What charge rate is best
Hello All,
I have a T-Hawk with a 400 speed electric. I use a 600 mah, 7 cell nicads. I do not know the c rate of the batteries and do not fully understand c rates. I also have a Super Brain 959 Peak Charger. It can be set from .5 amps to 4.5 amps charge rate. By default it is at 3 but I have been doing all of my charging at .5 amps. At this rate a fully discharged battery charges to full in about 30-40 minutes and then the charger pulse charges at .1 amp for 1 hour. My question is: Is .5 amps the best charge rate to keep the batts at tip top, And what is the c rate on these batteries if that is a legitimate question. Thanks Jim B :confused: |
Re: What charge rate is best
Originally posted by jboss Hello All, And what is the c rate on these batteries if that is a legitimate question. Thanks Jim B :confused: Steve |
Thanks
Thanks Steve,
At .5 amps ther barely get warm. How low shoud I discharge them. Should I hook them up to a light bulb until they are dead or just charge them after the plane cuts off the motor |
Re: Thanks
Originally posted by jboss Thanks Steve, At .5 amps ther barely get warm. How low shoud I discharge them. Should I hook them up to a light bulb until they are dead or just charge them after the plane cuts off the motor You don't need to discharge them except to check capacity once in a while, you should give them a slow charge @ 0.1C or 1/10th (60 mA) or as close as you can getof their rated capacity for about 16 hours occasionally to balance them out. |
Re: Thanks
Originally posted by jboss Thanks Steve, At .5 amps ther barely get warm. How low shoud I discharge them. Should I hook them up to a light bulb until they are dead or just charge them after the plane cuts off the motor Steve |
That works for me
Thanks Guys That answeres my questions.
This site is great . Where else can you get answers so quickly JimB :) :sunsmiley |
What charge rate is best
Is there anybody out there that can explain in a simple way that even I can understand, what is C-rate, howis it determined and what is the difference between mah, mv and ma.
Thanks |
What charge rate is best
Originally posted by eflyer2 Is there anybody out there that can explain in a simple way that even I can understand, what is C-rate, howis it determined and what is the difference between mah, mv and ma. Thanks Lets take a pack rated at 1800 mAh then charging it at 2C means you would charge it at 2 times 1800 or 3600 mA. If you discharge it at C/5 this meas you would discharge it at 1800/5 or360 mA. ma is milliamp - a mill is 1/1000 of something so in this case it is 1/1000 of an amp. Same for the rest mv is a millivolt, 1/1000 of a volt If we have 1 amp of current flowing for 1 hour we would have 1 amp hour or 1 Ah or 1000 mAh. 1 volt across 1 ohm of resitance (you didn't ask about ohms yet) will result in a a current of 1 amp. OK? |
What charge rate is best
Thanks Red,
Now if I put the those ma, mv, mah, ohms the things that get crossed in a bag, tie the end up and shake the heck out of it then plug it into a wall socket ....grin.. Will my Battery be charged ? OK- OK, let me put it this way, I have a 7.2 V 150 mah nicad, slowly now, how d I determin the C-rate and what do I tell my charger to do, charge rate, for how long. Please don't pay any mind to my opening remarks, a bit of humor helps keep me sane. Thanks for the help, |
What charge rate is best
Originally posted by eflyer2 Thanks Red, Now if I put the those ma, mv, mah, ohms the things that get crossed in a bag, tie the end up and shake the heck out of it then plug it into a wall socket ....grin.. Will my Battery be charged ? OK- OK, let me put it this way, I have a 7.2 V 150 mah nicad, slowly now, how d I determin the C-rate and what do I tell my charger to do, charge rate, for how long. Please don't pay any mind to my opening remarks, a bit of humor helps keep me sane. Thanks for the help, |
What charge rate is best
Thanks Red,
I am begining to understand, 1-C is the capacity of the battery (mah), in milli-amps (ma), ni-cads are charged at 2-C. Hope i'm right-- 2-C @ 150 mah= 300 ma x 10 = 3 amp charge rate. My charger is one of those 959 super brains and is ajustable for charge rates in amps, 0.5 ~ 4.5 amps. It is also adjustable for mv from 5 ~ 70, I'm not sure what this is yet, and it is adjustable for time in minutes. Now for NIMH batteries, do I charge at 1-C or 1/2-C, example 8.4v 730 mah, how do I find the charge rate of this one, would it be .75 amp. I know you can't hold my hand on this but I think were getting somewhere. Thanks again, Eflyer PS- the 959 charger comes with a very vague instruction sheet that tells you what the charger will do but does't tell you how to make the adjustments. |
What charge rate is best
Originally posted by eflyer2 Thanks Red, I am begining to understand, 1-C is the capacity of the battery (mah), in milli-amps (ma), ni-cads are charged at 2-C. Hope i'm right-- 2-C @ 150 mah= 300 ma x 10 = 3 amp charge rate. NO, NO, where did the X 10 come from. 2C@150mAh is 300 mA. or 0.3A My charger is one of those 959 super brains and is ajustable for charge rates in amps, 0.5 ~ 4.5 amps. It is also adjustable for mv from 5 ~ 70, I'm not sure what this is yet, and it is adjustable for time in minutes. Now for NIMH batteries, do I charge at 1-C or 1/2-C, example 8.4v 730 mah, how do I find the charge rate of this one, would it be .75 amp. For a C rate charge it would be .75 amps (or 750 mA). I know you can't hold my hand on this but I think were getting somewhere. If you can't hold your hand on it you are getting it to hot - Not good. (Battery humor here). Thanks again, Eflyer PS- the 959 charger comes with a very vague instruction sheet that tells you what the charger will do but does't tell you how to make the adjustments. |
What charge rate is best
Red, don't go away, I'll be right back,....grin
|
What charge rate is best
Red, I think my biggest source of confusion is comming from the charger, you guys are feeding me the right info but the charger is talking a different language, What may be the problem is this charger was not intended to do what I need, for one thing in large writing on th box it states " For 3 ~ 8 cell NI-CADs and NIMH batteries ", in the istruction sheet in fine Print it reads " for AA and Sub-C and Glow driver batteries, It also states in even finer print " Plug and play for Sub-C and LARGER cells ONLY",
Again, it is adjustable for charge rates of 0.5 ~ 4.5 and for peak threshold of 5mv ~ 70mv. It is not adjustable for mah rates. Could this charger be meant to charge R/C Car batteries. Thanks again, |
What charge rate is best
Originally posted by eflyer2 Could this charger be meant to charge R/C Car batteries. Thanks again, |
What charge rate is best
Red, does that mean that I can use my 12 volt car battery charger to charge my small e-flight batteries, you guys are telling me on one hand that the charger that I have is killing my batteries, while others are saying chargers are chargers and batteries are batteries and neither knows the other and it's all getting muddy again,
I guess it's like asking a doctor to explain whats wrong with you in lay terms, most can't do it, and the rest won't. Thanks again for trying, Eflyer |
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