Quote:
Originally Posted by sendler
Was the engine running? That poor halogen looks mighty yellow.
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Engine not running. Lights powered by a custom battery pack system running at about 13.3-13.5V. More detail on that below.
Yellow appearance is likely due to two factors:
1) Camera automatically adjusts color as best it can, based on what it sees. With the LED running rather brightly at 5700ēK it probalby selected that for color balance and the halogen is very yellow in comparison. If I shot with two halogens and no LEDs, I think it would have shifted the color balance to make the halogens look more "normal". The LEDs come with little power supply units so I presume they're being fed proper volts/amps as long as I provide the specified minimum of 12V to the power supplies.
2) My system runs at about 13.3-13.5V using a bank of deep cycle batteries, with alternator disconnected. So yes, with the [Corrected: halogen] getting less than the usual 14V, it would be a bit more yellow than when used in a typical car.
About the deep cycle pack I use:
Yes, lead acid deep cycles are nominally 12V and will run about 12V under halogen headlight load when fully charged. I achieve 13.x volts by running a "booster" pack of (8) 1.2V NiMH D cells wired in parallel. That 1.2V pack is in series with the 12V deep cycles, for a total of 13.x volts, depending on load and state of charge/discharge.
For electrical nerds here, the (8) D cells are rated 10 AH capacity each and can easily handle a discharge rate of 10A each, or 80A combined. So they're fully capable of handling the load of boosting the voltage fed to headlights + fans + wipers, which is their job.