Driving without mag or generator.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules
-
Topic author - Posts: 1997
- Joined: Sun Jan 06, 2019 12:23 pm
- First Name: Jeff
- Last Name: Humble
- * REQUIRED* Type and Year of Model Ts owned: 1926 Canadian coupe, 1924 TT C-cab, 1924 runabout
- Location: Charlevoix, Mi
- Board Member Since: 2006
Driving without mag or generator.
70 mile tour coming up and one of the participants has a T without a magneto and without a generator. Any experience out there how long the battery will hold out? Will be a full day of driving with perhaps 5-7 starts with the electric starter. Assumption is a group 1 6volt battery, not new, and less than fully charged at the onset.
Last edited by Humblej on Sun Sep 14, 2025 7:47 pm, edited 2 times in total.
-
- Posts: 7729
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- Board Member Since: 2021
Re: Driving without mag or generator.
That would depend on the size and condition of the battery, the battery's intitial state of charge, and the condition of the starter and the engine in general. Can the car be started with the crank? If so, I'd start with the crank to avoid issues with a depleted battery while on the road. OR, obtain a separate ignition battery and run the engine on that. A new riding mower type 12 volt battery could run the ignition for a good while if it had no other loads.
-
- Posts: 3909
- Joined: Sun Jan 06, 2019 10:56 am
- First Name: Dan
- Last Name: Treace
- * REQUIRED* Type and Year of Model Ts owned: ‘12 open express,'23 cutoff, '27 touring
- Location: North Central FL
- Board Member Since: 2000
- Contact:
Re: Driving without mag or generator.
“OR, obtain a separate ignition battery and run the engine on that. A new riding mower type 12 volt battery could run the ignition for a good while if it had no other loads.”
Good idea on carrying such a spare “emergency ignition” battery.
Can’t answer on the # of starts or how long that T in question for all day tour.
All I know is to expect the battery to be drawn down. Happened to me with a hand crank 1915 speedster, running only 12v battery ignition as flywheel was sans mag.
Tour around city of Memphis and my 12v car battery that was not new but charged recently ran down. Had to walk to gas station with the battery to charge it, walk back and continue the tour. A spare motorcycle battery would have been great.
Good idea on carrying such a spare “emergency ignition” battery.
Can’t answer on the # of starts or how long that T in question for all day tour.
All I know is to expect the battery to be drawn down. Happened to me with a hand crank 1915 speedster, running only 12v battery ignition as flywheel was sans mag.
Tour around city of Memphis and my 12v car battery that was not new but charged recently ran down. Had to walk to gas station with the battery to charge it, walk back and continue the tour. A spare motorcycle battery would have been great.
The best way is always the simplest. The attics of the world are cluttered up with complicated failures. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford
-
- Posts: 6351
- Joined: Tue Jan 08, 2019 4:56 pm
- First Name: Frank
- Last Name: Brandi
- * REQUIRED* Type and Year of Model Ts owned: Speedsters (1919 w 1926 upgrades), 1926 (Ricardo Head)
- Location: Moline IL
- Board Member Since: 2018
Re: Driving without mag or generator.
Distance is irrelevant as the coils don't take much juice. Headlights weren't mentioned and could be factor if not LED. As mentioned the starter condition is the major factor. My guess is the starter draw, 5 or 6 starts, wouldn't be an issue since a small 6volt mower battery do well.Humblej wrote: ↑Sun Sep 14, 2025 6:51 pm70 mile tour coming up and one of the participants has a T without a magneto and without a generator. Any experience out there how long the battery will hold out? Will be a full day of driving with perhaps 5-7 starts with the electric starter. Assumption is a group 1 6volt battery, not new, and less than fully charged at the onset.
Does anyone else have a 6volt car? bring jumper cables in any case.
The past is a great place and I don't want to erase it or to regret it, but I don't want to be its prisoner either.
Mick Jagger
Mick Jagger
-
- Posts: 7729
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- Board Member Since: 2021
Re: Driving without mag or generator.
In a case like the OP describes, I'd have a good, full size battery in the car dedicated to operating the starter only, especially if the car cannot be crank started. I'd have a separate battery for the ignition only, and I'd want it to be of substantial size and in good condition and fully charged. A second full size battery would be a good choice, and a riding mower type battery would be a good second choice. If the car can be started with the crank, that's what I'd use, and I'd want to get a functional generator installed asap on any car I used on a tour, more especially if it lacked a working magneto or if hand cranking was out of the question for any reason.
Last edited by TXGOAT2 on Mon Sep 15, 2025 9:20 am, edited 1 time in total.
-
- Posts: 7729
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- Board Member Since: 2021
Re: Driving without mag or generator.
A T will run on a near-dead battery if the ignition system is in good condition. However, it may not start using the starter if the battery is getting low on charge, since engaging the starter with a partially-discharged battery will drop the voltage severely, which is likely to render the ignition system inoperative as long as the starter is engaged. In such a case, the car would have to be hand cranked, or pushed, or jumper cables resorted to.
-
- Posts: 1531
- Joined: Mon Jan 07, 2019 10:27 am
- First Name: John
- Last Name: Codman
- * REQUIRED* Type and Year of Model Ts owned: 1927 Youring
- Location: Naples, FL 34120
Re: Driving without mag or generator.
I didn't See where you mentioned what battery voltage your T has. If it's 12 volts, the above posts are all good. If it's 6 volts, the garden tractor batteries are not going to work. In that case, I would recommend that you find another good 6 volt battery as a backup.
-
- Posts: 7729
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- Board Member Since: 2021
Re: Driving without mag or generator.
A 12 volt garden tractor battery will do a good job of powering the ignition on a 6 volt T with stock ignition. It will NOT operate the starter. It would probably burn out 6 volt headlights, tail lights, and brake lights, so it would be advisable to see to it that 12 volt power could only reach the ignition. The stock T ignition will perform well on 12 volts. In my experience, batteries always underperform their ratings, and where no on board source of power other than a battery is available, problems are to be expected. A T ought to have a generator or at least a working magneto so that headlights and tail lights can be run day or night, and the battery can be kept up to full charge for starting purposes if and when needed.
-
- Posts: 4874
- Joined: Fri Feb 12, 2021 12:24 pm
- First Name: john
- Last Name: karvaly
- * REQUIRED* Type and Year of Model Ts owned: 14/15 wide track roadster. 23 touring, 27 roadster pickup, 20ish rajo touring
- Location: orange, ca
- Board Member Since: 2020
Re: Driving without mag or generator.
How long will a T run on a 6V battery of unknown condition without a full charge?
A T with a good full size battery will run a T several days. Add electric starts = less.
I can recount a recent experience.
During a tour, on the last half of the last day, I noticed my generator wasn't. Plus I had to drive home the next day about 90 miles.
I was pretty nervous about the situation, but went ahead. Minimized starts (this T doesn't hand crank well, but can be started with a combination of hand & electric start if need be.) Made it home. 5 or 6 full re-starts for the trip home. When I got her parked I tested the electric start - Had plenty of power left for more starts. A lot of worry for nothing.



A T with a good full size battery will run a T several days. Add electric starts = less.
I can recount a recent experience.
During a tour, on the last half of the last day, I noticed my generator wasn't. Plus I had to drive home the next day about 90 miles.
I was pretty nervous about the situation, but went ahead. Minimized starts (this T doesn't hand crank well, but can be started with a combination of hand & electric start if need be.) Made it home. 5 or 6 full re-starts for the trip home. When I got her parked I tested the electric start - Had plenty of power left for more starts. A lot of worry for nothing.
-
- Posts: 526
- Joined: Sun Jan 06, 2019 8:15 pm
- First Name: Wayne
- Last Name: Jorgensen
- * REQUIRED* Type and Year of Model Ts owned: 1915 Runabout, 1918 Runabout
- Location: Batavia, IL
- Board Member Since: 2013
Re: Driving without mag or generator.
Before I recharged my mag, I used the following, small, 12v battery to buzz my coils on my hand crank 1915:
I could drive about 100 miles just using the battery to buzz the coils. I carried a spare, fully charged battery with me, and swapped it out at the end of day.
I could drive about 100 miles just using the battery to buzz the coils. I carried a spare, fully charged battery with me, and swapped it out at the end of day.
Wayne Jorgensen, Batavia, IL
1915 Runabout
1918 Runabout
1915 Runabout
1918 Runabout
-
Topic author - Posts: 1997
- Joined: Sun Jan 06, 2019 12:23 pm
- First Name: Jeff
- Last Name: Humble
- * REQUIRED* Type and Year of Model Ts owned: 1926 Canadian coupe, 1924 TT C-cab, 1924 runabout
- Location: Charlevoix, Mi
- Board Member Since: 2006
Re: Driving without mag or generator.
That gives me some idea.
-
- Posts: 1531
- Joined: Mon Jan 07, 2019 10:27 am
- First Name: John
- Last Name: Codman
- * REQUIRED* Type and Year of Model Ts owned: 1927 Youring
- Location: Naples, FL 34120
Re: Driving without mag or generator.
If you live in my skin, one mile less then you need to go.speedytinc wrote: ↑Mon Sep 15, 2025 11:36 amHow long will a T run on a 6V battery of unknown condition without a full charge?![]()
![]()
![]()
-
- Posts: 4874
- Joined: Fri Feb 12, 2021 12:24 pm
- First Name: john
- Last Name: karvaly
- * REQUIRED* Type and Year of Model Ts owned: 14/15 wide track roadster. 23 touring, 27 roadster pickup, 20ish rajo touring
- Location: orange, ca
- Board Member Since: 2020
Re: Driving without mag or generator.
I don't believe in Murphy's law.
I do believe in O'Tooles law.
He states that Murphy was an optimist.
I do believe in O'Tooles law.
He states that Murphy was an optimist.
-
- Posts: 235
- Joined: Fri Jan 04, 2019 10:01 pm
- First Name: Chris
- Last Name: Bamford
- * REQUIRED* Type and Year of Model Ts owned: 1924 Speedster 1926 Touring
- Location: Edmonton AB Canada
Re: Driving without mag or generator.
I’ve had some experience with this kind of operation. Starting out with a decent, fully-charged battery he should be just fine.Humblej wrote: ↑Sun Sep 14, 2025 6:51 pm70 mile tour coming up and one of the participants has a T without a magneto and without a generator. Any experience out there how long the battery will hold out? Will be a full day of driving with perhaps 5-7 starts with the electric starter. Assumption is a group 1 6volt battery, not new, and less than fully charged at the onset.
For peace of mind have a backup plan: could be simply a 20’ tow strap in case starting becomes a problem. Or maybe swap batteries with another T if his runs out. Or four able-bodied types push-starting him after each stop to preserve his charge.
Most fellow T owners will be happy to help in one way or another. Wouldn’t you? Wouldn’t he?
Back in the day lots of T drivers set out on journeys with way worse. Worst that could happen is delayed arrival and potentially a fun story to tell!
-
- Posts: 869
- Joined: Mon Jan 07, 2019 2:02 pm
- First Name: Vernon
- Last Name: Worley
- * REQUIRED* Type and Year of Model Ts owned: October 26, 1926 Coupe
- Location: New Orleans, LA
- Contact:
Re: Driving without mag or generator.
Had a '78 Honda Civic with carb. and points that made 2-1/2 days on dead alternator, over 100 miles.
Had a '84 Reliant with first gen computer that barely made it 20 miles to the first city after the alt. suddenly died.
The problem with using the starter on the T is that the battery may never recover after the trip; but the trip may be worth it.
Had a '84 Reliant with first gen computer that barely made it 20 miles to the first city after the alt. suddenly died.
The problem with using the starter on the T is that the battery may never recover after the trip; but the trip may be worth it.
Vern (Vieux Carre)