recharge after or before use ?


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shawntim

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Feb 13, 2002
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#1
I'm using the Rayovac 1-hr quick charger. Usually I charge the day before I use. After i upload the pics to my computer, I'd proceed to charge my batteries again.

But found out that when i wanted to use the batteries about 2 weeks later, they were flat only after 50 shots.. not quite.. experience tells me that it takes about 100-120 shots w/o flash on the 602 to flat out a set of batteries.

What is the usual practice ? does this happen to you ?
 

Willy

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Jun 2, 2002
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#2
hmm ...

i think not good to charge so often, most nimh batteries got a lifespan of approx 500 charges / 3 years ... whichever is earlier. Besides, although the memory effect is less noticable on Nimh batteries, it is still a good practice drain it totally before charging. I dun think the rayovoc is able to discharge batts.

I have 2 sets of backup ... so i only charge after the current set totally kee chia. (even when low batt, i still continue to take)

btw, wat type of batteries are u using? My Sanyo 1850 allows me to take up till 200+ shots on my A40 ...
 

shawntim

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#3
i'm using the Sanyo 1850 x 4 and Rayovac 1600 x 4.

Or rather.. is there a better way to determine how much juice is there left in the battery ? because 602z doesn't have a battery indicator.. when it's flat, it's flat real fast !
 

M

Midnight

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#4
Originally posted by shawntim
What is the usual practice ? does this happen to you ?
Did you keep the batteries in the charger to trickle-charge while they were not in use? That's the generally recommended method of ensuring that your batteries are always at optimal charge when you need them, because NiMH batteries tend to self-discharge rather quickly when not in use. I've heard estimates of the average self-discharge rate to be something like 2% a day, but I don't have the technical know-how to evaluate how accurate or reliable this figure is; suffice it to say, though, that trickle-charging's pretty reliable, and I do it all the time with my Rayovac charger too.

If you anticipate a need for multiple sets of fully charged batteries, then you should allocate some time to charging them right before you need them.
 

matthew

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Apr 19, 2002
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#5
Originally posted by Willy
hmm ...

i think not good to charge so often, most nimh batteries got a lifespan of approx 500 charges / 3 years ... whichever is earlier. Besides, although the memory effect is less noticable on Nimh batteries, it is still a good practice drain it totally before charging. I dun think the rayovoc is able to discharge batts.

/B]


Apparently its not good to completely discharge NiMH cells every time like you had to do with NiCD cells. It may actually reduce their life - 'cause then end up in the charger for longer.
The battery manufactures seem to be recomending only occasional 'conditioning' for the cells.

What really kills off most rechargeables is over charging - be carefull with the trickle charger...

I would recharge when flat immediately in a 'smart' charger, and then before the next outing, put them through the smart charger again - it will quickly top them up making up for what was lost in storeage.

Most trickle chargers are to dumb for my liking, the simply just pour in a small amount of current at all times - could lead to over charging.

The expensive computer UPS at work 'trickle' charges by monitoring the battery and only once every couple of hours or so does the charger actually kick in and give the battery a boost. It lets the battery rest. Must work, the Sealed Lead Acid cell in the thing is 5 years old and the UPS still has plenty of 'run time' when the power drops.


Batteries are delicate chemical balancing acts.
 

shawntim

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#6
putting them in the charger for a trickle charge for 2 weeks say about 336 hours or even longer until i next use my cam isn't exact a very comfortable idea.

so you're saying that a NiMH can auto self-discharge even if they are not kept in a circuit ?
 

Zerstorer

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Jul 8, 2002
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#7
Originally posted by shawntim
i'm using the Sanyo 1850 x 4 and Rayovac 1600 x 4.

Or rather.. is there a better way to determine how much juice is there left in the battery ? because 602z doesn't have a battery indicator.. when it's flat, it's flat real fast !
It does, but the warning come really late. The red outline of a battery appears when you have enuf juice for about 10shots. After that it turns red and you prolly have enuf for 1 more shot before it switches off and retracts the lens.

50 shots is really low. I'm using the same battery/charger combo and I still consistently get 100+ shots.
 

shawntim

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#8
Originally posted by Zerstorer


It does, but the warning come really late. The red outline of a battery appears when you have enuf juice for about 10shots. After that it turns red and you prolly have enuf for 1 more shot before it switches off and retracts the lens.

50 shots is really low. I'm using the same battery/charger combo and I still consistently get 100+ shots.
erhm.. i don't have a red indicator.. usually it will start to switch off by itself before i know what's going on.. when i switch it on agan, then it shows a white indicator after sometime. Then after evey shot it switches itself off. After 3-4 shots the camera cannot be turned on.

yup. 50 shots is very low. I get consistently 100+ shots per freshl charged batteries too.
 

M

Midnight

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#9
Originally posted by shawntim
putting them in the charger for a trickle charge for 2 weeks say about 336 hours or even longer until i next use my cam isn't exact a very comfortable idea.

so you're saying that a NiMH can auto self-discharge even if they are not kept in a circuit ?
Yup, NiMH cells have a relatively fast self-discharge rate compared to NiCD and alkaline cells. Actually, leaving your cells to trickle charge for weeks on end ought to be perfectly fine, as long as you're using a smart charger that utilises a low trickle charge current (for instance, less than 50 mA), which is indeed the case with the Rayovac charger. I certainly have no misgivings about doing so myself.

I would say that the only time you should worry about leaving your batteries in the charger too long is when you're using a 'dumb' slow charger that essentially attempts to pump the same current through the cells all the time regardless of their actual charge state, in which case you may indeed damage the cells at the chemical level.
 

Zerstorer

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#10
Originally posted by shawntim


erhm.. i don't have a red indicator.. usually it will start to switch off by itself before i know what's going on.. when i switch it on agan, then it shows a white indicator after sometime. Then after evey shot it switches itself off. After 3-4 shots the camera cannot be turned on.
Oh yes there is!
Take a look at page 17 on the manual.;P


yup. 50 shots is very low. I get consistently 100+ shots per freshl charged batteries too.
Did you leave your batteries out for 2 weeks? Is it a single occurence or does it happen all the time now? Anyway I always try to top up the batteries a day before shooting.
 

shawntim

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#11
yup.. i know it's there on my manual. but I've NEVER seen it on my camera.

i only shoot on weekends, and not every weekend i go shooting. When batts are not in use, I take them out. I don't leave them in the camera (afraid of leaks).

Usually i charge them before shooting, but like i quoted, i charged them after use. There was once i took out the batts to use about 3 days after my last charge, and they lasted my only 50 shots. this is how i discover this problem.
 

mpenza

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#12
I presume the batteries are at least 1600mAH and above.

are the batteries new? it may take a few charge/recharge cycles before they reach their full potential. I easily get over 200 shots on a fresh charge of batteries.

also, as mentioned, NiMH lose their charge daily.... someone said it's around 1% a day....
 

chenwei

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Sep 6, 2002
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#13
Originally posted by mpenza
I presume the batteries are at least 1600mAH and above.

are the batteries new? it may take a few charge/recharge cycles before they reach their full potential. I easily get over 200 shots on a fresh charge of batteries.

also, as mentioned, NiMH lose their charge daily.... someone said it's around 1% a day....
yup... i faced this problem b4, if u leave ur fully charged NiMH battery for a few weeks, the battery will become flat... ;(
 

shawntim

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Feb 13, 2002
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#14
Originally posted by mpenza
I presume the batteries are at least 1600mAH and above.

are the batteries new? it may take a few charge/recharge cycles before they reach their full potential. I easily get over 200 shots on a fresh charge of batteries.

also, as mentioned, NiMH lose their charge daily.... someone said it's around 1% a day....
\

i've charged them about 10+ times already.. should they have reached their max potiential?

I guess i get the gist here.. NiMH do self discharge..grr... then there's no point to charge several sets of batteries before going on long vacation etc..
 

mpenza

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#16
Originally posted by shawntim
\
I guess i get the gist here.. NiMH do self discharge..grr... then there's no point to charge several sets of batteries before going on long vacation etc..
guess so. might be good to bring the charger around unless you're on a trekking trip without access to electricity....
 

Zerstorer

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Jul 8, 2002
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#17
Originally posted by shawntim

Usually i charge them before shooting, but like i quoted, i charged them after use. There was once i took out the batts to use about 3 days after my last charge, and they lasted my only 50 shots. this is how i discover this problem.
There might be something wrong with your batteries. Mine can be left for over a week and still yield 100 shots. Does it happen to only one set or all your batteries?

Anyway a freshly charged set of Sanyo 1850s measure 1.41volts.
Leaving them for a day or so and it will drop to 1.38v and remain relatively stable for about a week.

Batteries that seem to go dead on the 602 measure at ~1.2V.

Sometimes it may be good to just have a quick check before setting off.
 

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