LED Map Light Upgrade for Functionality, not Aesthetics

Wanting to upgrade the Map Lights in our Gen 3 Prius. The primary goal is to allow the passenger (spouse) to use the map light for reading, but minimize the distraction for the driver. We want to put more of the light onto the passenger's lap and less into the driver.

Has anyone else done this? Hopefully, you have success to share, but even what did not work would be helpful.

I think we want to replace an omnidirectional filament light bulb with a more directional LED. I am not sure if the stock prius lens will help or hurt this.

From other web sites, the bulb seems to be a 168 type bulb. My understanding is that bulbs in the 5k and 6k color range will temporarily harm one's night vision. So, I'm thinking we want something in the 2.7k to 4k range?

But all of the aftermarket LEDs that we have found so far, are either omni-directional and/or are in the 5k to 6k color range.

 

I gather that you think that the frequency/color of the light has no effect of night vision. Perhaps you are correct? However, the use of lower frequency light (red instead of blue end of the spectrum) to preserve night vision has been widely believed and practiced by the military. And it still is by my astronomy friends.

I was going to send you links to the following two articles.

• The Science Behind Choosing a Red or Green Light for Night Hunting
• Rothblum - Night Vision and Nighttime Lighting for Mariners.pdf

However, it seems that I have posted too few chats to be allowed to do so.

 

Everyone, Thanks for all of the advice. If anyone has any further comments, I still welcome them. And they may be helpful to others who read this thread at a later date.

PriusCamper & VFerdman,
With respect to the reading light, I will plan to do that as well. However, would still like to see if we can improve the utility of the existing map light. (Just in case compliance is less than 100% ;-)

ChapmanF,
I'm inclined to agree with you. Got a great deal on some high output 6.5K LED bulbs that we put in the garage. Very bright. But am not sure that we like them and are actually thinking about replacing them. Then again, maybe if the bulbs have had a great Color Rendering Index (CRI), I would have felt different.

Georgina,
Thanks for the link and the suggestion. They don't say what the color temperature is in the ad. However my understanding is that Xenon White typically puts out a lot of light at the 6K end of the spectrum.

I was initially also concerned about, because the picture shows LED elements on the sides, in addition to the end, thinking this might put light out to the sides where we don't want it. However, looking more closely at the orientation of the socket suggest that it the light from these additional LEDs will probably go more to the front and rear, and not toward the driver. Still, I'm think we want a more directional bulb.

The comment that "each bulb has three 3030 SMD" LEDs on it, had me looking for what kind of 3030 SMD LED chips might be available. One supplier lists the 3030 SMD style LEDs as being available in at least 13 different color temperatures from 2.6K to 6.8K as well as with different CRI values. So with a bit of effort and a soldering iron one might be able to "upgrade" an LED bulb with more desirable LED chips. I'm lazy, so I'd rather find a bulb that already had the desired color and orientation. But, if that fails, then this would be a fallback option.

Robert,
Thank you for your suggestions. It sounds like you have some really helpful real world experience due to your flying. The "Night Vision and Nighttime Lighting for Mariners" article that I referenced earlier, agrees with much of what you observed.

"at low levels of illumination, the practical difference between the effects of red vs. white light on dark adaptation time is almost insignificant. This is not true, however, at higher light levels."

"In summary, recreational and commercial mariners should consider the advantages of using low-level white light and make a concerted effort to use less light. As with red lighting, the lights will need to be turned off for about five minutes before maximum rod sensitivity is obtained for detecting ships and potential hazards in the water. Low-level white lighting greatly surpasses red lighting in supporting good color discrimination and, therefore, accurate reading of charts and displays."​

So it seems that while light is much better for reading displays, but at the higher levels it takes longer to recover one's night vision than does red. Unfortunately, it doesn't explicitly answer how much worse a 6.5K source would be than a 2.7K source. Since the 2.7K is closer to red, it seems reasonable to infer it would be better, but don't have hard data.

Based on the excellent feedback of this group, and further reading, I'm inclined to try the following:

Get a LED directional bulb with light in the 2.7K to 3.5K range. (Buy one, if I can find one for sale, otherwise buy something else and try replacing the LEDs.)​

One problem will be aiming the light. Perhaps, if there is enough play in the socket, we might be able to get it good enough. The other issue is that the cover/defuser will tend to spread out the light, but I think if the bulb replacement is focused enough, we may end up OK. If not, may have to try to polish away some of the defusing features. But all of this sounds like a bit of work. So, it may take a while.

In any case, I will plan to report back to this thread, once I have something to report.