PT Surge Question - bulb in other mods?


Nov 23, 2004
From what I gather, this runs on 8AA or on 4AA, so they must have them as 2 parallel sets of 4 (I can't imagine overdriving by 100%)

This implies that a set of alkaline AA's can hold the higher current for at least a limited time. I'm wondering why people don't put this module in a 4AA light with a set of Nicads, which certainly can handle the current.


1) What's the operating V for the Surge?

2) Has anyone tried this lamp assembly in another body?

3) What's the runtime difference between 4 and 8?

4) How much dimmer is it on 4 AA?



Newly Enlightened
Mar 7, 2005
Hi twenty

The surge does run on 2 sets of 4AA in parallel. It can run with just 4 batts but it is brighter when 8 are used... brighter by a noticeable but not huge amount. I don't recommend using just 4 unless it's an emergency because it causes the battery holder to warp over time as the batteries on one side press against the battery springs while the other side doesn't press back. In theory, the light will run twice as long with 8 vs 4.

I use NiMH batts in mine even though PT recommends only alkalines. The output seems to be as good as or even slightly better than alkalines. Other threads on here discuss exploding surges... this is a bigger risk in a surge over most lights because using 8 batteries makes for a greater chance of mismatched cells which is the most common reason for exploding flashlights.... throw all those batts in a sealed light and I could see one exploding here and there. I drilled a 1/64th inch hole in mine to prevent hydrogen buildup since I don't dive with it and I immediately charge the batts when the light starts to dim since batteries give off more hydrogen when they are run totally dead.

Don't let my discussion of an exploding surge scare you... all sealed lights run this risk and I love my surge... very bright and yet compact for using 8 AA's... I bought mine at for $20.

The surge uses a bi-pin bulb, not a lamp assembly, that plugs into a circuit board mounted on top of the battery holder. You can play with the bulbs position slightly to get the best spot.

Hope I answered your questions /ubbthreads/images/graemlins/smile.gif