armyofda12mnkeys Posted August 31, 2010 Posted August 31, 2010 I wanted to just test and see if my turn signal flasher unit on my 78 XS400 is getting the power it needs. I was reading about voltage drop testing ... How can I voltage drop test this device? ... Do you have to cut into the wire going into it and out of it to measure it, or can you somehow do it without cutting into the wires (i assume so)? Thanks for any advice
Moderator drewpy Posted August 31, 2010 Moderator Posted August 31, 2010 I wanted to just test and see if my turn signal flasher unit on my 78 XS400 is getting the power it needs. I was reading about voltage drop testing ... How can I voltage drop test this device? ... Do you have to cut into the wire going into it and out of it to measure it, or can you somehow do it without cutting into the wires (i assume so)? Thanks for any advice i assume you put a volt meter on the battery terminals with the engine off, turn on the flashers and see the voltage drop on the battery.
armyofda12mnkeys Posted September 1, 2010 Author Posted September 1, 2010 well i think theres a way to specifically test the specific device you want (my flasher relay) ... vs just reading the battery. I'll figure it out in next few days, got a book on voltage testing. Anyway the values of just the battery were as follows: (ps bike never actually started, just ignition turned on (no engine) in following tests) motorcycle off: 12.78v (seemed to rise slowly from 12.74 over next minute) motorcycle key ignition on (light off): 12.45v motorcycle key ignition on (light off) + put kill-switch to Run: drops to 12.35v and bounces back up to 12.45v motorcycle key ignition on + put kill-switch to Run + turn light on: 12.33v motorcycle key ignition on + put kill-switch to Run + turn light on + turn on left signal: 12.31 cancel signal: then goes back to around 12.32 motorcycle key ignition on + put kill-switch to Run + turn light on + turn on right signal: 12.31 cancel signal: then goes back to around 12.32 think above test didnt help much.... need to test if that device itself is getting all the power it needs? it may just lose resistance through a frayed cable and you wouldn't know about it unless u tested that device right, as the other devices in parallel will use up their 12v and return 0 back to ground, and wouldnt neccessarily know about that flasher unit? think i need to test positive side of that unit, aka hook positive to positive of battery and negative to one? of wires the input of the flasher relay unit. and then test the ground side to make sure it used up almost all the Volts it was given.
motobrox Posted September 1, 2010 Posted September 1, 2010 You've got it, any component on the bike is intended to use up the voltage when in use. The flasher unit is a relay, look up testing a relay on youtube it's easy.
armyofda12mnkeys Posted September 1, 2010 Author Posted September 1, 2010 You've got it, any component on the bike is intended to use up the voltage when in use. The flasher unit is a relay, look up testing a relay on youtube it's easy. I saw one video where they had wires going around each prong/input on the relay (of a car), and then they plugged it in (so each wire still stuck out and could be tested). And then he tested each of the wires for continuity... Would this pretty much be the same for testing my relay? For voltage drop testing... should each of those prongs be tested (3 prongs on the flasher relay), or only one is really needed to test?
motobrox Posted September 2, 2010 Posted September 2, 2010 You've got it, any component on the bike is intended to use up the voltage when in use. The flasher unit is a relay, look up testing a relay on youtube it's easy. The relay is just a electromagnetic switch so it's unlikely it will drop voltage. But if it's a three prong relay just test it as they show the car ones, the principle is exactly the same. You should hear the relay click as it bridges the circuit and there shouldn't be any voltage drop
Ebola Monkey Posted September 2, 2010 Posted September 2, 2010 Test the voltage at the battery, then test the voltage going into the relay, and out of it. On my 650 for example I might have 12.3V at the battery, at the fusebox I have 12.1 going in, 12 coming out, 11.7 going into ignition switch, 11.4 coming out, 11.1 going into alternator brush. The resistance in the aging wire, and connections is causing a 1.2v drop by the time I get to the alternator. You may be getting 12.3 at the battery, and 10 at the relay. Under 11 they don't like to work, at least on my xs400.
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