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NIMH batteries


kevin917z

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ive been looking through the archives and havent been able to tell what the best nimh batteries are, people use 1400mh 1800mh 2000mh what is longest lasting and best

i am looking to buy about 18 nimh batteries and a charger but i dont know what to buy or where to buy them from at a good price

 

any help appreciated, thanks

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Check this site out for comparsion:

http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM

 

If ordering online, I tend to buy Maha thru this firm:

http://thomasdistributing.com/maha.htm

 

When I just can't wait and got to have them now, I go to the local target or Walmart and buy the Energizer brand (1850 mah for AA at about $12.99 for a pack of 4. They were on sale a few months ago for $9.99 and I wished I had bought more then.)

 

I've been told by many others that Maha are the best.

 

I use the maha c204 charger. The first web site I listed above thinks highly of them. What I've been told and what I've read if that you don't want to go with the fast chargers because they tend to lessen the life and power of the batteries.

 

Of course all of the above is JMHO

 

Garmin Vista

Garmin Street Pilot

and a partridge in a pear tree

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You generally want the highest milliamp-hours rating, but of course the cost is the trade-off. Just curious, why so many batteries? I usually keep a charged spare set on hand, and I am thinking of getting a solar charger to take with me (maybe mount the panel outside a backpack).

 

There is a good description of the battery ratings at web page

(warning: pop-up ads on that site)

 

Craig Miller

Chandler, AZ

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We use NIMH batteries in our GPS'rs and our battery hungry digital camera and usually in our mini Mag-Lites. It pays to have multiple sets and a good charger like the Maha C-204F with both AC and 12 volt capabilities. You can charge them in your vehicle as you travel, etc.

 

There is a wealth of information about NIMH's (as well as digital cameras) at this web site and you will discover that proper battery maintenance is a key to longer life.

http://www.cliffshade.com/dpfwiw/index.htm

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quote:
Originally posted by Ranger Roger:

 

I've been told by many others that Maha are the best.


 

Moe: Maha?

 

Curly: AHA?

 

Moe: You like to speag dat?

 

Curly: I like to talk dat!

 

Moe: Razbanyas yahti bennafoochia teeminah karonja that...uh, how do you say that Pickle Puss....he asky tasky what didja fat syke, you got it?

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try to do what I did.

 

Everything I carry uses AA batteries. My GPSr. my emergency beacon strobe, my CD player, my Ham Radio, my cell phone, and my mini-mag light all use AA batteries. This cuts way down on spares. I carry one extra pack of NiMH AAs in a pack for my ham radio, and 6 spare charged NiMH in a bag. I can take batteries from ANY item to use in ANY OTHER item in an emergency.

 

Yep, if you are just getting started, think of this.

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

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quote:
Originally posted by kevin917z:

been looking and i see the nimh's are 1.2 volts, does this mean they wont last long in the gps or 2 way radios??? compared to 1.5 volts?


 

I don't believe the 0.3 reduction in voltage reflects the duration of useable power. Instead it refers to the "peak" power output. Generally most of the dual AA cell stuff we power with nimhs will operate within the 2.4v to 3v range.

 

However, I have found that my wireless remote temperature base station needs all 6.0 volts from 4 AA cells. In reading the spec sheet, it does indeed specify exactly 6.0 volts and not a voltage range. But wait a minute, my Garmin Vista specifies 2 1.5v cells and it operates just fine on nimhs. I have to call the base station's tech support line to learn of the 6.0v requirement.

 

So...check the power requirements in the manual of the devices in which you will be using your nimhs and verify that they are in spec. Better yet, call the manufacturer and ask about the suitability of using 1.2v AA cells in the device.

 

FWIW,

 

BP

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quote:
Originally posted by kevin917z:

ive been looking through the archives and havent been able to tell what the best nimh batteries are, people use 1400mh 1800mh 2000mh what is longest lasting and best

i am looking to buy about 18 nimh batteries and a charger but i dont know what to buy or where to buy them from at a good price

 

any help appreciated, thanks


 

the figures you cite (1400mah, 1800mah, 2000mah) are the storage capacity of the cells. That is, a 2000mah AA battery has 42% more capacity than a 1400mah battery, and under the test load (which may not match the actual use) will power the load for 42% longer. The actual capacity delivered depends on how heavy the load is, so this is useful but only as a rough estimate.

 

"Best" could mean several different things. If you're looking for cost effectivness, you'll note that you're better off buying lower capacity batteries which have a much lower price. If you're looking for maximum capacity and are indifferent to cost, then the highest capacity batteries are what you want.

 

If I had to replace all the nimh batteries I own and the charger, too, I'd buy the 2000mah Mahas and the new Maha c401fs charger.

 

And I'd buy them from Thomas distributing (www.thomasdistributing.com)

icon_geocachingwa.gif

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No, no, no! Heh..

 

After studying the rechargable battery FAQ (written in part by a NASA engineer), and using NiMH batteries in everything from my Palm, to 4 FRS radios to the GPS and a digital camera for over 3 years here's my recommendations... (Nevermind the cordless screw guns for years and years and years.)

 

First, chargers, there are three types. The "best" would be the intelligent chargers that cost the most. These measure battery voltage and as soon as it drops slightly stop charging: 1-2 hours. Battery life is maximized.

 

Next best are the temperature chargers (such as most screw guns but not as common for smaller cells). These overcharge slightly, "cooking" off the chemical that allows batteries to be overcharged without destroying them. This reduced your battery life.

 

Worst are the trickle chargers (that charge for 15 hours). You need to fully discharge your batteries (risking getting the voltage too low or "reversing a cell", thereby ruining them) before charging to avoid overcharging and cooking the batteries (really reducing their life).

 

Now, batteries have a physical capacity limitation. Those with the highest milliamp rating have the last amount of the chemical that makes them resilient to "cooking".

 

Conversely, batteries with the most of that chemical and are most resilient have lower milliamp ratings.

 

So, if you have an intelligent charger, get the highest milliamp batteries. If you have a cheap trickle chargers, get the LOWEST milliamp rating or you're likely to end up having to replace the batteries.

 

All my NiMH batteries (AAA, AA, and individual "C" cells from cordless screwgun packs) charge up to 1.44 volts.

 

I recharge them when they get down to 1.1 volts, and the battery faq recommends NOT letting them get below 1.0 volts.

 

I HIGHLY recommend paying the extra for an intelligent (CPU controlled) 1 or 2 hour charger--treat your batteries well and they'll treat you well, the little extra expense will pay for itself in the long run.

 

Randy

 

PS: With a trickle charger, you CAN measure the voltage w/a digital voltmeter and charge them with a timer without cooking them (about 0.02666 volts per hour of charge--I'd recommend undercharging to extend life.

 

PPS: Store your batteries CHARGED and if not used during the year, recharge them twice a year (when you replace smoke detector batters and flip your mattress at spring/fall time changes). They naturally lose charge over time, and if get under 1.0 volts might not take a recharge.

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