DTRL's the voltage factor with relays ?

[macabethiel]

Hope this picture loads OK.

http://i296.photobucket.com/albums/mm191/macabethiele/Jeep%20DTRLs_zpsi1ksdnha.jpg (http://s296.photobucket.com/user/macabethiele/media/Jeep%20DTRLs_zpsi1ksdnha.jpg.html)

I fitted these round DTRL's yesterday cheap on e-bay at £6.59 the pair and used a relay that cost £2.78 from China.

As I discovered when I fitted DTRL on my Beamer the relays must have some sort of voltage activation as if you test the lights with your car battery they work fine. Once you fit a relay they need the engine to be running so that the charge voltage makes the relay work as a test without the engine running will either give you no lights working or they come on for a fraction of a second before they go out.

Hardest Job on the Jeep was to find somewhere to connect the power to the relay and hence the lights without running a cable through the bulkhead e.g. from Cig lighter power supply.
That got me thinking so I have taken a permanent live 12 volts from the fuse box under the bonnet and connected that up temporarily. When you start the vehicle the lights come on as they should but when you switch off they stay on for between 15-30 seconds until the voltage drops and they go out.

It might be this is going to cause a battery drain so I intend to put a second relay in place and take power for the relay from the washer motor in the reservoir under the front wing thus only adding a small load to the circuit. I have added a small fuse holder with a Mini Blade 2.5 amp fuse fitting to the power take off so its a properly fused supply. All cables in plastic trunking with connector block fitted inside a plastic chocolate type box.

It might be that no drain is likely so am not sure if the relay and connection from the washer pump supply is needed. It means a jack up and partial removal of a wheel arch liner to find the washer motor connection. The power comes through the ignition feed for the washers and the switch just earths the system so when the ignition is on the feed to the washers is live.

Anyone know if the second phase is needed or is it worth seeing if the battery drains via the DTRL relay ?

[S_Richardson]

How many amps does it draw to power them?

[macabethiel]

Not sure what the current draw of the DTRL relay is when not actuated if anything but the lamps are 18 watts at 12 volts. Looking at the details on the relay that I have pasted in I should be OK!
Daytime LED Car Running Light DRL Relay Harness Auto On/Off Controller Switch

Features:
100% Brand New And High Quality.
Mini size, light weight and waterproof
Suitable for all vehicle models. With light reducing and delay function
Simple wiring
Smart start: When you start the car engine, LED daytime running light will automatically turn on. When you turn off the car engine, LED daytime running light will delay off 12 seconds.
Voltage: DC12V
Current: 5A
Product Dimensions: 4.0 x 1.8 x 2.1 cm, total cable length: 15 + 58(longest ) cm

Wiring Instruction:
The red and black wire of the input end (the end with a fuse) are connected directly to the car battery. The red wire of the output end is connected to the positive pole of the LED daytime running lights, the black wire of the output end is to connect to the negative pole of the daytime running lights. The white wire is to connect to the headlights (or dashboard lights), when the headlights or dashboard lights are turned on, the brightness of the LED daytime running lights will be halved

Package Includes:
1 x Daytime Running Light Controller

[solarman216]

Rayf will be better placed than I to comment on this, but although they are called "relays" I suspect they are solid state devices, and as such could fail shorted for any number of reasons, so I would be putting a relay proper on the red battery wire that is ignition controlled, the only problem with that could be that as the power is shut from the DTRL "relay" immediately the ignition is off, the delay off of 12 seconds will not apply, now whether this will upset the internal timing device of the DTRL I do not know, Rick

[macabethiel]

Rayf will be better placed than I to comment on this, but although they are called "relays" I suspect they are solid state devices, and as such could fail shorted for any number of reasons, so I would be putting a relay proper on the red battery wire that is ignition controlled, the only problem with that could be that as the power is shut from the DTRL "relay" immediately the ignition is off, the delay off of 12 seconds will not apply, now whether this will upset the internal timing device of the DTRL I do not know, Rick

You are echoing my thoughts I had not considered relay failure. The loss of the "delay" would not bother me at all. I know LED's do take a time to go out completely so if there is some sort of capacitor built into the circuit might that explain the delay ?

Interestingly the ones on my Beamer that take the power supply from the accessories side of the ignition circuit still have the delay when you switch them off. I wondered if the circuit is buffered by the same system that shuts of the interior light slowly when you exit the vehicle.

[rayf3262]

I think the delay you are seeing is due the battery voltage settling from ~13.8V when being charged to the normal circa 12 odd volts in its quiescent state.
I would guess the "relay" is designed to switch at or around 13V.

[macabethiel]

I think the delay you are seeing is due the battery voltage settling from ~13.8V when being charged to the normal circa 12 odd volts in its quiescent state.
I would guess the "relay" is designed to switch at or around 13V.

That makes sense.