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Lights/speedo dimming - any fix?

Posted: Sat Sep 24, 2016 10:54 pm
by alanscottj
On my GP I have a Halogen conversion on the front, LED rear light, powered by a Varitronic ignition. When the scoot is at tickover and low revs the lights dim right down and the SIP speedo goes off. Is there anything I can do to remedy this?

Many thanks

Scott

Re: Lights/speedo dimming - any fix?

Posted: Sat Sep 24, 2016 11:48 pm
by paul d
Good question! I've learnt to live with mine. Can be a bit frightening mid corner on a country road with the brake light on while facing oncoming traffic.

Re: Lights/speedo dimming - any fix?

Posted: Sun Sep 25, 2016 9:16 am
by Donnie
Ive no experience of the sip speedos at all i have to say so dont know if its normal for them to switch off at tickover / low revs, certainly if it is then that would be a big negative for them. Anyway, fitting a battery which will run just the brake light only will stop the dimming issue when hitting the brakes (though hitting them mid corner seems a bad time to be touching them anyway) but I imagine if the sip speedo was also connected to the battery this might resolve the problem?

Re: Lights/speedo dimming - any fix?

Posted: Sun Sep 25, 2016 9:25 am
by Shipleystevep
I run my sip speedo off a battery on my static timed scooter

Re: Lights/speedo dimming - any fix?

Posted: Sun Sep 25, 2016 9:34 am
by Knowledge
Scott,

You have done the right thing by fitting an LED brake light lamp, but the issue is really with the Varitronic stator, which simply doesn't produce as much power as most six pole stators. It certainly isn't producing 55w+ at tick-over, which is why your lights dim.

A battery is an answer, as it will top-up the electrical system when the stator can't provide enough power. However, the SIP speedo can be temperamental with DC power. Search the threads on here for solutions to this or ask SteveP ^ for advice.

The 55w lamp will be consuming a lot of power, and perhaps an alternative lamp should be sought. I have heard some people say that a specific type of lamp, rated at 35w, appears as bright as a 55w item. Much will depend on your riding over the coming winter months. If you ride mainly in towns, this will not be to much of an issue, but if you crossing the Pennines in November, I can understand your need for lumens.

If you want advice on what 35w lamp is best, you might do well start a fresh thread on this forum.

Personally, I use a 6 pole stator modified to serve a Wassell DC system with battery and LED lights throughout, including two LED spots in the DL headset as my headlight. Lots of light, and lots of power for other accessories. I use a HHP CDI, using option 0 advance/retard setting.

Re: Lights/speedo dimming - any fix?

Posted: Sun Sep 25, 2016 9:36 am
by Knowledge
Duplicate post removed by author.

Re: Lights/speedo dimming - any fix?

Posted: Sun Sep 25, 2016 9:52 am
by Knowledge
Duplicate post removed by author

Re: Lights/speedo dimming - any fix?

Posted: Sun Sep 25, 2016 12:51 pm
by Adam_Winstone
Get rid of the headlight conversion, which is placing too much of a demand on your system or change to a system with a higher output.

One of the mistakes that many people make is in trying to fit forever more demanding headlight lamps to try to get a better headlight, when in reality the problem is commonly that the previous bulb was not getting enough power to light properly, so fitting a more demanding bulb/lamp simply makes the problem worse. Remember that a 25/25W bulb that has sufficient power supply will put out a better/stronger beam than a 35/35W that is struggling to light fully.

Adam

Re: Lights/speedo dimming - any fix?

Posted: Sun Sep 25, 2016 8:40 pm
by alanscottj
Cheers all, and thanks for the comprehensive answer there Martin. Adam, what you say make sense too. Lots of food for thought over the winter where I shan't be crossing the Pennines, more like around town!

Re: Lights/speedo dimming - any fix?

Posted: Mon Sep 26, 2016 9:45 pm
by Padge
I use these bulbs in both my Gp's (standard but mint headlights, new wiring etc) one has an Indian stator and the other uses a BGM 120w stator, both as bright as each other but BGM one slightly brighter at tickover
These bulbs are bright as fcuk, good beam pattern (as they are designed for the reflector of the lamp) and a slight blue tint to on coming traffic (but brilliant white on the road) can't recommend them enough

http://www.lambrettaupgrades.co.uk/apps ... ow/5871559

I order one or two every time I order off "Chiggy" can never have enough spare ones lol