AC or DC lighting? debate


16 replies to this topic
  • spidennis

Posted November 13, 2006 - 08:42 AM

#1

AC or DC lighting? debate

With the different ongoing threads about OEM voltage rectifiers/regulators failing on the factory AC lighting systems, and the DC conversion lighting and re-wiring stators and such, and not wanting to Hijack anyone's thread, here's a thread that's open to discuss the pros and cons of both. .... and don't worry about being strict to "the topic" as long as it's related.

As my OEM voltage regulator/rectifier is about to come in via ups today from TT OEM and seeing others with the same problem, is it not better to switch to a DC system for reliability? .... and to have a better lighting system? When a DC system goes bad, just what is the nature of those problems? If I'm on a 900 mile off road adventure ride, what would I rather have? AC or DC?

Anyone else have ideas on this subject? Those with DC systems, how do you like them? What would you change if to do it over? Halogen vs. HID?

  • MountainMax

Posted November 13, 2006 - 08:52 AM

#2

I think the DC is better and safer as it will allow you to have light with the engine not running. if we had HID's would be even better, but im not sure if a dual filament setup is out for the H4 bulbs that we use..

  • Asgeir

Posted November 13, 2006 - 10:48 AM

#3

DC as it charges the battery stronger when light is off and you have the HID capability.

I have the big stator and flywheel with bigger magnets from Trail-tech, the 150W reg/rectifier and the 8" HID. I am happy.

You could also mod the oem stator and put in bigger reg/rectifier as a budget way to go DC. (baja-designs way, see PDF on their website)

  • Asgeir

Posted November 13, 2006 - 10:50 AM

#4

Is there any downside of going DC, anyone ?

Some have said you cannot start the motor with the battery dead but I have tried that and it is not correct.

  • spidennis

Posted November 13, 2006 - 11:17 AM

#5

DC as it charges the battery stronger when light is off and you have the HID capability.

I have the big stator and flywheel with bigger magnets from Trail-tech, the 150W reg/rectifier and the 8" HID. I am happy.

You could also mod the oem stator and put in bigger reg/rectifier as a budget way to go DC. (baja-designs way, see PDF on their website)


I see you have a 04 model WR, with electric start right?
...... and I'm guessing this is the unit you used?
http://trailtech.net...-YFZ450-01.html
I wonder if this also fits the WR250F (03)?

.... and for your other post ....
going the ac route I can see as being cheaper
if you're making your bike street legal
as the WR models (w/ebutton) are quick and easy to adapt.

DC is more labor intensive, but seems to be the way
for better/more lighting and other electrical mods
and heated grips and backlights and such. Do you agree?

  • Asgeir

Posted November 13, 2006 - 01:01 PM

#6

Yes I used the YFZ one from Trailtech.

I looked up the WR250 and 450 stator pn and the are 5UM-81410-00-00 for 250 and 5TJ-81410-00-00 for 450. Different pn, so I do not know if it is the same, maybe Trailtech knows ?

I think the DC way is the way to go even if you do not need the extra lighting but as you are riding difficult terrain and need to use the e-start frequently the battery will recharge faster and beeing ready sooner for your next hic-up.

Of course it is more expensive.

  • Ibis

Posted November 13, 2006 - 02:57 PM

#7

If you can get a stock regulator not to blow out the AC side, I think the OEM AC/DC system is fine for general use. The AC side has more than enough for a 55/60 watt H4 and the 25 watt DC output is plenty for average e start battery charging. You can also keep your headlight on and not discharge the battery when riding slow technical stuff. My KTM is DC only and I have to remember to turn the headlight off when riding slower than the RPMs necessary to keep the battery charged.

That said, I'm in the process of converting my Baja only WR to DC. Several reasons. On the last Baja ride, the AC regulator did the 17 volt kaput thing and blew out the lights. Not good, especially when we occasionally end the day when it's really dark. Also, because at night the desert is sometimes darker than really dark, I'm going to DC only HID. The last reason is, I use grip warmers and the stock AC system doesn't have enough watts to efficiently run a 55 watt H4 and 35 watt grip warmers at the same time. Running grip warmers on the stock DC side will run the battery down. Converting to DC only with a TrailTech flywheel should give me ~110 watts DC and run everything while keeping the battery charged.

  • PBDBLUE

Posted November 13, 2006 - 05:03 PM

#8

If you are going to be converting to full DC be aware of one thing. If the DC regulator fails the bike will not run. Actually it will run until the battery is dead and then you will be walking. The WR is unique in that it requires 12 volts DC to run the CDI. No 12 volts DC = no spark! If you load up the DC circuit with a bunch of high wattage equipment the chances of a failure go up dramatically. If you choose to go that route make sure the aftermarket regulator you use has plenty of cooling and some additional heat sinking wouldn't hurt either. A burnt out headlight is a pain but a bike that won't run can be a really serious problem if you're a long way from the truck.

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  • MountainMax

Posted November 13, 2006 - 05:14 PM

#9

good points guys, I am a bit worried about my dc voltage regulator failing now, and getting me stuck, Maybe i should invest in a spare to carry on those long haul days, as a precaution. How many guys are losing the BD or other full DC regulators?

  • spidennis

Posted November 13, 2006 - 05:20 PM

#10

I've only been hearing (and experiencing) about the stock AC having problems.

btw, got the voltage rectifier/regulator in, installed it and problem is fixed ...
but for how low I wonder?
I did notice that there was a change in the part number,
so maybe that problem came to the factory's attention and fixed it? Let's hope
(new part number is: 5TJ-81960-02-00)

  • Desracer

Posted November 13, 2006 - 10:54 PM

#11

Well all the things I need to use run on DC power. The HID bulb is brighter and lasts longer, so it is also better than stock. My plasma bulb shorted out during a race and I lost the lights, very bad feeling to sit in the dark. I want to run the HID and a helmet light plus charge the battery. So 35 watts for the HID and 35 watts for the helmet light leaves only 30 to charge the battery and run the engine. Thats a 100 watts total. Most electrical problems are from bad connections or poor wiring jobs that cause failures. Problems do happen like my bulb and it ruins your day.

  • PBDBLUE

Posted November 14, 2006 - 06:14 AM

#12

I wasn't saying don't do it but wanted to make people aware there are some risks in going full DC. If you need to do it (i.e. - HID, etc) make sure the regulator is mounted where it can get some cooling and maybe add some additional heat sinking. Also using "thermal paste" ( http://www.radioshac...rentPage=search ) between the regulator and the mounting area will help. While you are right that a lot of failures are caused by connections heat is the #1 enemy of the regulator. With a 100 watt load the regulator will build quite a bit of heat that it must be able to dissipate or it will self destruct.

  • Asgeir

Posted November 14, 2006 - 11:49 AM

#13

Producing 100 to 120W should not be a problem with aftermarket reg/rectifier.

The Trailtech regulator/rectifier is 150W so it has probably better safety margins than the original oem does.

  • Ibis

Posted November 14, 2006 - 12:23 PM

#14

I wouldn't be too concerned about a reliability issue converting to DC. It doesn't matter if you're using the stock DC system or after market, if the DC goes out, it goes out! Besides, the TT or BD reg/rec are better units than the stock junk. The TT is rated at 150w and I think the BD is the same. If anyone is concerned, BD has a heavy duty reg/rec - $68 part #122005. I've used a lot of BD systems on my Baja XRs and never had a heat or reliability problem other then shorts or bad connections.

The AC current from the stator/rotor is non regulated full output and any excess power not being used is dissipated by the regulator by shorting to ground. This can cause the reg/rect to get hotter than normal. The reg/rect will actually run cooler by using lights, etc which results in less power shorted to ground. Mount the reg/rect to the frame (heat sink) and use at least 16ga stranded wire from the reg/rect to the battery and from the battery to the lights, etc.

  • Asgeir

Posted November 14, 2006 - 12:41 PM

#15

Here heat is a good thing, we can always use some extra warmth ;-)

  • spidennis

Posted November 14, 2006 - 12:49 PM

#16

I'd like to see what the desert racers are using, dakar, baja and such .... didn't a couple of WR250Fs finish the dakar rally last year?

  • PBDBLUE

Posted November 14, 2006 - 07:55 PM

#17

The AC current from the stator/rotor is non regulated full output and any excess power not being used is dissipated by the regulator by shorting to ground. This can cause the reg/rect to get hotter than normal. The reg/rect will actually run cooler by using lights, etc which results in less power shorted to ground.


While you are correct that the AC regulator is a shunt type the DC regulators are typically a "pass" design. In a pass regulator the power dissipation is a function of how much current is being drawn through it so the more load the more heat that is generated. As far as BD regulators being better quality I'm not so sure. Do a search and you'll find a surprising number of posts about failed BD regs. Unfortunately many users of the 1st generation BD kits for the WR were among them which is why BD is on the third revision of the kit.




 
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