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battery chargers

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frank125

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hello i have a question regarding battery chargers, i was going to go to walmart and pick up a basic charger for my aa's. i see there are quite a few diffrent chargers out there and some pricy. is there that much of a diffrence in these chargers to really save that much more life from the bateteries, or should i save my money and just get a basic charger. thanks for any help
 
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kb0nly

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A good charger can really make the difference between life and death of batteries.

I use a La Crosse BC-700 to condition and charge batteries of the AA and AAA variety and i can tell you it makes quite the difference in their life span. It monitors the batteries voltage and temperature when charging, and also has discharge and refresh (conditioning) modes.

Think of all the money you might spend on batteries, i probably have close to $100 worth of AA rechargeables around the house running almost everything, i want those batteries to last as long as i can for the money spent on them.

The BC-700 can be had for around $35 on ebay shipped, thats where i bought mine a year ago, before that i had a simple charger that always cooked the batteries. $35 is only a half dozen or less good quality high capacity batteries, its worth the investing to have a good charger.
 

hertzian

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How many batteries does your scanner use? Many cheaper chargers only charge in pairs, and the higher-end Uniden's use three batteries. If you are using a Uniden or other radio that uses three batteries, you'll want to make sure that the charger you pick will charge an odd number of cells.

There are many good threads here about the fine Maha/Powerex and LaCrosse chargers that will handle nearly everything and do a great job of charging.

If you need something right now off the shelf, at a very budget price, AND you are using 3 cells in the radio, the Energizer "simple" charger that charges AA/AAA and 9V batteries will handle that. It isn't the smartest charger around, but it is the least expensive that will take three at a time.

At the very least, you are making a wise decision to charge your batteries outside the radio.
 

newsphotog

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A good charger can really make the difference between life and death of batteries.

I use a La Crosse BC-700 to condition and charge batteries of the AA and AAA variety and i can tell you it makes quite the difference in their life span. It monitors the batteries voltage and temperature when charging, and also has discharge and refresh (conditioning) modes.

Think of all the money you might spend on batteries, i probably have close to $100 worth of AA rechargeables around the house running almost everything, i want those batteries to last as long as i can for the money spent on them.

The BC-700 can be had for around $35 on ebay shipped, thats where i bought mine a year ago, before that i had a simple charger that always cooked the batteries. $35 is only a half dozen or less good quality high capacity batteries, its worth the investing to have a good charger.
I'll second this suggestion. I love my BC-700. I use it in conjunction with Eneloop batteries. It's a great way to check the batteries' health.
 

DJ88

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I just purchased a LaCrosse BC700 and was wondering if anyone that uses one could tell me what charging current you use, 200, 500 or 700. I am using older Energizer 2450 and 2500 mAh and also have some brand new still in the package RayOVac AA4 NiMH. Thanks.
 

gmclam

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I just purchased a LaCrosse BC700 and was wondering if anyone that uses one could tell me what charging current you use, 200, 500 or 700. I am using older Energizer 2450 and 2500 mAh and also have some brand new still in the package RayOVac AA4 NiMH. Thanks.
I use the lowest setting the charger has (200ma) as that is what will give you the longest battery life.
 

slicerwizard

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I use the lowest setting the charger has (200ma) as that is what will give you the longest battery life.
So you've deliberately decided to not give your cells a proper charge, since the negative delta V charge termination will never trigger. Great advice to be passing on to others...
 

Bob_61

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So you've deliberately decided to not give your cells a proper charge, since the negative delta V charge termination will never trigger. Great advice to be passing on to others...
Could you explain what you reference to this negative delta V charge termination. Thanks, you know you learn something new everyday... :)
 

gmclam

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She me the technical info to back that up!

Thanks. How long does a charge take? The book says 13 hours at 200. Is that about right?
It depends on the capacity of the batteries. If you have a 2600mAh battery, charging at a 200ma rate would take about 13 hours.

slicerwizard said:
So you've deliberately decided to not give your cells a proper charge, since the negative delta V charge termination will never trigger.
I'd like the see the statistics/science or whathaveyou to back up that statement. Keep in mind that most of these scanners charge at a rate of 150mA, so 200mA is already higher than that. What I've seen is the problem is with the charger design and not the batteries per se. Chargers need to temprorarily increase the charge current to measure/determine if EOC has been reached. That function should be 100% separated from the charge current setting.
 

jackj

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frank125, ideally you need a charger that monitors and controls the charge to each cell independently. No two cells will have exactly the same capacity so for maximum life you should use a charger that monitors each cell. As for the rate of charge you should stick to a charge rate of 0.1 C to receive the maximum number of charge cycles from your cells, So a 2000 ma cell should be charged at a rate of 200 ma. You can exceed this rate and charge your cells at a faster rate in order to recharge them quicker but your cells won't give you the maximum number of recharges.

The really cheap chargers make no attempt to monitor the cell's state of charge. They just pump a set amount of current through the cell and keep that up as long as the cell is in the charger. These chargers can destroy your cells in just a few charge cycles if you don't monitor them and remove the cells at the end of the proper charge time.

The next step up are ones that use a timer to time the charge. When the timer times out they will reduce the charge rate to what they call a 'maintenance charge' which will complete the charge. But Ni-Mh cells don't like to be under a constant trickle charge so you should remove the cells at the end of the charge cycle.

The best chargers are ones that monitor both the cell's voltage and temperature and terminate the charge when these indicate the cell is fully recharged. These are pretty expensive chargers but will give you the best performance from your cells. But even these switch to a trickle charge rate instead of disconnecting the cell so you should remove the cells at the end of charge as well.
 

Highpockets

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I took the word of some of the power users here and ordered the LaCrosse BC700 it should be here Monday. If I don't like it, expect a PM. :D
 

hertzian

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0.1C is a "forming charge".

The best rate is 0.5C - 1.0C on a charger that uses delta-v on a normal basis. You have the tool to prove that to yourself over the long run. More simply, Delta-V is the detection of a slight DROP in voltage when a nimh battery is charged. The battery actually drops a very tiny amount of voltage when it is full, signaling the end of charge. Quality chargers such as LaCross and Maha/Powerex detect this very well - UNLESS the current being used to charge the battery is not strong enough to force this small drop of voltage to raise the flag. Hence, 0.1C is too small a current to force a DV, and you lovingly cook your cells away - slow roasting them even if they don't feel warm! That is one reason that forming charges on the LaCrosse and Maha are merely timed.

About the best thing anyone can do is visit the Candlepower forums - those guys are into batteries about as much as all of us on RR are into radios. This is a good starter thread:

Appropriate Charge Rate for NiMH Batteries

All the members of the Candlepower forums are extremely knowledgeable, and I would advise paying attention to the threads from "SilverFox" in particular - although many many more are just as helpful.

On that forum, you will also find specific battery recommendations, such as why old-stock of Energizers rated from 2400 mah and up are bad ideas, and why the RECENT 2300 mah seem to be ok for energizers - that is for a standard nimh cell. Other manufacturer's battery history and makes can be checked as well with reports and data from the users.

You don't have to believe these guys - if you take the time with your smart charger over the years, you'll see that what they say is true. To save time, keep your eyes open for SilverFox (just one of many great contributors)

It is a balancing act. Do you really care about getting the longest runs and lifecycles from your batteries, or is it ok to only use half their capability if you got them very cheaply? Should you run "Low Self Discharge, LSD", or regular nimh batteries that self-discharge 10% in the first 24 hours and 1% every day thereafter? If you are a photographer, or someone who burns through a set of cells every day, then regular nimh's with their slightly larger capacity are for you. If you go awhile without using the scanner, then low-self-discharge may be in your best interest.

All of this can be found on CandlePower whose members are smart-charger fanatics with data, photographs, charts etc to actually prove things.
 
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fourthhorseman

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nice write up sir,,

been running 10th RC for years,,from the days of yellow canica's in the sub C size maxed at 1200 mah..

now im running 6000 mah nimh..and 5000mah LiPo..and its FASST!

look out for a brand called REEDY NiMH,,they are fairly good,,high mah,,and with the low demand
that a scanner/radio have they last a long time,,and will have many,,many charge cycles in them..
http://www.ebay.com/itm/Team-Associated-Reedy-Aa-2700mah-nimh-4-ASC303-/150726983355?pt=Radio_Control_Parts_Accessories&hash=item2318073ebb

rc racers have been deep in the science of the rechargeable,,from nicad,to nimh,,now lipo..

Invest in a good charger,,preferably one with a USB out ,temp probe,,ect..If your serious,not alot are..but its another aspect of the hobby i find interesting

thanks for the link to the charge rate info,,,
 
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pathalogical

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I also use a LaCrosse charger, the BC 900. I get very consistent results using the discharge function at 250 mA. My Eneloops (2000mAh) are usually done in a bit over 4 hours. The batteries barely get warm.
 

E-Man

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Here is a Charger not to get IMO. Lasted 2 months of light use, and probably shortened the life of my Eneloops:

Amazon.com: Ansmann Energy 5207442/US 8 Plus Battery Charger and Maintenance Device: Electronics

While overseas, I got educated on counterfeit batteries. I have no idea if they have made it over to the US?, but to be safe, I only buy my batteries from Amazon or Thomas Distributing.

FWIW, the Sanyo dumb charger NC-MQN06U that was packaged with Eneloops purchased at Amazon, charges at 300mA.
 
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