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Rechargeable AAs

post #1 of 46
12/15/02 at 4:08pm
Thread Starter 
Hi guys
I have some questions about rechargeable AA batteries: will I get a decent life-span out of NiMH AAs in a portable amp/TA/MD application, or am I better off sticking with alkalines?Also I ve never done it but is it safe for the battery inside the unit to use rechargeable AAs in the external battery case of a MD recorder?
Some months ago I bought a Sanyo charger(NC-LC01EX) with 4 NiMH Sanyo R6 AAs 1600 mAh/1,2V but after some use they don t seem to last more than 1/3 the lifespan of a Duracel Alkaline and the sound deteriorates near the end. I don t know if the charger is to blame or Sanyo just makes a lousy battery.
Thanks
Mecano
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post #2 of 46
12/18/02 at 2:50pm
Thread Starter 
It seems that rechargeable AAs are not popular!
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post #3 of 46
12/18/02 at 3:22pm
I use rechargeable AAs for my Grado RA-1 amp. I rigged 2 separate battery holders with 7 AAs each, shorted one battery housing (the holder is for 8) and connected each to the 9V battery connector. That way, I get 9.5+V when the batteries are fully charged and it lasts a looong time. I have 2 sets of batteries, which is costly but in my opinion is worth it.

However, I do not use NiMHs. I use the Sanyo 1100mAh NiCds, the simple reason being that they retain their charge over a long time. The NiMHs drain fast just sitting there. They may be good for a camera if you're going to shoot 200 pictures in one day but for an amp with such slow drain, they're a pain in the neck. They might have a higher charge rating but what's the use if it's not available after 3 weeks?

I am not familiar with the drain of the TA or your MD, but have found that I get better mileage out of my PCDPs with the NiCds.

Note that mose NiCDs have 600mAh capacity. The Sanyos are the only ones I've come across that have almost double that. They are the light brown color with red and black text on them.

Hope this helps
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post #4 of 46
12/18/02 at 3:33pm
Thread Starter 
Thanks for the reply recephasan! I ll try the Sanyo 1100mAh NiCds
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post #5 of 46
12/18/02 at 3:58pm
You might want to read this article first: Battery shootout link

Although the NiMH batteries do discharge themselfves over time, it takes a couple of months to do so with the larger capacity batteries!! This is almost never a problem unless you have a device that uses so little electricity that it would take like 3+ months to discharge them!!

If you need a charger there is really none better than the MAHA c204F, or its newer sibling. Make sure to get the F model as it is a fast charger with an auuto-shutoff circuit. Slow chargers take forever with these large capacity batteries!!
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post #6 of 46
12/18/02 at 5:15pm

Re: Rechargeable AAs

Quote:
Originally posted by mecano

Some months ago I bought a Sanyo charger(NC-LC01EX) with 4 NiMH Sanyo R6 AAs 1600 mAh/1,2V but after some use they don t seem to last more than 1/3 the lifespan of a Duracel Alkaline and the sound deteriorates near the end. I don t know if the charger is to blame or Sanyo just makes a lousy battery.
I've actually got a set of the 1600 mah Sanyo's I use with my digital camera, and they last longer than the Olympus batteries (same rating). The Sanyo's are supposed to be a pretty good battery, from what I've read.

The charge on an NiMH battery will last reasonably long, but not as long as an alkaline. The difference is that you can't recharge an alkaline battery (also rate of voltage loss over the life of the charge). Further, the charge on an NiMH will deteriorate over time, so you'll lose charge even if the battery is not in use. Figure that an NiMH battery should probably be charged every month or two, whether used or not (in practice the charge will usually last much longer than that, but it doesn't hurt to charge an NiMH that isn't fully discharged, since there's no memory effect like the one with NiCad's).

If the charger was bad, it's possible to damage the battery. Overcharging an NiMH is bad, and can accelerate the decline of the battery. If the battery becomes very hot to the touch, it's getting too much charge (warm is normal).

I tend to prefer the Powerex/Maha's at Thomas-Distributing. I've got the 1800 mah AA's. Good charge life, and so far able to take all the abuse I've thrown at them.
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post #7 of 46
12/19/02 at 4:25pm
I must agree with Hirsch and ServinginEcuador. I use the Poweex batteries in AA and I have Kodak AAA size. The Maha charger is good. You may have a charger problem. One thing I have noticed about rechargeable's is that once they get near the end of a charge they drop off quickly.
I do not use rechargeables in my Total Airhead. I mostly use a 6 pack of AA's plugged in the the TAH's power jack. With this setup I don't feel it's worth the expense of recharge's since 6 AA's last about 3 months using the TAH for 6 hours a day 6 days a week. IF I happen to run it on the 3 AAA internal batteries I want all the voltage I can get, so no recharge's there either.
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post #8 of 46
12/19/02 at 5:37pm
Thread Starter 
Thanks for the inputs!
<Although the NiMH batteries do discharge themselfves over time, it takes a couple of months to do so with the larger capacity batteries>
I don t have to worry about that since I charge the batteries frequently-like 2 times per week
<If the battery becomes very hot to the touch, it's getting too much charge>
I never charged them too much as to get hot
<but it doesn't hurt to charge an NiMH that isn't fully discharged, since there's no memory effect like the one with NiCad's)>
so NiCads have this drawback….
Guys notice this:If I use the mzr-900 with the Sony gumstick (1400mAh/1,2v Nickel Metal Hydride NH-14WM)alone I get 10+ hours playback and the sound is fine even at the end(I always use line out mode)but if I remove the gumstick and use the external battery pack alone with one Sanyo AA I don’t get more than 6-7 hours and the worst is that the sound deteriorates after the first 4 hours.Since the Sanyos are well regarded the charger is obviously lousy .The MAHA c204F seems fine.
I just bought an MZR-50 from FCJ and this * lovable* dinosaur eats batteries much more than the newer Mdstuff!so alkalines will make my wallet suffer!.
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post #9 of 46
12/19/02 at 5:56pm
Quote:
Originally posted by mecano
<If the battery becomes very hot to the touch, it's getting too much charge>
I never charged them too much as to get hot

Basically, almost all fast chargers heat the batteries up to the touch. They should never get hot, per se, but if you use a fast charger that charges in less than about 2 hours, your large capacity batteries will get quite warm. I always make sure to charge my batteries with the charger door open, and near some vertilation, and if I remember I spin the batteries 180 degrees every now and again to reduce the heat build-up below them!!
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post #10 of 46
12/19/02 at 7:51pm
Thread Starter 
<I spin the batteries 180 degrees every now and again to reduce the heat build-up below them!!>
that’s a cool way to keep the batteries cool !
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post #11 of 46
12/19/02 at 8:17pm
Quote:
Originally posted by ServinginEcuador
and if I remember I spin the batteries 180 degrees every now and again to reduce the heat build-up below them!!
I've been trying to figure out how to do that with my 9 volt batteries...
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post #12 of 46
12/19/02 at 8:19pm
I second the Maha 204 charger. I have one and it's worked really well. Most of the NiMH rechargeable batteries are made in Taiwan, I haven't found much difference between more expensive 1600 Powerex batteries (manufactured by the same guys as the Maha charger) and cheaper 1600 Nexells. Rechargeable AAs work great w/ Olympus Digital Cameras - really convenient vs. battery packs.
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post #13 of 46
12/19/02 at 8:37pm
The rechargable batteries are most of the times 1.2V instead of 1.5, the more you have the more you are missing, if you use 4 of the recharchable you are using 4.8 instead of 6 volts, if you need some voltage requirements this is going to work fine, on the other side I saw many times that for flashes etc... the do not recommend recharchable batteries, why ??? If you insist in using the rechargable ones, get then two sets and rotate them every certain amount of time, I used to do that wiht my flash and I have no problems to the date...
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post #14 of 46
12/19/02 at 8:42pm
Quote:
Originally posted by Sovkiller
The rechargable batteries are most of the times 1.2V instead of 1.5, the more you have the more you are missing, if you use 4 of the recharchable you are using 4.8 instead of 6 volts, if you need some voltage requirements this is going to work fine, on the other side I saw many times that for flashes etc... the do not recommend recharchable batteries, why ??? If you insist in using the rechargable ones, get then two sets and rotate them every certain amount of time, I used to do that wiht my flash and I have no problems to the date...
If you want 6v, just use 5 batteries instead!!
It adds up to the same voltage!!!! (JOKE!!)
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post #15 of 46
12/19/02 at 8:45pm
Yes right, but sometimes they do not fit in the space, in my flash they do not fit in there, and that is true, but I preffer non portable devices anyway, on the street and at work I preffer to be alert!!!!
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