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Old Aug 25, 2006, 3:23 PM   #1
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If the same brand and power rated batteries are used in a camera e.g. 4 x AA in a Canon A series camera will they all drain at the same rate or will they differer in the value at the point they need recharging? I am just weighing up if I really need the separate charge circuits or if I can get away with just 2 circuits for the 4 cells.
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Old Aug 25, 2006, 4:07 PM   #2
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Hello Creeduk,

If you start off with premium cells and match them for voltage retention, capacity, and internal resistance, they should drain equally. Otherwise your camera will shut off when the weakest cell is completely drained.

In general, it is always better to charge cells individually. You can charge multiple cells in series as long as you let them trickle charge long enough at the end of the charge cycle to equalize them. It is generally not recommended to charge NiMh cells in parallel.

Tom
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Old Aug 25, 2006, 7:00 PM   #3
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I had initially read that separate charge circuits are the best way to go but today I was reading a few posts over at the ripvan100 site that claim:
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The independent bank charger - though a great idea - simply does not charge each cell equally with each other. We've gotten many comments from users of these kinds of chargers showing tremendous improvements with the LP4KN charger over the independent bank chargers for this exact reason.

Multi-cell bank chargers, (Like the LP4KN,) charge in pairs or sets of 4. While not as theoretically versitle as the independent bank charger, they do do a much better job of charging cells equally. (Which is really important when using them in a set.)
I guess they would as the want to promote a model that does not have the separate circuits. It appears the one you pointed out (and I see you did the tests) does have this feature.
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Old Aug 25, 2006, 7:39 PM   #4
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As an owner of two RipVan chargers, I have found they they frequestly do not provide a full charge to the cells (they cut off too early). I now use a charger that charges each cell individually, and I have been getting much more consistant charges. I also use a battery tester to check the charge level before using a battery.

I now use the La Cross BC-900 charger

http://www.thomas-distributing.com/l...ry_charger.php
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Old Aug 26, 2006, 1:22 PM   #5
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Hello Creeduk,

I (and others) have done testing on the Lightning Pack 4000N charger. If you pull the cells off the charger as soon as it has finished charging, it repeatedly comes in near the bottom of the pack. I believe they come in at somewhere around 85% of a full charge.

However, if you leave the cells in the charger to trickle charge for an additional 24 hours, it does a very good job of charging.

The problem is that you will find the same goes for most chargers out there. They all do a very good job of completely charging if you leave them on the charger for 24 hours.

The challenge is coming up with a charger that does a complete job of charging in 15-60 minutes...

RipVan100 is making the claim that their charger balances the cells better than other chargers and implies that it does that because it charges in parallel. This is not true. It does a good job of balancing the cells because it has an "aggressive" trickle charge. The cells are balanced during the trickle charge phase.

Tom
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Old Aug 26, 2006, 11:38 PM   #6
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This is great information Silverfox, it is greatto find people who have taken the time to check into these details. There are so many options with 15 minute chargers and 15 min IC3 (seems special battery technology) the smart cool chargers. Then the trickle it seems the majority actually use an overly aggressive approach to trickle from my reading. I read about one tester who used a C401FS to charge but then moved the batteries to the lowest amp trickle on a timer for ultimate charge readiness. Interesting but way more than most of want to be bothered with. Do you think there is any value in car kits or is it better to buy an inverter if you really want to charge on the go? I was toying with the idea of getting a great charger a few sets of 2500/2700 quality batteries either titanium, powerex, sanyo or even energizer (all get great reviews) and then adding a IC3 just for those fast emergency days. If they only last a few hundred charges they may still have done the job of saving my ass in a pinch.
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Old Aug 27, 2006, 12:37 AM   #7
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I recently purchased a MH-C401FS. I have an older Kodak 3.1 MP camera. I charged the 2 cells from that camera today, and one took much longer than the other to charge. That said, I'm glad I have a 4 circuit charger, and I have no idea as to why one cell was drained so much more than the other.
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Old Aug 27, 2006, 1:32 PM   #8
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Hello Creeduk,

Charging in a car is not ideal. Because of that I recommend that you keep an eye on things while charging in a car. When you leave the car, pull the cells from the charger and shut the charger off.

If you have a 100-150 watt true sine wave inverter you can hook up your Energizer 15 minute charger and have cells ready to go in the time it takes to enjoy a good cup of coffee.

I happen to prefer the Energizer 15 minute charger over the Ray O Vac IC3 charger because of convenience. I have successfully charged over 25 different brands of cells in the Energizer charger where the IC3 charger only fast charges IC3 cells. I will point out that the IC3 system will make cells last longer, but it relies on the resistive band at the end of the cell to signal to the charger that it is an IC3 cell. There have been reports of the band wearing off and the cell no longer functioning as a fast charge IC3 cell. The IC3 charger will trickle charge all brands of cells, butit takes a long time to charge.

Some things to keep in mind...

Heat kills NiMh chemistry.

Your battery is only as good as the charger used to charge it. A good charger can make crappy cells perform well, a bad charger can make premium cells perform crappy.

Good value is not necessarily the same as cheapest purchase price.

Batteries have a limited shelf storage life. Buy the freshest batteries you can find.

Don't leave your batteries on the charger for an extended period of time. If you want to keep a set "ready to go," invest in a timer that will allow you to charge for a short period of time every day, then shut off. You can just leave them sit and still have enough left to handle an "opportunity" that arises. Cells left sitting at room temperature will have around 50% of their charge left after 90 days.

Be mindful of the trade offs. There is no such thing as a free lunch. We are seeing higher capacity batteries, but are finding that the high capacity cells have lower cycle life and a higher self discharge rate. The extra capacity is nice, but don't expect the 2500 mAh(or larger) cells to last asmany cycles or handle abuselike your 2000 mAh cells did.

NiMh cells tend to get "sluggish" when they just sit around. The best performance comes when you do a full charge/discharge (down to 0.9 volts per cell) cycle every 30 days. You can get by with doing it every 90 days, but the key is to keep the cell voltage above 1.1 or 1.2 volts resting. There is much debate as to whether toput NiMh cells into long term storage (greater than 1 week) charged or discharged. Most people find that their cells work better when stored fully charged. However, if you are doing a monthly cycle on the cells, it probably doesn't matter.

Did I mention that heat kills NiMh chemistry? You cells may get warm at the end of the charge cycle, but if they get as hot as a baked potato out of the oven, that is too hot.

When you set up your charging area at home, if you place your charger on a non combustible surface that is resistant to liquids and out of direct sunlight you will not have to worry what will happen if something goes wrong. If the cell vents, the small amount of electrolyte will be contained. If things heat up the damage will be contained to the charger and cells and your non combustible surface will protect everything else. You can add a battery operated smoke detector for additional protection if you happen to want to charge unattended overnight. Another thing is to place your charging area so it does not block you from getting out of the house if it happens to start smoking.

These precautions may seem extreme, but I have been told that Murphy may have been an optimist ... :-)

Tom
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Old Aug 28, 2006, 2:31 PM   #9
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Tom, excellent advice. I was just reading a post by you from January over at candlepower and you had mentioned the energizer being the coolest running 15 min charger you had seen. I am currently looking for deals on these it seems to be the best compromise. My wife had her camera arrive (at long last 3 days shipping my eye...lol) so I have to get a shift on now.

The info about higher rated batteries havinglower cycle life is good to know I will probably go with around 2300 / 2500 and if I find 1800's or 2000's I will grab them for the kids RC cars etc.

Thank you for all this time and information Tom.




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