Charging System QUICK TEST

[Guest]

Ohms law is V=IR

Relating that to the pictured analogy, the voltage push (or pressure) required to overcome a given ohm resistance is in proportion to the amount of current in amp (flow) you want.

For a given R ohms, Current increases with voltage.

All of these forms are the same law; if you know the value any two, you can solve for the third.

V=I*R
I=V/R
R=V/I

In the case of your low battery

I=V/R (assume R is constant)
A lower V gives a lower I.

What does that have to do with heat? heat is the accumulation of energy converted to heat. Like if you burn a wooden stick, the energy in the stick turns to heat, current pushed through R gives off heat in a similar way. In fact this is considered an ideal conversion of energy to heat.

Electrical power is given by P = I*V (in words the voltage times the current is electrical power). Substitution for i or V we get two different forms

P = IV=I^2*R = V^2/R

In P=I^2*R we see power is proportional to resistance R for any given I^2.

Thanks for taking the time! I went outside and found the battery fully charged by the tender, so proceeded to do the quick test. The loose negative battery connection was probably causing the no-start situation I experienced after a 50 mile ride yesterday. The battery is about 3 years old (Yuasa), so I'll replace it regardless. Here are some numbers..
Key Off = 13.15
Key On = 12.33
Idle =12.66
2500 rpm (approx) = 12.80
5000 rpm (approx) = 12.89
Key Off =12.89.

Paid attention to the r/r bullet connectors... the wires do get hotter on the side after the connectors (away from r/r), but not super hot where they cannot be handled etc. The connectors certainly need to be refreshed.

Edit: Took another reading about 15 mins after shut down (no battery tender applied) and battery reads 12.66.

 

[posplayr]

Your stator is outputting pitifully but none of it is getting to the battery.
check your stator. Leg to leg and leg to ground test in phase b of stator pages.
if you fail that it is probably s burned stator because of s shunt r/r; join the stator pages aware club.

 

[Guest]

Okay, will do, thanks. Think I have a new stator in storage somewhere, bought about 15 years ago!
A friend was supposed to buy this bike last month, to export to Europe. Didn't go through due to the Covid travel situation. I'm glad he did not buy it, only to immediately have problems.

 

[Forden]

Here are my numbers. Looks like pretty weak charging, though at least it does increase a bit with rpm's--if anyone still watches this thread, thoughts appreciated. I've perused the stator papers (still in process of *understanding* them, haha) and want to be proactive about this now that I've finished some other work on the bike. I plan to install a new series R/R at some point in the not too distant future, wanting to assess the condition of the stator before then too.

Key Off = 12.51
Key On = 12.05
Idle =12.48
2500 rpm (approx) = 12.80
5000 rpm (approx) = 13.12
Key Off =12.68

Cheers.
Mike

 

[Baatfam]

Yah, those numbers aren't very good. Almost the same as mine when I replaced the regulator last winter...
Make sure you check your stator before you proceed too far. Mine was OK, just replaced the R/R with the SH-775 set up.
Afterwards I was getting 14.2 at 2500, and 14.5 at 5000.

 

[Nessism]

Here are my numbers. Looks like pretty weak charging, though at least it does increase a bit with rpm's--if anyone still watches this thread, thoughts appreciated. I've perused the stator papers (still in process of *understanding* them, haha) and want to be proactive about this now that I've finished some other work on the bike. I plan to install a new series R/R at some point in the not too distant future, wanting to assess the condition of the stator before then too.

Key Off = 12.51
Key On = 12.05
Idle =12.48
2500 rpm (approx) = 12.80
5000 rpm (approx) = 13.12
Key Off =12.68

Cheers.
Mike

There are no load stator tests you can do but they are not definitive so I'd go straight to the SH775 and then see how the charging system performs. If you look around a little you can find a simplified wiring diagram which may help you install the new R/R. If the charging voltage is still low then you can go after the stator next.

 

[Forden]

Thanks all, as always. I'll start shopping the SH775 (and continue cleaning connections...). meantime great ride this evening in the now cool Northeast fall weather.