View Full Version : Type D generator, cutout and battery questions I WANT TO LEARN !

Steve Swan
08-15-2017, 12:33 AM
It seems there have been a number of questions about the electrical charging equipment over the recent past. And some fellows asking me what I am running on my 27 JD and for my advice.

While I have reasonable yet albeit limited understanding of generator and cutout operation, I recognize there’s more I don’t know than I do know, most especially when it comes to fitting solid state cutout relays and AGM batteries, I am pretty much lost. And, with fellows talking about 3 to 2 brush conversions, solid state cutouts/relays and newer types of batteries, my understanding is certainly lacking. To note, I HAVE been researching all the threads and posts regarding the considerations of using modern day cutouts and batteries with both the 3 and the 3 to 2 brush conversion setups.

Rather than assume I know something or sound like I know what I am talking about, I am simply going to ask questions.

First, I’ll start off by describing the perfectly functioning setup on my ‘27JD.
1. I’ve never had the generator apart. I received the generator in a trade for parts I did not need. The generator was rebuilt, ready to install. I can only assume it is the original 3 brush factory setup.
2. The “solid state relay” (2 post) purchased from Flatlands M/C Company, a “6 volt” unit to fit “29-37” pn “4785-26”
3. The battery is a SLAA6-14A AGM type.
4. I am running original contact breaker points in the timer.
5. I am running a new coil from Replicant Metals.
6. At road speeds with no lights on, my ammeter reads 5 amps, therefore I am assuming my generator output is correct.
7. I failed to document the wattage of the headlight bulb; the headlight is a Made in Poland knockoff and came with the bulb currently in the headlight.

So, to the best of my ability, here are my questions:
1. In the case of a 3 brush setup, what type of modern replacement cutout/relay is recommended? (2 post, not 3 post, any solid state unit, correct?)
2. With the 3 brush setup, what type of battery is recommended?
3. On the Type D generator, does moving the 3rd brush in the direction of armature rotation (towards negative brush) increase output?
4. In the case of a 3 to 2 brush conversion, what type of modern replacement cutout/relay is recommended? (is a 2 post realy still used?)
5. What type of battery is recommended with the 3 to 2 brush conversion?

It is inevitable I will need to do maintenance on my generator in the future, such as lubricate bearings, clean commutator, replace brushes, etc. Future service being inevitable and having already considered possibly making the 3 to 2 brush conversion, this conversion is a decision I will make when the time comes. I have an at best rudimentary understanding of the advantages and disadvantages of 3 brush setups v.s. a 3 to 2 brush setup. I would appreciate in simple terms which setup is best suited in our modern era and what is most practical when fitting a modern battery and cutout relay.

At this point, I intend using Ed’s QuickStart2000 when my original points are beyond use. I do have a couple sets of points that are similar to originals, but I have not looked at them to see if they are an install and ride part or need some tweaks to make them fit and function properly. So, I bought Ed’s setup to have on hand when the time comes.

Anyway, these are all the questions I can think of at the moment. If there is anything I have overlooked or information additionally helpful, please share. I am here to learn as I intend to ride my JD and know I will have maintenance and repair issues down the road. I KNOW other JD riders are running in to issues with their setups and have similar questions. Those who have been down this road already will be a tremendous help sharing your knowledge and experience.


PS - referring to Peter440g’s instructions for converting a 3 to 2 brush setup,
“Conversion field coil wire removed from 3rd brush attached to armature and POD yellow
field coil wire potruding from genie case to POD green”

Can any solid state cutout relay be used instead of the Podtronics unit ?


08-15-2017, 07:44 AM
Hi Steve, There is no advantage to a 3 brush system. The third brush adjusts the output at a fixed rate regardless of the battery state of charge or demand with lights on or off. At times the system can over charge and under charge. The maximum 2 brush conversion output is also slightly higher than a 3 brush adjusted to max. I think because we are using undersize batteries in these old bikes, its important that the output is regulated for the batteries needs. I highly recommend Gene Harpers regulator with a 2 brush conversion. The conversion is super easy to do with the gen in the bike on the JD. All you do is remove the 3rd carbon brush and connect an extra wire that is coming from the regulator. Gene's regulator looks just like a relay cutout. The only identification of the conversion is the extra wire going from the regulator to the generator. I have this conversion on my JD and the charge rate is about 1 or 2 amps with a full charged battery regardless if the lights are on or off. There is also another overseas regulator available here in the states from Retrocycle. Gene Harpor is the expert and hopefully he will add to this information for you. I hope this helps.