mike71

Hello I have a few Nimah batteries they will take a charge but what I would like to know is there a way to test it to know if its any good.Is there something I can buy or make to do a load test on them?

guver

My Feedback: (325)

Many chargers can "test" or discharge a pack to test it. At the least maybe a loaded voltmeter would do. A nice set-up with graphing is also an option (like a CBA)

The most difficult thing might be choosing a "standard" or benchmark to compare to. If you wanted to make something then perhaps a string of bulbs an ammeter and dvm and a stop watch would allow you to make manual graphs (lots of work)

tacx

My Feedback: (1)

You need one of these.

http://www3.towerhobbies.com/cgi-bin...&I=LXWW16&P=ML

52larry52

My Feedback: (1)

tacx nailed it with the Tower Hobby tester. Don't forget to also order the correct test leads for your application. I have one of these and it works!!!

42etus

My Feedback: (2)

Actually the Tower Hobbies checker mentioned above won't tell you if your batteries are failing. Only an actual capacity test can do that. I cycle my batteries with a capable charger through several charge/discharge cycles and average the discharge mah that the battery can supply. If that number isn't at least 75% of the battery's rated capacity, I trash can it. For more battery info than you really want to know, go here http://www.hangtimes.com/redsbatteryclinic.html

jetmech05

I use a loaded volt meter as well.....I'll test the batteries after a full charge, wait for a few hours and test again. the voltage is going to drop some. 1.1 V a cell is discharged

pcolache

My Feedback: (1)

I also just ordered one of these. http://www.hangar-9.com/Products/Def...?ProdID=HAN171. I've been using my instructors when we are at the field. Seems like an in-expensive tool that we should all have. I was told to just make sure the voltmeter can test the pack while applying a load. Good luck.

jester_s1

I'm somewhat local to you. If you want, I'll do a discharge test on my fancy charger and that way you'll know for sure what you have. How old are these battery packs BTW?

Gray Beard

My Feedback: (-1)

Let jester check them for you and you can learn something in the process. THe only good way to check the pack is to cycle the pack a couple of times. When I get a new pack these days I cycle them about 4 times to get them up to there max. Then a couple of times a year I pull my packs and cycle them again to make sure they will go p to about 80% of there capacity. I saw that mentioned by 42. A volt meter is a good tool but you can only tell if a pack is any good by cycling. If it shows up bad on a volt meter it is way past time to toss it. Meet up with the jester, pick his brain a while. I us a cycler fom Hanger 9 and one from Hobbico. I think Hobbico products are crap but I do have one of there chrgers/dischargers so I can say that. I have used a lot of there products over the years and never been happy with there products or service. If I need a new electrical product I go to hanger 9 first and look at therre products.

j.duncker

My Feedback: (2)

A Cycler is good but you can manage with just a Walwart, a suitable car bulb and a voltmeter/ammeter.

Charge the battery fully.

Leave for 2-3 days.

Find a 12 volt bulb or other load to give a drain about equal to the capacity eg 600 mah should be loaded to 600 ma. approx.

Check the voltage after 40 mins and every 5 mins after that. Stop at 1.05 volts per cell. Work out what capacity you have. [Current in ma times minutes divided by 60]

Anything less than 75% should be binned.

I started doing this when the club I was with had a bunch of packs fail early in the season. I had some fairly small capaity nimh packs that i used in small models and found that they did 3 seasons reliably then it was a downhill slide.

I did buy a fancy charger/cycler eventually

OliverJacob

My Feedback: (12)

Get a charger/discharger. These are worth every penny. There are other methods, but this is the most convenient one.
Just connect your battery and let it do it's cycle.
It will show you the capacity of your battery pack and you will see when it's time to dump it.

batteryforrc

To test your packs, just turn on the first switch, check for proper operation, turn off the switch, turn on the second switch, check for proper operation, turn on both switches and go flying.

NOTE: If you don't want to carry the additional weight of a second battery pack, but would like some redundancy, just solder another wire onto your battery pack and run a single battery with two switch harnesses. Switch harnesses are much more likely to fail from vibration than batteries anyway....

Villa

Hi mike71
The volt meter recommended in the third post above is the way to go. As you can see, it is a "loaded" volt meter. This means the volt meter puts a load on the battery, then it reads the voltage. If you check the battery frequently you will learn to note when the voltage drops, which is an indicator of a problem. Most people do not realize that some batteries can read full voltage, yet any kind of load will drive them to a worthless condition. As a point of interest, and also to teach you a lifetime piece of information, connect a voltmeter to your car battery. It should read 12 volts or slightly more. Now crank the engine to start it, and note what the voltmeter reads. The voltmeter will drop down below 12 volts, while cranking, and after the engine starts, will go to close to 14 volts. If I do this on a cold day, and the voltage drops below 9.5 volts while cranking, I replace the car battery, assuming all other conditions are or have been normal.

jester_s1

The voltmeter and cycler are really two different tools for two slightly different purposes. Cycling a battery tells you if it's delivering its full capacity, which will alert you to materials breakdown internally before the battery fails. The loaded voltmeter tells you if your battery currently is charged enough to supply the voltage you need, but really doesn't tell you much about the remaining capacity unless you've also verified it with the cycler.