Simple hotwire question – please recommend what bulb to use

[Kestrel]

I want to hotwire a pair of simple 4xAA bicycle headlights (2.5 watt Specialized PreView 2.5's). (I posted this in /Incan and not /Bicycle since this is a simple bulb replacement question w/ a standardized bulb base). I just want to upgrade the lights with a simple drop-in replacement bulb, something inexpensive and hopefully local (i.e. no shipping) – a maglite bulb or even a generic department store bulb would be fine, for example. Each light will be using 4 NiMH in series. Runtime is not that important, but the issue is the plastic reflector and bulb mount, I figure that anything that will not melt the plastic will provide sufficient runtime for my purposes, ~45 minutes max. There are a few resistors inside the switch housing, but I am assuming that they only operate on the 'low' setting that the light has & are bypassed on 'high', which is the only setting I use anyway.)

Pictures, including a close-up of the bulb (the IMR16340 is included only for scale):

Printed on the light housing:
Batteries: 4 AA Alkaline
Bulb: 4.8V 0.5A Halogen
Bulb base: P13.5s

Data printed on the two individual bulbs:
HMP20 4.8VO. 0.5A JAPAN
K-15 4.8V HONG KONG

I know that all the data I have supplied is excessive for what should be a simple bulb swap, but figured that it couldn't hurt to include it.

Thanks much,
K

 

[yellow]

"better" bulbs were something like
4.8 V / 0.8 A


but these might cost something like 5-10,
so the MUCH better way were to get a cheap 2*aa light at dealextreme, or Kaidomain, and hope for the best (that it works reliably)
(as more expensive lights are not what You plan now)
Even the junk will be MUCH Much brighter

 

[Kestrel]

From reading another thread (as well as posted by yellow), one basic option is just to pick up something like this from Home Depot for ~$2 or so:
http://www.servicelighting.com/EiKo-40061-K15-B3-5-Miniature-Incandescent-Light-Bulb
However, something worth doing is worth overdoing, right? ;-)

KC Specialty Products seems to have a large selection of Pelican bulbs, many of which are on sale for ~$8 for a 2-pack. I will be ordering some ROP bulbs from them anyway, can someone recommend a halogen PR-base push-in bulb made by Pelican that might work for what I'm trying to do here?

Edit:
Perhaps something like this:
https://www.storesonline.com/site/529271/product/Pelican%20%202600%20Bulbs
#2600, only a Krypton bulb, but 0.75A for a 4xAA Pelican, appears to be a PR-base push-in, only $2.50

Or perhaps:
https://www.storesonline.com/site/529271/product/Pelican 3704 Bulb for Big Ed 4C
#3704, Appears to be a PR-base, for a 4xC, $7.50 for two. Supposedly 6V, might be a little bit more conservative than the # 3754 below.

I am leaning toward the Xenon PR-base 3754 (4.8v, 1.7A high bulb, 0.7A low bulb)
https://www.storesonline.com/site/529271/product/Pelican 3754 Bulb Set
The 3754-H is 8.2W, I'm thinking that if the ROP-L (3853-L) starts at 11 W (and subsequently overdriven) and is borderline in an un-upgraded (i.e. plastic parts) Maglite, this 3754-H should be OK in these lights here. I also checked out SilverFox's AA NiMH data and made sure that 1.7A isn't an unreasonable task for my cells (4x Duraloops and 4x 'Merkury' (?) 2400's)

Since I'm ordering from these folks anyway, $7.50 for two bulbs will work great for what I'm trying to do. However, I am unfamiliar with these bulbs and don't know the approx. wattage limit for these little lights. Spending a few extra bucks for a Xenon bulb for these lights would definitely be worth it for me.

 

[lctorana]

Here you go:

 

[lctorana]

There's also this that DocD found.

 

[Kestrel]

Here you go:

Thanks, that's a great chart.

I've decided to go with the Pelican 3754 (8.2W & 3.5W) for now. I have two spare lights plus these two, so if I melt one, no biggie. I'll post back how the 3754-H works in this light (with regards to heat & runtime) with 4x NiMH AA after a few bicycle commutes.

K