SrTelemaster150

I just picked up a used Multiplex MULTI charger LN-5014.

I have played around W/it on 1A charge rate but would like to charge faster when in the field.

What is the maximum X-C rate for 4.8v NiMh Rx & ignition packs?

Typical Ma capacity will be 750Ma Rx packs for my small aircraft & 2000ma for ignition & Rx on larger planes.

Also, do NiMh packs need cycling like NiCd? If so what discharge/charge rates should I use, how many cycles & how often?

Goldenduff

Nimh and Nicd can both safely be charged at .7x capacity although Nicd can go higher but .7 is easy to remember.

mach2

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Ive only been in the hobby a few months and ive only used life batteries until recently.

I got a 4.8v 2000 nihm. it says to charge at 200mah (.2 amps right?) for 11 hours. but youre saying its okay to charge it a .5amps (500mah right?)?

also, can a charger tell you when a Nihm is full? When my life battery is full, my "common Sense" charger tells me how many milliamps it put back into it. I charged my Nihm pack with the smart charger at .2amps for about 14 hours and it just kept going past the rated capacity (2000mah).

Do I have to set a max cuttoff range of 2000mah? And did i just mess up my new battery?

I cycled it three times like my LHS guy told me to. But i just simply used the 100mah wall charger for the specified time and discharged it with a battery bug (i made it by soldering a light bulb up to drain the batt). I could just keep doing it that way, but I want to charge it faster than 20+ hours.

Sorry for hijacking, but its pretty much the same question so i figured id piggyback it. And maybe the OP could benefit from this info too....

please let me know if there is anything im wrong with my methods or understanding. Like milliamp to amp converstions, etc....

thanks,
Jeremy

mach2

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oh, and to the OP, from what ive researched, the Nihm battery is not supposed to build a memory. So technically you shouldnt have to do that. But i think a lot of guys recommend doing it occasionally anyway.

Jeremy

Goldenduff

The charger will stop when it detects a a certain peak village, usually pre set at about 5mv. Sometimes this is too sensitive and the charger can stop prematurely, you can change the lake detection to 10mv but usually I think it's fine

mach2

My Feedback: (5)

Thanks. What is Lake detection?

Jeremy

Goldenduff

Predictive type error. Should be peak detection! Also village should be voltage!

Rodney

Your will get a lot of false or partially true info on Nixx batteries in the forums. The following sources will give you some good and factual information on how to treat and test your batteries. If you use any Nixx batteries, it will pay you to read them.

http://www.hangtimes.com/redsbatteryclinic.html
http://www.camlight.com/techinfo/techtips.html
http://www.whenshtf.com/showthread.php?t=2153
http://www.srbatteries.com/nimh.htm
http://dansdata.com/gz011.htm
http://users.frii.com/dlc/battery.htm

mach2

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thanks!

Goldenduff

Hang time hobbies is my preferred resource. I did recommend it as the first response.

eddieC

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When trickle or overnight charging Nixx cells, generally 0.1C or 1/10th battery capacity, the charge rate is too low to detect peak charge.  I've 'bumped' up the charging rate when in a hurry,  as much as .5C, but closely monitor temps and ma of charge.

KaP2011

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Just a warning. When I clicked on the third link down my virus program had a hissy fit and shut down my browser.

mach2

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Golden duff says that they can be charged at .7x, you said that in a hurry you only go up to .5c, and my 2000 mah NIHM says to charge at 200mah for 11 hours. which is .1c right? Which is also .2 amps right?

following your rule of thum, to charge a completely discharged 2000mah battery at .5, I would charge my battery at 1.0 amps (or 1000mah) for two hours to get a full charge. Is this correct?

Thanks,
Jeremy

eddieC

My Feedback: (2)

Quote:

Golden duff says that they can be charged at .7x, you said that in a hurry you only go up to .5c, and my 2000 mah NIHM says to charge at 200mah for 11 hours. which is .1c right? Which is also .2 amps right?

following your rule of thum, to charge a completely discharged 2000mah battery at .5, I would charge my battery at 1.0 amps (or 1000mah) for two hours to get a full charge. Is this correct?

I've never heard of .7C (or x?) rate of charge. My .5C rate is done for no more than 1 hour, and then on a near-fully discharged pack.. Charging above the overnight rate can cause the cells to vent, as can charging at the overnight rate for more than 14-16 hours. NiMhs are known to have false-peak issues, many of mine have, it's just something to work around. Start out conservatively, follow manufacturer's recommendations, but be flexible too. I have a 10-cell 3,000 ma NiMh pack that's 10+ years old and still used in an old-timer plane. It will false-peak about half the time, and I find it's one I have to 'hit' at .5-1.0C rate for 20 minutes to get it a little warm before it will take a full charge. It's bothersome, but I work with it.

You'll find there are no absolutes with batteries, especially as the technologies progress. Still, Ni-xx technology is well understood and is probably on the wane as Lipo, LiFe and LiMn take over. The SR batteries site listed above is a very good one, as are Red Scholefield's.

Goldenduff

.7x was .7 x (multiply) capacity. 

mach2

My Feedback: (5)

ill just keep following the recommended charge rate on the battery. And i think ill probably be sticking with LiFe since I learned about them and they are pretty easy for me to understand. And for the same mah, the price isnt crazy different.

oh, and i got my charger to read full. 5.8v. It must not have been full because it took 380mah. and i know one flight doesnt eat that much power.