Will Quarks go POOF with 4.5 volts?

jankj

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Will quarks (specs: 0.9-4.2 volts) go :poof: if I run them with 4.5 volts?

The reason I ask is that I have a little headlamp project where a quark head will be run with 3*nimh batteries. They won't fully approach 4.5 volts, but close to that when fully charged. Also, it could happen that someone would want to run it with alkaline batteries... (oh, the horror).

Now I know it won't take long time before 3 nimh batteries (or 3 alkalines, for that matter) are down to 4.2 volts, at least when you draw any significant current from them. But still: Am I likely to destroy anything if I exceed the specs by 0.3 volts?

I would be surprised if I would do anything wrong - particular since the quarks have a buck/boost circuit. But I would still like the advice of CPF experts on this before I try it.
 

the.Mtn.Man

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While it may not go "poof" immediately, logic says that driving electronics at a higher voltage than what they're rated for could shorten the life of the components.

But I'm not the expert you're looking for, so we'll see how long it takes before someone pops in here to prove me wrong. :)
 

jankj

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4.5 volts? Aren't three NiMH AA batteries in series a total of 3.6 volts?

A nimh fresh off the charger will easily measure somewhere around 1.4 volts. That figure quickly drops when you put a load on it. Nimh are rated 1.2 volts because this is representative than the fresh-off-the-charger value. Same with li-ion, they are 4.2 volts fresh off the charger, but are rated 3.7 volts.

I am exaggerating slightly with the 4.5 volt figure, but not much. (3*1.45v = 4.35 volts). There is also the possibility that someone some day will feed this contraption alkaline batteries.
 

jankj

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Would it make sense to use the 2^123 head instead? That stays in regulation down to 3.0v and handles much more than 4.5v....

Yup, it would. But I don't have one of those (yet). I do have two 0.9-4.2 volt heads that I am happy to rotate to whichever application I am using today.

The 2^123 head opens up some more very interesting possibilities... Of my 3*AA configuration I could shorten out one and run it with 2*14500... that would be quite nifty. Or I could get a 2*18650 compartment, that would be really sweet in deed (it is a headlamp DIY project, by the way).

But those will be future extension. Right now I'm looking for the quickest way with the materials at hand. Will I blow my 0.9-4.2 volt quark head if I exceed the specs with 0.3 volts?
 

Moonshadow

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Why try to run 'em off three batteries in the first place ?

Wouldn't it be simpler just to design your headlamp to run off either one or two batteries, which is how the 0.9-4.2V head is intended to be used ?
 

jankj

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Why try to run 'em off three batteries in the first place ?

Wouldn't it be simpler just to design your headlamp to run off either one or two batteries, which is how the 0.9-4.2V head is intended to be used ?

Yes, I can. I can shorten out one of the 3*AA slots I intend to use in less than 3 minutes. But 3*AA should be at least 50% longer run times than 2*AA.

I have this old crappy headlamp that is an excellent host for this project. It includes a fully functional 3*AA battery box. If I don't destroy anything I would appreciate the option of using 3*AA for longer run times.
 

guiri

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Why not put two of them to add up to the 2.4-2.8v and then turn the third one around for more amperage?
 

jankj

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Why not put two of them to add up to the 2.4-2.8v and then turn the third one around for more amperage?

Huh? Are you suggesting this configuration:

+1.2v- => +1.2v- => -1.2v+

in my 3*AA battery pack? (the => being my ascii art representation of how this battery pack is coupled in a 3s configuration).

Bad idea.:sick: Batteries are purposely made so current will flow one way through them. Reversing the current will most likely destroy the poor reversed cell and certainly won't be of any merit for any practical purpose.

But anyway, thank you all for kind your suggestions.

Back on topic, please: Will exceeding the specs of my 0.9-4.2volt quark head with 0.3 volts make the light go :poof: :thinking:
 
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amigafan2003

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Why not put two of them to add up to the 2.4-2.8v and then turn the third one around for more amperage?
:lolsign:

If you put two 1.2v 2000mah cells in series then you effectively end up with a 2.4v 2000mah cell.

If you parallel another 1.2v cell with the 2.4v cell then the 2.4v cell will try to charge the 1.2v cell = :poof:

This may help http://www.batteryuniversity.com/partone-24.htm
 
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march.brown

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Have you tried measuring the actual voltage across the unit ? ... Should be easy to do assuming that you have a DMM.

I just checked a dozen or so of my Hybrios and Eneloops which were charged the other day and the highest voltage was 1.388 volts with others as low as 1.387 and a couple at 1.386 ... I don't know what they measured when they came off the charger though ... Even if they were as high as 1.4 volts, that would still only be a total of 4.2 volts
Three primary cells might well be too high (initially) for comfortable use, but three rechargeables should pose no problems ... Bear in mind that there will be some voltage dropped across the internal resistance of the three cells and across any slight resistance in contact surfaces.

I can't see a problem with rechargeable batteries particularly if you check that their open circuit voltages (3 in series) is no more than 4.2 volts ... Three of my Eneloops charged a few days ago only work out at 4.164 volts ... Just checked some AA primary cells and they were all 1.515 volts each ... Also checked some Duracell Procell primary C cells and they were 1.610 volts each ... So, I would try to stay clear of the primary cells if I were you, though I personally wouldn't worry too much at only 0.3 volts (or so) over your 4.2 volt limit ... You need to measure the voltages though and if each cell is over 1.5, perhaps partially use them in another torch to bring the voltage down to within the 1.5 limit.


So no problem; I think that three AA Eneloops (or similar) would be within your voltage limit and would give a good ampere-hour capacity ... It would be easy to take extra Eneloops/Hybrios/GP Recyco or similar low self-discharge cells with you as spares.
.
 

the.Mtn.Man

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Just out of curiosity, have you tried asking 4sevens directly? Seems if anybody would know an answer to this question it'd be them.
 
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