Using stock rectifier with VR38SB regulator

[MacMcMacmac]

So, still having charging issues. The rotor continues to ohm out correctly. Headlight comes on after cranking, which indicates to me the alternator is putting out, but charging output is minimal. I checked the reg/rec and the diodes come up good, 7 ohm forward bias, infinite ohms reverse bias. 9 VDC to the rotor, which was all the battery was able to supply, so it seems to me the rotor is not getting short shrift. This indicates to me that the ground path is the problem. On the last ride, the battery was dying, but revving the motor resulted in the headlight coming up very bright.

I was thinking I could continue to use the stock regulator for rectification, but use an aftermarket VR38SB for the regulation. Am I correct in assuming ( which has gotten me into a whole world of problems lately....) that I can simply splice in the green and brown wires to the separate regulator and have the two units do a tag team with the rectifier for charging? I hope so, since it would be a simple addition. This unit tucks nicely inside the plastic box for the security chain on my 83. A notch for the wires from the pigtail and a good ground lead and you wouldn't even know it's there.

 

[xjwmx]

It sounds like you're shooting in the dark a bit. First thing is charge your battery fully and then see what happens. What does the battery measure when you measure 9v at the rotor? And what does it measure disconnected? If it isn't fully charged, that has to be your first step. Recently I had a charging problem and one of the three white wires had pulled out of the shell going to the reg/rec. It wouldn't stay in so I replaced the shell and re-crimped all the lugs there while I was at it. I was surprised how much tighter they would all crimp than what they were.

 

[gggGary]

Did you check your battery water?

 

[MacMcMacmac]

It sounds like you're shooting in the dark a bit.

DON"T SAY DARK!!!!!

Looks like my one year old battery has bit the dust, as I have had it on my charger for awhile and it still displays LO. I set it to auto charge rate and it went all the way up to 8A, so it would seem my Everstart has turned into a Neverstart. Mo' money.....

 

[5twins]

I see no problem with wiring in a separate regulator like you described, but it looks like you won't be needing to do that now.

 

[Paul Sutton]

It may be that the battery is putting too much load on your charging system. I suggest you check how things go with a new battery. Also, my charge system seemed faulty but I traced that back to too big a headlight. The stock headlights were 50/40W incandescent sealed beam which corresponds closely to a 35/35W H4 halogen. I had put in a 60/55W halogen and that was just too much load at below 3000 rpm.

Good luck.

 

[MacMcMacmac]

They sure seem to have a narrow "happy band" when it comes to the charging system. Maybe some leds are in order as well.

 

[MacMcMacmac]

Well, a freshly charged battery seems to have rectified (no pun intended) the situation, but charging still seems a bit lethargic at 1500 rpm and a bit above. Barely cracks 13v. I suppose that's good enough if you keep your idle at or above that, and don't hold the brakes on too much. There's the rub, my bike sees mostly stop and go city riding, so I'd like as much charging as possible. Does the Chrysler regulator perform better at low rpm?

Hmmm, you know Paul, I think I have a 60/55W halogen in there as well. Something to look into.

 

[XSLeo]

The Chrysler reg works about the same as your stock reg. It may have a slightly higher voltage setting.
At idle speeds the rotor isn't spinning fast enough to make more voltage than you have now. Not much you can do about that but keep rpm's up.
Some people have incorporated a relay inline with the headlight that is triggered by the neutral light so it urns off the headlight when in neutral. Like when waiting for the light to change.
I use the Chrysler reg on my 75. It works very well. I have converted to a LED tail/brake light and turn signals. I also run a H4 halogen bulb, just can't recall just now if it's a 55w/60w or 65 w. The one thing I found with the H4 headlight is it will find any weak spots in your headlight wiring circuit. The extra amp draw needs a nearly perfect set of connections on the wires and inside the switches.
The LED lighting help keep the battery charged and run the bigger headlight.
Your turns draw as much or more than the stock headlight. So converting them to LED is a good idea also. The current draw from the lights in the dash and gauges isn't much with incandescent bulbs, I don't change them till they blow. Finding bulbs that fit may be a bit bothersome. A lot of years used the bayonet base, round with the two pins sticking out, these are hard to find in LED but you can swap the rubber sockets for the blade type bulbs that are easy to find. I bought a bunch off Ebay.
Leo

 

[XSLeo]

Oh one more thing, if you convert the turns to LED you will need a new LED rated flasher. These are usually two prong flashers and will bypass the auto cancelling feature on the stock set up.
Leo

 

[xjwmx]

Just for the record, here's an internal diagram of the reg/rec, from the G supplement manual, I think. The rec part is done better than the reg part But you can tell how you would use the rec separately with a new reg, following directions for the new reg. They're independent. You would probably never need to, since being all silicon (the reg is an IC) it isn't likely to fail on its own.

 

[MacMcMacmac]

Sounds like some LEDs will get me as good as it gets with the stock system. I installed en electronic flasher quite awhile ago, since my right signals would not trip the mechanical one at idle. Surely another symptom that my charging system was not up to snuff. The reed switch in the speedo vibrated to death many years ago, so the signals were never self cancelling while I've owned this bike. I have the mini gauges installed, so all the instrument lighting is LED already.

Hmmmmm, I wonder if the superfluous oil pressure warning LED could be put to use as a charging warning lamp?

 

[joebgd]

I have a brand new clearance battery from pep boys, my blinkers work the charging system seems fine but in traffic for an he and I have problems. Unless something is operating different in traffic because of heat.....but ya definitely last time I had to crank the idle up to keep it running. I was out of gas in ab 50 less miles.

 

[xjwmx]

...I set it to auto charge rate ...

They say not to use more than 2 amps. If you put it on 2A, it will keep the voltage low so that the battery can't draw more than that. Then, as the battery charges and it draws less, the charger voltage will go up to where it needs to be at the end. The last time I charged a new battery it was off the scale low for about the first 1/2 hr, like nothing was happening. Some people say you don't need to charge a new mc battery; but it's supposed to be better for them if you do, and the instructions say to do it.

 

[Paul Sutton]

I have tried 3 different regulators and they all followed a similar voltage against rpm profile. The preset voltage of a regulator varies depending on the vehicle it was made for. The most common preset I have seen is 14.5V. Although the optimum charge voltage is considered to be 14.2V, in practice the acceptable level is 14.0 - 14.6V. Below 14V charging becomes slow and above 14.6V the water in the battery starts to undergo electrolysis more rapidly with the risk of the battery going dry if not regularly topped up with water.

A freshly charged battery will show a voltage of approximately 13.2ish Volts. This is a somewhat artifical value and will quickly drop to the stable 100% charged of approximately 12.6V. When riding you want the voltage to stay at or above 12.6V as this indicates you are managing to maintain the break even point where the system current drain matches the alternator/rectifier output. I have seen voltages of 11.8V at idle (1200rpm) with a 60/55W H4 and close to 12.5V with a 35/35W H4. With a non-LED headlight the XS charge system will struggle at idle, consequently some use 1500rpm as their idle.

Replacing the headlight with an LED will be beneficial as long as the current drain is significantly lowered. A 60W LED is still 60W. Changing the brake/taillights to LED seems sensible if you like to sit in traffic with the brake on. The XS SH burns about 42W with the brakes on, but this is very bright and drivers will be more likely to notice you - Safety Benefit. Indicators draw a similar amount but like brake lights they do not have to be on for long periods.

I think the cheapest solution is to have the ability to switch off the headlight when stuck in traffic in daylight.

I have recently fitted a super bright high level brake light on my sissy bar with a light output to match the two taillight bulbs. So on safety/visibility grounds it does make sense to me to replace my brake/taillight bulbs with LED and lessen the load on the charge system..

 

[xjwmx]

I had a halogen on mine for awhile with the rest of the bulbs all stock, incl. two tailight bulbs, and didn't have any charging problems at all. Stock chargingsystem. Replaced it with cheap wally headlight bulb because the halogen shell got frosty inside, so no way to buff it clear again. Still happy with the cheap headlight.

 

[Paul Sutton]

xjwmx, I also have a cheap crappy H4 LED but have not tried it yet. Think I will pop it in tomorrow to see what voltage my bike shows at various rpm. What I really want is an H4 LED which completely fills the reflector with light, the cheap one only half fills.

 

[Paul Sutton]

MacMcMacmac, I have tested my crap LED headlight in conjunction with standard filament tail lights so you can see the potential advantage regarding charge voltage. At 12.4V the High Beam setting draws 0.9A (i.e. 11W electrical load). This confused the RLU so it will need to be bypassed which is a simple task. I collected the following rpm/volt data:

• 1000rpm gave 12.8 - 13.0V (Above the break-even point)
  
• 1200rpm gave 14.4V (Factory Idle)
  
• 1500rpm gave 14.4V
• 2000rpm gave 14.5V (Regulator set-point)

Certainly there is a charging advantage by running LED headlights - but we knew this already! I notice that some LED headlights say something like 100W and 15W electrical load. Is this the typical way they are listed i.e. showing their light output equivalent to an incandescent bulb??

 

[Ozboy]

Hmmmm, I wonder if the superfluous oil pressure warning LED could be put to use as a charging warning

Check out this site for multi LED charge indicators. Got one on both bikes and boat and are awesome. I made a plate and bolted it under gauge cluster to the triple.
www.gammatronixltd.com

 

[TwoManyXS1Bs]

...I notice that some LED headlights say something like 100W and 15W electrical load. Is this the typical way they are listed i.e. showing their light output equivalent to an incandescent bulb??

That's the way I've seen other LEDs marketed, like CFLs...