Another update - so last night I hooked up the full test circuit with the 6V battery. Off one regulator was the 4 headlights (2x2) with the voltage open to max (bang on 6V according to the multimeter) and the current set to 600mA. Off the other regulator was the 2 tail lights with the voltage set to 4.5V and the current set to 300mA.
On the plus side all the LEDs worked fine however the headlight LEDs were noticeably dimmer than the when a single LED was driven with over 3V. The red lights were very bright. The switch worked to switch the circuit on/off but did not illuminate when switched on. I think I fried the LED inside the switch so have ordered another one.
To get the best out of the lights my options are:
- try again to get a 12V battery to fit (really don't want to fix anything to the underside of the bonnet).
- use a boost regulator for the headlights to increase the voltage to optimum level.
- run the lights off the tractors 12V battery and insert a timer board to the light circuit to protect the battery.
- be satisfied with the brightness provided by the 6V battery.
On option 1 the 12V battery will still have to be small (like 1.2Ah small) but will this not drain very quick? I've seen battery life calculators but am unsure what my total Device consumption is (mA).
On option 2 something like this looked like it would do the trick
http://www.ebay.co.uk/itm/141749333325?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
On option 3 I did order a timer board that arrived the other day but I have not used it yet so will have to test it and check how the reset works.
Option 4 is obviously the easiest but compromising is not in my nature! Something worth doing is worth doing right and all that.
