Which is the best 15 minute charger

Hi Guys,

I was looking to buy Ni-Mh batteries, when I stumbled upon 15 minute chargers, never knew such things existed(guess i've been living under a rock until now, lol)...

I was about to buy Energizer one, but found out people were having problems, that it didn't accept many Ni-Mh batteries (it shows some red light indicating batteries are defective, even for new one)...so I want to know does this charger only accepts energizer batteries..people having this charger comment..

Also what about Rayovac 15min charger, its quite cheaper than energizer, is it good or does it have any known problems, if any one knows..

Lastly, I am buying these batteries for my new Digital camera, but was thinking if they really charge in 15mins, I can replace batteries in my whole house, for remotes, etc...is it a good idea, or should I just stick to using them in camera's only..

Regards,

None. You don't want a 15 min charger. Even with special batteries, you have a good chance of killing the batteries quickly.

Many (all?) of the brand-name chargers only works with a specific set of batteries from the same brand. That is because they push the envelope so hard, that they have to know beforehand the exact behaviour of the battery. If the inner resistance of the battery isn't within a pre-defined tolerance for all possible voltage levels, the charger will refuce to charge the battery. The alternative would be that the charger cooked the battery.

If a quick-charger misses to detect the dV/dt when the battery is full, it will cook the battery. Better chargers detects the high temperature, but then you have already abused the battery. Some cheaper chargers doesn't detect the cooking and only have a timer to turn off the charge if no dV/dt was found.

If the charger is powerful enough, you may get a fire.

Any quick-charger that is cheap is a bad charger! The reason is that a really quick charger must control current, voltage and temperature for each individual battery. Notice that most chargers don't process the batteries individually, but normally in groups of two.

^^But i've seen posts of people using 15 minute charger and batteries and using it successfully for more than 2 yrs on this board...

I would also stay away from any fast chargers - The do kill batteries due to overheating - Yes, some may have got away with it but personally I'd not do it.

When using sintered NiCd batteries, the RC people have used senselessly quick-charging batteries for ages. But sinered NiCd batteries survives the heat. NiMH can not handle heat as well. A "normal" 15-min charge cycle will generate a lot of heat in the batteries during the charge - and as soon as the batteries are full and can't accept any more, the temperature will go sky high. Custom chargers for dedicated batteries tries to anticipate the batteries getting full, so that they are sure to slack off fast enough.

With a very fast charger, you loose the safety margin from warm weather.

I understand the need for highspeed charging without regard to cost for the RC people, since they not only charge the batteries quickly, they also drains them in a couple of minutes. With a 2-hour charger I can quite easily charge three sets of batteries every night. If that isn't enough, then I can most probably survive bringing a second charger.

My training and experience in industrial electronics (many years) reinforces the comments above to FORGET the 15-minute chargers. Use chargers that are specifically designed for the battery types you use.

Suggestion - rather than ruining batteries by overheating them and/or overcharging them, get some spare batteries and possibly a spare charger. That way, even if you are working an event like mad you can either just call on your pre-charged spare batteries to keep you going or you can charge one (or more) while working with a spare.

Hears a link to an old thread that covers this topic. I have the energizer 15 minute charger and haven't had a single problem with it. Ive used energizer 2500mAh, 2300mAh, and Digital (wal*marts off brand)2200mAh.

https://photography-on-the.net/forum/showthre​ad.php?t=312768

I have had a $100 8-battery 90-min charger "forget" to turn off the charge current once. When I went into the kitchen in the morning, I heard a sizzling sound. The cells were cooking and had ruptured, and the charger was wet.

A similar failure with a 15-min charger would have meant more than 6 times the amount of power pushed through the batteries, or more than enough for a nice fire. I don't think the fan is powerful enough to cool the batteries if the charging isn't stopped when the batteries gets full. We are probably talking about more than 20W per cell.

pwm2 wrote in post #3548521
I have had a $100 8-battery 90-min charger "forget" to turn off the charge current once. When I went into the kitchen in the morning, I heard a sizzling sound. The cells were cooking and had ruptured, and the charger was wet.

A similar failure with a 15-min charger would have meant more than 6 times the amount of power pushed through the batteries, or more than enough for a nice fire. I don't think the fan is powerful enough to cool the batteries if the charging isn't stopped when the batteries gets full. We are probably talking about more than 20W per cell.

As far as I know, the cause here is, the batteries were overheated. This should have never happened unless your charger is faulty or its quality is not upto standards, because all good chargers have temperature sensors...

Headcase650 wrote in post #3548123
Hears a link to an old thread that covers this topic. I have the energizer 15 minute charger and haven't had a single problem with it. Ive used energizer 2500mAh, 2300mAh, and Digital (wal*marts off brand)2200mAh.

https://photography-on-the.net/forum/showthre​ad.php?t=312768

hmmm....Interesting thread

It also suggest people are getting insane battery life with rayovac...guess I'm decided then...
Also one more thing, I will buying them off from ebay, and its selling real cheap there...for as low a $8...is it really that cheap, or is there chance of a fake...here's the listing btw for reference
http://cgi.ebay.com …ZWDVWQQrdZ1QQcm​dZViewItem

I'll appreciate if you have a look and tell your thoughts..

SkipD wrote in post #3548096
My training and experience in industrial electronics (many years) reinforces the comments above to FORGET the 15-minute chargers. Use chargers that are specifically designed for the battery types you use.

Suggestion - rather than ruining batteries by overheating them and/or overcharging them, get some spare batteries and possibly a spare charger. That way, even if you are working an event like mad you can either just call on your pre-charged spare batteries to keep you going or you can charge one (or more) while working with a spare.

+1 on this advice from me.

15 minute chargers cause huge internal heating in the battery and shorten their life. Besides the chance to kill the battery, it can also cause loss of capacity and degradation.

J.

TheMafioso wrote in post #3549190
As far as I know, the cause here is, the batteries were overheated. This should have never happened unless your charger is faulty or its quality is not upto standards, because all good chargers have temperature sensors...

No the cause here was that a supposedly high-end temperature-controlled charger for some reason failed. The result was that the batteries overheated.
The problem is that a similar failure with a 15-min charger could have killed me.

pwm2 wrote in post #3550623
No the cause here was that a supposedly high-end temperature-controlled charger for some reason failed. The result was that the batteries overheated.
The problem is that a similar failure with a 15-min charger could have killed me.

AND the temp based chargers - at best - can only have a temp sensor near the case. The heating starts on the inside and you can't measure it there. If you jam enough current in fast to a charging battery, that temp can rise extremely rapidly even though the case temp is still in limits. This can lead to all sorts of bad things where the least of your worries is the destruction of the batteries.

The 15 minute chargers are just a bad idea for so many reasons especially when extra batteries are cheap.

J

I have been running the 15min duracell charger for a while now and works like a champ with the 430ex flash...

pwm2 wrote in post #3550623
No the cause here was that a supposedly high-end temperature-controlled charger for some reason failed. The result was that the batteries overheated.
The problem is that a similar failure with a 15-min charger could have killed me.

Yes, that's what I meant by charger bieng faulty, even the best of components can fail.A corollary to what you're saying would be that 90min chargers are also unsafe, but you can easily verify, its not the case...

JohnJ80 wrote in post #3550993
AND the temp based chargers - at best - can only have a temp sensor near the case. The heating starts on the inside and you can't measure it there. If you jam enough current in fast to a charging battery, that temp can rise extremely rapidly even though the case temp is still in limits.This can lead to all sorts of bad things where the least of your worries is the destruction of the batteries.

The 15 minute chargers are just a bad idea for so many reasons especially when extra batteries are cheap.

Hmm, I agree to what you're sayin, but chargers have other mechanisms to detect, the fully charged battery that includes minus delta V, and safety timers. Good chargers automatically put the charge on trickle once it detects battery is fully charged, but it didn't happened in this case, since he forgot and put it overnight accidenltly, and neither did safety timers kick in.....It seems to be a clear case of somethin going wrong with the charger's circuit...

Ultimate CC wrote in post #3551681
I have been running the 15min duracell charger for a while now and works like a champ with the 430ex flash...

See this post and you'll find plenty many in the thread HeadCase650 mentioned, with some people claiming that they're running 15min batteries successfully for 2, 3 even 5 years....So 15min batteries may not seem pretty theoritically but they do work practically...