Rexlight stops working at 1.14V with NiMH?

[bullpup]

I have been using eneloops in my Rex. I turned it on and it just flashed off. I tried all modes and nothing. I tightend the head and tail to make sure it was in contact. Still not working. I switched the batteryand it worked. I measured the battery taken from the Rex. It was 1.14 volts. Would this be low enough to turn of the light all of a sudden? Any thoughts

 

[leeleefocus]

Re: Rexlight stops working at 1.14V?

Test the voltage of the battery while it is under load. if its an alkaline you will probably see it drop down to well below the open circuit reading.

 

[glockboy]

If alkaline, 1.14 volts is a dead battery.

 

[bullpup]

Thanks. It was the eneloops and I edited the post. I think I will go to Radio shack and pick up a 15 ohm resistor and a battery holder and see if I can make a load test that I saw iin another post. Just scared me how it just shut off. No dimming or anything to hint it was running ou of juice.

 

[protein_man]

My light dims for about 20 minutes before shutting off on an eneloop and it turns completly off when the cell reaches and open circuit voltage of 0.95 Volts. Maybe you got a dud light?

 

[Vikas Sontakke]

My light dims for about 20 minutes before shutting off on an eneloop and it turns completly off when the cell reaches and open circuit voltage of 0.95 Volts. Maybe you got a dud light?

But will it turn on again if you were to turn it off during those 20 minutes?

- Vikas

 

[bullpup]

Just a follow up. If the light goes dead suddenly and I put it on my BC-900 charger on a discharge cycle of 500 ma. Will the voltage displayed be the voltage of the battery discharging under 500 ma load? Is this enough of a load to tell me the true battery condition? Thanks again for alll the replies. I never knew flashlighting was such a science!

 

[big beam]

1.14V on a nimh is just about dead.not much left at that piont and under a load I'm sure it's under 1.0V

DON

Sorry bullpup
Yes that will work but the rex draws like 2 AMPS so the batt is under more load in the light than the charger is drawing from the battery.So the voltage will be even less than the charger says when it's running in the light.

 

[bullpup]

Any one have an idea of what size resistor to buy at radio check to test the Battery for the rexlight. I was going to buy a 15 ohm. Should I get a bigger one?

1.14V on a nimh is just about dead.not much left at that piont and under a load I'm sure it's under 1.0V

DON

Sorry bullpup
Yes that will work but the rex draws like 2 AMPS so the batt is under more load in the light than the charger is drawing from the battery.So the voltage will be even less than the charger says when it's running in the light.

 

[adnj]

At 1.0 volts, you need a 0.5 ohm resistor to draw 2 amps.

 

[orbital]

I had a E2 lithium to burn in my Rexlight and what I found was interesting.
With normal use of it in different modes ect... it did last about an hour total, big deal you say. Thing is, there was no dimming at all.
This morning we had a huge thunderstorm and I got up to check the radar, no light in the Rex, I thought well whats wrong now. Put in a normal primary...OK.

Point being, the regulation graph that Kai gave is a bit off only because I saw no dimming through the life of an E2.
Lithium primaries are simply too expensive to use all the time, but for people who like flat graphs,__________

 

[SilverFox]

Hello Bullpup,

You should be able to get a good idea of what is going on by using your BC-900.

Under a 500 mA discharge load, the voltage won't drop as much, but a discharged cell will see a lower voltage than a charged cell. You may have to play around with it a little, but if you compare the voltage under a 500 mA of a fully charged cell, then run it to 50% discharge and compare it again, then run it until it completely shuts off and compare it again, you should have a good idea of how the voltage under a 500 mA load corresponds to how much runtime you have left on your light.

Tom

 

[bullpup]

Thanks Tom. I was just surprised how it shut off without warning.

 

[Lighthouse one]

You won't find any resistors nearly that low at a Radio SHack.....You need an electronics store....

 

[zeeexsixare]

There are plenty of 5W 10, 15, 20, 100ohm resistors at RS. I bought some for my car mod. Check the RS website.