whereas the XS is barely above or at 12 at idle, and only gets cranking when the rpms get above 2500. There are tech tips on here along with many threads on the processes to check the Reg/Rect unit with a DMM.
T.C.

[Geezer]

Check the voltage at the brown wire to ground with the ignition on. It's best of you turn the kill switch off for this. Then compare the reading you get from the positive side of the battery to ground. Be sure also to have the ignition on for the battery to ground voltage test.

If you're getting less volts at the brown wire, the problem is a voltage drop and keep looking for the problem. On the other hand if there is no voltage drop, the problem is the regulator.

In my experience the problem is a voltage drop 98% of the time...

Geezer

[webbcraft2150]

I have the Kuryakyn LED voltmeter on my '80G. I mounted it on the handlebar below the master cylinder with two sided tape and so far its holding up well. The Kuryakyn unit has a "bar" of LED's that light up depending on charge rate. Has an auto dimming feature for nights to. Its about 5 years old now and is still going strong.