SANYO Announces C- and D-sized ‘eneloop’ Batteries

PhotonBoy

Flashlight Enthusiast
Joined
Mar 11, 2003
Messages
3,304
Location
Annapolis Valley, Nova Scotia, Canada http://tinyu
I think PTC means Positive Temperature Coefficient'

see: http://www.freepatentsonline.com/EP1102338.html

"1. A PTC device exhibiting positive temperature coefficient behaviour and having a pair of outlet electrodes formed integrally on its surface, wherein the PTC device is characterized by at least one of said pair of outlet electrodes being an electrode section formed on a PCB substrate on which are mounted said PTC device and other electronic components such as field effect transistors, semiconductor integrated circuits, and the like."
 

phenwick

Newly Enlightened
Joined
Jan 3, 2007
Messages
86
Location
St Louis, Mo; Metro East
At least we are seeing advancements in the eneloop field. I think capacities will increase with time. I had a slight fear that Sanyo might abandon the eneloops if they never caught on with the main stream consumer.

I also like the flexibility of the charger, using adapters for the C-D and AA-AAA positions. They could have chosen to have made it 2 of each size and left it at that. Nice touch.

On another note, I can't tell you how long I have been waiting for "antibacterial" cells.:laughing:
 
Last edited:

metlarules

Flashlight Enthusiast
Joined
Jan 30, 2008
Messages
1,027
No Thanks! I'll stick to my $5 nicads at 7000mah that have the same lsd properties. Why is the capacity so low? The Accupower evolutions are lsd and 10000mah.
 

Bones

Enlightened
Joined
Feb 3, 2007
Messages
991
Location
Foothills Country
CONTAIN A PTC?!?!

this is going to get complicated....

Perhaps not, providing the device itself exhibits predicable behaviour, which I presume it must:

eneloop-ptc-device.jpg


I'm curious as to whether this is a new approach to protection devices.

I like that it appears to step up the resistance as the temperature rises rather than wait until a critical junction is reached and then just shut down.

Wouldn't this approach be more reliable, offer better protection to the cell and, perhaps most importantly, lesson the odds of being left in the dark?
 

cy

Flashaholic
Joined
Dec 20, 2003
Messages
8,186
Location
USA
thought exact same thing before getting my AA enloops.

now my thinking is entirely changed. if your application requires a total discharge in one setting. then std NMH is your best choice. applications in the real world for me anyways... almost never need a total discharge. usages is in spurts with down time inbetween. with std NMH it's self discharging during waits.

so actual battery performance for say a digital camera is improved. actual usable MAH has gone up, despite total MAH has gone down.

No Thanks! I'll stick to my $5 nicads at 7000mah that have the same lsd properties. Why is the capacity so low? The Accupower evolutions are lsd and 10000mah.
 

lctorana

Flashlight Enthusiast
Joined
Jun 28, 2007
Messages
2,123
Location
Melbourne, Australia
I have large numbers of 4, 4.5 and 5Ah NiCad D cells, all of which exhibit negligible self-discharge.

Whether I buy many Eneloop Ds will come down to price.

But, that said, w00t!

:twothumbs:D:cool::clap::thanks::thumbsup::party:
 

rizky_p

Flashlight Enthusiast
Joined
Mar 26, 2006
Messages
1,440
Location
13th Colony
Re: SANYO Announces C- and D-sized 'eneloop' Batteries

i am a bit puzzled with the capacity. But the new charger looks nice.
 

cy

Flashaholic
Joined
Dec 20, 2003
Messages
8,186
Location
USA
what brands are you using?

all mine are titanium NMH C & D cells and exhibit self-discharge.

energizer AA 2500 are among the worst cells I've ever used. high self-discharge rates and high % have gone dead.

I have large numbers of 4, 4.5 and 5Ah NiCad D cells, all of which exhibit negligible self-discharge.

Whether I buy many Eneloop Ds will come down to price.

But, that said, w00t!

:twothumbs:D:cool::clap::thanks::thumbsup::party:
 

JWP_EE

Enlightened
Joined
Apr 22, 2008
Messages
216
Location
New Jersey
By adding a PTC in series with the cell the internal resistance will go up. You will have the cell resistance and the PTC resistance. It is the current through the PTC that causes the PTC to heat up although external heat and heat from the cell will change the trip point.
The amount of current the cell can supply will now be set by the PTC trip point. The trip current is usually 2X the hold current. When a PTC trips it goes to a high resistance and will stay there until it resets (cools).
This is being done for short circuit protection. But what you pay for this protection is less voltage from the cell for a given current (small voltage drop across the PTC) and possibly less current capability if you are looking to draw large currents.
I hope this is only being done on the C and D cells.
 

Mr Happy

Flashlight Enthusiast
Joined
Nov 21, 2007
Messages
5,390
Location
Southern California
Since AA size Eneloops can comfortably supply more than 10 A when shorted, I expect the unprotected D size cells could manage 40 - 50 A, perhaps more. Perhaps Sanyo thought this was a bit of a concern since an accidental short would lead to red hot wires, smoke and possibly burns.

It could be that this is another reason why the big names like Energizer only supply D size cells in 2500 mAh capacity.
 

Black Rose

Flashlight Enthusiast
Joined
Mar 8, 2008
Messages
4,626
Location
Ottawa, ON, Canada
The only issue I see with the charger is that it appears the charge rates for all cells except the AAAs seem to go against the 0.33C minimum charge rate rule for charging NiMh cells.

I showed the picture of the charger to my wife. Her response..."What, no 9V rechargables?"
 
Top