My '26 coupe currently has no generator as it was lost in the mail on its' way to being rebuilt. It is equipped with a generator hole cover and the battery starts the starter motor just fine on BATT and the Wally built magneto (Total Recoil) provides the necessary voltage for operating all systems on MAG.
Question: In the absence of a generator, does the magneto recharge the battery? Jim Patrick
If you have a good mag, some voltage can be robbed to do some battery charging.
Jack is right but you can trickle charge the battery using the magneto. All you need is a 25-30 amp diode and a 12 volt headlight bulb. Connect the diode from the magneto post and run the current through the 12 volt bulb to the battery. The diode rectifies the AC magneto voltage and makes it DC. The Headlight bulb regulates the current and drops the voltage.
Fun Projects sells a kit with the necessary components, but it is intended to charge a 'hot shot' battery used only to fire the coils. While it might eventually recharge a starting battery, I doubt most people would ever drive long enough between electric starts for the magneto to replace the energy the starter drained from the battery.
Actually if the T is in good tune and your magneto is healthy then you can get a pretty constant 1 to 1.8 amps of charge into a 6V battery. At even one amp of charge your battery can recover in about 17 minutes of driving and less than that if it is a high speed drive. The average T owner is so accustomed to "overcharging" as being OK that I have never had anybody believe me that when using a cutout they ought NOT to set their charge rate any higher than 3-4 amps. Just every person I try to convince otherwise will then always assume that "more is better" and so 4 becomes a 5 amp setting and then a 5 becomes 6. I just got off the phone with a guy who has his cutout equipped car with "rebuilt" generator set up at 12 Amps. He is having problems but thinks that he needs at least that much charge and is looking for advice that agrees with his thinking. He is convinced he needs more charging and I didn't convince him otherwise. He will end up with an alternator most likely and since the alternator has a built in VR he will end up charging even less than the 3-4 amps he was sure wasn't enough - go figure. My son has a '16 roadster with a healthy magneto and our HSBCK1 kit is all he has on it and we check that full sized 6V battery regularly and find it is always "up" to full charge. Of course it will not keep up with headlights too but since he has a full sized 6V battery in there - he can run with the headlights on for several hours and we are religious about putting an external charger on it when he gets home. Its not a bad simple setup for a car that is a typical daytime car with only occasional short night trips.
Does this magneto set up also work for a 12V battery.
For the 3-4amp setting of the generator You don't need to convince me it even works great for a 12V system.
Headlights.....That's the part I wasn't thinking about. I knew there was something about it not being able to keep up, but was thinking of the wrong thing.
The charger will indeed work with a 12V battery but at a lower charge current since there is less difference in voltage between the magneto voltage (peak AC) and the battery voltage.
I don't know if they are still available, but Bittner made 6 and 12v magneto chargers, I ran a 6v one for many years to a 8v deep cycle battery in my 16.
There was a real problem with the Bittner chargers. They were not made real well and several folks had their magnetos rendered useless by them
The other real problem with the Bittner device is that he was charging about $100 for something similar to the one John sells for about $25. Its other other real problem was that it would not work with stock coils and timer.
I used one of John's on my '15 Touring for several years and many thousands of miles, and it was still working great when I sold the car a couple of years ago.
Never had a problem with mine, using old coils and tiger timer for several years. Disconnected now though, developed a miss on magneto when the coils had been checked and tuned so if I need battery charge for night, just hook a wire back up and run engine and lights on battery.
The anode MUST be connected toward the mag post or the next post might be: "How Do I Recharge Flywheel Magnets In the Car".
anode ------>|------ cathode
I found this instructions on the internet several years ago, worked fine for me.
I notice in the lower right corner it says "To clear shorts leave on contact for 30 secs".
That is some spectacularly bad advice.
This topic is 'just in time'. This is a message from Belgium .
I recently got a 1913 touring without generator . I like to keep it as original as possible without installing a generator if at all possible .
I was wondering about trickle charging as John explains . I have a starter added on later on a 12 V battery .
A HSBCK1 kit seems the answer , but here are a couple questions : how do you know or how can you check the magneto is " healthy " or how much extra current is produced during driving for charging ?
Lights (or LEDs ) are becoming a necessity in Europe : red stop and amber turning lights in the back, white parking lights and amber turning lights in front , not to mention headlights compulsory in certain countries .
That is for "occasional use " , but a wise safety feature .
Kerry , do you have more advice ?
Thanks to all
To test magneto output use the Regan - Patterson memorial test procedure:
Wire a #1156 bulb across from the mag post to ground. I made mine by soldering a foot of wire and two alligator clips to the bulb, then wrapping duct tape around the bulb base.
Start the engine and measure the voltage at the mag post. It ought to be 5 - 6 volts AC at idle and about 18 - 30 volts at higher engine speed, typically enough to burn out the bulb in a few minutes time. The cheaper the voltmeter the better, I use an analog unit from Radio shack that cost $9.95.
Here is the proper way to charge the magneto. Please follow this rather than the one posted by Kerry. Of course you can use three 12 volt batteries instead of the six volt types shown.
Thanks Royce , but this gives voltage . Don't you want to know the amps to see if you have spare power ? Is there no minimum ?
Do I need new glasses Royce? what in gods name is the difference in the two sets of instructions? other than some ones idea of clearing shorts.
Right or wrong for those instructions, all I can say is, other than the short instruction which I didn't use, I went from a dead magneto to a crank start magneto and several years later still the same, as well as using the magneto as a battery charger.
I'll let the electronic engineers comment on the merits of the repeat of 1/4 turns.
2 things to watch for, flash the earth side as you don't want to fuse the magneto pick up post thread and if true or not face the car east/west or west/east.
Kerry and others:
I totally agree with Royce on the advice that says how to remove "shorts" in the magneto. It is easy to change the statement into something more accurate by saying "to INSTALL a short into your magneto ring and then perhaps blow the ring itself open - many folks have used this procedure of holding the power in place for ......" I cannot see any possibility of doing anything good for the mag ring by holding 144 amps through that mag ring for 30 seconds. 36 volts/.25 ohm of resistance=144 amps - OUCH!! The power that the ring is forced to deal with is 144x36=5184 watts. Man that is a lot of heat.
I agree that it is a good idea to apply the juice via a momentary ground scratch wire to the hogshead somewhere to save the magneto post threads. I also would like everyone here to know that I recharged the mag in my son's 16 roadster using 18 volts total and it came back to full output from less than a few volts. The usual Model T rule of "more is better" is still alive and doing damage I guess. Everyone seems to think that overkill is necessary and advisable. Since it takes less than .04 seconds of applied power for the field to build up in the mag ring - there is little to be gained by repeated applications. The entire mag ring is in series so the applied strength is the same everywhere but I suspect seriously that if you could actually measure the amount of magnetic strength a magneto has after each jolt you probably would discover that the strength would go up and down depending on magnet/winding alignment. Entirely possible that the first jolt left your mag hotter than the last one but in any event the last one is likely the only one that determines your magneto strength assuming you are moving the flywheel and thus the magnet alignment to the mag ring on each movement.
I never recommend anyone try in in-the-car recharge unless they have nothing to lose - then go for it but give you magneto ring a chance to survive by cutting the voltage by half to 18 (I used modern 12V battery and my son's 6V T battery in series) The car has a good hot mag and the magneto ring was not damaged. Your mileage may vary.
You can measure the charge rate from our HSBCK1 to your battery simply by inserting a DC ammeter in series with the circuit at the mag post, light bulb, or battery end. You can use your test meter if it has a 10 amp DC scale by selecting that scale and putting the meter in series. Don't try to use a digital meter unless you just like to watch make-believe numbers jump around Model T's just love it when people use digital meters on them to measure things. It is even more fun when the digital meter is a lab grade($$$) Fluke meter and the owner thinks that makes a difference.
Thank you all for your input. If a good magneto and a well tuned car can generate sufficient excess voltage to charge the battery while driving for 17 minutes, as John Regan suggests, in current wiring diagrams, is the magneto wired to the battery so that this voltage is used by the battery? If not, can the magneto be wired to the battery through the ammeter in place of the generator so that the battery can receive this excess voltage? If so, can someone provide a schematic with which to do this? If one drives, say one hour (43 minute over the 17 minutes needed to charge the battery), since there is no cutout, can the battery be over charged and if so, how can this be prevented? Jim Patrick
No, the magneto is not connected in any way to the battery on a stock Model T. To do so without the diode mentioned above would result in discharging the magnets. To use the magneto as a battery charger, you will need the diode and light bulb mentioned above. If one were to know exactly what they were doing, they could probably buy the individual components and build the thing themselves, but it is much easier to just buy the kit from Fun Projects. It will come with very detailed instructions on exactly how to do it safely and effectively.
In an unmodified Model T there is no connection between the magneto and the battery. The purpose of the magneto is to supply 6 - 30 volts AC to run the ignition coils.
The "magneto" in a Model T is actually what engineers today would call a permanent magnet AC generator. As John says, you can purchase one of his devices which will provide a limited amount of DC voltage to slowly recharge a small battery.
Again, the reason Kerry's drawing should not be used is because following those instructions will in most cases ruin the magneto coil ring.
That's not quiet true Royce, nothing wrong with the instructions for recharging the magnets, many instructions for in car or out of car charges from different publications state the same way and I think if you have established the fact that your coil ring has a short, you have nothing to loose to clear it per instructions.
You seem to have interpret the part of clearing shorts as part of the re-magnetizing, I see it for more of what it states, to clear shorts!
Actually the drawing you have posted seems to be incomplete, instructions for 1/4 or 4x90degree turns and charge is missing, several publications are available from different sources for in car and out of car re-charge, all stipulate 1/4 turns.
That instruction won't "clear shorts." It will only cause melted solder. Also there is no reason to turn the motor over and repeat the process every 1/4 turn, that is just nonsense written by someone who has no clue what they are doing or why.
In any case the picture I posted from the 1919 Dykes manual is correct and has no errors, and can be used without any disclaimers. That's why I posted it. It is correct, and your drawing is mistaken.
Do you want to ring Russ Furstnow and tell him he has no clue what he's doing or why? I'm sure you would know him, right?
Hello to all ,
It seems this subject is coming up on a regular base .
In previous forum discussions I found the following previous sessions simply on internet. There must be more :
--magneto voltage output testing - of Nov 15 2009 by Mark C Vlasak
--magneto output voltage - of March 31 2007 by Vray
--magneto output - of Feb 6 2008 by Bernard Byers
--Mag output- of Nov 2 2010 by Tyrone Thomas
If we put all this wisdom together we may end up with a valuable landmark article we could all agree on .
One thing that is very interesting is that FORD never once published worst case or minimum specs on the magneto with regard to either voltage, amperage or anything else. They did take some measurements once and published those measurements. Many people have tried to turn those measurements into some sort of Ford spec on the subject but those Ford numbers are the only ones ever published and they are also the same exact numbers repeated by many repair manuals including Dyke's. They all used Ford numbers and copied them - not one specification was ever put out by anyone. How do I know - the numbers of output voltage, frequency and amperage all agree exactly between Ford and Dyke's and others proving nothing except for a small problem - the Ford numbers are impossible and have a glaring mistake in them and guess what - Dyke's book has the exact same mistake ha ha
There is no specification how much power you can legally rob from the T magneto without causing the coils to quit working properly. One can only compute the power taken by the headlights when the car ran on magneto headlights and then use that power as the amount you can steal but that didn't work too good since the headlights burned out rather quickly. Lots of test data can be taken but there is no specification that Ford ever put together to state the exact amount of Magneto power that a working magneto should have. Others like St. Louis Electric Works did some real testing on this and came up with the only known "go-nogo" tester I know of. We reproduce it as our MT-1 and it works really great. We are currently sold out of them but should have more on the shelf soon. That tester appears on many of Dyke's pages.
I've been pondering the reason for the instruction to rotate the crank 1/4 turn through a full revolution to properly charge the magnets.
While I have no data and I'm not sure I buy into it, one theory might be that the purpose of the rotation is to bring the magnets under different coils.
On the off chance that a coil might be partially shorted or the coil to magnet gap slightly to big, rotating the crank would increase the chances that each magnet would be flashed by a "good" coil with a minimum gap.
All the coils are wired in series. All the electricity much flow through all the coils to make a connection. If any coil is shorted, none of them work. Applying 36 volts for anything more than an instant will melt solder and ruin any good coils.
Rotating the crank is entirely a waste of time and effort. You can recharge the magnets out of the car by just laying the coil ring on the flywheel / magnet assembly and doing the same thing. Again rotating anything is not necessary. More is not better.
Something that has not been mentioned in this discussion is how dangerous this can be if done indoors. Batteries give off flammable and / or explosive fumes. When recharging a magneto be sure to flash the connection at the magneto post, not at the battery. It is good practice to install a brass acorn nut on the magneto post to protect the threads when doing this.
I could see some magnets having more gap than others and could even see the remote possibility that two or more turns in the same coil are shorted together, but not to ground. If this happened, that magnet would receive less charge as the field is determined by amp-turns. No doubt, each coil gets the same current, but there is a remote possibility the number of turns could vary, due to manufacturing defect or internal turn to turn short. I suppose that if there was a short to ground in the last couple of coils, that you would still charge the first 14-15 magnets and not the last one(s). These are the only reasons I could think of for rotating it 90 degrees and doing it again. I don't see trying to 'clear shorts' for the same reasons mentioned by Royce and others.
that is only Royce's opinion, he is not offering any expertise on the subject as others of more knowledge in the field of electronics can, and have published, very detailed information on charging the Model T Magneto is available through some T vendors as well as on a web search.
Actually Kerry I am quite competent to make a statement on the function and performance of such a simple electrical circuit. I am a very accomplished avionics technician with decades of experience and many hundreds of hours of formal electronics, electrical and avionics classroom training.
Please also note that John Regan is an electrical engineer and he also agrees in his post above.
That's good Royce, I don't pretend to know much about electronics as I'm only have a degree in the science of Mechanical Engineering, so I rely on the expertise of others in that field, the de-shorting and recharging facts go way back to 1923 in Ford bulletins by the Technical Editor, even using as much as 110 volts to check if short has been rectified buy a lower voltage contact, the 4 way recharge, is quoted in publications as, 'rotating the field coil insures a full, even charge'
I sure many have been lucky to end up with a functional magneto by a single charge.
Rotating the crank makes perfect sense to me for a balanced charge. It compensates for any variance in the distances between magnet clips and the coil carrier or a shorted coil. An air gap reduces the strength of the magnetic field exponentially. It may be extra work but certainly not a waste of time if you want to ensure equally charged magnets.
And a coil shorted within it self will not keep the rest of the coils from working. Only if a coil is open will it affect the series.
I had a great deal of success in 2010 in charging my magnets in the car using the 4 way method that has created such controversy in this thread. I charged the magnets using (3) 12 volt batteries and zapping it 32 times. (8) quick zaps at each of the (4) 90 degree points. As Royce says, a 30 second contact to "clear shorts" is spectacularly bad and harmful advice, as anything more than quick, instantaneous (less than a sec.) zaps is dangerous and could destroy your magneto. Three years later my car runs like a dream on MAG, so I must have done something right and will do it the same way again if it ever becomes necessary, which I doubt if it ever will.