C rating???
#1
C rating???
I read somewhere that stock motors need a higher C rating for the battery? Is this true and why? I would think the more turns the motor is the LESS C rating would be. Did I misread this? What C rating would be good for a 13.5 turn brushless set up in a T4.1?
#2
Any you can use all with your t4
#3
When you run a particular turn class, such as 13.5 truck, you want the battery to have more than enough amperage and not just be adequate. If everyone is running the same motor, battery performance or lack of is noticeable.
I would recommend 30c and up.
I would recommend 30c and up.
#4
You gotta be able to drive though too, if you got a 50c and too fast then you dont need it. Supposidly more c means it doscharges faster giving the esc and motor more juice. But dont try to go 100 when you only need to go 20.
#5
Tech Apprentice
C rating is the capable discharge of the battery while remaining under ~140*F
most batteries will list the indefinate and the burst(10seconds), it may apear like 35/45C or 45-90C
there is also the charge C rating on the back(usually) of the battery, this will tell you how many amps it can be charged at. a 5000mah battery with a 1C charge can be charged at 5amps MAX, a 2C can be charged at 10amps, a 10C (like some nanotech) could be charged at 50amps.
the vehicle will determine how much electricity to discharge from the packs, a battery only dumps max power when direct shorted (crossing the wires).
to measure the draw of your electronics hook up a 30C battery to them and measure the amps being drawn when you hit full power with full load on the drive wheels(driving on the ground) to do this easily, get a nice (mine is made by goldstar and was $400) multimeter with a min-max read feature, tape it to the car and gun it.
a mamba monster/HPI Flux system draws about 154amps or just under 35C for example.
if your ESC is rated at 100amps never run less than 25C, 150amps, never run less than 30C, 75-90amps never under 20C
a higher C rating doesn't mean faster if the lesser C rate battery had a higher C rating than the ESC in the first place, as it would provide full draw easily.
a 75amp ESC will not draw more power from an 50C battery than a 25C battery, as the 25C battery is more than capable of delivering 75amps. in this case the 50C battery will NOT be faster than the 25C. but it would be faster than a 15C, as the 15C would not deliver 75amps very effectively.
higher C rated battery=cooler battery, and ESC, safer battery(no swelling/no explosions), and longer life from battery(not being abused chemically from discharge... the way you balance and charge it is another story)
... sorry if the post is a bit 'here and there' ... A.D.H.D. means that i don't really pick an choose what info comes out.. and an extreme understanding of the subject means the lucky bits that do come out are a very small and random selection from a much much larger available selection stuck between my ears. as i'm trying to switch medication, i tried to read my own post to see if i accurately answered your questions. . but found it very difficult and couldn't. go figure.
if you need more info,ask again and i'll try again in the morning. (2:54am and i'm starting to bug out a bit)
cheers, all.
Phil.
most batteries will list the indefinate and the burst(10seconds), it may apear like 35/45C or 45-90C
there is also the charge C rating on the back(usually) of the battery, this will tell you how many amps it can be charged at. a 5000mah battery with a 1C charge can be charged at 5amps MAX, a 2C can be charged at 10amps, a 10C (like some nanotech) could be charged at 50amps.
the vehicle will determine how much electricity to discharge from the packs, a battery only dumps max power when direct shorted (crossing the wires).
to measure the draw of your electronics hook up a 30C battery to them and measure the amps being drawn when you hit full power with full load on the drive wheels(driving on the ground) to do this easily, get a nice (mine is made by goldstar and was $400) multimeter with a min-max read feature, tape it to the car and gun it.
a mamba monster/HPI Flux system draws about 154amps or just under 35C for example.
if your ESC is rated at 100amps never run less than 25C, 150amps, never run less than 30C, 75-90amps never under 20C
a higher C rating doesn't mean faster if the lesser C rate battery had a higher C rating than the ESC in the first place, as it would provide full draw easily.
a 75amp ESC will not draw more power from an 50C battery than a 25C battery, as the 25C battery is more than capable of delivering 75amps. in this case the 50C battery will NOT be faster than the 25C. but it would be faster than a 15C, as the 15C would not deliver 75amps very effectively.
higher C rated battery=cooler battery, and ESC, safer battery(no swelling/no explosions), and longer life from battery(not being abused chemically from discharge... the way you balance and charge it is another story)
... sorry if the post is a bit 'here and there' ... A.D.H.D. means that i don't really pick an choose what info comes out.. and an extreme understanding of the subject means the lucky bits that do come out are a very small and random selection from a much much larger available selection stuck between my ears. as i'm trying to switch medication, i tried to read my own post to see if i accurately answered your questions. . but found it very difficult and couldn't. go figure.
if you need more info,ask again and i'll try again in the morning. (2:54am and i'm starting to bug out a bit)
cheers, all.
Phil.
#6
Batteries can usually be charged higher than what they are listed at.
#7
Tech Regular
This topic drives me nuts as there seems to be no definitive answer. I asked a similar question last week and was told that a higher C-rated battery will give better performance than a lower C-rated battery even if the lower rated battery can supply the max current the ESC can handle. I was told it is because of the battery's lower IR that allows the motor to pull the current easier and thus more power.
Which is it?
Which is it?
#8
Tech Champion
Know what you are saying, this discussion recurs regularly. All I can offer is in general those who suggest it doesn’t matter typically only offer C based amperage limits to support the position. Those who suggest it does matter generally offer on track experience as well as other ways to measure battery performance, including at lower amp draws, such as internal resistance and voltage under load.
I do believe there is a practical limit however, from what I have seen there is diminishing benefits after about 40C, for typical stock-spec 1/10 offroad buggies and trucks.
Thought this post described it well, in a nice simple way:
I do believe there is a practical limit however, from what I have seen there is diminishing benefits after about 40C, for typical stock-spec 1/10 offroad buggies and trucks.
Thought this post described it well, in a nice simple way:
Last edited by Dave H; 10-05-2010 at 08:37 AM.
#9
Tech Champion
Whether it's a worthwhile benefit is for each to decide, but there are small but distinct differences.
Also worth mentioning that in modifed, some use a lower C battery to reduce punch, to make the car easier to drive.
Last edited by Dave H; 10-05-2010 at 08:41 AM.
#10
higher c-rated batteries will give you more punch
#11
Super Moderator
iTrader: (31)
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Location: RIP 'Chopper', 4/18/13 miss you bud:(
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Know what you are saying, this discussion recurs regularly. All I can offer is in general those who say it doesn’t matter typically only offer C based amperage limits to support the position. Those who say it does matter generally offer on track experience as well as other ways to measure battery performance, including at lower amp draws, such as internal resistance and voltage under load.
I do believe there is a practical limit however, from what I have seen there is diminishing benefits after about 40C, for typical stock-spec 1/10 offroad buggies and trucks.
Thought this post described it well, in a nice simple way:
I do believe there is a practical limit however, from what I have seen there is diminishing benefits after about 40C, for typical stock-spec 1/10 offroad buggies and trucks.
Thought this post described it well, in a nice simple way:
Not need really, but there is a benefit to higher C ratings for stock-spec classes. High C batteries have to have low internal resistance to achieve the high dicharge rates without burning up. The low internal resistance results in higher voltage under load, even under moderate loads. Bottom line, more acceleration/punch, and slightly higher top speed.
Whether it's a worthwhile benefit is for each to decide, but there are small but distinct differences.
Whether it's a worthwhile benefit is for each to decide, but there are small but distinct differences.
#12
Super Moderator
iTrader: (31)
Join Date: Nov 2008
Location: RIP 'Chopper', 4/18/13 miss you bud:(
Posts: 15,473
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C rating is the capable discharge of the battery while remaining under ~140*F
most batteries will list the indefinate and the burst(10seconds), it may apear like 35/45C or 45-90C
there is also the charge C rating on the back(usually) of the battery, this will tell you how many amps it can be charged at. a 5000mah battery with a 1C charge can be charged at 5amps MAX, a 2C can be charged at 10amps, a 10C (like some nanotech) could be charged at 50amps.
the vehicle will determine how much electricity to discharge from the packs, a battery only dumps max power when direct shorted (crossing the wires).
to measure the draw of your electronics hook up a 30C battery to them and measure the amps being drawn when you hit full power with full load on the drive wheels(driving on the ground) to do this easily, get a nice (mine is made by goldstar and was $400) multimeter with a min-max read feature, tape it to the car and gun it.
a mamba monster/HPI Flux system draws about 154amps or just under 35C for example.
if your ESC is rated at 100amps never run less than 25C, 150amps, never run less than 30C, 75-90amps never under 20C
a higher C rating doesn't mean faster if the lesser C rate battery had a higher C rating than the ESC in the first place, as it would provide full draw easily.
a 75amp ESC will not draw more power from an 50C battery than a 25C battery, as the 25C battery is more than capable of delivering 75amps. in this case the 50C battery will NOT be faster than the 25C. but it would be faster than a 15C, as the 15C would not deliver 75amps very effectively.higher C rated battery=cooler battery, and ESC, safer battery(no swelling/no explosions), and longer life from battery(not being abused chemically from discharge... the way you balance and charge it is another story)
... sorry if the post is a bit 'here and there' ... A.D.H.D. means that i don't really pick an choose what info comes out.. and an extreme understanding of the subject means the lucky bits that do come out are a very small and random selection from a much much larger available selection stuck between my ears. as i'm trying to switch medication, i tried to read my own post to see if i accurately answered your questions. . but found it very difficult and couldn't. go figure.
if you need more info,ask again and i'll try again in the morning. (2:54am and i'm starting to bug out a bit)
cheers, all.
Phil.
most batteries will list the indefinate and the burst(10seconds), it may apear like 35/45C or 45-90C
there is also the charge C rating on the back(usually) of the battery, this will tell you how many amps it can be charged at. a 5000mah battery with a 1C charge can be charged at 5amps MAX, a 2C can be charged at 10amps, a 10C (like some nanotech) could be charged at 50amps.
the vehicle will determine how much electricity to discharge from the packs, a battery only dumps max power when direct shorted (crossing the wires).
to measure the draw of your electronics hook up a 30C battery to them and measure the amps being drawn when you hit full power with full load on the drive wheels(driving on the ground) to do this easily, get a nice (mine is made by goldstar and was $400) multimeter with a min-max read feature, tape it to the car and gun it.
a mamba monster/HPI Flux system draws about 154amps or just under 35C for example.
if your ESC is rated at 100amps never run less than 25C, 150amps, never run less than 30C, 75-90amps never under 20C
a higher C rating doesn't mean faster if the lesser C rate battery had a higher C rating than the ESC in the first place, as it would provide full draw easily.
a 75amp ESC will not draw more power from an 50C battery than a 25C battery, as the 25C battery is more than capable of delivering 75amps. in this case the 50C battery will NOT be faster than the 25C. but it would be faster than a 15C, as the 15C would not deliver 75amps very effectively.higher C rated battery=cooler battery, and ESC, safer battery(no swelling/no explosions), and longer life from battery(not being abused chemically from discharge... the way you balance and charge it is another story)
... sorry if the post is a bit 'here and there' ... A.D.H.D. means that i don't really pick an choose what info comes out.. and an extreme understanding of the subject means the lucky bits that do come out are a very small and random selection from a much much larger available selection stuck between my ears. as i'm trying to switch medication, i tried to read my own post to see if i accurately answered your questions. . but found it very difficult and couldn't. go figure.
if you need more info,ask again and i'll try again in the morning. (2:54am and i'm starting to bug out a bit)
cheers, all.
Phil.
In your case with the Savage you may make a valid point but it's off base from the OP and IMO you'll just confuse him and others......
#13
Tech Apprentice
The OP has a completly different situation than your Savage. A BL 13.5 in a 1/10 truck is never going to pull those kind of amps, thus the esc has no effect on or issue when looking at the C rating of a battery. The esc's max amp/current limit is ONLY an issue when you have a motor that can pull big amp numbers like your savage can. 99% of the time in 1/10 scale the esc is never going to be an issue when looking at amps and current draw.
In your case with the Savage you may make a valid point but it's off base from the OP and IMO you'll just confuse him and others......
In your case with the Savage you may make a valid point but it's off base from the OP and IMO you'll just confuse him and others......
uh,, i don't own a savage. lol where are you getting tht i'm talking about a savage from?
i'm talking in general.
FOR THE GUY WHO SAID BATTERIES CAN USUALLY BE CHARGED HIGHER THAN THE SAFETY LABEL ON THE BACK OF THE PACK... DON'T TELL PEOPLE THAT.
... yeah all capital letters... Lipo over amped=fire. that is a serious serious safety issue. you can hurt yourself, burn your car or house down. if your insurance finds out you were charging a Lipo, your insurance will not cover the damage... they'll instantly know there was no firebag and in the case of either a car fire or house, that is between $1000-$1000000 damage. don't forget it's often insurance who pays for the fire dept. no insurance, that's out of pocket in some cases, $250k-$3million.
if your house burns the neighbours house,, you're in a pant load of trouble, if your car is next to another and it burns, again... trouble.
.. think i'm lying, go ahead, but every year my ol man has been trying to keep a straight face when he see's the lipo in the burning wreckage. for over 20yrs he's been having to tell people their insurance isn't going to cover all sorts of f' ups. Lipo's are one of them, and it's why insurance companies pitch in on the costs for fire cheifs and marshalls to get the best in forensic reporting. (saves them money on VOID claims.)
Often a Lipo will not even charge equally (in ballance) when put over 1C, never mind over the tested safe limit. the higher the charge, the faster and greater the balance change will be, if you're not using an intellegent balance charger, you're f'd. one bad cell and fire. 50% of all people are using chargers that cannot detect an over volt on an individual cell. and almost all of those chargers will allow the cell to hit 4.30v before shuting down the charge current and balancing back to <0.03v , this greatly shortens the life of the cell(s) in question and can chemical change the internal resistance of the cell, causing it to grow further out of match each time, once teh process has started inside, then just charging and discharing at even just trickle 0.5amps will continue to break down the poly inside the cell(s).
this is how perfectly good packs only last a couple cycles, user error. this is why fires are started, this is how your $1000 car turns into a ball of flame on the back straight of the track.(got r/c insurance.. lol.. still would be void).
i'm sorry to rant on, but this is a serious issue. but i spend alot of my time relocating affected families from fires, trying to find them a motel for a month, trying to get them some clothes to wear, even just shoes, or a winter coat. nevermind just trying to talk to people who've lost evryting.. family almbum, jewelery, computers with all their data, the family car that was in the garage, toys, everything.
PLEASE NEVER EVER charge over the C rating on the battery, doing so isn't worth it and you only wreck the pack faster. it's called GREED, and it's a sin for a reason (no i'm not religious, but religion is mostly based on good ideas)
-------------------
BACK ON TOPIC:
a C rating of higher than 15 more than what your ESC is even capable of drawing constantly is the maximum performing battery you can use. anything higher is just a waist. if you're worried about how much PUNCH you're going to get, always buy the battery that will give you the most punch for the highest power vehicle you own, and you'll have maximum power with all of them.
maximum performance is as follows,
2S-3S (VXL/Sidewinder/Mamba, etc)= 35~40C .... (20-30C recommended)
3S-4S (Mamba pro, Ezrun, etc)= 40~45C .... (25-35C recommened)
5S-7S (Monster, ezrun, turnigy, 150-200amp etc)= 50~65C .... (35-45C recommended)
anything higher in those is a waist, even 5C less than the max will still give you 98% of the max. there is a very small difference once you get above 5C more than the ESC can draw... 10C less will give you 92-97% of the MAX.
as i've said in many many posts all over the forums before, the C rating is what the pack is rated to be able to be capable of discharging while staying at a safe temperature (below 140*F). having a battery that can safely discharge constantly at the maximum the ESC is even capable of discharging is fine, as the burst capabilities are even higher (burst is for the first 8~12seconds) , for offroad racing you will never burst your throttle more than 8~12seconds.. ever. not even on the half a kilometer track at muskoka madtrax's (largest track in canada) where you can easily hit 120km/h if your car is capable.
getting a higher C than your ESC needs just insures that your battery will stay cool, will have a longer life, will not amplify any factory defects in cell chemistry, and 0-5% less resistance.. and peole forget how fast electrons actually move, even at 20% higher resistance in a lipo pack that only translates to the first eigth ~ third of a second of acceleration(depending on torgue required to move the vehicle). granted the first half second triggers a ripple effect. but in most cases it's negligible. Driver skill and straighline braking makes up more of a variable.
.. i hope this clears up some misconceptions about C ratings, savages(i own a vorza).. and stops anyone from listening to people who say you can ignore safety labels.
Cheers, eh!
phil v.
#15
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My bad, was reading your novel and saw the HPI Flux chapter and made the Savage connection. In the end are you telling me that with a 1/10 scale and a 17.5 for example I'm not going to see a difference between a 20C pack and say a 40C pack? (both being = mah)
Last edited by racer1812; 10-05-2010 at 11:34 PM. Reason: I'll be nice....