TOPIC:

Hi, I am a new rider that picked up a sweet 1983 kx550, that has some quirks.

Most recently, when I've tried to charge the bike with my Pro Series 4000, the 12v light just blinks. Actually it lights up like it is going to work for a second, then just the 12v light blinks red. BUT....if i turn the key on and then plud it in....it looks like the charger is working fine. Any ideas??

Blinking issues is similar to whats shown here

DO NOT TRY TO START YOUR BIKE OR TURN ON THE IGNITION KEY WHEN IT IS HOOKED UP TO A CHARGER OR OTHER VEHICLE THAT HAS THE ENGINE RUNNING! That can very quickly damage your motorcycle's electrical system. Don't do it! Fiddle with the charger with the bike's battery cables disconnected. Ed

Never put more than 2 AMP's in a motorcycle battery.
Steve

I only use it in the 2 amp setting, but the charger defaults to 4.

Usually I plug it in and switch it to 2 and it works fine. Now with the blinking, there isnt time to do that. It just flashes the default setting, then the 12v light starts blinking and the charger is unresponsive at that point.

Disconnect the battery then check the voltage a few hours later. Might have a dead cell.
Steve

josmking wrote: I only use it in the 2 amp setting, but the charger defaults to 4.

Usually I plug it in and switch it to 2 and it works fine. Now with the blinking, there isnt time to do that. It just flashes the default setting, then the 12v light starts blinking and the charger is unresponsive at that point.

If it defaults to 4 amps it WILL shorten the life of your battery; no ands, ifs, or buts. Bike batteries take 2 amps MAX.

If you turn bike's the ignition key on or try to start the bike with the charger (or a running vehicle) hooked up you can damage the bike's electrical system regardless of the charger's settings.

My advice - get a proper 2 amp or LESS charger and a new battery. Charge the battery properly before installing it in the bike. Then go for a nice ride. Ed

I think the battery is bad.
Or, one of the high current diodes in the rectifier is leaky/shorted, possibly the regulator is bad.
A shorted battery or wiring screw up or short might blow the actual charger up if not current protected.

If the external battery charger keeps defaulting to the high current mode, I would think the the load on it is high.... which means low resistance with respect to it and on through to the battery + and chassis ground.
Which can include, a very low voltage charge in the battery, or a shorted / sulphated cell, or a bad diode in the regulator and or rectifier block, or a shorted wire in the system... etc.

However, why was the 2 amps max comment made? I don't remember hearing this before.

The only time I've seen a reference to 2 amps is in the FSM saying that the 12v charge system should be able to do that.

Has anyone put a DC current meter in series with the battery terminal as in the FSM with the engine running and a slightly discharged battery? I haven't.
I bet it is more then 2 amps.
Maybe a lot until the battery voltage rises and the factory regulator shunts around.

Also, why would turning the engine on while having a charger connected damage the electrical system?

When charging a battery off the bike, I use a variable power supply and watch current vs voltage. I just keep readjusting the "charge" voltage so the current into the battery, during fast charging, is at 3-6 amps and then as the battery voltage rises, or can hear the electrolyte bubbling a tiny bit, roll the voltage down as it charges up so it is around 300ma-500ma for a while, like a few hours.

missionkz wrote: However, why was the 2 amps max comment made? I don't remember hearing this before.

I've owned my KZ650 for 38 years. Over that period I have bought a number of different bike battery brands. Every new battery includes instructions on how to charge them, and every one warns not to charge above 2 amps. In fact, they normally recommend 1 - 1.5 amps. The images below are from the last battery I bought; notice the amps recommended. You can charge a bike battery at much higher amps if you want, but it WILL shorten the life of the battery - no joke. I suspect this is why I see folks crying about their battery only lasting 2 years or so instead of 5 or 6 years.

Trying to start a bike from a running vehicle or charger can damage the bike's electrical system. A search on this site will give better details, but the bottom line is that the bike will draw more current from a charger or running car or other vehicle than would normally be available from its own charging system. ed

I realize you probably have already surmised much of this, but for others who may read this, I thought I'd use your questions:

missionkz wrote: ...However, why was the 2 amps max comment made? I don't remember hearing this before....

I believe it goes back to the old float chargers. They would often have a 2 amp setting as their "low" setting for 12 volts. Float chargers were not smart, and could easily go over two amps into a very low resistance load, like if you accidentally hooked up a 6v battery instead of a 12.

Normally, though, the charger would put out much lower than 2 amps into a partially charged 12v battery (of motorcycle or car size), around 1 amp. So based on that, convention has been to use 2 amps as the max setting for charging motorcycle batteries (even though that doesn't really equate to 2 amps in actual current). In my tests, the 2 amp setting delivers about 1 amp, which is about right for a new battery as Ed's photos show.

missionkz wrote: Has anyone put a DC current meter in series with the battery terminal as in the FSM with the engine running and a slightly discharged battery? I haven't.
I bet it is more then 2 amps.

I haven't either, or at least I didn't make any notes if I did. But, I did measure what a float charger does to a new, wet-cell, lead acid battery. (As I see you did with a regulated supply as well.) The initial voltage when adding the acid to the dry battery was 12.62v.
The 2-amp float charger initially put 1.1A into the battery when first connected at 12.62v.
After 4 minutes, the current was 1.0 amp and the voltage was 13.15v.
After another 2 hours and 51 minutes, the current was down to 0.3 amp, and the voltage was 14.37v.

If the voltage was forced up to 14.5v at the very outset, as a bike charging system might do, the current would have been much higher, but I'm not sure how much. We can assume more than 1 amp, at least. A bike can easily put out 5 to 10 more amps than the bike's normal load would take, so some significant portion of that would go to the battery. Once again... not sure how much.

As a side note, the voltage readings are with significant ripple when using a float charger. This affects the accuracy of a typical meter. The actual RMS voltage applied is slightly higher than what the meter will read. (The meter measures average voltage, not RMS.) The same goes for the current.

missionkz wrote: Maybe a lot until the battery voltage rises and the factory regulator shunts around.

(Maybe a lot more than 2 amps) I agree, it's definitely possible.

missionkz wrote: Also, why would turning the engine on while having a charger connected damage the electrical system?

Having the engine running while a 14.5v or higher, external voltage source is connected can cause the regulator to shunt every cycle. That would generate a lot of heat in the regulator and the stator (in a permanent-magnet alternator system). This should not be an issue with bikes using car-type charge systems... that is, with excited field alternators.

Having the electrical system turned on, but engine not running, with an external voltage source connected, should not have any affects, as long as the voltage is not excessively high. (That is, no effects beyond the normal dangers of leaving the ignition turned on while not running, like heating the coils on a points bike, or heating the field coil in an excited-field alternator.)

In some poorly designed regulators, either of the above conditions may overheat the detection circuit in the regulator, though most regulators should have protection against that.

missionkz wrote: When charging a battery off the bike, I use a variable power supply and watch current vs voltage. I just keep readjusting the "charge" voltage so the current into the battery, during fast charging, is at 3-6 amps and then as the battery voltage rises, or can hear the electrolyte bubbling a tiny bit, roll the voltage down as it charges up so it is around 300ma-500ma for a while, like a few hours.

That's fine but requires a lot of monitoring. The beauty of the float charger (besides it's raw simplicity) is that the voltage is free to float to whatever the battery wants. If the battery needs more current, the voltage stays low and the charger delivers more current. If the battery is nearing full, the voltage goes up and the charger delivers very little current.

I use the 2 amp setting on the float charger, but in case I think I might forget to turn the charger off after a day or so, I use an inline resistor. This resistor accentuates that inverse relationship between voltage and current. I use a 2.2 ohm, large wattage (I think 10 or 20 watts) resistor for those cases. Then it's safe to leave the charger connected for days.

After I connect the resistor to the above mentioned, charged battery, after 5 hours, the current is down to .08 amps, and the voltage is only at about 13.9 volts. That puts the battery in a condition where it is just barely being topped off.

A float charger, with nothing connected is just a rectified sine wave with the peak carefully selected by transformer design. So as the voltage of the battery increases, less and less of the voltage sinewave is actually used. Thus the average output voltage "floats". (With no battery connected, the average is actually very low, like maybe 6 or 7 volts. The battery is what raises the average.)