Tigerlight doesn't seem as bright

[dkelly]

Tigerlight doesn\'t seem as bright

When I bought my Tigerlight approximately 1 year ago, I was, as expected, impressed by the brightness. Lately, it seems that it is not as bright. I don't think it is my imagination but I don't have a way to test it objectively. I opened it up and put a voltage meter on the wires where they connect to the bulb and turned on the switch. It registered 4.62 volts with the bulb burning. Is this the correct way to measure battery voltage? Is this voltage correct? If this is the correct voltage I guess my next step would be to replace the bulb. Any info would be appreciated before I contact Tigerlight.

 

[Josey]

Re: Tigerlight doesn\'t seem as bright

Hey dkelly:

My fully charged (or nearly so) Tigerlight reads 7.91 VDC. It drops after I turn it on, but you should measure it after a full charge (10 hours) and after it has a chance to settle down after the full charge.

4.62 VDC sounds very low. You may have let it get too low. NiMH batteries can be damaged permanently if they get too low.

I doubt that there is anything wrong with your bulb. If you can't charge the battery back up to about 7.9 VDC (resting full charge), you probably need a new battery.

In the future, you may want to pay attention to what Jim Sexton is doing. Not many people seem to be talking about it, but his easy TL11 mod turns the stock TL into a rocking socking light, with tons of throw and flood. It is a wonderful light and worth checking out if Jim does a second run.

Josey

 

[Josey]

Re: Tigerlight doesn\'t seem as bright

PS: You can measure the votage from the gold contacts on the outside of the light.

 

[dkelly]

Re: Tigerlight doesn\'t seem as bright

Thanks for the tip about measuring at the gold contacts. That is much easier than taking the cap off. My light was taken off the charger after approximately 20 hours of charge and measured after approximately 5 minutes of run time. I will remeasure again immediately after taking it off the charger.

 

[pjandyho]

Re: Tigerlight doesn\'t seem as bright

I somehow suspect that your battery is failing you. After all, NiMH has a tendency for memory failure.

 

[Frame57]

Re: Tigerlight doesn\'t seem as bright

dkelly,

I think you've either damaged your pack or your charger isn't working properly. First of all is the red charging light on ? If not, check the open circuit voltage of the charger, it should be around 11 Vdc. If it isn't check your DC power supply it should be in excess of 12Vdc.

If all this checks out open up the charger cradle and check for cold solder joints on the input and output of the circuit board. The quality of these joints are some times poor.

The NiMh battery pack is considered discharged at 0.9 Vdc per cell that's 5.4Vdc for the pack.(the pack is made up of 6 cells). Your pack is way below minimum voltage and may be permanantly damaged.

Hope this helps

Jim Skinner

 

[js]

Re: Tigerlight doesn\'t seem as bright

dkelly,

Your battery pack is definitely messed up. Under load it should still be well above 6 volts. But it isn't due to "memory" failure. These batteries don't suffer from the memory effect; and actually, according to the experts NO batteries suffer from the memory effect, unless you're in orbit or on the moon. But whatever. Cells can still fail, or if the pack is over-discharged this will CAUSE cell failure and reversal. Leaving the light sitting around for months at a time without charging it will also hurt the batteries. It sounds as if you've got at least one bad cell.

The open circuit voltage on the gold harness charging contacts will be well over 12 volts. Something like 17 or more volts. The LM317T will go full open in order to try to get the proper current from an open circuit (impossible) and will thus have the same voltage as the power supply, which is an unregulated "12" volt AC-DC wallwart, which is running at around 17 volts OPEN CIRCUIT. This drops under load.

Anyway, what Frame57 said is the right thing to do: does the red LED come on and stay on any time the light is on the charger? If not, something is wrong. Check the open circuit voltage of the wallwart and harness charging contacts.

Actually, if you don't want to bother with all of this, call TigerLight. Their CS is fantastic. They'll fix you right up.

 

[dkelly]

Re: Tigerlight doesn\'t seem as bright

Well, after a few more measurements, maybe it is my imagination that my light is not as bright. My charger seems to be charging and below are a few numbers I took with my volt meter.
Fresh off the charger 7.31 volts
After about 10 minutes 7.15 volts
When first turned on 4.6 volts
After a few minutes of being on 5.2 volts
After being turned back off for several minutes 6.79 volts

While on it is below the 6 volt mark Jim specified but only by .8 volts. Maybe I will call Tigerlight and see what they think. Thanks for all the info guys.

 

[js]

Re: Tigerlight doesn\'t seem as bright

[ QUOTE ]
dkelly said:
Well, after a few more measurements, maybe it is my imagination that my light is not as bright. My charger seems to be charging and below are a few numbers I took with my volt meter.
Fresh off the charger 7.31 volts
After about 10 minutes 7.15 volts
When first turned on 4.6 volts
After a few minutes of being on 5.2 volts
After being turned back off for several minutes 6.79 volts

While on it is below the 6 volt mark Jim specified but only by .8 volts. Maybe I will call Tigerlight and see what they think. Thanks for all the info guys.

[/ QUOTE ]

Your battery is DEFINITELY bad. No question. It should be at least 8.4 volts when fully charged hot off the charger. It should keep pretty near to 7.0 volts under load. No, it's not your imagination. I can tell you for a certainty that your TL is nowhere near as bright as it should be. Call TigerLight and get a new battery.

 

[dkelly]

Re: Tigerlight doesn\'t seem as bright

I talked to Michael at Tigerlight and he agreed that my battery was bad. He resolved my problem to my complete satisfaction through Dan at Tactical Warehouse. A big thumbs up to both Tigerlight and Tactical Warehouse. Michael returned my call well after normal business hours using his cell phone. I called Dan even later that night and he answered the telephone and I had a great conversation with him. Both excellent guys to deal with.

 

[js]

Re: Tigerlight doesn\'t seem as bright

[ QUOTE ]
dkelly said:
I talked to Michael at Tigerlight and he agreed that my battery was bad. He resolved my problem to my complete satisfaction through Dan at Tactical Warehouse. A big thumbs up to both Tigerlight and Tactical Warehouse. Michael returned my call well after normal business hours using his cell phone. I called Dan even later that night and he answered the telephone and I had a great conversation with him. Both excellent guys to deal with.

[/ QUOTE ]

Yes. Yes they are! Both of them are just simply the best. I can think of a couple companies and businesses that could take a clue or two from the two of them.

 

[The_LED_Museum]

Re: Tigerlight doesn\'t seem as bright

On my TigerLight, the battery (with about one minute of previous use) measures 8.73 volts open circuit, and 6.37 volts when the lamp was turned on.

The charging terminals on the outside of the TigerLight are "hot", and you can measure the voltage that way.
That's how I measured the voltage on mine.

 

[Josey]

Re: Tigerlight doesn\'t seem as bright

Hey The LED Museum:

That seems high when off and low when on. Did you measure the 6.37 VDC just after the light was turned on or after it had been on for a long time?

My stock TL with something a little less than a full charge measures:
7.87 VDC off (off for a couple days)
7.18 VDC 15 seconds after turning on
7.01 VDC 1 minutes after turning on
6.92 VDC 2 minutes after turning on
6.87 VDC 3 minutes after turning on

Then turned back off:
7.57 VDC 1 minute after turning off
7.61 VDC 2 minutes after turning off
7.64 VDC 3 minutes after turning off
7.66 VDC 4 minutes after turning off
7.67 VDC 5 minutes after turning off

Josey
.

 

[Josey]

Re: Tigerlight doesn\'t seem as bright

Hey The LED Museum:

I just saw your post on the other TL thread here. Sounds like your TL was way undercharged so you popped it into the charging station. I don't know how theTL charger regulates, but my solar charge controllers will charge at a higher rate when the batteries are low. Maybe that is why your (fresh off the charger?) rate is so high. And maybe because the battery was still a long way from a full charge, the voltage dropped quickly after turning the light on.

Does this sound right? Or am I misreading how you charged and read the voltage? I have the feeling that keeping the TL battery pack properly charged is the key to its long life.

Josey

 

[The_LED_Museum]

Re: Tigerlight doesn\'t seem as bright

I'll re-measure the open-circuit and closed-circuit voltages again probably tomorrow morning when I take the TigerLight off the charger. That way, I'll *know* the battery pack is fully charged.

Since I received my TigerLight in mid-February, I honestly don't remember in what state the battery pack was when I measured those voltages.

I don't believe the charger is regulated or otherwise governed (ie. it is not "intelligent"), so the charge rate should be pretty much the same regardless of whether the battery pack is partially or fully discharged.

 

[turbodog]

Re: Tigerlight doesn\'t seem as bright

You know, the plague/challenge of the computer age is to educate/convince people not to open unknown/unexpected attachments/etc.

The same challenge of the rechargeable light/tool industry is to get people to not:
1) over discharge the batteries
2) leave these things on the charger (even a smart charger)

I hate to sound like a know-it-all (someone's got to end this madness), but the way to get the absolute LONGEST life from your batteries is to charge them fully, take them OFF the charger, and only put them back on when they start to "dump" or noticably begin to "dim" or "slow down (drill/etc)".

This has nothing to do with memory, but it has EVERYTHING to do with voltage depression and cell stress/heat from repeated/prolonged overcharging. Even a smart charger will raise the temp of the battery significantly. This will accelerate cell failure, period.

The voltage of your tigerlight/magcharger/etc is easy to figure. Take the # of cells, 6 in the case of the tigerlight, and multiply by 1.2 volts per cell (7.2 volts total). This should be pretty darn close to MOST any rechargeable tool/light's voltage measured under a typical load (this voltage will remain pretty constant except when right off the charger and right at the end of the run).

Typical load in a tigerlight would be using a stock bulb. Granted, a drill/saw is harder to measure and is harder to define a "standard" load situation. I would guess that in the case of a motorized tool, a simple no-load full speed condition would be close enough. There are other variables present in the drill though, maybe I should not have opened that can of worms.

If the voltage is under this value (7.2) by some rough multiple of 1.2 then one or more cells have prematurely discharged or are shorted.

Take the following example:
tigerlight pack is 6 cells
typical runtime is 60 minutes (arbitrary #)
should be approx 7.2 volts under standard load
voltage right off charger under load = 7.8
voltage after 5 minutes = 7.2
voltage after 20 minutes = 7.0
voltage after 30 minutes = 6

You can see that somewhere between 20 and 30 minutes, 1 cell (1.2 volts of power) discharged before the others. This lowered pack voltage to 6 volts (7.2-1.2=6). If this had been around 4.8 then 2 cells would have discharged. This was his original measurement.... right?

These cells will usually recharge to 1.2 volts per cell, so final voltage, or voltage right off the charger, or voltage RIGHT after turning the light on means...... nothing. Unless (always an exception) the cells are REALLY bad, but most packs fail from 1 or more cells being weak, not failing completely.

Take the following data. I collected this from a light I own. It has a 25 watt mr-16 bulb and 5 4500mAh cells. Runtime is approx 90 minutes. The initial reading is right off the charger. Column 1 is the time, column 2 is the pack voltage.

time voltage
0.01 6.56 (instantaneous reading when light was fired up)
4 6.32
9 6.15
15 6.04
21 6.012
27 6.012
43 5.99 (nominal voltage achieved, 1.2 volts per cell)
51 5.96
60 5.91
68 5.87
76 5.8
86 5.72
89 5.67
94 5.59
95 5.56 (see note below)
96 5.53
97 5.49
99 5.39
100 5.32
101 5.26
102 5.14
103 4.79
104 4.57 (nasty yellow color)
105 3.94 (test ended)

At 95 minutes, pack voltage was 5.56 volts. 5 cells in the pack means that each cell was still providing 1.112 volts. This was right about the time when your naked eye would notice that the brightness was falling off. So, when you think the pack is dead (which it pretty much is), you should still measure practically 1.2 volts per cell.

At 104 minutes (nasty yellow), the cells are still at .914 volts each.

Hope you guys all got something from this, and that I didn't make too many typos or wander too much.

 

[brightnorm]

Re: Tigerlight doesn\'t seem as bright

I had similar questions about my Tigerlight, most of which were answered by this very informative thread.

Brightnorm

 

[Josey]

Re: Tigerlight doesn\'t seem as bright

Hey Turbodog:

My TL is new enough and works well enough that I believe that the battery pack is in excellent condition. And I did not overcharge it. And it had been sitting unused for at least a couple of days. And prior to that, I had used it for maybe 5 minutes since the last charging.

So how come it measured almost 7.9 VDC in that resting state? (Honest question, not an argument.) After I ran it for 3 minutes in the test above, (and before I had the benefit of your excellent post) I put it on the charger for about 2.5 hours. Now, after a long rest, it reads 8.4 VDC. How come?

How did The LED Museum's light hit 8.7 VDC in an almost dead state (6.37 VDC when in use)?

Are you saying that it is better to let the battery pack drop to about 6-6.2 VDC before recharging than it is to occasionaly top it off (but not leave it in the charger) to keep it up around 7.2 VDC?

Josey

 

[turbodog]

Re: Tigerlight doesn\'t seem as bright

A good quality nicd/nimh cell will "top out" or "peak" at about 1.4 to 1.45 volts per cell. So 1.45 x 6 = 8.7 volts. Notice in the runtime/voltage data above that my cells at 4 minutes were 6.32 volts. That's 1.264 volts per cell, and that pack wasn't a very good set. Rate of charge affect peak voltage (higher not always neing better). Most cells are rated for a 16 hour charge. That same cell on a 15 minute charge will peak a LOT higher. This will result in a slightly higher voltage from the pack for the first ...... say..... 25% of its runtime. Then it will look like a regular trickle-charged pack.

When to recharge....

We want to avoid overcharge. Don't forget this principle. If I top up my pack weekly/biweekly and let it reach full charge, I'm unnecessarily taking lifespan from the pack. But, if I top up and do NOT reach full charge I miss an important feature of the "full" charge. Equalization of the cells.

Example:
tigerlight pack
6 cells

Say cells 1-4 and 6 are perfect cells as it relates to self-discharge. Say cell 5 drops twice as fast. This doesn't always mean it is weaker (as it pertains to overall mAh capacity), but for some reason it still drops twice as fast as the rest of the pack. A slight charge will charge all cells by the same amount, but cell 5 will not reach full charge. Eventually cell 5 will fail prematurely from being stressed due to its high self discharge. Why? When you use the light, all cells give up amps/electrons/"power" at the same rate. Cell 5 will empty before the others and we all know what happens to cells that get emptied... they die a horrible death.

But, fear not, most decent mfgs use cells that are matched from the factory for Mah capacity. This help them to all die/empty about the same time. If you DO have a cell with a high self-discharge rate, it's likely gonna die sooner anyway no matter what you do.

Bottom line.... you will likely see little to no difference in lifespan if you drain then fill or dran and slightly fill. Just don't completely drain or leave the thing on the charger forever.

 

[dkelly]

Re: Tigerlight doesn\'t seem as bright

Here are some measurements that I made of my Tigerlight that seems to have a bad battery. The first set are right after being on the charger for 18 hours. The light is not turned on.

7.42 0 minutes

7.32 2 minutes

7.26 5 minutes

7.20 10 minutes

7.15 15 minutes

7.12 20 minutes

7.08 30 minutes

7.04 45 minutes

7.0 60 minutes

6.97 90 minutes

6.94 120 minutes

It seems funny the voltage would drop this much with no discharge. At this point I turn the light on and start making measurements.

4.0 immediately after turned on

4.84 on 5 minutes

4.66 on 15 minutes

4.18 on 30 minutes

3.62 45 minutes (noticeable dim)


I turn the light back off and immediately take this last reading.


5.2 off after 45 minute run time