Charging output w/3 phase alt

MexicoMike said:

Interesting - never seen anything like that in the USA.

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It's just the old British system of describing fuses by the blow rating.



However for some time now, the ROW has decided to follow the practice of describing automotive fuses by their continuous ratings, it's a bit con-fuse-ing as the 1-1/4" (30mm) glass "blow rated" fuses as used on many British bikes and cars are still available, although the 1.0" (25mm) glass fuses are continuous rated. http://www.vehicle-wiring-products.eu/V ... /fuses.php



Check your factory manual: "Fuse rating: 35 amp (17½ amp continuous rated)" so the relevant information is given.

http://www.classicbike.biz/Norton/Repai ... mmando.pdf

L.A.B. said:

pvisseriii said:

FWIW back at you. Those seems like regular 180w single phase numbers on a pre Markiii Commando.

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All "pre MkIII" Commando alternators were the 120w RM21. "MkIII" alternators were 180w single-phase RM23.

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Yes I realize that it has been upgraded to 180w from 120, it just seem to coinside with my reading with a 180 single phase on my 750. My seal beam is 65/55 though. 100/80watt, Jesus jenny, that a heavy draw. That's 10 amps on hi beam alone. Not much left for the horn or backup lights. Mike, You must be using a squeesy bulb type horn, eh?

MexicoMike said:

OTOH - I seem to recall that I blew some 20A fuses back when I was first trying to get the bike to run 5 years ago but my memory could be faulty...

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It's more likely the wiring was faulty? :wink:

Yeah, I like your assumption better - it was the wiring, not my memory!

SO...the correct fuse, based on what we commonly have here in the USA would be a 17.5A, NOT my 35A, right?

MexicoMike said:

SO...the correct fuse, based on what we commonly have here in the USA would be a 17.5A, NOT my 35A, right?

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Right! Or at least the nearest equivalent, which is usually 15A or 20A.

I'm currently using a 15 A USA-style fuse in both bikes. I ran a 10 A fuse for several years in the 750 and it never blew.

Mike, I think your wiring harness would burst into flames before that 35 amp fuse would blow! :wink:

debby

I think you are probably right!

Watch it with that high-watt bulb Mike. I have run those in a few bikes. In a Harley with exposed headlight shell, it did just fine (on stock wiring, although - not having checked - maybe that's a relayed connection. In a full-faired BMW, on an Eastern Beaver relayed connection, it SEEMED just fine but when I was in the headlight shell for one reason or another I found the socket the bulb plugs in to just about melted - dunno how much longer it would have lasted, but I wouldn't have taken any bets.

This again was in a fully faired bike where the headlight wasn't getting any airflow, so maybe not a great comparison, but my point is, those high-watt bulbs throw off some major heat.

Light output was good, although the most impressed I've been is with normal wattage "Raybrig" bulbs. They are spendy though.

Best regards - BrianK

Thanks Brian - good info. I have never run the light for extended periods so that's worth checking. I have to admit that I really don't recall specifically ordering that hi powered light. But obviously I did. I don't ride the Commando intentionally at night so I can't think why I would have wanted that. Guess it's one of those "seemed like a good idea at the time" or possibly "ordering while under the influence."

I'll be back in the US in about a month so maybe I'll just get a "standard" DOT-approved bulb.

Mike your tests are very thorough and apart from the fuse and overkill headlamp I'd leave it alone.

I did a functional test after installing a Sparx 3 phase and I recall that with my 55W (low beam) headlight on the battery would begin charging at about 2500 rpm. I'm happy with that.