Need some Re-training in Recharging

After only a few weeks of joining this forum, not only have I spent a few hundred dollars on lights that I didn't *need* (at least until I got here /ubbthreads/images/graemlins/icon3.gif) , but I also realized that my knowledge of rechargeables is weak to say the least.

I'm a police officer and have used rechargeable flashlights for almost 15 years without giving them any thought. After my shift, I'd just toss the light back into the charger in my locker until my next shift...

I just bought a couple new lights in my effort to "downsize" some of my gear - a Surefire L4 to replace my Stinger, and a Tigerlight 8" to replace my Maglite.
For the L4, I bought a couple Pila Li-Ions and a charger, and the Tigerlight comes with a NiMH battery and charger.

If you've made it down this far, I'm getting to my point now.
#1 From my reading, I now know that it's *bad* to keep the Tigerlight in the charger all the time. Since I work 4 days on and 2 off, I could keep it off the charger for the 4 days, but how much damage would I be doing by keeping it on the charger for the 2 full days that I'm off? The idea of having to come back to the station on my days off just to unplug my flashlight is a bit unrealistic.

#2 Finally, from what I understand, it's ok to keep the Pila Li-Ion bulbs in the charger during my days off, right?

Thanks for the patience and input. I'm slowly learning, but for now I want to make sure I do things right with these new lights.

Scott

The pila cells have circuitry built into them that will actually take themselves off the charger, so they're pretty much ok to leave on. Furthermore, the lithium chemistry is tolerant of pretty much any type of charging schedule you want.

The tigerlight is another story. It's actually MORE sensitive than the magcharger to overcharge. Why? The TL uses nimh cells instead of the MC's nicd. Nimh give off more heat at full charge/trickle charge status than nicd. This extra heat will slowly cook/kill the battery pack.

So, how do you keep the TL charged w/o having to come back? Maybe you could take it home with you and have a separate charger there? After all, it's a handy light. What about a timer? They are cheap, and could be set to charge the light an hour or two a day. This is actually probably the best idea that I can think of, short of having 2 TLs and rotating them.

Both these lights are good choices and should work well for you. Be aware that it you want a cheap reliable rechargeable incandescent light, you can put a pila 168s cell into a streamlight scorpion body. You just need to swap the bulb for a streamlight strion bulb.

Also, your pila cells will charge back up a LOT faster if you don't discharge them all the way. If I discharge to 10% capacity, they'll charge back in an hour. If I use the last 10%, it takes a LOT longer for some reason.

Hang onto your wallet.

[ QUOTE ]
turbodog said:
"If I discharge to 10% capacity, they'll charge back in an hour. If I use the last 10%, it takes a LOT longer for some reason."



[/ QUOTE ]

This is due to the fact that if the cell voltage falls too much below 3 VOlts, the charger will trickle charge the cell until reach 3 volts, then will start the real charge.

This is because the phase change inside the cell (from amorphous to cristalline) has to be initiated slowly.

Anthony

Hello Scott,

Turbodog has some very good points. I would just like to add a couple of thoughts.

I am a bit of a cautious person. I don't leave batteries on chargers. I have some high capacity D cells that I leave on the charger overnight, but in general when I go to bed or leave the area, I flip the switch on the power strip and shut everything off.

I have heard of NO problems with Pila batteries being left on the charger for extended periods of time. I would feel better if you had them on a noncombustible surface if you are going to do that. However, I feel there is very minimal risk involved. I would be more concerned with someone else coming in and using your Pila charger to charge an unprotected battery.

Li-Ion cells can "rapidly vent with flame" when they are held at voltages over 5.4 volts for extended periods of time. Since the Pila charger is set to a maximum of 4.6 volts the most you could do if the protection circuit failed is destroy your battery. There is not a lot of test data available for this situation, so I tend to error on the side of caution.

Please note that NiMh and NiCd batteries can also "rapidly vent" but it is without flame. You end up with a bit of a mess to clean up, but you don't burn the house down.

The TigerLight uses a NiMh battery pack and as Turbodog has pointed out, if you leave it on the charger 24/7 and never use it, it will cook the battery pack to death. If you use it during your shift, the cooking effect is reduced because it has to charge back up.

It takes about 12 hours to fully charge the Tigerlight battery pack from empty and that should give you about an hour of run time. If you use it for 15 minutes, it should take about 3 hours to fully charge back up. If you have a rough idea of how you are using the light, you can figure an approximation of how long it needs to be charged.

Depending on how much you use the light, I would suggest that you leave it on the charger during your shift. When you are off shift, slide it back a quarter of an inch to break contact. When you come on shift, push it back in to engage the charger.

Of course, this would only work for occasional use. If you use the TigerLight for an extended period of time, it will need an overnight charge to bring it back up.

NiMh cells have a self discharge rate of 1-2% per day. If you have 60 minutes of run time from the start, after two days off you would end up with 57.6 minutes leaving the light off the charger during those two days. The question you have to answer is how important is that 2.4 minutes?

Tom

Thanks for the info so far. Sure, I'll end up with some nice lights after all this, but it was easier to have ok lights and remain ignorant about the charging and all.

As far as keeping the Tigerlight in the charger while I'm working, that will be pretty tough, especially trying to get my locker to fit into the cruiser. /ubbthreads/images/graemlins/tongue.gif
So if the Tigerlight will only lose a couple minutes per day, but it would remain just as bright as if it were fully charged but just for a shorter time? If I'd lost 15 minutes from keeping it uncharged, after that 45 minutes of bright light that I had left, would it start to dim, or pretty much shut down?

Sometimes I'm not good with change when I'm so used to something, so I could be making this more of a project than it needs to be...Tom, I know you're a fan of the Tigerlights - would you say the benefits outweigh the inconveniences? Once I eventually do kill the battery, will I be able to easily find a replacement like I can with the Mag? Does Pila make Li-Ion batteries that work in it?

And if I'm understanding, even if I simply kept my Mag and used it as I have been for years, I'm risking "killing" the batteries just the same as I would if I kept the Tigerlight in the charger all the time, since the NiMH and NiCd batteries have similar warnings?

Sorry for all the questions, but I do appreciate you guys taking the time to answer them and educate me. I'm even annoying myself with all the questions. /ubbthreads/images/graemlins/smile.gif

The Surefire P6 with the 3 watt LED drop in can be used with a Pila 168S.

FROM: bugoutgearusa-
"There is no modification needed. These are direct replacements for the Surefire P60/P90 lamp. The runtime on a P60/P90 lamp is approximately 45-60 minutes. By replacing the Surefire P60/P90 module with the 3W drop-in LED module, run time is extended to over 4 hours.

Bulb life is also extended. The average LED bulb will last between 10,000 - 100,000 hours. The average Surefire P60 has a life span of approximately 25+ hours.

Lastly, since the 3W LED drop-in module does not utilize a filament, it is much more impact resistant than a Xenon bulb(which has a filament)."

Hello Scott,

Are you aware that TigerLight supplies a 12 volt adapter so you can use your charger in the car?

Light output from the TigerLight (as well as other non regulated lights) is related to battery voltage. As you use capacity from the battery, the voltage will drop and the light will get dimmer. It just so happens that NiMh cells hold their voltage pretty constant. As a matter of fact the general advise is that when you notice the light dimming, it is time to recharge it.

Go into the battery section and check out the thread "Charger Comparison." You will find that there is an initial drop in voltage, followed by a pretty flat section, ending with a sharp drop off.

To answer your question... you will notice very little dimming throughout the run time until the very end. At that time the light will go dim very quickly.

I am a big fan of the TigerLight as well as the improved battery packs and lamps that Jim Sexton has made available. I have two TigerLights. One I keep stock and loan out as needed. The other one I have changed the battery pack and lamp to make it brighter. The stock light always works. The modified one with a stock lamp, or a lower powered lamp always works as well. The modified one with a high power lamp will usually work, but I have had some lamps fail on me.

If I want to show off, I grab the brightest light I can. If I "need" the light, I grab my stock light.

Changing the battery is about as hard as changing the battery in a smoke alarm. There are a few more pieces, but it is quite simple. There are no Pila set ups for the TigerLight.

In everyday use leaving the light on the charger all the time, I would guess that the battery pack would last a couple of years. Taking care of the battery pack could extend that to four years or more.

Finally, feel free to ask questions. That is what we are here for.

In my humble opinion, anyone who stands between me and the bad guys deserves all the support I can give. Thank you for your efforts in keeping the world a little more civilized.

Tom

Have you considered using one of those timers that you can plug electric appliances to? They look like small boxes with two round knobs on the outside (those control the time when you want the device to turn on or off). You can set the timer to run for only a few minutes on your days off. When you're on duty, either modify the charging schedule or don't use the timer at all.

First,

I will say that I have never seen a Tigerlight. That said, some people here who I trust implicitly, Silverfox and js, tell me it is one of the finest lights made at that price point.

If I were an LEO, I would charge this light while on patrol using the DC charger and not even worry about an AC charger for that use. I would keep the AC charger at home, in case I wanted to use the TL at home on my days off.

My experience with high capacity NiMH cells, (2000MaH cells or higher), is that they cook pretty fast when left on the charger consistently.

I have seen packs that would barely light the bulb after only a month or two of constant exposure to continous current.

I never leave NiMH cells under current for prolonged periods of time.

NiMH cells are the BEST cells for high powered lights in my opinion, but just like any other specialty product they need to be appropriately charged and cared for.

If no other options are available, then using one of the timers is a good option.

Good Luck!

Bill