Topic: New regulator/rectifier not charging

[rupaulpierce]

Just checked before pulling sprocket cover... Jumps up to 35V AC around 4K rpm.


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[TwoTired]

Just checked before pulling sprocket cover... Jumps up to 35V AC around 4K rpm.

The AC voltage can't build if there is too much electrical load, particularly at idle.  What mods have you made to increase power loading for the bike?

Cheers,

[rupaulpierce]

Just checked before pulling sprocket cover... Jumps up to 35V AC around 4K rpm.

The AC voltage can't build if there is too much electrical load, particularly at idle.  What mods have you made to increase power loading for the bike?

Cheers,

None, other than it being a CB400F engine in a CB350F frame.

[TwoTired]

So, you don't have a brighter headlight or ignition "upgrade"?

I worked on a 400 once that had the headlight rewired to have both beam elements on with the high beam selection.  Yes, it struggled to keep the battery charged.

You might try switching the lighting off at idle while measuring the AC output.

Ac output needs to be double the battery voltage to drive current to the battery.  Only half is applied to each diode for Rectification.  The resulting DC voltage must be higher than the battery voltage for any restorative effect.

Cheers,

[rupaulpierce]

So, you don't have a brighter headlight or ignition "upgrade"?

I worked on a 400 once that had the headlight rewired to have both beam elements on with the high beam selection.  Yes, it struggled to keep the battery charged.

You might try switching the lighting off at idle while measuring the AC output.

Ac output needs to be double the battery voltage to drive current to the battery.  Only half is applied to each diode for Rectification.  The resulting DC voltage must be higher than the battery voltage for any restorative effect.

Cheers,

Nothing like that. These measurements were taken with the lights off.


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[rupaulpierce]

Just checked before pulling sprocket cover... Jumps up to 35V AC around 4K rpm.


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My language may have been misleading. It “builds” to 35V AC at 4K rpm, no “jump”.

[scottly]

Sounds like you have an intermittent problem going on. With the white harness wire disconnected from the reg, measure the resistance between the wire and the negative battery terminal (the field coil resistance). Use jumpers with alligator clips so your hands are free. Do a "wiggle" test on the wires under the cover, and see if the reading jumps around.   

[rupaulpierce]

Sounds like you have an intermittent problem going on. With the white harness wire disconnected from the reg, measure the resistance between the wire and the negative battery terminal (the field coil resistance). Use jumpers with alligator clips so your hands are free. Do a "wiggle" test on the wires under the cover, and see if the reading jumps around.

4.7-4.8 ohms with the wiggle.


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[Bodi]

Something is weird, you should not have 30v anywhere. Stator wire voltage to ground is not a very useful measurement though. For this 3 phase system each wire pair works together, when one wire is positive to another there is a diode pair to let the power flow. With a low impedance battery, the voltages measured between yellows can not be much higher than the battery voltage, maybe 2V allowing for the diode drops and wiring. Measuring voltage between them, connected to the rectifier and battery with engine running, can diagnose diode failures. Measuring with them disconnected does not tell you much.

[rupaulpierce]

Something is weird

Most definitely.

AC voltage between yellows. Everything connected, stock components, engine idling.

A-B: 14-15
A-C: 14-15
B-C: 14-15

[Bodi]

Do you have a meter that will measure DC Amps? 10A max is sufficient, many digital meters will do this. I believe your bike has two wires to the battery + terminal, fat one for the starter and a smaller wire for everything else. If you measure the amps between the smaller wire and the battery terminal, you can see the charging/discharging current. You should have an amp or two charging with the engine at ~4000 RPM if the battery is not fully charged. Do not try to measure the starter current unless you have a meter good for ~100A.

[madmtnmotors]

Your AC voltages look good per the manual.

[rupaulpierce]

Your AC voltages look good per the manual.

So why am I not seeing charging voltage measured across the batt terminals?


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[Bodi]

Charging is amps, the voltage depends on the system load vs alternator output power... and battery condition. The alternator does not have a lot of excess power over what the ignition and lighting need, and at low RPM the battery makes up what it can't supply - alternator may be 100% good but the battery will discharge by holding system voltage as high as it can. At higher RPM the alternator should have enough wattage to power the bike and have a bit left over to charge the battery, but the battery condition and charge state will control the voltage. If you measure the current in or out of the battery you will see this, it "should" send an amp or two back to the battery until that battery is fully charged: its voltage would be 14.5V or so for a fully charged wet cell battery with correct acid SG. The regulator will reduce alternator output to match the system load then, so the battery should have no current in or out if all is well and it's over 4000 RPM..

[madmtnmotors]

Your AC voltages look good per the manual.

So why am I not seeing charging voltage measured across the batt terminals?

I would be looking at connections, both ground connections to the frame as well as harness connections. Stator connections tend to be the highest amperage connections and suffer the most. Here is an example of some of the ones I've seen:

[rupaulpierce]

Thanks Bodi. I've seen the below test laid out several times, somewhere else by scottly I think. When jumping the white wire I'm not getting anywhere near 15V, so I don't think this is about the regulator limiting output. I'll check the amps though to be sure.

H - Assuming D, E, F, and G have not found faults. We can verify all the of the charging system minus the regulator is functioning correctly, by using a temporary jumper to connect the disconnected white wire (normally attached to the REGULATOR) and connecting the White directly to the the battery POS terminal.  Repeat the B and C tests.  However, if at any time the battery voltage rises above 15V, stop the test.  Such an indication would prove the charging system capable of maintaining a known good battery.  If this test never achieves 15V, then there is a wire/connector issue in either the ground path leading back to the battery NEG terminal, a wiring/ connector issue withe the rectifier RED path to the battery POS terminal, or you made a mistake in D through G.

Seems like madmtnmotors must be right about a bad connection somewhere. How much resistance is acceptable in the ground paths... for example, the green reg wire in the harness to the neg battery strap?

[rupaulpierce]

I would be looking at connections, both ground connections to the frame as well as harness connections. Stator connections tend to be the highest amperage connections and suffer the most. Here is an example of some of the ones I've seen:

I previously cleaned the stator plug and hit each connection with dielectric grease. Maybe I've got a bad ground somewhere.

[madmtnmotors]

I would be looking at connections, both ground connections to the frame as well as harness connections. Stator connections tend to be the highest amperage connections and suffer the most. Here is an example of some of the ones I've seen:

I previously cleaned the stator plug and hit each connection with dielectric grease. Maybe I've got a bad ground somewhere.

Electrical troubleshooting can be maddening. Many times it's a process of elimination figuring out what it's not… 

[BRG-BIRD]

Check your grounds. That was the fix for the charging issue on the 75CB550F, the green ground wire under the fuel tank was not tight.

[rupaulpierce]

How much resistance is acceptable in the ground connections?

I'm seeing .3-.4 ohms at the stator, rectifier, and regulator connections.

[rupaulpierce]

Do you have a meter that will measure DC Amps? 10A max is sufficient, many digital meters will do this. I believe your bike has two wires to the battery + terminal, fat one for the starter and a smaller wire for everything else. If you measure the amps between the smaller wire and the battery terminal, you can see the charging/discharging current. You should have an amp or two charging with the engine at ~4000 RPM if the battery is not fully charged. Do not try to measure the starter current unless you have a meter good for ~100A.

Would testing amps between the fused loop in the small red wire and the batt neg terminal work?

[rupaulpierce]

Seemed like I was making power but it wasn’t getting anywhere, so I started checking resistances in the + wires. Bingo!




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[madmtnmotors]

I love it when a plan comes together. 

I hope the single crimp connector is temporary? The double crimp connectors go a long way towards keeping future problems at bay.

[rupaulpierce]

I love it when a plan comes together. 

I hope the single crimp connector is temporary? The double crimp connectors go a long way towards keeping future problems at bay.

Yes temp solution. Would like to repair the oem connector, but it would probably be easier to just run the wire outside the plug as it is now.


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[madmtnmotors]

I love it when a plan comes together. 

I hope the single crimp connector is temporary? The double crimp connectors go a long way towards keeping future problems at bay.

Yes temp solution. Would like to repair the oem connector, but it would probably be easier to just run the wire outside the plug as it is now.


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Yes, you can repair the connection with higher quality “double crimp” connectors and either use the original connector block or bypass the connector block with the connector of your choice. As long as you use quality connectors both methods will work reliably.