NIMH Batteries in SURGE??

[Gerry]

Can I somehow use NIMH AA's in the SURGE flashlight??
Is there a circuit to boost the 9.6v to the 12v required?
Is this a good thing to do? Thanks Gerry /ubbthreads/images/graemlins/help.gif

 

[Darkaway]

Gerry,

Welcome to the board. I've been using NiMH in my Surge for over a year. Never had a problem. It may not be quite as bright as with alkaline or lithiums, but it's still plenty bright.

And BTW the Surge batteries are configured in series/parallel. Each bank of four AA's is wired in series and the two banks are connected to each other in parallel. In other words, it only needs the voltage from four AA's and will run just fine with only four batts in the holder. Try it. It has no boost circuitry. It just won't run as long with 4 batts.

Some will say that that running it at the lower volatge of NiMH will shorten the bulb life and that may be true.

Of course for maximun brightnessa and runtime I would run 8xAA alkaline. But if you're a NiMH freak like me, you can run the Surge on 4.8v (1.2v/batt x 4 batts) any time you want.

 

[Gerry]

Thanks; What kind of run time do you get with your 8 NIMH??
AND Thank's for your Welcome.
Gerry /ubbthreads/images/graemlins/blush.gif

 

[Darkaway]

Sorry, I don't have any hard numbers for you. I only use my Surge as a backup for a couple of minutes at a time when I need more throw than my L4 can provide. I ran it for 15 minutes or so one night on the beach (4x1800mAh AA)with no problem but that's about it. And I never carry it with the full 8 cells because I need to trade weight for runtime. And I try to avoid running my NiMH AA's down even halfway to prolong their life. But I can tell you that this light really sucks up the juice so I would go with 8x2100mAh AA's if you want runtime with NiMH.

 

[Kill-O-Zap]

I would estimate as follows:

2000mAh * 2 (parallel banks) / 1200mA (bulb draw) = 3.3h

That's just an estimate. Probably will be somewhat less in real life.

 

[Ray_of_Light]

I have measured 3 hours runtime before the Surge starts giving yellowish light. This is with 8 x 2100 mAh batteries. My Surge withstands well the heat produced in this uninterrupted period of lighting, and the first bulb has lasted more than 40 hrs.

I charge the Surge batteries with a cunstant current power supply (1 A) that disconnects when the battery temperature raises above 45 °C. Batteries have to remain in the carrier.
This system requires a 45 °C thermal switch in the BATTERY carrier, to interrupt the charge.

In a emergency situation, you can connect a DC power suppply (6.9 V) using the bulb as a current limiter. You can disconnect the power supply when the light from the bulb is barely of reddish color: at this point the batteries are at about 45 °C and raising. If you leave the power supply connected, the batteries will seriosly be damaged.

Of course, while charging the lens cap of the Surge must NOT be in place... you can safely close the light when the batteries are cold again.

Hope this helps

Anthony

 

[Kill-O-Zap]

Very interesting; so you take the bezel off, and clip some leads to something on the light, and then after charging, unclip, reinstall the bezel, and go? If that's correct, that's pretty cool. How do you install that temp switch? Where do you get it? How safe is it to rely on just the 45°C for the shutoff?

Thanks!