Road Toad lights suddenly dimming

[spudman]

Hey guys -
While riding my model 99 Road Toad today, I noticed that the headlight output had become very dim, as well as all of the turn signals, brake lights and the dash indicator bulbs. The horn was barely audible. Everything was fine just a day ago. I checked the voltage at my Battery Tender pigtail (which is wired to the battery via some "Y-adapters" I made) and with the bike running, the voltage was barely 5 volts. I know I obviously have a problem somewhere, but I'm at a loss as to where to start with the diagnosing. I was going to check for continuity in all the wires coming out from the stator cover first. Are my symptoms usually indicative of some "common" problem like a voltage regulator, rectifier, lighting coils, etc.? Any suggestions are greatly appreciated! I've searched the forum for quite some time tonight and haven't been able to find threads relating to exactly how to "test" the parts I mentioned above either (if that is in fact possible to do). Finally, I'd like to replace my battery with a newer "sealed" battery and was wondering if such a replacement exists. Thanks in advance for any help or suggestions!

[matt glascock]

I'll throw my hat into the ring. I had similar symptoms on my Toad and the problem was that the battery was dead, dead, dead. The charging system was operating properly, but the battery simply couldn't take a charge. Do you have a good spark? Has the emergency lighting switch on the headlight bucket accidentally been moved to the "DC" position. You could remove the tank and seat and visually inspect the wiring to determine if there is any compromise resulting in an electrical "leak". For probably the best and most streamlined approach if all of the above check out, the Hodaka Official Wombat Workshop Manual has an excellent review of troubleshooting procedures for the electrical system including simple yet effective tests to confirm the integrity of the coils, condenser, rectifier, and regulator. Different bike yes, but the magneto and charging system on the Road Toad is much the same. I'd try a new battery and follow the initial charging procedures precisely. I'm not aware of a sealed 6V battery but again, I'm not aware of a lot of things. The Wombat Workshop Manual is the best money you can spend to keep your bike in spec. Ditto on the Original Hodaka Ace Series Workshop Manual. Good luck with the Road Toad.

[spudman]

Thanks Matt! I didn't even know that such a workshop manual existed. I'm assuming you're referring to the one available from Strictly Hodaka for about $46.00 (part 209004)? I'm going to start with checking that wiring tomorrow and I'll remove the battery and check that as well. Something tells me I'll be ordering a workshop manual too. Oh...and yes...I do have good spark and the headlight bucket switch is in the "AC" position.

[Hydraulic Jack]

Not saying this unit fits the Toad, only that if you look for one, you will probably find one that will work.

https://www.1000bulbs.com/product/56320 ... gI92_D_BwE

Not to mention that they are far cheaper than any standard lead acid battery intended for bikes. I found a 12v SLA universal battery at the hardware store that perfectly fits my 70's vintage road bike and it has been working for a year now. They have blade connections not screw posts, but that isn't a problem, and for some reason they tend to hold a charge longer than standard wet batteries.

[thrownchain]

Start with a fresh battery, with the bike running Rev up the motor some and check the charging voltage which should be in the 7 volt range to charge a 6 volt battery, (for a 12 volt you should be putting out close to 14) .

[spudman]

I just ordered a new maintenance free battery a few minutes ago. I went with this one:
https://www.amazon.com/MotoBatt-MBT6N4- ... att+MBT6N4
I looked at my current lead acid battery and it appeared that 2 cells were good but the third was filled with some black goop much different looking than the more clear-colored acid/distilled water solution in the other two cells. Still, when I emptied that goop out and replaced it with distilled water and threw it on my 6 volt Battery Tender brand charger, it only took 30 minutes to reach a full charge (at least according to the solid green light on said charger). Just curious thrownchain...when I put the new battery in and start the bike and rev it up a bit to check the charging voltage, where exactly should I connect my volt meter? Is it OK to just use the pigtail for the Battery Tender that I have wired into my system? Thanks for your advice as well, Hydraulic Jack.

[Hydraulic Jack]

Charging voltage is always checked at the battery terminals with the battery installed and fully charged. All new batteries require charging before use. Doesn't matter what the sales guy says, or what style battery you have. Trickle charge to full capacity before installing. The bike will not, repeat not, charge a battery from a discharged condition. Cars and trucks won't either. The charging system is intended to maintain, not charge, a battery.

As for green lights on chargers.......the green light only indicates what the manufacturer intended it to do, which has nothing much to do with state of charge of the battery and far more to do with voltage achieved and load and time required to achieve that voltage. Long story short, the only way to determine the state of charge on a flooded, lead acid battery with maintenance plugs is to use a hygrometer to verify density (specific gravity) of the acid itself. The specific gravity when charged should be 1.265. If you use the four ball device, it would be four balls floating. In your case you may find that the cell you emptied and refilled is dead, SG 1.0, no balls floating. Generally speaking, you can not remove liquid from a dead cell and refill with water, or acid, and expect the cell to revive, certainly not in a half hour. It was dead for a reason, and the liquid probably wasn't the reason.

In your case, let that "fully charged" battery sit overnight and check the voltage. It will probably be 5 or less instead of the 6.75 it should be if it were actually fully charged. 6V in a 6V battery is a dead battery. Each cell should produce 2.25 to 2.3 volts max, for a total of 6.9 give or take. 6.6 or 6.7 is normal and pretty good. I have found that SLA batteries usually float at a bit more than their flooded cell brothers. Wouldn't be surprised to see 7 volts out of a fully charged at rest SLA battery.

[spudman]

Thank you VERY much for that excellent information Jack! I'm hoping that my new battery will solve my issue and that I won't have to do any further disassembly/diagnosing. I'll do the charging voltage test on the fully charged new battery once I get it and install it. As for the old battery, I'll let it sit a day or two and then check the voltage to hopefully confirm that it is in fact shot. I'll borrow a hygrometer from a friend and check the specific gravity as well.

[matt glascock]

Yep, PN 209004. Its a great manual. Mine remains near the top of the stack always.

[spudman]

Hydraulic Jack....you were right on the money. My supposedly "fully charged" battery was 5.29 volts this morning after being left off the charger overnight. Thanks again for your help!

[spudman]

Well, I installed my new MotoBatt MBT6N4 sealed battery tonight. The lighting is all working fine when the bike is running. BUT...when I measure voltage while the bike is running (at the terminals) I'm getting between 8.2 and 8.4 volts (depending on RPM). Is this OK or is this too much? I bought the Wombat shop manual and while there is tons of great info in there, there is no mention whatsoever of a voltage regulator. It does show a "current limiter" in the 125 Wombat electrical diagram with a green wire, so I assume this is what became the "voltage regulator" (same green wire) on the Road Toad. The thing is, there is no mention of how to test the regulator or what the charging system voltage output should be in that Wombat shop manual. Anybody want to chime in? Thanks! Oh...and I DID perform the tests on the rectifier and all were fine.

[matt glascock]

Spud, the current limiter included in the electrical system on the Model 94 Wombat is quiet rudimentary compared to the voltage regulator you have on your Road Toad. In fact, from a suggestion offered me on a recent thread (M94 lighting lightening), I upgraded the "limiter" on my Wombat rider to the Toad "regulator". The Wombat manual will provide great information for servicing many of the operating systems on the Road Toad but there are some differences, as you pointed out. In general, the Road Toad is a somewhat more sophisticated machine (Reed valve induction, oil injection, electrical system, etc) but with that, they are more alike than different. In reality, the Road Toad was introduced three years after the Model 94 Wombat and is thus more evolved. Unfortunately, PABATCO never offered a Shop Manual for the "painted tank" models so we have to extrapolate a bit. I'm not trying to be cavalier with your hard-earned money, but if you can find one on the cheap, you might also find benefit in obtaining a Road Toad owner's manual. In addition to exceptionally clear and well done exploded parts diagrams and wiring schematics, there is a clear explanation of how to service, adjust, and bleed the oil injection system. If between the Wombat Shop Manual the Road Toad owner's manual there are unanswered questions, this forum is frequented by guys (and at least one gal) who know every thing there is to know about these machines and share their encyclopedic knowledge with those of us trying to keep these insanely cool bikes alive. How cool is that?

[spudman]

Thanks Matt. I already have the Road Toad owner's manual. While there is much information to be had in it, alas...there is no mention of proper charging system output or how to test the regulator. At this point I'm just going to order a new/used regulator and hope that it limits the voltage going to all my lights the way it should. Now that I think about it, I'm not even sure that just because I'm getting 8.2 to 8.4 volts at the battery with the bike running that this means that the same voltage is actually making its way to the bulbs. Wouldn't that be dependent on where in the electrical system layout that the regulator is actually placed? Speaking of that...I'm not even sure that I know where exactly it is on my Toad! I know the rectifier is bolted to the battery box, but is the regulator down under the seat too or perhaps up under the gas tank?

[Hydraulic Jack]

First your question: is 8.2 to 8.4 volts too much?

A. No. sounds about right, and very much in line with the rated output of Hodaka lighting coils in those years when Hodaka cared to state what it was.

Another question implied if not asked, is the voltage at the bulbs the same as at the battery?

A. Should be or at least as close as the resistance of the wire loom will allow. Why not check it?

Someone with specific background in Hodaka current limiters should offer something a bit more dispositive, but in my limited electrical background a current limiter and a voltage regulator are not the same thing and don't try to do the same thing. Current has more to do with amperage than voltage. The explanation as to which does what is esoteric and I have not mastered the language, but it's out there to find. Point is that a current limiter limits the number of amps that can pass out into the system, and a voltage regulator does not. An example of a current limiter is a common resistor. A voltage limiter or regulator holds voltage down to a fixed range when offered a source with more potential output than the regulator is set for, but within that range will do nothing much to limit the amperage output. It may respond to amperage demand by allowing the voltage to float up a bit, but doesn't per se limit current. Regulators are more complicated than current limiters and often use electromagnets to control voltage in older systems. These days regulators are solid state and I think use MOSFET devices to regulate voltage output, but don't hold me to the actual gizmo that does the work these days. I took electricity classes about the time transistors came into common use. Things have changed (but I do still have a tube powered CB radio.)

So, a current limiter should act to prevent a current spike from cooking off your bulbs, whereas a voltage regulator will hold an upper limit on voltage output, allowing the load on the system to dictate what amperage is used. One protects the bulbs from burn out, the other protects the battery from over cooking.

If I had to have one or the other, I would opt for the voltage regulator. I just don't think the Hodaka system puts out all that much amperage to start with, and unless you are down to one light bulb, I don't see a risk of over-amping the system. Not to mention that Hodaka chose to change from one to the other within the same model of bike. Must have had a reason.....

[spudman]

Thank you Hydraulic Jack! I hear ya' in terms of what Hodaka put in their specs for the lighting coil output. The exact text in my owner's manual reads, "Over 6 volts at 2500 RPM (with 45 watt circuit load) - Under 9 volts at 8000 RPM". I guess my biggest concern is that I'm going to fry the filaments of all my 6 volt bulbs by putting 8.4 volts to them. Small bulbs don't worry me, but the sealed beams are getting harder and harder to find. That said, I too don't fully understand the whole voltage versus amperage thing, so maybe the voltage my charging system is putting out isn't all that out of the ordinary after all. Any other model 99 Road Toad owners out there...feel free to check your output and let me know what you've got!

[Hydraulic Jack]

The headlight should be running on AC. I would have to look at the wiring diagram to know if the AC headlight output is directed to the headlight before or after the voltage or current limiter. But, the charging system puts out only 45 watts according to the book, which tend to limit things greatly.

The relationship between watts, volts and amps is W=VA. The system puts out electricity at varying amount according to rpm: 6v at 2,500 to 9 at 8,000, numbers rounded up. Wattage is a function of demand or load based on what uses the electricity, in this case light bulbs and battery, but the system also has a maximum design value available from the lighting coils (45), so just as the voltage varies with rpm, so does available wattage. Running down the road with the lights on you have a headlight at 35W, a taillight at 5W, and perhaps a backlight bulb or two in the speedo at 1.5W each. Right there, you are talking 43W, leaving very little left over to use if the system is putting out its rated maximum. That little bit of left over is what keeps the battery charged. Hopefully.

If you hit the brakes, that changes the taillight to an added 20W draw. That's 63W in a system that maximum puts out 45W. The extra is supplied by the battery. With so small a charging margin and so large an overdemand from such things as brake light and turn signals, you can see why the battery is worked hard and needs to be checked frequently and recharged when needed.

It is the very easy to achieve combo of watts used being frequently being in excess of watts produced that leads me to prefer a voltage limiter to a current limiter. With a good battery in circuit to absorb excess current in times of low demand, I don't see why the system would need to limit current. It barely makes enough to keep things lit as it is. But the battery can be damaged by excess voltage, so anything much over 9 volts would eventually be harmful, whereas at the correct voltage, excess amperage available would only charge the battery faster, which isn't such a bad thing.

[matt glascock]

Maybe I can flesh out a bit of the language pertaining to basic electrophysics. One of the most useful formulae in the understanding of electrical circuits is Ohm's Law which states specifically voltage = current x resistance (V=IR). Voltage can be thought of as the potential difference in charge across a conductor that allows for the flow of electrons. In simple terms, voltage (V) can be considered the "pressure" that drives the flow of electrons. In the equation "I" refers to current in amperes. This is the actual flow or electrical current, as a stream of electrons, along a conductor. In Ohm's Law, resistance (R) is the feature of the conductor which works against the free flow of electrons along said conductor. Think of it is terms of a simple hydraulic system where a source of pressure (voltage) moves water through a pipe. The pressure in the system (V) is equal to the amount of water flowing (I) multiplied by the resistance (R) or V=IR. As Ohm's Law is an equation, you can see that changes in one variable bring about reciprocal changes in the other variables to maintain equality. In other words, if you increase the current, you have to decrease the resistance to maintain the same voltage and so on. Both inappropriate voltage and inappropriate current can result in electrical failure of the lighting system. Think of shuffling your feet across the carpet and then touching a lamp. You've just accepted 10's of thousands of volts with negligible current. Unpleasant but not deadly. Touch that same finger to the 220 volt service in your basement and you're dead. Massive current is the lethal component. (differences in direct and alternating current notwithstanding). Its also the reason you can plug a 40 watt bulb and a 100 watt bulb into the same electrical outlet in your home and neither will blow. Why? Same voltage, and less current due to more resistance. Devices in our Hodies to protect the lighting circuits are ultimately tasked to maintain ~6 volt potential across the filaments of the bulbs by limiting the current or adding resistance. A couple volts either way won't matter. Oh, on my Toad, the regulator is mounted under the tank. I can only assume that is the stock mounting position.

[spudman]

Thanks once again Hydraulic Jack for a very informative response! At this point, all I'd love to be able to do is somehow "test" my voltage regulator and I just can't seem to be able to find any solid information on how to do that. If the 8.2 to 8.4 volt output that I measure at the battery terminals while the bike is running is in fact "OK", then I guess I shouldn't worry. I did order another used regulator though, and I'd really like to be able to test and somehow compare it to the one I have installed now. Oh...and as an added bonus, here's the wiring diagram for the model 99 Road Toad.

[Hydraulic Jack]

Not sure you can readily test a voltage regulator without subjecting it to a volt source, unless you have a spec sheet showing internal values. But you can test your charging system with a voltage regulator in the system and then test it with the same part removed. That should give you an idea of how well the regulator works, and as long as you don't go riding into the sunset with the regulator or limiter removed, you shouldn't jeopardize your components.

Unfortunately I don't have a Hodaka road bike to test, having pulled out the lighting coils many moons ago. Ed has said that he can fire a 12V headlamp using a 6V Hodaka system and get a good strong light, so quite possibly there is untapped potential in the charging system. I imagine he is doing so without a 6V regulator in the loop, or the headlight is powered before the AC gets to a limiter.

[spudman]

Thank you again Matt Glascock and Hydraulic Jack for the info. I'll play around with the test meter and see what I can find!