Sanyo 2500mAh battery discharge issue

[xtechchu]

My affected batts are from the 04-10 batch... Really does look like some sort of common problem with the batts produced during this period. =^(

From your Work Week (WW#10) of the Sanyo batteries made seem also got problem. From this post most of the affected batteries are from WW#08, 09,10,11 & 12. Thus, it is likely all the battries made during WW#08, 09,10,11 & 12 could some kind of fast discharing problem.

That's my observation!

 

[Zplus]

Just to chip in a little bit, in general this is true, but for ni-mh a fast charge is preferred for a better end of charge detection. NiMH has a much smaller -deltaV compared to NiCad. Doing fast charge increases this deltaV to a more detectable level. Failing to detect this result in dependency on thermal detection and timer, both of which often result in overcharging which kill battery faster than doing a repeated fast charge.

There might be some truth in it. And it seems to increase as the mAH goes up. So for higher capacity batts if you slow charge it, most likely you will not really fully charge it coz the deltaV is too small and you are relying on other means of detecting full charge.

I realised that when I bought higher capacity batts and the old slow charges does not seem to fully charge them. They seem 1/2 full even though the old charges indicate full charge. Now using the later fast chargers.
;p

 

[ullyss]

My experience.

Batteries : Sanyo 2300 and 2500

Charger : Sanyo Charger

Method : Slow charge / flash charge

Usage : Canon Flash 580.

Comments : I can only manage less than 5 to 10 flash before battery is unusable.

After 3-4 days of not using the fully charged batteries, Sanyo 2500 indicate 0% on my flash, totally flat. Sanyo 2300 is a little better, indicate 50% on bar. Batteries discharge too very fast.

Using Maha charger, this is worse of the lot I hate this charger!
Slow charge on my sanyo 2300 and 2500 which took the entire 12 hours! After less than 2 days of not using the fully charged battery, both models are unusable! Sanyo2300 indicated 25% on the bar, 2500 is 0%.The maha charger cannot be used on the sanyo batteries, the batteries discharge too fast.

The old Sanyo 2100 was much better, slow discharge, I could use the batteries even after 7 days and its still usable. I stopped buying Sanyo rechargeables as it is impossible to use.

 

[madmacs]

charged 8 AA 2500mah at the same time using sanyo charger about 1+ weeks back. after charging confirmed all at least 1.2v, then put in battery container and keep away.

today tested the 8 batteries:

batch 04-09-SG: 3 batteries still over 1.2v. 1 battery drop below 1.0v
batch 04-09-SH: 1 battery still over 1.2v. 3 batteries drop below 1.0v

seems like not consistent even within batches. fyi these 8 batteries are always used together in my PB-E2 grip.

also tested 4 AA 900mah and 4 AAA 900mah which have not been charged for months. all still over 1.2v.

 

[karnage]

Just to chip in a little bit, in general this is true, but for ni-mh a fast charge is preferred for a better end of charge detection. NiMH has a much smaller -deltaV compared to NiCad. Doing fast charge increases this deltaV to a more detectable level. Failing to detect this result in dependency on thermal detection and timer, both of which often result in overcharging which kill battery faster than doing a repeated fast charge.

Hey guys, read this in the batteryuniversity website too...

"It is difficult, if not impossible, to slow-charge a nickel-metal-hydride. At a C?rate of 0.1-0.3C, the voltage and temperature profiles fail to exhibit defined characteristics to measure the full charge state accurately and the charger must rely on a timer. Harmful overcharge can occur if a partially or fully charged battery is charged with a fixed timer. The same occurs if the battery has aged and can only hold 50 instead of 100% charge. Overcharge could occur even though the battery feels cool to the touch."

So does that mean that the Sony & Varta 15min chargers are better then, in terms of getting a fuller charge?

 

[madmacs]

i'm currently testing 2 new sets of konnoc 2500mah AA's for comparison. charged with sanyo charger about 2 weeks ago. both sets still show >1.2v. also they don't seem to get as hot as the sanyos when charging. :think:

 

[whoelse]

My Kodak 2300mah, GP 2500mah are ok. Sanyo 2500mah new purchase discharge like lao-sai. No wonder so cheap, is it fake stuff?

 

[madmacs]

My Kodak 2300mah, GP 2500mah are ok. Sanyo 2500mah new purchase discharge like lao-sai. No wonder so cheap, is it fake stuff?

more likely a flaw in some batches of 2500mah...and 2300mah to some extent.

 

[Adiemus]

So... does that mean we boycott Sanyo batteries? :dunno:

What's the next best step then? I've got tonnes of Sanyo batts that "lao sai". So if I need to get more how? :cry:

 

[whoelse]

Bought from East Gear, dun tell me...

 

[Piper]

which Maha charger are you using? thot Maha charger should be quite good. and quite ex too.

My experience.

Batteries : Sanyo 2300 and 2500

Charger : Sanyo Charger

Method : Slow charge / flash charge

Usage : Canon Flash 580.

Comments : I can only manage less than 5 to 10 flash before battery is unusable.

After 3-4 days of not using the fully charged batteries, Sanyo 2500 indicate 0% on my flash, totally flat. Sanyo 2300 is a little better, indicate 50% on bar. Batteries discharge too very fast.

Using Maha charger, this is worse of the lot I hate this charger!
Slow charge on my sanyo 2300 and 2500 which took the entire 12 hours! After less than 2 days of not using the fully charged battery, both models are unusable! Sanyo2300 indicated 25% on the bar, 2500 is 0%.The maha charger cannot be used on the sanyo batteries, the batteries discharge too fast.

The old Sanyo 2100 was much better, slow discharge, I could use the batteries even after 7 days and its still usable. I stopped buying Sanyo rechargeables as it is impossible to use.

 

[Pro Image]

So what's the final conclusion to the Sanyo batteries after all the posts?

Slow or fast charge?

Which charger is the best?

Should we still use Sanyo batteries or change to Varta/GP?

 

[madmacs]

So what's the final conclusion to the Sanyo batteries after all the posts?

Slow or fast charge?

Which charger is the best?

Should we still use Sanyo batteries or change to Varta/GP?

varta like quite ex leh. i think i saw $89 for charger and 4 2500 AA. and cant remember eastgear tell me varta batt must use varta charger or the other way around. :think:

anyway my new konnoc's seem to be holding the charge way better than my sanyo 2500s in my "full charge and leave it unused" tests. maybe later today i will finally use them in my flash and see how far they can go.

 

[karnage]

AP @ SLS supposedly sells the Varta one for $60 (charger + 4 AA) but I just went the other day and it was sold out...

Varta charger can charge other brands too but not in 15min la. Someone here has it and tested it... Anyways, contemplating the Sony 15min charger also... dunno which is better. Varta has IC3, which supposedly allows the battery instead of the charger to control the charging process... Sony ones seem more dangerous in this sense... haha! But Sony can use up to 2500mAh, Varta currently max at 2000mAh...

 

[AhV]

all right brothers ..hear ye ...hear ye


I have just received a reply from SANYO and they are willing to offer me an immediate replacement. I am still skeptical about the replacement as they could still give the same problem. Anyway, at least they were apologetic and is willing to investigate to find out the root cause Of cos, it wouldnt be complete without our help. I could have kept this good news to myself ...nah ..I wanna share it


I am going to start a thread here soon. So, pls read through it later and give me the necessary details


Well..there is still hope that we may get NEW batteries

:lovegrin:

 

[espn]

AP @ SLS supposedly sells the Varta one for $60 (charger + 4 AA) but I just went the other day and it was sold out...

Varta charger can charge other brands too but not in 15min la. Someone here has it and tested it... Anyways, contemplating the Sony 15min charger also... dunno which is better. Varta has IC3, which supposedly allows the battery instead of the charger to control the charging process... Sony ones seem more dangerous in this sense... haha! But Sony can use up to 2500mAh, Varta currently max at 2000mAh...

The Varta although max at 2000mAh, it lasts longer than a Sanyo 2500 mAh any time and also holds it's charge better.

The Sanyo 2500mAh, has it's battery drained overnight on my optical mouse, I switched to Varta immediately and for a week, my mouse is still running.

I've my Sanyo's sitting on my table now, I have no idea what to do with it. Some friends said I'm crazy to use Varta's on my mouse, but it lasts longer than Sanyos, charge up faster, and holds it's power better.

 

[Dennis]

My Sanyo 2500 seems to hold charge OK and is fast charged by Sony 15 min charger.
Has been a week since inside my winder box and is still running. Tried also on my remote and also doing fine up to 3 weeks. Will consider getting the Lacrosse (see link) to pair with my Sony 15min charger for ultimate battery management. My old Sanyo 2300 however does not hold charge as long.

http://forums.clubsnap.org/showthread.php?t=156971

The Varta although max at 2000mAh, it lasts longer than a Sanyo 2500 mAh any time and also holds it's charge better.

The Sanyo 2500mAh, has it's battery drained overnight on my optical mouse, I switched to Varta immediately and for a week, my mouse is still running.

I've my Sanyo's sitting on my table now, I have no idea what to do with it. Some friends said I'm crazy to use Varta's on my mouse, but it lasts longer than Sanyos, charge up faster, and holds it's power better.

 

[cyrilng]

Not sure if this info has been posted elsewhere before but Sanyo will be coming out with their new Eneloop batteries to counter the discharge problem.

http://www.letsgodigital.org/en/news/articles/story_5065.html

http://us.gizmodo.com/gadgets/gadgets/sanyo-eneloop-rechargeable-batteries-134903.php

 

[philshots]

This doesn't sound too good for Sanyo's 2500mAh batteries ... Time to switch to other brands?

 

[batteryman]

Dear all, having read your forum I thought you might like a contribution from someone in the industry. I've been working in the portable battery industry for over 23 years. I have direct communication with Sanyo, Varta, Panasonic & others factories & engineers. As well as selling these products to wholesalers & retailers I am also a heavy user of rechargeable batteries.

With regards to the high discharge of the Sanyo 2500s this is reasonably correct as it is also the case with most other brands.

Firstly there's not much point swapping to most other name brands selling 2500s as most are made by Sanyo in the first place so they're the same battery! Energizer, Sony, Kodak, Varta, Ansmann & many others are mostly rebadged Sanyo's.

How to tell if they're Sanyo? 1. Made in Japan (no Energizer factories there!) Look on the base (negative end) of the cell. If HR is printed into the metal base then it's a Sanyo. This is not the case for the 15 minute offerings by Rayovac & Varta although these IC3 cells are made for them under licence by Sanyo in a new Sanyo China based factory.

The problems with cheap copies. Low cost China brands are generally lower in capacity than stated. Some of the capacity claims are just outright lies although some brands have improved a lot. Much more importantly the cycle life is dreadful. The cycle life of Sanyo has dropped significantly for the high capacity cells (around 300-500 cycles) compared to the still excellent HR3U 1700mAh cells (around 600-900 cycles) but is still way superior to the China brands. China brands generally not only start low in capacity (after conditioning, a must for all new & long term stored NiMHs) then the already lower than stated capacity can drop off by as much as 50% within a few dozen cycles. It's not unusual for many of these types to be virtually unuseable within about 150 cycles.

Get the right charger. My own experience was initially very dissapointing with the Sanyo 2500s. They'd self discharge in a couple of days. With my experience I should've known better! I was using an old charger. Most faster chargers have an inbuilt safety timer. If the charger was made before 2500s came on the market chances are they have an inbuilt safety timer that will terminate charging well before the 2500s are fully charged. I then got one of our newer chargers from stock made by MW & sold under many brand labels. This model is called MW6178 & fast charges at 1000mA then & this is an important bit, the charger then goes to a 100mA trickle charge. Why is this important? Because fast charging never fully charges nickel type batteries in the fast charge stage alone. Internal resistance increases with the temperature rise of the cells such that the batteries only get 80-95% charged. The faster the charge the less you get in. The IC3 15 minute types only 80% fully charge however since you can recharge in 15 minutes who cares! The lesson here is make sure you're charger is designed for the capacity of battery you are using!

Since swapping chargers I'm now getting fantastic results from the Sanyo 2500s. They still self discharge a lot of their capacity in 2-4 weeks but I charge them before I use them when I know I'm going to take 80 or more shots in a day or so, otherwise I leave them in my Minolta Dimage 7i ready to use with very few dissapointments since changing chargers. I take 2-6 shots most days for our web site & advertising & recharge about once a month. I'm using autofocus mainly as well as the LCD monitor so the camera is being worked reasonably hard.

I also use a set of the Varta 15 minute IC3 batteries. Fantastic product. Just like Sanyo 2100s down to 1700s their self discharge rate is lower than the 2500s. This is more so the case when you use the lower capacity cells. I get a few less shots but when I'm driving in the country & stopping to shoot often, then run out of battery power I plug the charger in via the car cigarette lighter, one soft drink & a cigarette later & I'm shooting again! Of course a spare set of charged batteries eliminates this requirement.

New Stuff. I'm testing the Sanyo 2700s (HR-3UG) which will come on the market soon with excellent results. We tested these & the Sanyo 2500s on our Cadex analyser at IEC 0.2C > 1.0V per cell & found capacity to be a remarkeable 100% even though Sanyo state a lower minimum capacity on the cell label.

Finally I'm also using the new Eneloop cells in my Microsoft cordless mouse on my laptop. Three weeks of daily hours of use later they're still going strong & this is straight out of the packet. They haven't seen a charger yet! My 2500s failed in the mouse after about 2 weeks.
If you don't like self discharge you're going to like Eneloop. 2000mAh capacity is quite acceptable also.

I hope this helps those of you on this forum.