To the electrically minded

Alright, another battery (no pun intended) of tests done, with fewer answers than before.

I went radioshack and purchased the 4700 uF, 35V capacitor (big guy). Soldered it in parallel with one of the lamps and hooked them up in parallel to the regulator output WITHOUT sense wire. Results were

[110W LOAD @ 14V, NO SENSE]
1000 rpm: 11.3V (implied 88W output)
1500 rpm: 13.5V (implied 105W output)
2000 rpm: 15.5V (implied 121W output)

This would seem to indicate that that the charging system is a little low, but not really. The trend indicates 150W capacity at 3,000 and 220W at 5,000. Then repeated with sense connected to 2 lamps and capacitor all in parallel.

[110W LOAD @ 14V, SENSED]
1000 rpm: 11.2 V
1500 rpm: 13.3 V
1800 rpm: 13.5 V --- stopped here no matter higher rpm

My on paper stock load (basic running) is 55W+4x8W+4x3.4W+20W ~= 120W. Actually readings were 9.2 amps at 12.3V across the battery means ~=115W so i'm definitely running within the accuracy of my tests and the bike's electrical system doesn't seem to have any unexpectedly high loads anywhere. So, unregulated, I should break even at about 2000 rpm. No great, but really that bad?

I hooked the regulator all back up onto the bike as per normal, sense wire and all. Everything normally run on, nothing weird, I got the following across the battery:

1000 rpm: 11.83 V
2000 rpm: 12.08 V
3000 rpm: 12.22 V
4000 rpm: 12.38 V

I then took all fuses but main out. and got across the battery

1000 rpm: 13.5 V
2200 rpm: 14.5 V
2800 rpm: 15.5 V -- holds steady at 15.5 at all rpms higher.

So it would see that the regulator portion is working correctly. The voltage drop from battery to regulator on positive and negative side as .2V. On sense wire to battery positive was 1V, but if anything, that would just cause overcharging by reporting battery voltage lower than actual.

Is my stock load just too high? A week or two ago, I did order a second rotor off ebay for 10 bucks. Due to arrive tomorrow. I can always replace it hoping to get more output.

I'd really like to not spend another 115 on a rewound stator.

I should explain the lower idle wattage output. I was having a vacuum leak on the #1 intake boot for awhile, causing lowest possible idle to be 1500. Today's results match at 1500 at about 105 Watts. However, I am now able to idle at factory spec of 1050, producing roughly 88 watts.

Cool, you checked the regulator and it appears to be good. Why was it necessary to install the capacitor? Were you unable to read the voltage otherwise? Or did you just want to filter the regulator output?

So what is on your fuses other than the main fuse that would suck up that much current?

If you don't have an ammeter to measure the current through the main fuse (30A?), then you can always install a current shunt and measure the voltage drop across it. Then start pulling fuses until you find the offending circuit.

I was using a current shunt to take the readings. 9.2 amps is correct according to the wiring diagram. At idle, running lamps, meter lamps, headlamp, and coils pulls a total of 120 amps at break even.

If I was running at 13-14 volts, that would be about 8 amps. Due to lower voltage, draws about 9.

I tested each sub circuit and all were in line with expected draw. No offending circuit.

The ignition should use around 40 watts, or less, at idle, at 13v. The dwell time is so long compared to the inductive reactance at idle, you can basically assume they are resistive loads. The duty cycle is about 28% at idle, but increases to about 33.3% at higher rpms. So if we assume 13v, and the coils are 2.8 ohms, that makes 4.6 amps. We multiply that by the duty cycle of .28, and we get the average current for each coil is about 1.3 amps. So each coil is using about 17 watts (1.3A x 13v). Together that's about 34 watts for both coils.

The headlight should use about 50 watts at 13v.

The tail light uses around 7 or 8 watts.

So that is 50 + 34 + 8 = 92 watts. I round off to about 100 because of the the gauges and other variaous accessories. If you have more running lights, you might be over 100.

Your results show the effects of AC content on a DC regulator's sense circuit.

The sense line is a little low on voltage which would explain the slightly high battery voltage on your last test, but it's not part of your main problem (as you mentioned).

In an earlier test, you got well over 110 watts at 2000 RPM (just before the bulbs blew, with no sense line hooked up).
But now, with it hooked up normally, you are not even breaking-even on the battery at 4000 RPM.
I'd be curious to see what would happen if you disconnected the sense line, but left all of the other fuses connected (lights on etc).

We also know that at 13v, you get over 110 watts at 1800 RPMs, with the sense line connected. This means the bike is using more power than we are accounting for, or is it possible the testing has depleted the battery? That could explain some of the low readings.

The battery voltage test is crap. Do an Amp test.

On the stator, each combonation of yellow wires will output 75vac + after 4,000 rpm. No yellow wire should have continuity to ground

Did you ever do a proper Diode test?

Also, how quick does it start?

Is there a ground wire from the regulator that attaches directly to the main ground lead?
What is the condition of the main wires?
Is the main ground wire attached to the engine?

After checking your ground wires and with a NEW battery. Or your present battery, confirmed by a motorcycle Specific Gravity tester. Nothings fully charged unless the specifig gravity tester says it is.

You need to do an amp-draw test. With all possible electrical loads on, you should still have a Positive 1 to 3 amps @4000 rpm.

With engine idling, remove your ground wire from the battery, set your amp-meter up, then start swithching all your loads on (Hi beam, brake light, turn signals or flashers) and increase rpm to 4000.

Sometimes aftermarket halogen bulbs will raise the amp draw past normal charging capabilities.

Post edited by: Capt. Quirk, at: 2007/06/05 03:04

A regulator is a VOLTAGE regulator. To know if it's working he needs to measure voltage. Amps will tell him where the power is going, but in the end he needs to see 14v on the fully charged battery while it's running.

@loudhvx

My running load is actually higher. I have 50W headlight, 34W on coils, two 8W front running lights, two 8W running tail lights, and 4 3.4W running meter bulbs putting my total somewhere near 130W counting straight from the wiring diagram at 13V. Using the current shunt, I was able to show all my loads are in line with the expected values from wiring diagram. ( measuring 9.2 amps at 12.3V across shows I'm using roughly 113W at idle, not even break even for loads, certainly not going to charge, and WAY from gassing.

I am going to do as described and charge battery up tonight and do voltage tests without sense wire connected. Last time I did it (on the old reg/rect), it was rather disappointing.

@Capt.

I have done the set of stator tests. At 4,000 rpm, I get about 69-71 VAC between each pair of stator coils and there are no ground faults. I will however consider the ground fault test while the engine is running and warm, as I have up to this point done the test cold. Perhaps heating causes a ground fault in the stator.

I have done proper diode tests as well as rectifier isolation tests with the controlled 2-headlight load. I'm 100% certain the diode portion of the reg/rect is working properly.

It starts fairly quick. After a new charge off the bike, the starter turns happy quick. After more and more starts over a week is slowly degrades. This would fit the other symptoms where the battery is only discharging at startup. During running, the electrical system is just at or just below breakeven, so that battery never really discharges heavily but never charges either.

Both the regulator positive and negative out have a thick 16 AWG wire running straight from the reg to that battery - positive one has an inline 10AMP fuse. I'm very certain the hookup for charing the batt is more than satisfactory.

The battery is 4 weeks old, and I had the same problem with the old battery. I'm highly doubtful it is a battery test. I have not however done a spec-grav test. The one 4 ball tester I had was crap -- I need to get a good float style. I'll see about getting it on the way home from work today.

Along with Lou's sense free test with charged battery, I will post the results of a full amp draw test with and without sense wire tonight at various rpm.


----

Out of curiousity, does anyone know which electrex stator would fit a kz750n-1? Is it the ESG010 or ESG110?

Also, any opinions on changing my front running, tail running, and meter lamps to LEDS to reduce current load. I have a feeling spending $100 would be better spent for a long-term solution on a new stator than trying to mod the bike to draw less to compensate for bad charging.

Post edited by: dnpurdy, at: 2007/06/05 10:37

If I'm not mistaken, you need to overcome the charging voltage, not amperage, to charge a lead-acid battery, right?

5 amps at 12 V will do nothing, but 500 mA at 14.5V will definitely charge slowly over time. Am I correct in my understanding that you need to break ~13.6 volts across the battery to overcome the electrochemical bond of the lead sulfate?

I don't know a lot about actual battery chemistry, but as long as the voltage applied to it is above the ambient voltage of the battery, current has to be flowing into the positive terminal. This means it's charging, or at the very least, it's not discharging. I find the actual voltage varies as the battery charges, but when the battery is fully charged, the battery's ambient voltage is somewhere around 13v. Temperature affects the voltage (which is why some car systems have a temp. detector integrated into the voltage regulator).

If you can get 13.6v on the battery, most likely it's getting some positive charging.

When my battery is dead, and I put it on a trickle charger at about .4 or .5 amp or so, it has around 13.1v on it.

I just checked a good battery that's on a trickle charger. It has 14.22v on it, and it's getting 45mA. It's been on the charger for over 24 hours (it was dead2days ago). It's about 60 degrees, and the battery is under 2 years old.

I took the battery off of the charger, after 10 minutes the ambient battery voltage is 13.36.

I'll check it again in about an hour.

Post edited by: loudhvx, at: 2007/06/05 11:41

After 2 hours it's 12.92 volts.

Hey guys. I know a thing or two about battery chemistry.

A fully charged battery should be around 12.7-12.8V after its been left standing for an hour or so. What you really want to do is check the specific gravity of the acid.

Discharged batteries can take a large current in until a certain point when the acid start to boil lightly, this is where you want to switch it to higher voltage and drop the current down. A taper charger does exactly this.

The charging system is basically a voltage limited power supply. If your motorcycle battery is badly discharge or damaged, it could keep sucking current from the system all the time and never reach a point where it stops taking current at 14V.

To rule out the battery, you'd have to properly charge it and check the specific gravity.

It is also important to know where the breakeven point is to the battery, ie. what rpm you have to run before you stop drawing current from the battery.

It could be like lou and I have been discussing in our other thread - that at idle you are draining too much current to replace while running.