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Need help about rechargeable Batteries :(

post #1 of 16
Thread Starter 
Hi everyone!! I found this forum a while back when visiting the r3mix site. And most of the time only lurk in the background reading all the inspiring tweaks you guys build.

I own a Sony CDP + Tuner model D-T401. But I found out that the new Sony rechargeable Ni-MH (1400Mh) batteries wont start charging in my portable after I connect the my AC adapter to the wall. I digged out the manual and it says the batteries I bought was not supported

Is there any way or tweaks to make my portable to charge the Ni-Mh?? Pls advice.
post #2 of 16

The D-T401 can charge only the proprietary Sony battery pack (I forgot the model number) that looks like two AA batteries linked together (the same battery pack supported in my broken D-E301). It came in NiCd (650mAh) and NiMH (1200mAh) versions. The Sony batteries you bought will only (re)charge in the newest Sony CD Walkman players (e.g. my D-EJ721) and the newest Sony MD Walkman MD player/recorders (e.g. the current MZ-R700DPC).
post #3 of 16
Thread Starter 
Arghh.. this is bad news. Actually I bought 2 sets (4 batteries) without consult the my manual first. My bad I read some posted here about hacking the portable to accept the normal rechargeable. I'm interested in trying about this hack. Could someone provide the link please?
post #4 of 16
You should examine the battery compartment for extra metal contacts of any sort. It usually gives clues to mods/tweaks you can do to have it except a charge.

However another idea is getting a good external charger and better non-proprietary batteries.

The Panasonic portables don't NEED panasonic AA/AAA NimH's you just have to take off some plastic covering on some batteries so some extra metal contacts touch the battery.

The extra metal contacts usually don't do anything but "sense" if you are using "proprietary" batteries. Basically a simple way for them to charge the right battery types instead of actually relying on microprocessors and "smart" sensors like external battery packs. Likewise this is the same reason external chargers offer higher performance...because they are "smarter".
post #5 of 16
kinda off topic but i've been using a "Power Plant CD battery" - i get ~25 hours out of it. check it out: http://www.innergypower.com/Consumer...html#cdBattery

note: it's heavier than my discman though, and about the size of a jewel case. not exactly convenient.
post #6 of 16
Thread Starter 
Thanks for info. So it wont charge now in my discman. Cool! I will try check the Power Plant out. Can I use Panasonic Charger BQ-2CM to charge it? The DC spec is rated at 2.4V 125mA and my discman adapter is rated at 4.5V 500mA. I know the Panasonic is a slow charger but is there any -ve effect to this?

After I read the manual, I am delighted to see that my Sony D-T401 output is rated at 15mW@16ohms. No wonder my ears cant stand the volume pass the 5 level. And those who is experienced anyone knows how is the quality output of this portable?

Sorry for asking too many questions. Please enlighten.
post #7 of 16

If you inspect your battery compartment, you'll find a small knob sticking out at one end that needs to be pushed in order for the charging circuit to work. That said, it is better to get an external charger. It will charge your cells better and they'll last longer (no overcharging).
I haven't seen the Pana charger you mentioned, but at these specs it can charge 2 empty AA 1400 mA cells for about 16 hours without too much risk of recharging.
post #8 of 16
Thread Starter 
Thanks blr. I think I'll go the external route.
post #9 of 16
Well, after years and years of using cheap NiCd and NiCd/NiMH chargers (all of which are either "overnight" chargers that have no charging control whatsoever or are "quick" chargers and charger/conditioners that not only are timer-controlled but also tended to overcharge batteries to varying degrees of extent), today I decided to bite the bullet and spend $34.99US plus tax at RadioShack for a "smart" but rapid charger that charges two to eight AA or AAA batteries in less than three hours (but with no overcharging! WOO-HOO!! ) or one or two "9V" batteries in about eight hours. The RadioShack catalog number in #23-422. (BTW, that charger's smart-charging feature works only for AA and AAA batteries; with "9V" batteries, only timer charging control is available.)

I proceeded to charge a (much-used) pair of RadioShack #23-149 850mAh NiCd AA batteries - they got "fully charged" in about half an hour - and the batteries NEVER even became warm! WOW!!! (Too good to be true... It turned out that those NiCd batteries were somehow damaged by improper charging. And a follow-up test on a set of Energizer 1200mAh NiMH AA batteries indicated that they charged in under two hours - and they got fairly hot to the touch. They got hot even charged with the Eveready charger designed specifically for those batteries, too.)

I am currently running that pair of batteries in my Sony D-EJ721 PCDP to determine if they last anywhere near as long between charges as the same batteries that I had charged with my previous chargers. If they do, then my judgment of the types of battery chargers will be ranked in order from best to worst:

Best: "Smart" chargers (regardless of charging speed)
Tolerable: "Overnight" chargers with timer control
Worst: "Quick", "Fast" or "Rapid" chargers with timer control

Hope this guide helps.

post #10 of 16
you pretty much rank the chargers right.
Among the so called "smart chargers" there are variations however. Look at the manual and see what termination method the charger uses. Good smart chargers use slightly different algorithms for NiMH and NiCd cells because of their different charging characteristics.
Properly charged batteries should not warm up much more than 40C even when fast charged. heat during charging is the enemy #1 of recharg. batteries.

PS: Don't rush to trow your NiCads away. Try to cycle them several times (does your new charger have a discharge function?) and evaluate again.
post #11 of 16
blr, I actually had four Nicads - but two of them were actually shot. (I found that when I tested the "shot" nicads with a battery tester, the battery meter reading fluctuated wildly.) And my new charger doesn't have a Refresh function; I couldn't find a "smart" recharger/conditioner in stock, even though the store supposedly carries that model.

P.S. my new charger claims to have "Delta V/Zero Slope" termination, with a timer used as a backup.
post #12 of 16
An update on my "shot" NiCads:

One pair of them took just 10 minutes to charge; the other, less than half an hour. (Those NiCads are supposed to take over an hour and a half to charge them.) And the run time between recharges was MUCH shorter than they were supposed to last! And I had completely discharged them (using a SEPARATE discharger) before charging them! Which means that those NiCads have been damaged beyond repair! (And yep, I had intentionally overcharged them quite a few times with a charger that claims to charge 650mAh "standard-capacity" AA NiCads in seven hours - and with NO termination control whatsoever.) But NONE of the NiMH batteries that I tried on my new charger (which, BTW, uses a "reverse-pulse" charging technology) suffer the same problem so far; their charging time is very close to what RadioShack claims.

So, what do you think I should do with those NiCads?
post #13 of 16

*singing, on-key*

Home, home on the range!

(Someone, please reply!)

I would like to add one so-called "disadvantage" of "smart" chargers:
If you buy a brand-new set of rechargeable batteries - which typically are sold completely uncharged, thus the warning "charge before using" - the VERY FIRST charge on a "smart" charger will ALWAYS be a crappy one. Successive recharges will be much better.
post #14 of 16
You're right Eag.
New batteries need break-in. Not that your portable will sound better after that (LOL), but the cells need couple of charging cycles to reach their full capacity.
Also, for the first couple of charges the voltage characterstics are not well pronounced. It means that the slight voltage drop at 100% charge point may not be there, which in turn may confuse the "smart" charger and lead to overcharging.
What I do is deep cycling new cells 2-3 times through a timed 1/10 charger, before put them in the fast "smart" one.
post #15 of 16
This is an update about that "smart" charger of mine:

I tried fresh new Energizer 1600mAh NiMH AA batteries in that charger - and even after the third charge the charger stops charging after just half an hour - well shy of a full charge.

I guess that "smart" chargers aren't ideal for brand-new rechargeable batteries. Now I'll have to go back to RadioShack and get a "timed" 15~18 hour charger. Unfortunately, none of my "slow" chargers are recommended at all for NiMHs, and my other existing NiMH-compatible chargers charge much too quickly for a break-in. And another thing, the only such timed overnight charger available at RadioShack is a 4-cell unit that charges AA, AAA, C and D-cell rechargeables for $14.99; the least expensive charger (for AA, AAA and 9-volt batteries) costs $7.99, but is considered a "quick" charger by design (takes as little as 6 hours for a full charge).

And one BAD thing about slow chargers that deliver MUCH less than 1/10 of a battery's capacity: They require waaaaaay too long of a time to fully charge those batteries - and that significantly increases the likelihood of that dreaded "memory effect" during charging, so that you'll never get a full charge.
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