Your usages of rechargeable 1.2V Ni-MH or 1.5V Li-ion AA/AAA batteries?

[Lynx_Arc]

fivemega say's .........

In fact, you suppose to get 1.5V out so:
3300/1.5=2200 mAh or 2.2Ah

If you test it with 1A discharge, you should get:
2.2/1=2.2 hours
2.2x60=132 minutes

Your math is all wrong in order to translate the output of a 3.7V battery to a 1.5v battery you have to convert to watt hours and convert back.
3.3A (3300mah) x3.7V= 12.21Watt Hours. 12.21/1.5V = 8.14Ah. so you could get 8 hours but taking the losses in conversion likely closer to half that or 4 hours using a buck circuit so if you are getting less than that likely the battery is less capacity than 3300mah. There is no saying that they can't put a 2600mah battery in it and use a mediocre circuit and get less than that.

 

[old4570]

Your math is all wrong in order to translate the output of a 3.7V battery to a 1.5v battery you have to convert to watt hours and convert back.
3.3A (3300mah) x3.7V= 12.21Watt Hours. 12.21/1.5V = 8.14Ah. so you could get 8 hours but taking the losses in conversion likely closer to half that or 4 hours using a buck circuit so if you are getting less than that likely the battery is less capacity than 3300mah. There is no saying that they can't put a 2600mah battery in it and use a mediocre circuit and get less than that.

Not my math ....
This is the math I shared :
How much is mWh in mAh?
Most people are used to seeing mAh ratings , they see the "2800" and go "wow, look at the capacity". The way they get the mWh rating is by multiplying the 3.7V nominal lithium cell voltage by it's actual mAh rating. So if we reverse this, 2800mWh/3.7V = 756mAh. Or in this case 3300mWh/3.7V = 892mAh … ( Li-ion battery Capacity )

What fivemega was on about = the 1.5v output ....
What I was on about = Li-ion capacity ..
So we are trying to mix apples and oranges ..
Sorry Lynx , not sure bout your math ..........

 

[old4570]

NIMH battery @ 1A discharge ...

Starting Voltage or resting Voltage was 1.37 volts

100mAh discharge = 1.27 volts
200mAh discharge = 1.17 volts
500mAh discharge = 0.99 volts
1 Amp discharge = 0.76 volts

What I tested the Xtar @

100mAh Discharge ...
Initial voltage sag was around 1.25v but slowly increased to 1.38 volts ...
200mAh Discharge ...
Initial voltage sag was around 1.18v and is slowly increasing ( currently 1.26 volts )
And the 1A discharge was 0.88 volts

So ........... Some test data to mull over !

 

[KITROBASKIN]

Can we be assured that your unit is accurately discharging at the stated level? Seems like I had connection issues in the battery bay contacts when I tried to get an amperage reading years ago; ended giving up.

 

[Lynx_Arc]

Not my math ....
This is the math I shared :
How much is mWh in mAh?
Most people are used to seeing mAh ratings , they see the "2800" and go "wow, look at the capacity". The way they get the mWh rating is by multiplying the 3.7V nominal lithium cell voltage by it's actual mAh rating. So if we reverse this, 2800mWh/3.7V = 756mAh. Or in this case 3300mWh/3.7V = 892mAh … ( Li-ion battery Capacity )

What fivemega was on about = the 1.5v output ....
What I was on about = Li-ion capacity ..
So we are trying to mix apples and oranges ..
Sorry Lynx , not sure bout your math ..........

My bad as I didn't see any mwh or mah on the figure and assumed it was about 18650 and couldn't backtrack the posts for some reason to be sure. The only 14500s I've seen are only 800mah which isn't 3300mwh.

 

[old4570]

My bad as I didn't see any mwh or mah on the figure and assumed it was about 18650 and couldn't backtrack the posts for some reason to be sure. The only 14500s I've seen are only 800mah which isn't 3300mwh.

It's what's claimed on the Label ..
I have discharged both batteries ( I got 2 ) and will be recharging them when some NIMH I am putting through the BC8 charger are done .
I plan to discharge in two different chargers over next few days to get some numbers .
Doing paper math is well and good ....

 

[old4570]

Can we be assured that your unit is accurately discharging at the stated level? Seems like I had connection issues in the battery bay contacts when I tried to get an amperage reading years ago; ended giving up.

Assume nothing !
My charger was calibrated quite a few years ago .
What we can assume is that there is VOLTAGE sag under load .
How that voltage sag affects performance ?
Chargers usually stop discharging @ 0.8v for NIMH , butt ..............
These Li-ion are different .. So when I discharge them for capacity (?) , it will be according to the charger - the cut off voltage !
I can lower it ( and I will ) and discharge till the protection circuit cuts in ( see what happens - charger might not like it )

 

[KITROBASKIN]

OK, the son's X-Box controller abruptly crashed at a critical time on the li-ion AA's. Moreover, he thinks they did not last as long as alkaline AA's. He does not remember using Ni-MH, but I remember them not lasting long at all. The big thing was the lI-ion stopping in a bad way, losing game progress, instead of first getting a warning the battery was getting low, and being able to save session achievement.

 

[Lynx_Arc]

OK, the son's X-Box controller abruptly crashed at a critical time on the li-ion AA's. Moreover, he thinks they did not last as long as alkaline AA's. He does not remember using Ni-MH, but I remember them not lasting long at all. The big thing was the lI-ion stopping in a bad way, losing game progress, instead of first getting a warning the battery was getting low, and being able to save session achievement.

Not unexpected at all...... converting 4v to 1.5v is likely regulated with a cut off for low voltage in other words they should hold at 1.5v then nothing when they are depleted.

 

[old4570]

Ok , had a bit of warm weather !
Things are cooler but silly humid !

First AA was discharged at 0.1A for just over 10 hours on my hobby charger .
Voltage varied from around 1.43v to as low as 1.22 volts during the 10+ hour discharge ..

2nd battery just hit the discharge cycle :
Will be discharged at 0.2A till depleted .. ( 7.42am )

 

[PhotoTime]

Sorry, wish to side track abit.

I am thinking of using the Li-ion AA batteries on my wireless mic. How long can they last, assuming that there is no blockage between the transmitter and receiver, and the distance is at most 10m.

 

[old4570]

I discharged the AA Xtar @ 0.2A till termination ( protection circuit cut in ) and got 1915mAh .

 

[old4570]

Digital Cameras !
Thats where these batteries might work really well !
Back in the day , early days of digital cameras . They were powered by AA .
And one of the big issues at the time was Voltage levels ..
NIMH simply could not maintain the needed voltage levels . So the cameras always stopped working early ! ( Running NIMH )
And folks had to resort to expensive Alkaline camera batteries that had higher voltage .
I still have a couple of old digital camera ( PENTAX iSTD ) but only 2xAA li-ion .. ( THey need 4 )

I did find an old Kodak digital that runs on 2 AA , seems to work fine ..
Will see .... I will run that old Kodak and see what happens . ( On the two Xtar AA li-ion I have )

 

[Lynx_Arc]

Digital Cameras !
Thats where these batteries might work really well !
Back in the day , early days of digital cameras . They were powered by AA .
And one of the big issues at the time was Voltage levels ..
NIMH simply could not maintain the needed voltage levels . So the cameras always stopped working early ! ( Running NIMH )
And folks had to resort to expensive Alkaline camera batteries that had higher voltage .
I still have a couple of old digital camera ( PENTAX iSTD ) but only 2xAA li-ion .. ( THey need 4 )

I did find an old Kodak digital that runs on 2 AA , seems to work fine ..
Will see .... I will run that old Kodak and see what happens . ( On the two Xtar AA li-ion I have )

The problem here is many cameras had such heavy current draw that most batteries with higher voltage caved in voltage shortly due to the heavy load on them such that nimh actually worked longer in them.

 

[old4570]

?
Eeeer !

I ran Pentax .... iSTD / K100 / K200 / Kx
All of which used AA batteries ..
I tried Alkaline / NIMH / and Alkaline Camera Batteries ..
NIMH was the worst .. ( Shortest run time ) , then came stock Alkaline and the best were the Camera Alkaline .
I still have 2x Pentax iSTD cameras ( Pentax's first digital SLR ) and I have replaced the AA with li-ion batteries designed to replace the AA .
But both cameras have the Battery grip , which takes AA ..
And these li-ion AA might be perfect ..
Also I only have 2 AA li-ion , so I put them in the old Kodak Digital pocket camera ( 6.1mp ) and looks to work a treat .
This camera was also voltage sensitive and wanted those silly expensive Camera Alkaline .
So am looking forward to seeing how they go in the old Kodak . ( Xtar AA Li-ion )

 

[aznsx]

Sorry, wish to side track abit.

I am thinking of using the Li-ion AA batteries on my wireless mic. How long can they last, assuming that there is no blockage between the transmitter and receiver, and the distance is at most 10m.

I have no knowledge or good info about these cells - however, that's an example of one of the last type(s) of applications I would be inclined to try them in. That thought stems from fear of RFI / noise from the switching supply / regulator that I suspect is incorporated. That may be a non-issue and they may work fine for that app, but do keep an eye out for any potential interference which might occur, and if you try them let us know how they work out and if you note any such noise issues. No harm in trying them, and it would be good to know how they work out in practice.

 

[PhotoTime]

I have no knowledge or good info about these cells - however, that's an example of one of the last type(s) of applications I would be inclined to try them in. That thought stems from fear of RFI / noise from the switching supply / regulator that I suspect is incorporated. That may be a non-issue and they may work fine for that app, but do keep an eye out for any potential interference which might occur, and if you try them let us know how they work out and if you note any such noise issues. No harm in trying them, and it would be good to know how they work out in practice.

Thanks.

But the main issue is that we can only test it on the live event, so, it is not really possible to test it.

 

[PhotoTime]

?
Eeeer !

I ran Pentax .... iSTD / K100 / K200 / Kx
All of which used AA batteries ..
I tried Alkaline / NIMH / and Alkaline Camera Batteries ..
NIMH was the worst .. ( Shortest run time ) , then came stock Alkaline and the best were the Camera Alkaline .
I still have 2x Pentax iSTD cameras ( Pentax's first digital SLR ) and I have replaced the AA with li-ion batteries designed to replace the AA .
But both cameras have the Battery grip , which takes AA ..
And these li-ion AA might be perfect ..
Also I only have 2 AA li-ion , so I put them in the old Kodak Digital pocket camera ( 6.1mp ) and looks to work a treat .
This camera was also voltage sensitive and wanted those silly expensive Camera Alkaline .
So am looking forward to seeing how they go in the old Kodak . ( Xtar AA Li-ion )

Are you able to advise how long can the Li-ion AA last in your camera?

 

[old4570]

1915mAh . This was the result of a 0.2A discharge .
How long 1900mAh lasts (?) would depend on current draw .

 

[KITROBASKIN]

Other pair of Xtar AA Li-ion's went through son's X-Box controller. I'm saying it lasted quite a long time but do not have any hard numbers to compare with alkaline. The boy found some alkies for replacement. He does not like the sudden drop when the Li-ions are depleted. One can only hope his $60 controller does not get poisoned with battery bile.