I hesitate even mentioning this because don't really want to start a firestorm, but I am considering replacing my generator with an alternator. My car's electrical requirements (6 volt ignition system, tails/stops, and headlights) are loading my stock generator more than I am comfortable with. So I'm considering installing a 6volt gear driven alternator. My dilemma is that I know nothing about the types for sale out there. Are they all pretty much the same animal from different vendors? Or do some units have a higher reliability than others? Which ones should I consider and which ones should I avoid. Please advise.
I was having problems with my generator and decided to change to an alternator. I bought one from Buckeye Auto Electric in Painesville OH and have been very happy. It works on my 6 volt system and is plug and play. Any questions feel free to give me a call. 313.980.7048. Rick
I am not in a position to advise, but am curious as to why you think you're overloading your generator? The electrical usage you have described is typical to every T with a generator.
Your battery is providing your power, and your generator is keeping the battery charged. Are you having issues with the battery running down?
As an aside, if you do go with an alternator, plan on replacing your wiring, as stock wiring is not up to the demand that the vastly increased amperage from the alternator will place on it.
If you go alternator, get a Texas T unit. Bird Haven is good to deal with and will stand behind it.
Being an electrical dummy, the question has me wondering. Isn't the generator putting out the same "amount of juice" to the battery no matter how much is being "sucked out" of the battery by the coils, lights, horn, etc.? If that's the case, I would think it makes no difference to the generator how much current is being drawn from the battery. As long as the ammeter shows a charge when the engine is running, isn't the battery happy (if there's a VR to prevent overcharging)?
John Regan or Ron Patterson will have the best info, but my foggy understanding is that the generator output when using a cutout is roughly fixed and is set by the position of the third brush.
With a voltage regulator, the output of the generator will vary depending on the electrical demand. The position of the third brush sets only the maximum generator output.
Your car, your money, but an original generator in working order should take care of all your daily needs for ignition system, tails/stops, and headlights. Just adjust the third brush to charge maximum about 12A continuously, that makes 90w at about 7 volts charging voltage.
With an accessory voltage regulator that'll be adjusted down when not needed, and if the battery gets run down after several hours driving with lights on, then you can just plug it into a float charger at home - you'll have to drive really far with the lights on until all the juice in the battery is gone and I bet you'll be home for a nights charge in between
Is it the output of the generator that varies, or is it the output of the VR? In other words, doesn't the generator provide constant output and the variation is from the VR?
The voltage regulator rapidly switches the current to the generator field coils on and off via the opening and closing of points, which modulate the generator's output.
My understanding of the FP regulator (which is installed on the generator), is that the output of the generator stays constant to where ever the third brush is set, and the VR takes the excess voltage beyond what the system needs to keep the battery charge up and shunts it to ground. The generator is a rebuilt unit and functioning fine, the ignition system is non-stock. The generator output is set at 12 amps currently, however I can only drive for a couple miles with the lights on before the system voltage appears to drop and the coils start cutting out. The system works great just doing daytime driving, but the minute the lights come on my drives need to be limited. I don't see my amp requirements ever being over 14-15 amps, but pushing a generator that hard scares me.
What ignition are you running? It sounds like you have a short somewhere if it's draining the battery that fast just by turning on the lights.
Electronic coils. Amp draw about 2.1-2.3. Lights are 25 watt halogen: draw 4 amps ea. (same as 32 cp bulbs. Tails/stops draw about 1.8 amps. No shorts in the system or ignition switch I could find. Battery probably takes a steady 1.5 amp to keep it charged. The more I think this over the battery gets my attention,but last I checked it all the cells were OK.
I've found the best results are always obtained by opting for the most complicated and expensive remedy first. ;- )
Oh - wait ! April Fools Day was last Saturday !!
Sounds like you may have a short.
A quick and dirty way to check for a short is to disconnect the ground cable from the battery and then touch it lightly to the battery post.
If you have a short, it'll often spark just a tiny bit.
There's a half-dozen other ways to check as well.
Kevin- don't do it, just fix the problem. A properly working generator will operate your electrical system just fine.
Don't fall victim to the myth that the original system is flawed- just fix the problem.
I gave up the generator for alternators 12 years ago. best T move I've made.
Yes Jerry, but you also use a water pump.
The generator third brush sets the MAXIMUM amount of current that the generator will put out. But that max only appears at the higher RPM. At idle the generator is not putting out very much if any current. The VR is a device that senses the present state of charge of the battery and allows ALL, SOME, or NONE of the instantaneous generator power to be sent to the battery. That power is measured at all times by the ammeter. If the battery is low and the RPM's are low then the battery may not charge at all but that is OK for a time since the battery has a lot of reserve and all power will be put back into it once the engine revs up and the car starts making speed UNLESS the generator is adjusted to only put out a small amount of current. The proper adjustment of the generator third brush is very important so that the VR has a lot of dynamic reserve at the generator to quickly replenish the battery as things start to demand power from it. The main job of the VR is to prevent overcharge when the battery is full and the third brush setting is high. If the third brush is not set high enough to carry all of the loads (lights, coils...etc) then driving the car will result in a battery being discharged somewhat at the end of the drive. How much discharged is determined by the rate of flow out of the battery versus the charge rate into it. When the battery is needing charge the VR will allow ALL of the power of the generator to pass to the battery and will only start to limit it when the battery nears full charge. If the T is running on magneto during the daytime there is no load at all on the battery ( except intermittent brake lite) and the VR will basically shut the generator OFF once the battery is fully recovered from starting the engine.
I know this is lengthy but I tried to give you all of the possible scenarios so you could see how it works. The VR is connected between the generator and the battery and has to deal with variance on both its input (generator power) and its output (battery state of charge). Thus it is very busy all the time. It also watches for something like a sudden battery disconnect that would thus destroy the generator due to no load. It shuts the generator off completely when that happens to thus save the generator.
Thanks, John. Like I said, I'm "considering" the alternator, not sold on it. I know several fellow Model T folks in my club that swear by alternators over generators. That being said, as long as the generator is capable of providing my electrical needs, I'm good with it. Need to spend some time doing a few more adjustments to see if I can get the results I want. By the way...what is the maximum number of amps a generator can safely put out without melting down?
Kevin- the generator IS capable of providing your electrical needs. Send it to Ron Patterson and he'll check it out for you. With a properly functioning generator and good wiring your system will work perfectly.
You have to use common sense. If a guy removes a junk generator and replaces it with an alternator he will then adopt an incorrect opinion that generators are flawed.
The battery is a very vital part in the charging system - it's the voltage regulator in the original system. Check the cables and connections and considering the poor performance with lights on, I'd suggest you may be better off with a new battery rather than changing your original generator
Alternator is the way to go you only have one wire built inregulator. get it from Langs or Snyders there are several others that sell them. $225.00.
It might be in the way you interpret the ammeter readings. If you are driving most of the time with the lights on, you will show a constant discharge on the ammeter. You might be able to adjust the generator to just about equal the draw with the lights on when driving at high speed but it would still show discharge at idle. If you set the generator this way you will overcharge the battery when you drive with the lights off.
Most of us do most of our driving during the daylight hours with the lights off. In this case, adjust to put out a maximum of 3 to 5 amps when driving at normal crusing speed. If your battery stays charged, you are OK. Occasional night driving with lights on should not be a problem unless you drive all night or you have a worn out battery.
If you want your ammeter to read more like that of a modern car, you can use a voltage regulator and if you do a lot of night driving that is what I would suggest you do.
An alternator will not give you better charge than a good working generator, but it will charge at a lower engine speed.
I've got one on the bench that's fried. Just got a rebuilt from Brent Mise that's awesome. And by the way Brent I'm sending you a bunch of cores and armatures.
Rebuilt generator that is.
Quote: "The generator output is set at 12 amps currently, however I can only drive for a couple miles with the lights on before the system voltage appears to drop and the coils start cutting out. The system works great just doing daytime driving, but the minute the lights come on my drives need to be limited."
How old is your battery? Has it been load tested? It sounds like your battery is not very good.
If your T is a driver and you want worry free charging output at low engine RPM an alternator may be just right for you. If you aren't worried about being original go for it. Another option might be to use LED headlights, much smaller power drain. A generator will put out without a doubt, last time we ran my old 26 we had borrowed a generator (modded for a T) and ended up driving with the lights on during the day so as to not overcharge the battery. As I go thru the car this week bringing it out of about 10 years of storage I will be installing an alternator.
My generators are mostly set at 12 amps, like yours. I have never had a problem keeping the battery up, nor have I ever fried a generator. I'll also say that I don't use halogen headlamp bulbs as you are doing. When you're driving down the road, with headlights on, what charge/discharge are you showing on your ammeter? Mine is usually showing a charge from 0 - 2amps under those conditions.
Sometimes, when using dual filament headlamp bulbs, people will make a wiring error and have all 4 filaments light up at the same time. That WILL draw your battery down fairly fast.
As Ken suggests, I am also wondering about the health of your battery.
Jerry, I'm beginning to wonder about the health of the battery as well. Having all kinds of fun dealing with the latest incarnation of the Black Death here in northern WI. As soon as I feel better. I'm going to head up to the garage and do a cell test on the battery. Its only two years old, so you wouldn't think that would be an issue. But could be wrong on that. The 25 watt halogen bulbs draw the same as 32 CP bulbs: 4 amps/ea.
How accurate is your ammeter Kevin? Got an original in your 26/27 or is this a different car? The repro version of the ammeter for the 26/27 is sometimes off by more than 50%. I have a drawer full of them that various folks have sent me. If the battery is not being topped off every time you drive by your charging system then the battery won't last much more than one or two seasons unless you are in the perfect habit of topping it off each time by using an external charger.