MTFCA Forum

Wiring isn't my strongest subject but I am tinkering on my Maxwell and want to do enough temporary wiring to try to get it going before I spend the big money on a correct wiring harness. Unfortunately, much of the original wiring has been removed so I don't have anything to go by for determining the correct gauges of the wires. Could I just go heavy enough to be safe for anything. I guess that the 2 batteries should use pretty heavy cables like 1/0 gauge, shouldn't they? The batteries are wired separately to the starter switch and when the switch is depressed the 6 volts put 12 volts into the dynamo so should the switch to dynamo cable be the same gauge or heavier?

Any advice would be appreciated.

This parts guide has the original gauges listed. I used 00 for my battery cables because I’m paranoid. Godspeed!

Tadpole,
Thanks for sending the parts list. That is perfect. I am guessing that the total combined voltage for the 4 dry cell batteries would be 6 volts, do you think that is right? I know that the old radio and telephone dry cells were 1.5 volts each and 4 would make for 6 volts. I did find a picture of an old #6 battery that was that listed ignition along with the other uses and all those #6 batteries were 1.5. I can still get those batteries but they are expensive so I will try it with a a lantern battery first.

To be honest, I’m not sure on those little batteries without reading up on it. They were needed to help the Simms mag spark at low RPM’s as the dynamo turns the engine and were used in conjunction with a special coil. That coil was mounted to the passenger frame rail directly beside the mag, it is still attached on my Maxwell but it is no longer used. I have a book on the Simms-Huff starting system that I will scan and see if it helps any. When the late Rich Eagle redid his 1915 Maxwell he swapped the Simms mag for a better Bosch one.

Glad you got the Maxwell! Welcome to the club!

What year Maxwell are we talking about here? A 6V lantern battery?? For ignition only?

The Maxwell is a 17. I was just getting down to work on the wiring when I hit a big snag; the starter switch is incomplete. I hadn't noticed it before but I got to looking at the side cover and the two terminals that should have been there were missing. I removed the cover and found that it was just a piece of sheet metal that someone had screwed on to cover the opening. Inside the switch the lower rocker is completely lose and of course the contacts that would have on inside the cover are gone. Anyone have a good switch or know of a work around?

Mr. Dennis is very good with those switches and might have some parts, otherwise you could hunt for an engine that still has the switch on the side. In a pinch you could go the old fashioned way and forgo the starter function of the dynamo, just using it as the generator and wiring it direct to the regulator, crank starting each time. That's what I did until I got around to rebuilding the fancy little switch.

You could get really fancy and separate the systems, keeping a six and a twelve volt battery under the seat, wire the six to the generator charge and the twelve to the starter hookup? flip a switch for the starter and use just the twelve volt battery. You would have to charge the twelve volt battery before you went anywhere each day.

I have a couple of possibly stupid questions but I am sure that you all can set me straight.

Does the magneto only generate the power to run the engine and the dynamo recharges the batteries and runs the lights?

For simply running the car, you have no need of the dynamo being connected to batteries, right?

If I were to attempt to start the car on the "dry cells" and magneto I would need to ground out the dynamo to prevent from damaging it, right?

Would that be done by running the wire from the post on the side of the dynamo to ground?

If my previous assumptions are correct, and assuming that the magneto can generate a charge and the batteries will energize the "intensifier coil" until the car starts, to kill it I would need to ground out the magneto wire that is supposed to run to the ignition switch. Is that right?

colonelpowers wrote: ↑

Mon Sep 23, 2024 4:00 pm

I have a couple of possibly stupid questions but I am sure that you all can set me straight.

Does the magneto only generate the power to run the engine and the dynamo recharges the batteries and runs the lights?

For simply running the car, you have no need of the dynamo being connected to batteries, right?

If I were to attempt to start the car on the "dry cells" and magneto I would need to ground out the dynamo to prevent from damaging it, right?

Would that be done by running the wire from the post on the side of the dynamo to ground?

If my previous assumptions are correct, and assuming that the magneto can generate a charge and the batteries will energize the "intensifier coil" until the car starts, to kill it I would need to ground out the magneto wire that is supposed to run to the ignition switch. Is that right?

Joshua,

That all seems to make sense. However, why risk your dynamo, or whatever Maxwell calls it, by asking a group of Model T guys about a Maxwell. Is there a Maxwell club? Possibly on the AACA forums? I don't want to chase you away, or be "anti-Maxwell", I just don't want to see you do any harm to your car.

No such thing as a non-deliberately stupid question, I’ll take a crack at some answers to them in order:

Yes, the mag ignition is a separate system from the charging system. It is AC, Dynamo puts out 6 volts of DC.

Correct, to run the car with a mag ignition you have no need for the charging system. The dry cells and coil were required to help intensify the spark in the mag at the RPM at which the dynamo turned the engine. Not sure what that was, but you might be able to hand crank it faster? Sort of like how a Model T doesn’t like to start on mag using an electric starter, but will respond better to a good fast yank on the crank.

I assume that like many generators, the Simms-Huff unit will burn itself up without a load on it if ran a lot.

Yes? I believe you can ground out the dynamo by grounding the small post on the bottom, that is the charge output post and originally led to the regulator on the dash. The big post on top is for starting power. You could also unhook the belt from the dynamo’s pulley, and run a smaller belt to the fan only.

Yes sir, that or retard the spark and starve it for fuel is how I would kill the engine.

Here are some wiring diagrams that might help some, both the distributor and mag systems for same Maxwell.

Not sure if the coil and dry cells are needed once the engine starts? I think they are disengaged when the starter pedal is released. I will have to do more research on that…

There is a good Maxwell group on Facebook if you use that. They are mostly brass era though, there is not a big following for the more mass produced cars in what they call the “Flanders” or “Chrysler” eras. The Model 25 was Maxwell’s response to the little Ford dominating the market.