Lipo C ratings

[Cardnim]

Hi guys,
My old battery puffed up and is now useless, so I have now only one Lipo left so I am going to buy another.
But before I do, is the C rating important?

My old batt:
7.4v
5400mAH
45C

My new batt:
7.4v
5000mAH
55C

Was my car jsut too powerful for the old 45C and therefore it puffed up and went bang? If so, then I dont want to waste my money, buy a new battery and have the same thing happen.

My problem is you see that I need a lipo battery with "feet" on the hardcase, and the only ones Speed Power (the company I want to use) do with feet are 45C.
Do I need to get 55C batteries? :confused::confused::confused:

Thanks!

[leeleefocus]

If the c rating they have given it is an honest rating then yes a 45c 5000mah battery is way more than you'll ever need. The only problem is that C Ratings are not always honest and the only way to find. this out is to buy and test the battery.

[Cardnim]

Really? Bummer.
Thats alot of money to fork out only to find it puffs up and goes pop. :(

(Does someone want to lend me a 45C till I test it? hehehehe. )

Not sure what to do now. Lipo info seems to be 5% fact and 95% heresay and personal opinion. Not very scientific. That CANT just be the way it is, can it?

[JustARcFan]

If you buy a good quality lipo I'm sure you will be fine.

[Cardnim]

Thanks guys.
Im buying another Speed Power direct from their factory in Hong Kong (£42 delivered cant be bad!!) so I'll go with that and get the 45C.

Thanks for all your help. :)

[woody_woody]

as long as you dont use a esc that draws more than then the lipo can give yu will be fine

[Cardnim]

Thanks woody - but this the thing - how the frig do you know what the esc draws and what the batt can give?!?!? ARGH. I just order my batt so I dont want to have just thrown my money away!!

[JustARcFan]

What motor are you running and which esc do you have?

[Cardnim]

Thanks for the assist.

Here's my setup:
Speed Passion GT2.0 (LPF) esc
Speed Passion v.3 6.5t motor

If it helps, here are the web pages for the motor and esc.
http://www.speedpassion.net/en/productDetails.asp?p=13865V3&c=MTR

http://www.speedpassion.net/en/productDetails.asp?p=EXT98802LPFb&c=ESC

Thanks.

[JustARcFan]

I have the same set up in 1 of my cars and it's a good combo.

I'm 100% sure you will be fine with your Speed power lipo's.

They are very very good and will last for a long time if you take care of them.

[Cardnim]

Thanks so much RcFan - really appreciate the help and advice - and everyone else who helped out.

Ta muchly :)

[Richard Lowe]

Don't worry too much about the quoted C rating of lipo's these day, they're all good enough :)
It was only in the early days of the gold Trakpower's when the ratings were down aboun the 20c mark it made much difference.

[Cardnim]

Cheers Richard, thats good to know. :)
Thanks for the help.

[blue_pinky]

Some simple facts about lipo's:

1) The C rating is a way to calculate the continuous current that the battery is able to supply, when/if asked by an esc. C rating x Capacity = Continous current draw available.

2) You could put pretty much ANY C rated battery in your car with ANY esc (with a lipo/low voltage cutoff) and it would be fine if used properly!

With lower C rated battery your car is just slower, and won't run for as long. The C rating of the battery indicates the limit to it's current delivery to the ESC when asked. Even a 10C battery would be totally fine with the highest power rated ESC known to man...it'd just be slower, and won't last very long!

3) Lipo's only puff up when they are damaged. There are many possible reasons for this. A few suggestions might be: because it's been over discharged, over charged, charged incorrectly, old and worn out, connected up to your esc incorrectly, shorted out or has a manufacturing defect of some sort.

The original post asked if the car was just too powerful? Simple answer...NO!

The battery is the power source! Your car is only as powerful as the battery. Your ESC and motor can only use as much power as your battery lets them have, they will just handle it better the higher rated they are.

But...if your batteries are too big for your ESC and motor, you could damage your esc and motor! And if your battery is too high powered for you to drive, you'll damage your car!!! ;) But since all the racing ESC's/motors/lipo's are designed to work with each other, as long as you use them right they'll be fine...it's not as dark an art as it might appear!

Hope it helps :thumbsup:

[Cardnim]

Awesome post Blue; that sounds like the type of scientific answer on Lipos that I knew had to be out on Tinternet somewhere! Thank you.

Sounds like my battery that puffed up was old an dworn out, as it certainly wasnt over discharged/charged and it was always charged correctly. Thanks for clearing that up!

...and yes, I guess you have seen me drive. Too fast = me damaging my car.

In fact, my batt has just bleeped to tell me its charged again, so its off to break something else! Awesome. :p

Thanks again.

[blue_pinky]

Hehe...no worries, happy to help! Enjoy :D

(I suffer from the too fast thing too!!! All those big numbers are just too tempting :lol:)

[bigred5765]

Thanks woody - but this the thing - how the frig do you know what the esc draws and what the batt can give?!?!? ARGH. I just order my batt so I dont want to have just thrown my money away!!

simple answer is that doesnt matter if u run a 25c lipo or a 50c lipo you cant damage it buy your car being to powerfull for the lipo, thats not how it works, it will just make the car seem only slightly slower or slightly faster, ur car used under normal condition can never damage ur lipo,usualy bad charging or miss use is what damages them

[mark christopher]

i dont agree with some of the comments here

if my motor and speedo can draw100 amps and my 20 c lipo can supply75 amps from its c rating my speedo will try to draw max power it can so the lipo is under max load during that time
i agree it will just show as low power on the track and seem flat.

now if my 40 c pack can supply 150 amps my speedo will be able to draw its 100amps BUT the lipo is only being pushed to a third of its capability, so as its under less load and strain it will definatly last longer

over straining lipo will damage them long term