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(Real) Intelligent NiMH Chargers?
Anti_Climax asks: "I, like many Slashdot readers, have a lot of battery powered devices. With the large number of cells that are in use at a given time, I have taken to using NiMH rechargeables (Ten 2.0Ah Cells for $10 at the local Fry's Electronics). My current charger is a timed unit that was made when 1.3Ah was the norm. I have accepted the fact that if I want my cells charged properly and quickly, I will need to invest in an intelligent charger. With the dozens of manufacturers in the market right now, the Google results are promising but far too broad. What have been your personal experiences in this area? How many of the supposed Smart Chargers are anything but? Who's offering the best deal for my dollar? While I don't need my cells to charge in 15 minutes, I would like to find an inexpensive Intelligent charger that can charge 4 or more high capacity cells (in pairs or individually) in an hour or less."
This subject was covered a while ago in this ask slashdot. I remember because I bought my charger just after it being published.
My advice is that you just buy whichever one that *clearly* states that is microchip (that is deltaV) controled rather than stopped by timer. Mine is a Hama and it works well.
For the batteries, check this comparison. To sum it up, the more mAh the better, brands are usually not that important.
The Duracell charger that is sold at wal-mart for $23 (it comes with 4 batteries) is a good cheap one-hour CPU-controlled charger. It can do 4x AA or AAA size, NiCd or NiMH. I know it's DeltaV because if you take one battery out for 5 minutes while it's charging, and put it back, it will take exactly 5 minutes longer to charge than the others. I think it should work fine with high-capacity batteries.
I have a Rayovac charger that I'm quite happy with. It's a 'smart' charger that'll charge NiMH batteries in about an hour individually, up to four at a time.
The model number is PS4. Info here.
I got mine at Walmart for under $30 with a couple batteries.
I got a very nice intelligent charger from my local hobby shop. It'll do ni-cd and nimh, and has 10 user defined programs. I got it for speedy charging of bicycle headlight battery packs for a 24 hour race and a full-duplex wireless intercom system, but it works great for any pack up to 8 cells.
It stops on delta v or capacity - you program in that your packs are 2AH and it'll stop after delivering that much capacity if delta v doesn't stop it first. You can program the charging current and the delta v trigger. After the charge it complete it'll perform a trickle charge as long as the cells are connected so you know they won't self discharge and you don't have to worry about leaving them on for too long.
And it has reverse polarity and short circuit detection and protection.
I've been very pleased with it. It was about $50, though, but for such a useful charger it was well work it. You can certianly find less expensive models that will automatically charge the cells you have. I like the configurability, but I have lots of different packs in lots of different configurations.
-Adam
For AA and AAA batteries, use IC3. The IC3 chargers will charge standard batteries in about 4 hours, and IC3 batteries in 15 minutes. The cost differential is virtually negligible.. really. A 4-bay IC3 charger, and a couple sets of IC3 batteries will run you about $60-80 depending on what you get.
If you need something that does other sizes, that's different.
"Champagne for my real friends - and real pain for my sham friends!" http://ericblade.postalboard.com/
This one is excellent and well-reviewed in a number of publications: http://www.ccrane.com/quick_charger.asp. I have had mine for a while now and can attest it's excellent. It handles from four AAA through 4 D-cells. It has a slow-start (which prevents the batteries from getting hot), and for NiCd, it even discharges the batteries to 1.0V before recharging them. The spring clip is VERY strong, which helps assure good contact (at least I assume that's why they're so strong). You can leave the batteries in it, too, and it will keep them topped off.
It's not cheap (US$40) but it's been well worth it to me. I use rechargeables for everything and in every size except 9V. I get my batteries from http://www.batteryspace.com/. I like the AA 2250 mAh (currently 24 for US$30); they seem to last forever in my digital camera. My 11-year old daughter goes through batteries like crazy for her CD player, radio, clocks, toys, and flashlights, and going all-rechargeable was one of the best moves I ever made. I do keep a spare set of alkaline D-cells for my radio in case of extended power outage, but haven't had to use them yet (My 8 9500 mAh D-cells, like the A-cells, seem to last forever.
The C. Crane charger says it only does NiCd and NiMH, but I also recharge "rechargeable Alkalines" http://www.rayovac.com/products/recharge/rec_alk.s html in it with no problems.
Get a Maha charger. Get either the C4012FS , the C204F, or the C204W.
All are good, the C401FS is their most intelligent charger and has a gentle charge time of 5 hours or a fast charge time of ~100 minutes. I own the C204F and it has been solid like a rock for two years. With the 204F you still have to recondition the batteries every 5 charges or so, the C401FS eliminates that need so I'd go with that if I were buying a new charger. Use the C204W if you want easy international power use.
... is that it would be useful to find a good, compact case for carrying batteries. I often carry 2 or 4 spare charged AA batteries in a pocket, and on several occasions I've found myself with a pocket full of very hot batteries. They seem to be able to move themselves into a configuration that results in a discharge. Aside from the annoyance, this doesn't seem very safe.
;-)
I do have a couple of large bags that have a set of straps for batteries. But that means carrying a huge bag just to transport a few batteries. What would be nice would be a cheap plastic box just big enough to hold four AAs and protect their contacts. I've been on the lookout, but I haven't seen this for sale anywhere.
I wonder if there's a Tupperware container of the right size?
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
We've been using Maha Powerex batteries and have been very satisfied. I ordered 25 sets of something very similar to this MahaEnergy and it has worked fine. They are easily better than other batteries I've tried.
Why arent rechargable NiMH batteries more popular? These things should be flying off the shelf. The only application that they are not good for are products such as fire detectors where the NiMH self discharge would cause reliability problems.
Anyway they pay for themselves in less than 5 recharges (assuming 50 cents for non rechargable and 2.00 for a rechargable). Then you have at least another 100 charges left after that(they claim 500-1000). 100 charges * 50 cents = 50 bucks saved.
Charging time is not a factor anymore both druacell and energizer offer 1 hour and 30 min chargers. There is also a 15 min charger out there by Raynovac but you need to buy rayovac batteries (they include a chip).
The only barrier I see is high intial cost. I guess people only look at the short term.
Veramocor
I stay in mumbai and i got a MH C204F from US and just recently from mumbai got Sanyo 2100mAh NiMH batteries ...
they charge in 4 hrs and thats pretty decent to normal chargers which take 16 hrs
I got the batt for 450 RS (9.5$) gr8 deal
Striving to be common...
My current favorite is the Great Planes Triton charger -- I like it so much that I've got two of them. It'll charge anything. If you need it to run off of 110v AC current, this page will probably help set you up cheaply. You'll need to make a battery holder to hold the cells, but you could easily charge 10 at once, or possibly even charge them inside whatever you're using them in.
(And this tells how to find the best price on it right now.)
Note that most NiMH cells will only tolerate being charged at up to 1 C -- so don't charge your 2 Ahr cells at more than 2 A if you want them to last (and one amp, 1/2 C, would be better.) I don't know what they do to the 15 minute cells to let them be charged at 4 C, but whatever it is, most NiMH cells do not have it. No charger, no matter how smart, is going to remove this limitation for you.Of course, chargers like the Triton are probably overkill for what you need, especially at $130, but I certainly love mine ...
You should take a look at this. I followed the advice therein and bought a Maha charger and Powerex batteries and have been pleased with their performance (I have an Olympus E-10 which is notoriously hard on batteries, standard batteries, e.g. Duracell, die in the middle of taking the first picture with it!)
I've heard there's a 12v car cord for the IC3 charger, which would be tempting if the thing weren't so expensive to begin with. As it turns out, running a regular desktop charger from an inverter isn't too horribly inefficient.
The problem is that some of the quick-chargers, like the one that came with my camera, do a fast-start and don't even bother measuring the cells until 5 minutes later. If their AC input is constantly cycling on and off, this destroys batteries. I'd probably do fine with a deltaV unit running off an inverter.
At the moment I've got enough AA's that I can charge them at home and only rarely need to charge them in the car anyway.
a simple analog circuit to switch from high to low (trickle) charging current is all thats needed.
any charger that uses a timer is silly.
fyi, frys carries 2300mAh batteries now.
rechargables aren't popular because the "big battery" companies (duracell and energizer) will *never* advertise them. why tell consumers to buy something once that they can reuse over and over again for 5-10 years when you could tell them to buy something cheaper that they'll have to keep coming back and buying more of every couple months?
this is the same reason the name brand rechargables are worthless low-power shit. they *want* rechargable batteries to seem bad. i -always- see people at the rechargable rack in the store pick and buy the name brands first, despite the power output being advertised. consumers are clueless. hell, they allowed bush to steal an election and fuck up the world; you think they'll bother to learn about batteries?
Rechargeables are not the best idea for low(est) power devices. A common TV remote control operates on two, sometimes three Alkaline cells for two or three years, sometimes even longer. Most, if not all, remote control chips are optimized for this operation mode. True, if you press a button on a remote, it draws a lot of power for the infrared LEDs. One ampere is not unusual. But it sends very short pulses (or else the LEDs would literally burn), and the real power does not come from the battery, but from an electrolyte capacitor contacted in parallel, via a very small resistor, to the battery. It is rapidly discharged by the LEDs, and then charged again by the battery. The battery just has to provide a very small current to recharge the capacitor after each pulse, and an even smaller, permanent current for the controller chip. Alkaline cells have a very low self-discharge factor, so they can work like this for years. The remote control continues to work even if the alkaline cell is nearly dead (1.3 V), but with a reduced range (because of the lower available energy due to the lower voltage) and with a noticeable recovery time. When the voltage is so low that the chip does not work properly, it starts to send nonsense to the TV (and may under certain circumstances crash the microprocessor inside the TV - nobody is perfect).
If you replace the alkaine cells with NiCD or NiMH, this lowers the available voltage by 0.3 volts per cell (NiCD=1.2 V, alkaline=1.5 V), thus reducing the available engergy for the LEDs, thus reducing the range of the remote control. Those rechargable cells discharge themselves, so you need to recharge them often. But at that time, you want to use your remote control as well, so you need two pairs of rechargeable cells, and you need a charger. Probably a good one, so it does not kill your cells while loading them. And after some time, your rechargeables are dead because they had nothing "to do". So you need two new pairs of cells, probably after two years. Just about after the same time that you would have bought the first new pair of alkalines (the first one is usually included).
Just calculate for yourself: Using rechargeables in remote control is nonsense. And if you are concerned about the environmental impact: At least here in Germany, there is a well-working return system for alkaline (and zinc carbon) cells (in fact, you have to return your used cells).
The same is also true for other low(est) power devices, like clocks and calculators with liquid crystal displays (LCDs), and most analog quartz clocks. Radio controlled analog clocks need a little bit more power and a "high" voltage for the receiver, so they can not drain alkaline cells as much as clocks without receiver and remote controls.
My "BRAUN" electical toothbrush uses a single NiCd cell which is permanently charged when it sits in its "docking station". After about one year of permanent "keep alive" charging, the cell is now nearly dead. It still can hold enough energy to work for five minutes, but when it is disconnected from the wall outlet for more than a few hours, it simply does not work and needs two days to recharge. The cell is sealed into the toothbrush, having a predetermined breaking point in the case to take out the cell for disposal, so I can not replace the cell without permanently damaging the toothbrush. A trick I've seen too late on TV: Do not permanently charge the toothbrush, discharge it while using, and connect it only to mains when it is empty. It will need round about a day to charge. This will avoid the memory effect.
About batteries and cells:
A cell consists of two electrodes (the positive anode and the negative cathode), the electrolyte, and a case. Depending on the materials used, a single cell has 1.2V (NiCd and NiMH), 1.4V (zinc air button cells), 1.5V (alkaline and zinc carbon), 1.55V (Silver / Quicksilver button cells), 2V (Pb=lead acid), 3V (Lithium), o
Denken hilft.
well their C and D cells suck but the AA's are pretty good energizer has out a new 2200 mAh (as commented by the other poster)
In a free market economy then the Big players should lose out to newer small companies which offer the products people want.
Agreed I don't think people actually look to do an ROI or something on a battery. Its the same situation with compact florescent lightbulbs. 35% of the energy usage plus they last 5 times as long, yet they aren't popular.
Veramocor
* charge NiCd's in Li-ion mode, add a power switch to unit so you don't have to plug the 24v in "hot", and fill the hole on that damn piezo "siren" inside with epoxy-- it's still audible, but only if you're in the same room.
If a job's not worth doing, it's not worth doing right.
It's not that simple. You can't just terminate the charge when the battery reaches a certain voltage. You have to monitor the battery voltage and detect when the voltage slope either becomes negative or decreases. Plus, you need things like cool-off periods, reverse protection, dead battery detection, and so on. A microcontroller makes things much simpler and cheaper than an analog circuit. Plus, it can charge multiple types of batteries.
I've been using the astroflight 110D for a few years on my battlbot batteries(3 Ah NiCD and NiMH). Its worked great for me. Recentely I've gotten into small robots and am starting to use li poly batteries, so I went ahead and replaced it with the triton chargers...its worked great so far. You can get either one from robotcombat
--
http://www.rezap.com.au/
This Australian microcontroller-based charger will do conventional non-rechargeable alkalines, titanium, nicad, nimh, and rechargeable alkaline-manganese cells, in all sizes. I'm not associated with the company, but I do own one, and it really does work (apparently safely - despite the dire warnings on the side of non-rechargeable alkalines about charging).
You can supposedly get up to 15 cycles from a normal alkaline, 25 from a rechargeable one. It's quite slow at nimh and nicad, but alkalines recharge fairly fast and don't have self-discharge issues.
These guys are working on exporting these things to the US.