Author Topic: Resistor type  (Read 722 times)

Offline RoyC

  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1102
  • Karma: 7
Resistor type
« on: 28.09. 2017 14:10 »
I have some indicators with 10w (total per side = 20w) bulbs,
I think that I will want a 20w / 25w resistor.
Looking on ebay I have found one, but, it asks for ohms, I haven't got a clue what they are on about.
Can anyone help please.
http://www.ebay.co.uk/itm/25W-Golden-Aluminium-Load-Resistor-Wirewound-Various-Values-High-Quality-New/122180980450?_trkparms=aid%3D555019%26algo%3DPL.BANDIT%26ao%3D1%26asc%3D20151005190540%26meid%3Dbee8261b28384ed4a34f8764e467d48b%26pid%3D100505%26rk%3D1%26rkt%3D1%26&_trksid=p2045573.c100505.m3226
My bike is a 1958 A7SS
Staffordshire UK

Online Bsareg

  • Valued Contributor
  • ****
  • Join Date: Mar 2016
  • Posts: 264
  • Karma: 2
Re: Resistor type
« Reply #1 on: 28.09. 2017 17:24 »
You will have to know the voltage you need to drop (12 to 6v etc) and the current (amps or the wattage of the bulbs) you need to draw, in order work out the ohms.
C11,B40,B44 Victor,A10,RGS,M21,Rocket3,REBSA

Offline RoyC

  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1102
  • Karma: 7
Re: Resistor type
« Reply #2 on: 28.09. 2017 20:50 »
Thank you Reg.
My bike is a 1958 A7SS
Staffordshire UK

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8098
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Resistor type
« Reply #3 on: 28.09. 2017 20:51 »
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, .
Australia
Muskys Plunger A7

Offline RoyC

  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1102
  • Karma: 7
Re: Resistor type
« Reply #4 on: 28.09. 2017 21:01 »
G'day Roy.
Heres a calculator.
http://rapidtables.com/calc/electric/watt-volt-amp-calculator.htm
Cheers
Thanks for that Muskrat, just the ticket.
Roy.
My bike is a 1958 A7SS
Staffordshire UK

Online Bsareg

  • Valued Contributor
  • ****
  • Join Date: Mar 2016
  • Posts: 264
  • Karma: 2
Re: Resistor type
« Reply #5 on: 28.09. 2017 22:29 »
Nice calculator., but remember that it's the current and voltage drop across the resistor that will determine the wattage of the resistor
C11,B40,B44 Victor,A10,RGS,M21,Rocket3,REBSA

Offline mikeb

  • Resident Legend
  • *****
  • Join Date: Dec 2014
  • Posts: 512
  • Karma: 10
Re: Resistor type
« Reply #6 on: 29.09. 2017 07:25 »
Roy why do you want a resistor for anything?. they suck power. that's bad on a E3L.
people use them with LED indicators to increase load if they have the wrong kind of flashing unit - better to get the right flasher.
or to drop the voltage for a bulb (eg 6V bulb on 12V system)  but that doubles the power consumed by generating heat. get the right bulb.

its better to get the right part than load up old electrics - are you sure you need resistors? what's the task?
New Zealand
'61 Super Rocket  - '47 B33 -  '18 Triumph Street Triple RS

Online JulianS

  • 1962 A10
  • Resident Legend
  • *****
  • Join Date: Mar 2017
  • Posts: 937
  • Karma: 20
Re: Resistor type
« Reply #7 on: 29.09. 2017 09:42 »
I though a resistor was only needed when LED bulbs fitted, and then they  are usually available from the supplier of the indicator kit, such as Paul Goff or Vehicle wiring products?

http://www.vehicle-wiring-products.eu/section.php/151/1/indicators

Offline mikeb

  • Resident Legend
  • *****
  • Join Date: Dec 2014
  • Posts: 512
  • Karma: 10
Re: Resistor type
« Reply #8 on: 29.09. 2017 09:49 »
Quote
I though a resistor was only needed when LED bulbs fitted
even then only if its an old-school flash unit. just get a new sort. $1.50 off e-bay.

EDIT: i may be slightly lying. in theory I'm right but i recall having to put ?220 ohm 1/2 watt resistors across the 12v LEDs on the b33 to make them work. still that's much less current than the low resistance loads that mimic incandescent bulbs. flasher like this:
http://www.ebay.com/itm/12V-2-Pin-Beeper-Motorcycle-Flasher-Relay-Turn-Signal-LED-Indicator-Blinker-New-/162258494835?hash=item25c75c2573:g:CBgAAOSwo4pYEqMe&vxp=mtr
New Zealand
'61 Super Rocket  - '47 B33 -  '18 Triumph Street Triple RS

Offline RoyC

  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1102
  • Karma: 7
Re: Resistor type
« Reply #9 on: 29.09. 2017 14:18 »
Roy why do you want a resistor for anything?. they suck power. that's bad on a E3L.
people use them with LED indicators to increase load if they have the wrong kind of flashing unit - better to get the right flasher.
or to drop the voltage for a bulb (eg 6V bulb on 12V system)  but that doubles the power consumed by generating heat. get the right bulb.

its better to get the right part than load up old electrics - are you sure you need resistors? what's the task?
The indicators that I have, have 10w bulbs in them, I have tried LED flasher units (don't work) so I thought that 2 x 10w bulbs plus a 25w resistor then I could use an ordinary flasher used for 21w bulbs.
Option 2
I have ordered a 12v 21w flasher that may work with my 10w bulbs http://www.ebay.co.uk/itm/12V-21W-3W-2-pin-Motorcycle-Scooter-Flasher-Relay-Can-Unit-With-Audible-buzzer/191789180692?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
My bike is a 1958 A7SS
Staffordshire UK

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 4979
  • Karma: 48
Re: Resistor type
« Reply #10 on: 29.09. 2017 14:36 »
Assuming the bulbs are 12V, at 12V they are going to pass the current required to draw 10W of power and that's it. The fact that the flasher is rated for 21W just means that only half of its available current will be delivered, and that is as it should be for headroom and longevity of the flasher. No resister should be needed for the incandescent bulbs.

Richard L
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline Clive54bsa

  • A's Best Friend
  • ***
  • Join Date: May 2012
  • Posts: 126
  • Karma: 1
  • Orange SoCal
Re: Resistor type
« Reply #11 on: 29.09. 2017 17:25 »
I saw this the other day, I was thinking about it for my B50 MX Dualsport.
http://www.signaldynamics.com/self-canceling-turn-signal-module/


'54 GF,  '61 SR,  '71 B50MX

Offline mikeb

  • Resident Legend
  • *****
  • Join Date: Dec 2014
  • Posts: 512
  • Karma: 10
Re: Resistor type
« Reply #12 on: 29.09. 2017 21:06 »
Quote
No resister should be needed for the incandescent bulbs.
i'm with Richard on this. should work fine without resistors. at worst may blink slowly.
when tested if its not suitable I'd change flasher unit rather than load up the electrical system more with resistors.
New Zealand
'61 Super Rocket  - '47 B33 -  '18 Triumph Street Triple RS

Offline RoyC

  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1102
  • Karma: 7
Re: Resistor type
« Reply #13 on: 30.09. 2017 09:01 »
Thanks for that. I hadn't thought of it like that.
My bike is a 1958 A7SS
Staffordshire UK

Offline RoyC

  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1102
  • Karma: 7
Re: Resistor type
« Reply #14 on: 30.09. 2017 09:10 »
Assuming the bulbs are 12V, at 12V they are going to pass the current required to draw 10W of power and that's it. The fact that the flasher is rated for 21W just means that only half of its available current will be delivered, and that is as it should be for headroom and longevity of the flasher. No resister should be needed for the incandescent bulbs.

Richard L
There will be 20w power draw (10w x 2) so 21w flasher should work and no resistor required, I hope. Will see when flasher arrives.
My bike is a 1958 A7SS
Staffordshire UK