Battery/Charging Voltage

[TopCatGr58]

Just an update regarding Geezer's Reg/Rect!

I just put a new (Walmart) battery in my bike after filling, and proper charging beforehand. One surprise is that the NEW battery only shows ~ 12.5 volts fully charged! However my old tired battery was only showing 12 volts max!

Secondly, I fired up the machine, and at IDLE, with Geezer's Reg/Rect, it was cranking out 14 volts!!! But revving it did NOT take it over 15 volts, so it's working just right! Starts a heck of a lot easier and stronger also!

T.C.

[bikerphil]

Walmart batterys are great, aren't they? It they take a sh!t , you just throw 'em away and you're only out $45.

[XJ Rob]

I did not clean the bottom side of the VR. I wasn't aware it needed to be grounded. I did however clean all the wires that get bolted down by the screw. I will try that. Also I will do the voltage drop test to see if there is any.

I was just surprised to see 12.9 volts from the battery. I thought maybe my DMM was off. I never heard of a high reading for a battery.

I'm out of town till Sunday so I'll check it all out Monday and report back on what I find,
Thanks for all the help

[TopCatGr58]

Walmart batterys are great, aren't they? It they take a sh!t , you just throw 'em away and you're only out $45.

Well, inflation has hit, they are now $50.00 plus $9.00 core charge. I found a stamp on the top of the new one, 09 03 18 and then found similar stamp on the old one 05 03 18 ! Was surprised to see the same last numbers, but I'm surmising that the 05 was the manufactured date/year, so it was appx 5 years old, and this new one was made in 09!?

My B-I-L will get the old one for some night fishing lighting and radio!

Okay Rob, will be looking for your update!

T.C.

[bikerphil]

An older but still good battery is good to keep on the workbench for testing stuff. I always keep an extra.

[XJ Rob]

What I found

Ok I went out this morning and cleaned the mounting area of the V/R.

Key on (killswitch off) I have 12.38V at the battery. At the ign switch, Brown wire has 12.00V. At the Plug going to the V/R brown wire has 11.90V. Difference is less than .5V. Depending how long I keep the key on, the voltage drops on everything. I'm assuming that I have some corrosion somewhere in the harness seeing I have cleaned all terminals. Should I really worry about less than .5V? I think I'm going to keep an eye on the battery level and ride. If I have any problem I'll replace the plugs and terminals. I'm charging below 15V at 2500 rpms. It would be interesting to find out what other XJs are putting out.

[Geezer]

You have found the problem and when the bike is running and the corroded connections warm up, the voltage drop will increase. This is something you need to address or it will only get worse.

Geezer

[XJ Rob]

Geezer,
How would I go about pinpointing where the problem is? Or should I just replace all of the connectors? Sounds like it could get expensive.

[Geezer]

The 3 most common places for this problem are the ignition switch, the rectifier plug and the connection from the solenoid to the harness...

Geezer

[XJOK2PLAY]

Ok I went out this morning and cleaned the mounting area of the V/R.

Key on (killswitch off) I have 12.38V at the battery. At the ign switch, Brown wire has 12.00V. At the Plug going to the V/R brown wire has 11.90V. Difference is less than .5V. Depending how long I keep the key on, the voltage drops on everything. I'm assuming that I have some corrosion somewhere in the harness seeing I have cleaned all terminals. Should I really worry about less than .5V? I think I'm going to keep an eye on the battery level and ride. If I have any problem I'll replace the plugs and terminals. I'm charging below 15V at 2500 rpms. It would be interesting to find out what other XJs are putting out.

Hi, XJROB,

I have an XJ1100, and I decided to try installing a pair of 50 w Halogen driving lights, a lighted toggle switch, and install a voltmeter to keep tabs on stuff. So, after reading your thread, I decided to take some voltage checks for your comparison. For the record... I have no charging or starting issues.

Bike off, battery at rest: 12.76 volts @ battery.
Ignition Sw. on, bike off: 12.44 volts @ battery.
Ignition Sw. on, bike off: 11.10 volts @ 20a. ignition fuse block.
Bike running, @ battery, 1100 rpm idle: 14.4 volts
After 20 min's warm up, 1100 rpm idle: 14.0 volts
5000 rpm, @ battery: 14.6 volts.

The voltmeter I installed was wired w/ #14 guage wire, the negative ran direct to the negative battery terminal, the positive ran to the fused side of the 20 amp Ignition fuse in the fuseblock, (Switchleg side.)

The new voltmeter guage read the same as my DMM.

New lights are awesome, and voltage reads 14 volts going down the road. Drops to 12.5 at idle. Hopefully won't drain the battery, but I have them wired seperately so they can be independantely shut off if I notice a problem.
Wired from a seperate circuit in the ATC fuseblock, 15 amp fused.

Hope this gives you some voltage comparisons. At no time did my charging voltage exceed 14.6 volts, even when first started.
HTH's ya.
Bob

[XJ Rob]

XJOK
Thanks for the info
I have to ask. Did you have the new lights on when you did the running test?? I thought about extra lights but I think it would overload a system that is already over-charging. Heat up wires and start a fire under the gas tank.

I have pulled every wire out of the connector and cleaned it the best I could. Inspected each wire/terminal closely for any kind of corrosion and I don't see anything.

I took the info Geezer gave and checked for a drop at the brown wire of the V/R and I'm losing almost .5V. All of my readings were from the ground side of the battery,to the brown wire on the V/R, underside of the ign. switch and in the H/L bucket. I haven't ran the bike as of yet to see if I'm still over charging while running since I started this "Quest".

I'm waiting for a shim from randy before I put it all back together again.(should be a day or 2 yet).

I won't ride right now anyway. I'm working night shift right now and I'm way to tired to get on the bike and be 100% when I get home.

When I do get it back together I'll post what the results are.
I use to love electrical diagnostics (Till Now)
Thanks again for the info.

[XJOK2PLAY]

XJOK
Thanks for the info
I have to ask. Did you have the new lights on when you did the running test?? I thought about extra lights but I think it would overload a system that is already over-charging. Heat up wires and start a fire under the gas tank.

No. These readings were w/o the driving lights on. The running voltages I posted however, would be w/ the headlight on of course, low beam.

It's not the voltage so much that I'm watching, as is the amount of amps the system puts out.

XS puts out 20 a. max... XJ puts out 26 a. max.

I've been told by a friend of mine who has done this on his XJ once that it will work fine for about 2 1/2 hrs. continuously, then the bike will start cutting out due to starving the battery of the needed amps...
It's not the voltage, it's the amount of replacement amps back to the battery. As long as your lighting load is on it's own, seperate circuit from the fuse box, and you've wired them w/ heavy enough wire, and placed them on the right size fuse, you don't have to fear a wiring meltdown. Mine are wired on #14 ga. wire, 15 a. fuse. 2x50w= 100w. divided by 12 v.= 8.33 a. total load added to the charging system.
But, since I added an additional switch for them seperately, I have the control to run them or not as needed... instead of adding them to the bike's wiring and switches, etc.... I wired them seperately.
If you were to add that load to the bike's existing wiring harness, fuse, switch, reserve unit, etc. could be a different story.
As it is, the only thing I have to watch is how long I run them, and simply turn them off if it drains the battery down, and let the bike charge the battery back up. I doubt if I'll be riding at night more than 2 1/2 hours at a time anyways.
But the extra light is WAY cool... and much needed for safety! (Especially as bad as Okla. roads are getting these days! Potholes everywhere!) Couldn't believe the HUGE difference it made! I can actually see where I'm going now...
Not to mention wildlife jumping out, etc.

As far as my voltage w/ the driving lights on while riding, I observed 12.6 v. @ idle, and around 14 v. when riding.
I LOVE my new voltmeter guage I added... installed it on the left side of my Vetter faring. Now I can keep better tabs of the charging system...
May consider an amp guage one day, too.

[XJ Rob]

Update

Just wanted to post the end result of the whole Charging issue. I put the shim in I was waiting for (Thanks randy). Re-synced the carbs and put it all back together. After I was finished but before I put the seat on, I pulled the DMM out to check the charging voltage. 14.4V at 3000+ rpms. 13+ at idle. Maybe all the cleaning of the connectors is the reason. I'm still going to get a volt gauge to keep a close eye on it. Thanks for all the help.

[Yahman]

Now get out there and ride!






But not before your well rested.

Larry

[XJ Rob]

Ok Larry,
Now if it ever quits raining I'll ride but they are calling for colder temps and rain most of the week and the weekend. I just can't win .