396 batteries dead in 4 hours!

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n0xmz

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I've had this scanner for a few weeks now and I've been very happy with it's performance. The batteries (1.2 v NiMH) lasted all day - about 10-12 hrs. Now they're lasting about 4-5 hours! I'm not running the backlight constantly (only a few seconds on open squelch) and the volume is normal , about half-way.

The only thing I've changed is that when I'm in the car (total of about 30 min. today) I'm using an amplified Motorola speaker. I don't know the input impedence of this speaker but I've been told that it's fairly high so as not to damage the audio amplifier in the scanner.

Any ideas about what could be causing this?
 

KB3KBR

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how do you charge them? external charger? if not then you need to let them charge in the scanner for 14 hours that's how long the charging circuit tells it to charge.
 
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n0xmz

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I use a 15-min. rapid charger. I always use this charger and never had the problem until today. Maybe the charger is going bad. I dunno. I have a handheld ham radio and I'll run it over the weekend and see how it handles the batteries from the same charger to compare.
 

rocksteady

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Rapid chargers seem to beat up rechargable batteries. Use a standard charger or use the adapter to charge them internally. I have duracell 2650's and they last a long time..

Rocky
 

ka3jjz

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Very likely one or more cells have gone bad. A lot of folks seem to use external chargers rather than use the internal one in the 396, from the traffic I've seen on the 396 Yahoo group

73 Mike
 

W4KRR

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I also vote for a bad cell. If you have no way to test them, then just get a new set, you should notice a big improvement in run time.
 

JnglMassiv

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If you're able to do so, test each cell with a voltmeter. If one is significantly lower than the others, you have a suspect.

Minorly offtopic tangent:
Does the Uniden internal charger circuit monitor the charging conditions or is it simply a timed charge? If it's a timed charge, there's no reason to expect anything close to a complete refill, right?
 

GTO_04

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If you're able to do so, test each cell with a voltmeter. If one is significantly lower than the others, you have a suspect.

Minorly offtopic tangent:
Does the Uniden internal charger circuit monitor the charging conditions or is it simply a timed charge? If it's a timed charge, there's no reason to expect anything close to a complete refill, right?
It's a timer-based charger. So you need to keep it plugged in for 14 hours for a complete charge if you are using the stock batteries. If you put some 2700mAh batteries in it will take longer than 14 hours.

I agree with the others that you may have a bad cell. I use the Powerex 2700 and charge them with a Maha Charger on the slower setting, which takes about 6 hours. It charges each cell individually which IMHO is better. That way you know each cell is fully charged.

GTO_04
 

JnglMassiv

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It's a timer-based charger. So you need to keep it plugged in for 14 hours for a complete charge if you are using the stock batteries. If you put some 2700mAh batteries in it will take longer than 14 hours.
Ya but since it cuts off at 14 hours, you don't get a full charge without cycling power.
*Shrug* I always have used (and will continue to use) an external charger.
 

GTO_04

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Ya but since it cuts off at 14 hours, you don't get a full charge without cycling power.
*Shrug* I always have used (and will continue to use) an external charger.

I agree absoultely. And I think it's best to use an external charger like the MH-C401FS or the C801FS.

GTO_04
 

RoninJoliet

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I use the Duracell 2650's in my 396 and GRE500....In a Everready NMhid charger @350mah it takes about 7-8hrs=2800....In the radio its 150mah@19 hours=2850mah....Most NMhid used when these scanners came out like the PRO96 were 1800mah so the manual says 14hours, now we have more power-2650 so you have to add about 4 more hours....I get 10-12 hours on both radios on the 2650 Duracells depending on how long they sit unused or how quick you use them after charge and how many backlites are being used on the scanner.....
 

n0xmz

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Good points about the bad cell. I shall test them this weekend. I used some other cells today and they did just fine.

Thanks!
 

jafo818

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Rapid chargers degrade battery life over time. If you buy new batteries that are exactly like the ones you have, you should get the old battery life again. But after a lot of charges, it'll happen again.
 
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