i had a problem with my rechargeable batteries, so i emailed the seller, well here's the email exchange
at the moment, i've just cut & paste the swap it so that it reads chronologically, may edit it to point form for easier reading later
quite a bit of new info, at least for me...should be useful for those that power portable equipment using nimh batteries
as u can see by the timing of the replies, they've been responding quickly
----- Original Message -----
From: lee sze yong
To: W Cube Enquiries
Sent: Sunday, July 18, 2004 2:18 PM
Subject: potential problem with sanyo charger
model no.: Sanyo NC-MQR02
bought from w3cube 08-04-2003
i recently had 2 occasions where the 4 AA 2100NIMH batteries charged by the charger produced little or no chargeupon switching on my digital camera, the batteries allow less than 5 shots before the low battery sign appeared, and the camera switched off after that.
fyi, i'm using a canon A70, and there are no problems with AA alkaline batteriesi
noticed that the charging sound made by the charger is slightly different, plus prior to this problem, the light was blinking before the end of a charge cycle
i've cleaned the contacts, i'm going to change the adaptor used to connect to the standard 3 pin socket just to make sure which is at fault
incidentally, i've just charged 6AAA 800NIMH batteries [in 3 cycles] prior to this problem occurring.
These batteries have turned out fine, but they are not listed on the instruction manual [800NIMH was not out then, 750NIMH being the standard]
Anymore troubleshooting that i can do b4 needing to send it in, & if so, do i send in to Sanyo [where?] or back to w3cube?
i understand that the warranty is likely to be expired, any indications on costs
thanx for reading this long email, would have posted at your forum, but there was no scheme to submit my email address to register at that time
regards
siyong
www.otbp.blogspot.com
www.opsw.blogspot.com
----- Original Message -----
From: W Cube Customer Support
To: lee sze yong
Sent: Sunday, July 18, 2004 3:34 PM
Subject: Re: potential problem with sanyo charger
Hi Sze Yong,We are sorry to hear about the problem you are encountering with the Sanyo NC-MQR02 Quick Charger.From the age of the batteries as well as the description of the problem, it may seem like the batteries may be near the end of their operational life. Although NiMH batteries do not suffer significantly from memory effect, after repeatedly charging non-fully-drained batteries for an extended amount of time (over 1 year), the accumulation of these effects, as well as another similar syndrome called "voltage depression" can add up to cause permanent damage to the batteries.Another thing to note is that if the batteries have been stored away for a while (> 4 weeks) while they had been flat, the batteries may be damaged as well. All rechargeable batteries self-discharge automatically and if the batteries were already flat when kept, the continual self-discharge on the flat batteries will cause an irreversible chemical change within the batteries which can cause them to not function properly anymore. If any rechargeable batteries are not needed to be used for a while, always store them away on a full charge.Also for NC-MQR02, blinking light signals that the charger is having problems with the chemistry of the batteries. This also normally means that either the batteries are non-rechargeable (eg. Alkaline), or that the rechargeable batteries are in a poor condition. This could be also possibly explain why the AAA batteries exhibits no problem with the charger. The charger is able to charge your AAA batteries as it is an intelligent charger and can accomodate any AA batteries up to about 2500mAh and AAA batteries up to about 1000mAh.Troubleshooting wise, it is best if you can confirm if the problem lie with the batteries or the charger by charging a different set of AA batteries. Sanyo do not offer any warranty on their charger products and our in-shop warranty is only within the first week. While we can perform a charger and battery analysis test, this is a time consuming procedure (takes more than 1 week due to the need to discharge and charge the batteries as well as test the performance of the charger in question quite a few times) and cost S$20 Nett. Thus, we recommend that you try to isolate the problem as being with the batteries or the charger by the suggestion above first before proceeding with any course of actions and item replacement.If you have any questions regarding the above, please feel free to let us know.
Good luck! :-)
Warmest Regards,Customer Support
W Cube Pte Ltd
Tel: +65 6337-4831
Fax: +65 6337-0431
Email: Support@W3Cube.com
Address: No. 1 Coleman Street, #03-14 The Adelphi, Singapore 179803
Website: http://www.W3Cube.com
----- Original Message -----
From: lee sze yong
To: W Cube Customer Support
Sent: Monday, July 19, 2004 12:14 AM
Subject: Re: potential problem with sanyo charger
thanx for the infolearned quite a few things, like charging them fully for "storage"
tot nimh batteries can take 500 charges & have minimal memory effect
looks like i got to get a new one with the refresh function
btw, do the new sanyo / or other brands have chargers that can take 4AAA?
do u mind me putting the info below online?considering posting it on my blog + perhaps forums @ www.sgheaphones.net
have charged another set, and all seems ok for now...
regards
siyong
www.otbp.blogspot.com
www.opsw.blogspot.com
 
Hi Sze Yong,Thank you for your reply!Regarding your questions,
1. NiMH batteries usually can be charged 500 to 1,000 time. However, this is subjected to the condition that between the charges, the batteries is not subjected to any out-of-the-ordinary situations which may damage the batteries in between the charges. Two usual situations (which are similar) in which batteries can be unknowingly damaged are:- The storing away of flat rechargeable batteries for an extended period of time (As mentioned previously).- Allowing the nominal voltage of the batteries to fall below 1V. (See Point 2)
2. Rechargeable batteries have a non-linear decay graph. When fully charged, it usually hovers around 1.4~1.6V, but this rapidly falls to 1.2V. This 1.2V can be supplied consistently for quite a long amount of time, till near the end of the battery life, in which it will again fall from 1.2V. Usually for most digital equipments such as digital cameras, it will automatically indicate that the battery is flat once the average voltage of each batteries falls to about 1.05V to 1.1V. But sometimes, if the batteries are used in slow drain devices such as flashlights, the voltage of the battery can fall below 1V and once again, if this is allowed for too long, a permanent chemical change can occur within the batteries which can damage them permanently. This is why users of rechargeable batteries should never use flashlights to fully discharge batteries.
3. Currently, all Sanyo chargers can only charge up to 2 AAA batteries at any one time. For 4 AAAs, you may wish to consider our Maha MH-C204F 3-Hours Smart Charger (S$39 Nett), or MH-C401FS 100 Minutes Cool Charger (S$49 Nett). Maha chargers have a strong emphasis on maintaining battery performance and both have built-in circuitry (Discharging or Flex Negative Pulse) to prevent memory effects. Maha chargers also come with a 1 year 1-1 exchange warranty.
4. Please feel free to share the information about battery maintenance with others. However, we do request that:- The information should not be posted on any commercial sites (due to conflict of interest),- The email is quoted as it is and should not be modified,- The email is credited to us (i.e., W Cube).
5. For the batteries, we are glad to know that another set of batteries seems to be working fine. This probably indicates that the fault lies solely with the batteries. In this case, your charger may not need to be replaced.If you have any other questions, please feel free to let us know. Have a nice day! :-)
Warmest Regards,Customer Support
W Cube Pte Ltd
Tel: +65 6337-4831
Fax: +65 6337-0431
Email: Support@W3Cube.com
Address: No. 1 Coleman Street, #03-14 The Adelphi, Singapore 179803
Website: http://www.W3Cube.com