Ni-Zn Battery


sircam

New Member
May 21, 2007
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#4
Sorry for not taking the time out to read this lengthy article because I'm very well informed about different kinds of batteries and their underlying technologies. Since this is a complicated subject, I will simply state this upfront very vehemently for the benefit of all K-x owners here:

DO NOT USE Ni-Zn batteries in your K-x ever.

Use only Lithium Ions (1.5V, AA) or Ni-Mh (1.2V, AA).

Alkalines (1.5V, AA) are absolutely safe to use, but I'd suggest you only use them in a dire emergency for reasons of convenience and speed during shooting.
 

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darrrrrrrrrr

Senior Member
Sep 19, 2006
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Singapore
#5
Read sometime back on PF of a guy getting his Pentax flash killed by NiZn batteries.
 

pinholecam

Moderator
Staff member
Jul 23, 2007
10,944
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#7
Some love him, some hate him...
I'm neutral :cool:
Yes, Neutral, but posting a link to his site moves ups the site hits and makes it come up on any google for 'Pentax'. For the well informed, it may still be ok, since we can take his load of bull with a pinch of salt. For the new and uninformed, it means not buying Pentax, cause some guy has loads of 'information and knowledge' says pentax is :thumbsd:
 

Moonlightsg

Senior Member
Jan 28, 2010
764
1
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#8
voltage is something that must be correct... if the voltage is higher than the k-x can handle... then bye bye to your K-x...
he say Ni-Zn have 1.7v, while all the AA battery powered device only built to handle 1.2-1.5v....

not like current(A) which is higher mean more power stored...
 

pinholecam

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Jul 23, 2007
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#9
voltage is something that must be correct... if the voltage is higher than the k-x can handle... then bye bye to your K-x...
he say Ni-Zn have 1.7v, while all the AA battery powered device only built to handle 1.2-1.5v....

not like current(A) which is higher mean more power stored...
There is certainly an option to mix the batteries 1x1.7+1.3x3 for higher voltage and potentially more stable camera usage indication. However the risk to that is uneven loading in the batteries themselves (charging into the lower voltage batt and heating up) and potential (though low) explosion.
 

Moonlightsg

Senior Member
Jan 28, 2010
764
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#10
mix the batteries is confirm :nono: :sweat:
the 3x1.3v will like a resistant to the 1.7v...
it is not funny to put stress on the 3x1.3v as pinholecam say may have a potential small explosion or battery melted...
 

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pinholecam

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Staff member
Jul 23, 2007
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#11
mix the batteries is confirm :nono: :sweat:
the 3x1.3v will like a resistant to the 1.7v...
it is not funny to put stress on the 3x1.3v as pinholecam say may have a potential small explosion or battery melted...
:think: someone should write to Myth Busters or Brainiac and let them do the dirty job :D
 

poppyer

New Member
Jun 24, 2009
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#13
:think: someone should write to Myth Busters or Brainiac and let them do the dirty job :D
Actually I am not quite understand this "don't mix batteries" story, although this is widely told.
if the batteries are sequentially connected, and all of them are rechargables. where does the danger of explode come from?

And, for the NiZn stuff, doesn't make any sense since the price at the same level of eneloop. not too mention you need to buy ANOTHER dedicated charger....
 

Jan 10, 2005
238
0
0
#14
Sorry for not taking the time out to read this lengthy article because I'm very well informed about different kinds of batteries and their underlying technologies. Since this is a complicated subject, I will simply state this upfront very vehemently for the benefit of all K-x owners here:

DO NOT USE Ni-Zn batteries in your K-x ever.

Use only Lithium Ions (1.5V, AA) or Ni-Mh (1.2V, AA).

Alkalines (1.5V, AA) are absolutely safe to use, but I'd suggest you only use them in a dire emergency for reasons of convenience and speed during shooting.

If I may ask, "Why?"

Having read the fried flash thread on Pentaxforums, it doesn't seem to indicate that its a NiZn problem. So I'm still searching for more info on whether NiZn is safe for our use. I'm currently stocked up on eneloops, so will wait for NiZn v2.0 as well as more competitors to come on board.
 

pinholecam

Moderator
Staff member
Jul 23, 2007
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#16
Actually I am not quite understand this "don't mix batteries" story, although this is widely told.
if the batteries are sequentially connected, and all of them are rechargables. where does the danger of explode come from?

And, for the NiZn stuff, doesn't make any sense since the price at the same level of eneloop. not too mention you need to buy ANOTHER dedicated charger....

Yes, in primary (or was it secondary) school textbook, we all learned that batteries connected series will simply add up the voltages. What it did not include was that the batteries have their own impedance. This is all fine when the batt are from the same manufacturer and model, but when you add in something like a NiZn batt with NiMH, 2 things happen. Firstly, there is an impedance mismatch resulting in loading on the odd battery. Secondly, the higher voltage of the rouge battery can also charge into the batt with lower voltage (in fact thats how the batt charger works). My personal take, being a bit of a "MacGuyver", is that the risk is low. I would experiment with it if I did not have to pay for the batteries since they can be damaged in this way.
I won't take the moral high ground here to say 'NEVER'. Its just a at your own risk kinda thing.

The potential for adding in a NiZn is higher total voltage above the cut off. Eg. If Kx was set to cut-off the camera at 2.5V and we used NiMh (1.3v) we would be 1.3x2=2.6v, which is 0.1v away from cut off. That is why, when the voltage drops under load, the camera cuts-off in the case now. Adding in a 1.7v NiZn, makes this 1.7+1.3=3v, which is 0.5V from cut-off.
 

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poppyer

New Member
Jun 24, 2009
217
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#17
Yes, in primary (or was it secondary) school textbook, we all learned that batteries connected series will simply add up the voltages. What it did not include was that the batteries have their own impedance. This is all fine when the batt are from the same manufacturer and model, but when you add in something like a NiZn batt with NiMH, 2 things happen. Firstly, there is an impedance mismatch resulting in loading on the odd battery. Secondly, the higher voltage of the rouge battery can also charge into the batt with lower voltage (in fact thats how the batt charger works). My personal take, being a bit of a "MacGuyver", is that the risk is low. I would experiment with it if I did not have to pay for the batteries since they can be damaged in this way.
I won't take the moral high ground here to say 'NEVER'. Its just a at your own risk kinda thing.
Yes, I am told and read that "don't mix diff batteries" everywhere, and this is deep in my mind.
but one day I think about it. the impedance (or internal resistance) is just a resistance. so we can think of a real-life battery as a ideal battery + a small resistance, sequentially connect. the resistance just produce some heat. so there is nothing about impedance mismatch.

sure the battery with lower capacity (or with higher impedance, which waste some capacity into heat) will dry out first. but the reverse recharging only happens when it is so deeply charged that its voltage becomes negative (but this is very very unlikely, the camera will shut up way before that). so it is not that high voltage will charge low voltage, it is positive voltage will charge negative voltage (corrects me here if I am wrong). but even this reverse-charging happens, since all batteries are rechargable, it won't hurt a lot, not to mention exploding.


just curious. :)
 

pinholecam

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Jul 23, 2007
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#18
Yes, I am told and read that "don't mix diff batteries" everywhere, and this is deep in my mind.
but one day I think about it. the impedance (or internal resistance) is just a resistance. so we can think of a real-life battery as a ideal battery + a small resistance, sequentially connect. the resistance just produce some heat. so there is nothing about impedance mismatch.

sure the battery with lower capacity (or with higher impedance, which waste some capacity into heat) will dry out first. but the reverse recharging only happens when it is so deeply charged that its voltage becomes negative (but this is very very unlikely, the camera will shut up way before that). so it is not that high voltage will charge low voltage, it is positive voltage will charge negative voltage (corrects me here if I am wrong). but even this reverse-charging happens, since all batteries are rechargable, it won't hurt a lot, not to mention exploding.


just curious. :)

I agree. When I was a kid, I actually connected the batt w/o load (ie. shorted) to make them heat up. Furthermore, the voltage and charge use to charge the batteries are much higher than the 1.7v vs 1.3v delta of the batteries. Then again, anyone try it and it explodes in their face, will cut this from this forum and sue me :D
So 'official' statement is : "At your own risk" :D
 

Moonlightsg

Senior Member
Jan 28, 2010
764
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#19
another point to talk about... if the Ni-Zn battery will use up the power when the voltage fall to 1.65v
which mean that the K-x battery bar will show green all the way without droping to yellow or red... so the Cam may just shut off due to lag of power even the green bar showing a sec ago?
which mean it may damage your memory card if the writing at that point of time???
 

pinholecam

Moderator
Staff member
Jul 23, 2007
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#20
another point to talk about... if the Ni-Zn battery will use up the power when the voltage fall to 1.65v
which mean that the K-x battery bar will show green all the way without droping to yellow or red... so the Cam may just shut off due to lag of power even the green bar showing a sec ago?
which mean it may damage your memory card if the writing at that point of time???
Dont talk already....


.....Just Try Lor.....

If things go wrong, then you can post here to tells us what happens when ... Battery No Enough...
:D
 

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