Can you see me now...? Hack auxiliary lights - Wire in a relay...?

[radguzzi]

Some time back I bought a set of aux lights to put on the EV Hack and I finally got around to installing mounts this past week.  These are simple VW dune buggy type lights. 

I made some neat mounts that attach to the leading link front end so as to form a conspicuous triangulated light pattern.

So the question is whether to wire a relay into the wiring system for these lights.  I will use a separate switch vs trying to incorporate them in the low or high beam of the EV.

I am not leery of wiring simple systems, just need a sanity check.  Any electrical experts here. 

Thanks,
Rob

[Old Jock]

I wouldn't qualify as competent in anything, let alone an expert.

What's the Wattage? Guessing somewhere in the 40-50W range, unless they're LEDs, so yes I'd definately use a relay. That's going to be approx 100W so around 8.5 amp, 20A relay should be fine, remember to fuse it if not going through a fused supply already

Which alternator is on that bike, the old Bosch system probably wouldn't be up to it, the Ducati system probably.

Depends how you want to do it, personally I'd wire the relay through the Hi Beam and the switch, so when you go to Hi Beam you got them on (when you want to via the switch) but just going to LoBeam is a one button operation. Here in the UK I believe that's also the law.

Just if you were somewhere there was a lot of traffic it would be a lot of fumbling in the dark to switch to Lo Beam and kill spotlights.

John

[Wayne Orwig]

What wattage?

Sort of looks like an H3 bulb in there, so likely 55 watts each. You really need a heavy fused wire directly from the battery, then either switched by a good relay, or a good switch. I prefer relay, then you can use smaller wiring to the switch.

And at that wattage on a 99 EV, I hope you have a voltmeter. It will work, but at anything below about 3000 RPM, the battery will likely be discharging. And the charge you get even at highway RPMs will be marginal.

LEDs are a much better option for that system.

[moto]

Wayne is an expert, and I agree with what he said.

Some key points I would emphasize:

The most important thing is to put a fuse in the positive side of the circuit near the battery.

A relay is just a remote control switch. Any properly rated switch or relay will do fine, and not cause any appreciable voltage drop. To figure out the rating in amps that you need, divide the watts by the volts, adding both circuits together. If Wayne is correct that the lamps are 55 watts each, you get (55 / 12) x 2 = 9.17 amps, say 12 amps for a safety factor.

Switches have both AC and DC ratings, and they are not the same. Typically the DC rating might be 1/10 of the AC rating. So watch out for that. (mouser.com/blog/which-switch-who-cares-if-it-is-ac-or-dc).

You do need a big wire directly from the battery if this is not an LED lamp. Maybe not as big as you think, though. Post your wattage and I'm sure Wayne will give you the right advice.

I'd really like to see more details of your mounts, if you don't mind. This is a perplexing problem to solve in my experience.

Looks good.

Moto

[radguzzi]

Thanks John, Wayne, moto,
Yup, indeed the bulbs are H3 so I'll find a set of LED replacements.  No need in taxing the charging system for no reason.

Odd that I could not find any locally, I hate to not support the local stores but I will do the on-line purchase if need be.  Some that are available are the exact replacement for reasonable money.
Add a simple switch and in-line fuse is and this is an easy fix.

Moto,
Nothing fancy for the mounts, I'll take some photos and post them to you.

These are the LEDs I installed on the Old Convert... The mounts were incorporated in the Vetter mounts.








Thanks all for the reality check, LEDs it is...

Best,
Rob








 

[moto-uno]

  How are you going to warm your hands after a cold ride with LED lights :) ?  Peter

[radguzzi]

  How are you going to warm your hands after a cold ride with LED lights :) ?  Peter

Note the huge hand warmers, one on each side.  Seen here just below the tank. 

On a really cool day I use Gerbing heated gloves and with the LED light not draining the charging system I don't have to worry about the battery...

[Kiwi_Roy]

Whatever you do make sure the relay drops out when you turn the engine off otherwise they will quickly drain the battery.
It's also good to have a Voltmeter attached to the city light, that will let you know if it's unsafe to shut the engine off because the battery is too low for a re-start.
Of course LEDs are the way to go a couple of 10 Watt spot lights will make as much light and they may not need a relay as they can afford to lose a few Volts without effecting their output.
However I must say those big old spots do look the part on an old bike if you can afford the amps they draw.