Brum Scott regulator?

[Russell]

My 58 Brum seems to need a really strong battery to be able to start (no chance on the alternator only emergency ignition setting), so much so, that after a long run with the headlight on it can be very difficult to start, sometimes impossible. So I’m trying to improve the charging circuit to keep the battery in top condition, and was thinking of changing the original rectifier for a Wassell WW10221N regulator, and wondered if anyone had experience of these, specifically what the yellow and green wires are for? Their diagram talks about D and F terminals which don’t seem to exist on my Millar alternator.

Also does anyone know what the normal running charging currents are supposed to be? could it be the alternator that’s not supplying enough current?

The headlight ammeter shows around 0A when idling, increase the revs a bit and it shows about 1A, but with headlight on it shows around -1A at idle and has to be rev’ed quite high to go positive.

Cheers
Russell

[Barrie]

The charging system is a bit strange ,it’s a form of balanced charging system, in other words it switches in alternator windings as you select lights etc.
THE BEST IMPROVEMENT would be to uprate the system using a modern reg/rectifier ,
Rewire the alternator to single phase from bi phase and running the output of the regulator straight to the battery ,Via the ammeter, change the polarity of the bike to neg earth because the reg works on neg earth only, this wold also mean changing the condenser to a neg earth type.
I would say you have at the moment a switch/wiring fault that is why the emergency starting system does not work or one of the alternator windings is u.s..
AS for the regulator you have seen this is for DYNAMOS not alternators ,take a look at Scott Technicalities, the electrical section

[gammakeith]

It sounds like the Brum charging system is similar to that of the early Hondas with which I am familiar. As Barrie says, it is relatively easy to rewire to feed the full alternator output to a solid state rectifier/regular (6 V ones are easily obtained). Worth considering changing headlamp bulb to LED versions as well then minimal charge current should be more than enough. My Honda 70 now has lights that do not vanish at tickover 🙂

Keith

[Russell]

I’ve looked for suitable LED bulbs but never found any, have you a source you can recommend?

[Barrie]

Just the change to proper regulation will make the electrical system much more efficient, run standard bulbs

[gammakeith]

@Russell wrote:

I’ve looked for suitable LED bulbs but never found any, have you a source you can recommend?

https://www.dynamoregulatorconversions.com/online-shop-for-led-bulbs-and-light-boards-etc.php

The above would be a good place to start though they are quite expensive. Alternatively, there are lots on ebay (most 12V LED bulbs will run reasonable ok in 6V systems) that can be modified to fit if you are handy with a soldering iron. I am a big fan of LED bulbs. It saved us having to upgrade the battery in our motorhome as the LED lights I installed use minimal current. As said before, the lights on my Honda used to go out at tickover (they are fed direct from alternator not via battery). Now they stay on at tickover and are MUCH brighter.

Keith

[Tman]

The LEDs are supplied with AC? That’s supposed to be a no-no as they’re polarity-conscious.

Edit….Seems like things have moved on since I last looked and the items available now are indeed bi-polarity.

[Russell]

I’ve managed to source a suitable regulator and LED bulbs from Paul Goff at https://www.norbsa02.freeuk.com/ 😀

[gammakeith]

@Tman wrote:

The LEDs are supplied with AC? That’s supposed to be a no-no as they’re polarity-conscious.

Edit….Seems like things have moved on since I last looked and the items available now are indeed bi-polarity.

Yes, I guess the cheapness of surface mount components means that adding a rectifier to the circuit board adds little to the cost of the bulbs. Thus, many will run on AC and don’t mind which way around they are connected. The only issue is that they usually need a regulated output. Some of the early 12V ones would blow as they didn’t like the 14.4 Volts of vehicle electrics. Its better now but a solid state regulator is still advised.

Keith

[Russell]

I’ve now fitted the A Reg Six regulator and LED bulbs from Paul Goff at https://www.norbsa02.freeuk.com/ and all working fine, lets see if the battery lasts a bit longer 🙄

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