Battery type / current draw in Nova X series?

[RA_pierce]

My batteries say that they have "no memory effect". What does that mean?
That I can recharge them even though their not empty?

Yeah I'm pretty sure that's what it means.

I have some confusion I would like to clear up about my X105...

I use duracell 1000mAh NiMH batteries for it...

I can't measure current because my multimeter is lost.
Sometimes my laser mode hops to TEM02 when the batteries start dying... I have to turn it off and as soon as I turn it back on it returns to TEM00. If I give it time to cool off if goes back to TEM02... ???
So I switch out the batteries to new ones and it goes back to normal most of the time.
And then yesterday something weird happened...

My laser was working perfectly normal in TEM00 on my Duracell NiMHs.
And then I put in the other set (used to the point that mode hopping and decreased power output occurred) and it worked just as well as the first set as if it was never drained... ???
I found some used Power Pix batteries and tried them out to see if they worked.
My laser output ~5mW and switched between TEM01 and TEM00.
So then I put the first set of rechargeables back in and I got TEM02.
I didn't like it. So I put the other set of NiMHs (the more used ones) and I got TEM02 again.
So both sets of batteries Caused mode hopping.
Overnight I recharged one set and the output was stable again. I normally run it at 10-15 second intervals with plenty of time in between... but eventually (after about 5 minutes) I got more mode hopping (same, freshly charged batteries). Then I let the laser cool for a bit. Then I turned it on for 60 seconds straight. I turned it back on after 10 seconds... TEM00. Twenty seconds later I ran it for 30 seconds... TEM00. After 5 seconds I turned it on again to check for mode hopping... TEM00. ??? What the hell is going on? Suddenly it's perfectly stable again... at first I assumed the mode issues had to do with temp, but even when I let it get warm it stays stable. I don't know if I want to put the other batteries back in because I don't know if it will go back to TEM02...???
Any explanations? :-/ And sorry for the long story... i tried to make sure it all made sense...

 

[IgorT]

Well, we already discussed, that some of these lasers like to mode hop when the current is very low. I am much more afraid of the mode hopping, that happens when a laser is warm.

You said you were using empty batteries and got TEM02, then full batteries and got TEM00 and then immediatelly the empty ones again, and it remained in TEM00 (if i understood correctly). Your laser was still hot from the good batteries, so that is what kept it stable on the bad ones.

I'm pretty sure these lasers are regulated quite well, and when the diode is hot, it's resistance is lower, so when you put in the bad batteries again, the minimum voltage for regulation was actually low enough (due to the lower Vf) for the bad batteries to keep it at a higher current, than they would otherwise. That's why it didn't mode hop.


You need to do some more tests with FULL Ni-MHs. I have three 1000mAh pairs, so when i'm using one, i'm always recharging the other two. I never actually let it drop out of regulation, i replace the batteries when they reach 1.283V each. I don't know what would happen if i left them in much longer.

If you do lots of tests with full batteries and the mode hopping doesn't happen, you're ok. And the alkalines are not a good indicator of your lasers health, as they can show a much higher voltage, but sag immediatelly under load.


Since this lasers are regulated, it is a shame to continue using them, once they drop out. Don't use the Ni-MHs for more than 10 minutes total run time. And if you really want to test it, you should use completelly fresh batteries for every test. Check the voltage of your batteries when you take them off the charger. It should be 1.48-1.51V for best preformance.

Once your laser starts mode hopping, take the batteries out, and measure their voltage immediatelly and let me know what it is.

If you can, you should also measure the current with completelly full batteries and again, when it starts mode hopping.


Let me know if and when you do these tests.




EDIT: I just read your post again, and noticed that your multimeter is lost.... You might want to consider getting a new one. DMMs are really cheap these days. You can probably get one for under $10.. It won't be a professional tool, but good enough for voltage and current measurements, and besides, a DMM is a must, when you're playing with things like lasers.

Without those measurements it is impossible to tell what is going on, especially since you don't even know how full your batteries come off the charger (or is it a delta peak charger?). If you could at least borrow a DMM, it could help you determine if you need to return your laser or not.


EDIT EDIT: The more i read your description, the more i get the feeling, your only problem is, that you don't recharge your batteries often enough..

 

[IgorT]

My batteries say that they have "no memory effect". What does that mean?
That I can recharge them even though their not empty?

Yes, that's what it means. Memory effect was mostly an "urban legend" to scare people into buying expensive battery recyclers.

Ni-MHs don't suffer from this effect. In fact, the battery memory effect only really a problem on satellites, where a battery was charged by a solar cell, and since the satellite has a constant orbital velocity, the battery would be charged and discharged to EXACTLY the same levels during each orbit.

Since people don't really discharge and charge their batteries to exactly the same levels, this was never actually much of a problem. Most of the time, when people thought it was memory effect, that killed their cells, it was in fact just using them, that did it. And complete discharge cycles before charging a battery, actually uses the battery more. I have actually lost an expensive Li-Ion laptop battery pack due to such stupid cycling.


Some people still recommend discharging Ni-Cds fully before charging them, but with Ni-MHs it's of no concern. In fact, it was never as big a deal as some people made it sound. But i have to admit, that i used to be one of those people at one time. :

 

[FireMyLaser]

That's great man. I feel smarter by the minute I spend here.
Now if you excuse me, I have some batteries to recharge. [smiley=tekst-toppie.gif]

 

[RA_pierce]

Well most of what you understood was correct, except when I put FULL batteries in it mode hopped for a little and then stabilized shortly after. If it was because of low current it should have been stable with the fresh batteries to begin with.
I thought maybe it was too hot so I cooled it off and tried again. And I don't think it's heat now because it remained at TEM00 even when it was warm.
That is what confused me...
I haven't discovered a real pattern in when it mode hops. I just know it normally does when the voltage is less than 1.28V per cell and sometimes, it seems, randomly. I'll see if I can get a multimeter and new batteries this weekend.

I'm not gonna return it because when it's not acting up it kicks ass.

 

[IgorT]

I see.. I have a laser like that.. It mode hops when cold regardless of current, but as soon as it warms up, it's ok. I am also not going to return it. But it's just a DX200 and i already returned it twice..

Lasers that mode hop when warm make me MUCH more worried. Your laser obviously has two problems - low temperature AND low current (and the two can be related).


Most of the time we hear of lasers mode hopping as they warm up, that's why the opposite behavior can be confusing, but as long as it works well on full batteries and stabilizes itself by warming up anyway, you have nothing to worry about. I just hope it doesn't get worse.