I've got an problem with the charging on my bike (batterywent flat while riding) and have used all the troubleshootingFAQ on this site and some others (including the Electrex troubleshooting guide for charging systems, which seems really good and goes into a lot more detail than the manuals).

I have run a heap of checks and all but one indicate the charging system is OK. The one check that raises a question isa voltage check that only the Clymer and the OEM Honda manual recommend. Theirrecommended check isto disconnect the battery negative terminal and the negative lead, and measure the voltage between them.Clymer/Honda say itshould be 8V with the ignition off and with the RR (regulator/rectifier) still connected. On my bikethat reading isabout 12.6V(battery voltage = 13.1V).(Current leakage is 0.4mA. When theRR is disconnected, and ignition is off, I get 0V, which is what the manuals recommend. Charging voltage is about 13.8V, and with lights on drops to about 12.5V).

1. Question about 8V leakage test: the Haynes manual doesn't suggest the same check, and nor do any other manuals/FAQs I've come across, so I'm wondering if the 8V leakage check itself has been discredited. Has anyone else tried this testand found that a higher figure than 8Vis OK? Also, doesa figurehigher or lower than 8V actually indicate a problem with the RR, or something else?

2. During troubleshooting I've noticed that even at idle, after about 5-10 minutesthe RR gets hot, like about 190 deg F/ 90 deg C. Is this normal?

Thanks for your feedback.

 

i'm not sure about you first question. will have to check on that when i get a chance.

but an answer to your 2nd question, is yes, it will get hot. that's why it has cooling fins. the rr or part of it regulates the juice going to the battery. and so to keep the battery from overcharging, it dumps the excess juice as heat. hence the reason why the rr gets hot.

 

That's known as a voltage drop test, however usually its done with the cables still connected. It is mainly looking for excessive voltage drops due to corroded and/or loose wires.
If you have a VOM and not a DMM you would get about a .4mV voltage drop running it in series with the ground cable and battery. That is the amount of voltage being used to push the dial and being burned up in heat in a VOM. On a DMM, you should either get no reading or a verylow one (less than 1-2 volts) Since a DMM has such a high internal resistance it does not flow current and complete a circuit(unless its cheap). It is trying to read what is there without influincing the reading. If you are reading the voltage with one end on the postive battery teminal and the other to ground and then to the bat ground a .4v drop is also acceptable. Since you are reading the voltage drop across accesories that have power all the time.

One thing to take into account is that lead acid batteries can only be deep cycled 2-3 times before they are totally worthless. Will it still start, maybe, run, maybe. Every time you deep cycle a battery you lose about 1/3 of its capacity/filtering. So 3 full kills of your battery = 28.7496% of the original capacity/filtering. on 225 cca with 45amp/hrs that is
63.82 cca and 12.94 amp/hrs, which is total crap. Sometimes you can overcharge a battery and regain some of the lost capacity by boiling the plates and starting the electrochemical process again, but mostly not. Batteries act as filters for voltage spikes and ac current coming of the alternator/generator/magneto. The diode bridge(reg/rec on our bikes) mainly rectifies the ac current to DC, but their is still residual AC (cheaper to only rectify one side of the signal) on the ground side and the output is pulsed on the power side. Hence diming lights that flicker a lot when your battery gets older.

Deep cycle batteries do not apply to this rule since they are designed to be totally discharged/recharged repeatedly. I have never seen a bike deep cycle battery.

 

Thanks heaps you guys. Sure is helpful info. I had no idea that regulator/rectifiers normally got so hot. I'll need a bit more time to digest and fully understand the info about the voltage drop test and the difference between the VOM and DMM. I have been using a cheap-ish DMM, and Honda does recommend a couple of particular test instruments.

The main thing is that with the above info itseems my RR is probably OK, and you're right about the battery - it has been pretty flata couple oftimes due to memory failure (with a 90/130W headlight bulbit tends to go flat quite quick if I forget to turn it off!).

Thanks again.

 

Is it a crapsman? I would either use a fluke, or LG(what I have), or any on one of the tool trucks like snap-on, matco, mac, or cornwell. The crapsmans are widly innaccurate, slow and have very little internal resistance, so they affect what they are reading. A DMM is a Digital Multi Meter, which like it says is totally digital and usually completely isolated. DMM's like this http://us.fluke.com/usen/products/Fluke80SeriesV.htm

A VOM is a Volt Ohm Meter, 99.99% of the time is analog, and is un-isolated. They have uses, but not so much in modern vehicle electrical systems. They are the dial indicator meters like this http://www.specialized.net/ecommerce/shop/layout.asp?product%5Fid=080X280

 

[Edited to include answers to questions from drakito... result of PMs].

Hi - could you help with a bit more advice about the 8 Volt open circuit test result that Honda specifies. It seems very absolute (ie 8V, nothing more nor less), yet doesn't require the battery to be at any particular voltage and they require the ignition switch to be "off". So I'm guessing the 8V spec is something to do with testing the RR (since the next test involves disconnecting the RR to get the 0V result, which I assume is to check that there are no shorts in the wiring thats on the live side of the ignition switch.)

See the attached extract from the Honda manual.

Honda isn't explicit about the measuring instrument for this test but elsewhere they refer to a "Kowa TH-5H circuit tester", and the photo in the Honda manual beside the 8V test looks like some pix on the net of a Kowa TH-5H VOM. The Kowa site doesnt give any specs about sensitivity.

The ElectroSport charging system troubleshooting guide indicates that there is a voltage drop across the diodes & whatever else is in the RR which is >1.5 V in one direction, and around 0.5V in the other. (Doesn't say what they use to measure it, DMM or VOM. I assume DMM).

My conclusion from your info and the above is that the 8V test is only relevant for a specific VOM depending on the current draw of the VOM. The 12.6V I get with my DMM is presumably due to the DMMs much higher resistance and therefore lower current draw from the battery (charge of 13.1V).

Does that conclusion make sense?
[Drakito's reply: Yes! Your conclusion, to me, seems right on.]

The other question I have is about the regulator. Wikipedia sayssome regulators need a certain minimum voltage forthem to work. This might explain why I had enough spark to push-start the bike, but voltage was so low that regulator didn't work, the battery didn't charge during the ride, and gradually discharged until it had nothing left to throw at the spark plug coils. Does that conclusion make sense too?

[Drakito's reply: It does as well. However, like I said earlier on batteries, it could also be unable to hold a charge and continued to drain itself down, even with a charging input. Especially if the voltage/current required exceeds the voltage/current produced by the RR. Remember as voltage decreases, current must increase to do the same work. Some batteries get a dead cell that will actually drain the other cells down and draw current in the form of heat.(Batteries consist of 6 2.10V cells) With a dead cell, after charging, you would see less than 12.6V at the battery, more like 10.5-11.0 or less. The minium voltage that is needed varies on the size of the diodes or regulator. There is a threshold voltage level that below, nothing will happen at all. Once it is reached the current can flow across the diode and complete the circuit. A good example is a Light Emitting Diode(LED). A LED needs 2.4-3.0V to light up, less than 2.0 volts and it will not light at all, more than 3.0V and you can damage the LED(try sticking 12V to single LED, BOOM!). The threshold of operation is constrained by the matierials and size off the unit used. A standard 1 amp diode needs .7V before any current will flow. The .7V is used as heat(the bigger the diode the greater the heat, hence the big cooling fins on the RR)]

Really appreciate your knowledge, thanks.

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