Say What? Too much charging?

Goodysnap · Post by **Goodysnap** » Fri Jun 18, 2010 9:09 pm

OK guys, I need a little assistance. I've been pooring over the electrical section and my Superhawks wiring for the last couple of days and I'm at a loss. It started about a month ago when my High beam blew. No big deal, been riding for 600miles at least this season, new bulb in and 200 miles later it blows again. No other bulbs affected.

So I break out the meter and amp probe and find crazy high voltages. Obviously found thats whats taking out the sealed beam. Thanks to the great post I check over the factory rectifier and stator today which OHM and diode checked OK. WTH? I made sure to clean and check the ground path of the rectifier as well as the engine to frame.

I'm running a brand new Interstate battery of the correct part# that I filled and charged myself early this year.

Voltage appears great at idle, but continues to climb as I accelerate. Highest was 17V with lights on at 5K. About 3.5 Amps coming out of the rectifier.

I only use the starter when hot as the clutch slips frequently enough I dont like to use it when cold and ussually run with lights on at all times. The voltage still climbs well above 16V with lights off.

I'm Using a Snap On Vantage Pro for my voltmeter and a handheld inductive amp probe. I'm fairly confident my #'s are accurate.

I picked up a Radio Shack rectifier yesterday but after checks I'm convinced there is nothing wrong with the original.

Any Ideas greatly appreciated.

Wilf · Post by **Wilf** » Fri Jun 18, 2010 9:58 pm

I'm thinking too much charging is impossible unless there is not enough of a load on the charging system or perhaps the rectifier is indeed bad.

Normally the battery and ignition circuits (and headlight, when switched on) provide enough of a load to prevent overcharging, so I would confirm a good connection to the battery. Since the engine runs properly, I wouldn't suspect poor connections in the ignition circuit.

Have you checked for AC voltage at the rectifier output? Anything over minimal would point to the rectifier as the problem.

If you already have a Radio Shack rectifier, why not install it right away? That way you get improved rectifier efficiency and you might also prove the original rectifier to be the problem.

If the battery will no longer accept a charge, it may not be providing enough of a load to the charging system.

I'm curious about this--let me know what you find out.

Wilf

Goodysnap · Post by **Goodysnap** » Sat Jun 19, 2010 6:03 am

When I performed my checks yesterday my sealed beam was wasted both low and high. As I have a new one on order. I would tend to think that these voltage #'s are still way too high even without the headlight. The battery accepts a charge well and slowly falls down to normal 12.5-12.8 volts after shutting off the bike. Thanks Wilf. I'll be messin with it over the weekend.

Goodysnap · Post by **Goodysnap** » Sat Jun 19, 2010 1:21 pm

Ok so today I reistalled the old sealed beam that still had low that was good. Changed the recifier to Radio shack style and have the same numbers as with the original. Went through battery connections and redid a new eyelet on the power feed wires. Main positive and negative cables were good.

I found that if I disconnect the pink from the headlight switch to the stator that the voltage remains between 12-13V at any situation peaking at about 1.5 amps or there abouts. As soon as I reconnect in more than doubles at 3.5 amps or slightly higher. It seems to be limiting at 17.5V max.

Wierd to say the least.

I do have quite a bit of vibration while riding(Engine). Makes my hands numb at times. Keeps breaking the support bracket on the crash bar (lower). I toyed with the thought that the vibration may be blowing the bulb, but the high voltage made more sense when I found it to be so high. I'd rather not be runnin around with it that high anyway.

Have a great fathers day everyone.

Brent

teazer · Post by **teazer** » Sun Jun 20, 2010 3:11 am

AFAIK the CB72 system has a rectifier but has no voltage reulator in the circuit. None. As I understand it the battery tends to act as a voltage regulator of sorts but that's about all.

What i don't understand is why that usually isn't a problem - one would expect it to be.

Maybe an electriciam amongst our numbers can better explain what happens and why. It should be possible to buy a voltage regulator - use a simple Zener diode with suitable hat sink.

e3steve · Post by **e3steve** » Sun Jun 20, 2010 7:30 am

Sorry guys; too tired today (jet lagged from HK trip!). I'll offer some words when I catch up on some zeds...... N'night...z.z.z.z.z......

Goodysnap · Post by **Goodysnap** » Sun Jun 20, 2010 1:59 pm

So I just could not wait for the new headlight. Went down and grabbed a H4 halogen and fit to my old blown out sealed beam. The lowest wattage I found locally was a 60/65W, which from what I've read here can tend to be a bit high for a stock charging system. I figure I can always put the stock one in that I ordered later. Amperage is about the same, however the voltage is much more acceptable and not going above 14V at any time.

This leads me to believe that my vibration may be contributing to the premature failure of the headlight. Time will tell , as I'll have to see if I can do some fine tuning to get this vibration down to a minimum.

Brent