QUADIFYRC MODS AND REVIEWS
  • RC Cars
  • Car of the Month
  • Quad Reviews
  • Quad Mods
  • COUPONS AND DISCOUNTS
  • Long Range
  • About & Contact

QUADIFYRC RC Car Review and Upgrade Guides

UNderstanding Lipo "C" Ratings for RC Cars (plus voltage and Capacity)

28/7/2020

11 Comments

 
Lithium Polymer (Lipo) battery technology has been perhaps the best leap of technology in the RC world. The relatively high energy density and absurdly high continuous current capability has meant that quadcopters have become a viable hobby and electric RC cars can now outperform their Nitro cousins without most of the fuss.
Picture
Voltage as measured in volts (v)
A single lipo cells has a maximum charge voltage of 4.2v which is usually reported as 3.7v for real-world purposes. Voltage can be increased by connecting these cells in series (s for series) and is reported as 1s (1 cell in series), 2s (2 cells in series) 3s (3 cells in series and so on). Voltage is additive when cells are placed in series i.e. 1s = 3.7v, 2s = 7.4v, 3s = 11.1v and so on.
Capacity as measured in milli Amp hours (mAh)
Lipo cells can vary in capacity, these are measured in mah and signify the amount of 'fuel' the lipo battery can output before it is depleted. All else being equal the larger the capacity they larger the physical size and mass (weight).
C - Rating
Where voltage and capacity are simple physical parameters, C-rating is slightly more complex. It is closely tied to capacity and has no relationship to voltage. In short the C rating signifies the maximum continuous output that the battery can maintain. Strictly speaking the C value multiplied by the capacity is the maximum continuous current output which we measure in Amps. The best way to describe this is to give examples:
  • 1500mah battery x 30C = 45,000mA = 45 Amps maximum continuous output.
  • 1500mah battery x 60C = 90,000mA = 90 Amps maximum continuous output.
  • 3000mah battery x 30C = 90,000mA = 90 Amps maximum continuous output
So it's interesting to see from above that increase Capacity has a similar effect to sticking with the same size and increase C-rating.
Picture
The stock 1500mah 25C battery from the WL toys 144001 can theoretically allow 37.5 Amps
Picture
This 144001 upgrade battery with larger capacity is also 25C but the larger 2600mah capacity means it can theoretically allow up to 65 Amps
Picture
Quadcopter batteries tend to have higher C ratings. Although this CNHL Black 4s 1500mah battery has 4 cells, I have split it to 2 x 2s batteries that I use with my 144001. 1500mah @ 100C will theoretically allow up to 150 Amps continuous which I have seen on these.
Will a battery with a larger c-rating push more amps to my ESC?
This is a misunderstanding I see a lot. Batteries don't push current, current is demanded from them by the circuit in question, in our case the ESC/motor (much less so for the servo). The only way a larger C-rated battery will make your car go faster or put too much current to your ESC is if the current battery is a bottle-neck. Without measuring equipment the easiest way to see if your battery is the bottleneck is if it is warm or hot after running. As you can probably figure the battery in this case is being pushed to its limits and this is where the performance of your battery can start to diminish. If this is the case and the new larger or higher-C battery can supply more power to your motor/ESC then you should get more power and hopefully not overload the ESC (or motor). Personally I'd rather have an over specced battery and limit throttle/punch on my ESC to have more consistent control and operate within system capability.
Picture
The stock ESC for the 144001 does not have a published rating but my best guess is around 40 Amps. Update: It's actually 60 Amps - thanks Richard Dzidek. This means that realistically a battery with a higher c rating and or capacity than stock should give you a little more punch on heavy acceleration
Picture
The ESC on my favourite 2838 brushless combo for the 144001 (see upgrade guide here) is rated for 35 Amps only meaning the stock battery will also perform just fine. Another reason I like this combo for upgrading so much
Picture
Soon I'll be pairing this big Flycolor 80A ESC with a large, high KV motor for speed runs. The stock battery with 37.5 Amps max continuous current is well below this. To avoid being the bottleneck I'll need to go to a battery with a larger c-rating and/or larger capacity. In reality I'll go both to give me a big overhead.
Hopefully this helps you understand things a little better and at least gives you a good starting point. One thing to be wary of is that C-ratings can be used as a bit of a marketing tool so since the concept is a little more obtuse - I'd recommend comparing within a brand but not so much between brands. Overall RC cars are not as demanding on lipo batteries as quadcopters so you can see there is more wiggle room. If you must have the best batteries Gaoneng (GNB) batteries are probably the best commonly available ones from the demanding quadcopter world with CNHL in second.
If you found this helpful also check out my article on upgrading your charger for RC car batteries
Thanks for reading, if you found this article useful please feel free to like or share, the facebook links below directly link/like this article. Links are affiliated and help me buy the bits I need to produce this type of content. If you are looking for RC ​cars, quads or parts check out my coupons and discounts page which I keep updated with only the RC cars, parts and quads I like at a proper discount
11 Comments
Dave
15/10/2020 06:32:39 am

Hello hows it going what would be the burst rate on a continuous 35c 2200mAh 2s battery cheers

Reply
QuadifyRC
15/10/2020 09:07:30 am

Hey Dave, It's going great! Burst rate = 35c x 2200mah = 77000mah = 77A. That is plenty for most setups. FYI it's 855W which is just over 1 horsepower at full noise

Reply
Daniel
16/2/2021 11:08:24 pm

855 Watt @ 3S 😉
Dave have a 2S Battery.
So the battery can deliver 647 Watt at 2S 🙂

QuadifyRC
16/2/2021 11:21:44 pm

🤦‍♂️ Daniel is correct on the wattage below, I'm too used to seeing 2200mah batteries in 3s

Neil
17/2/2021 10:33:17 am

Excellent right up, most of what you have written I had a basic understanding of after much research myself, but this explains it so well, however just one question, you mention you'd Personally rather have an over specced battery (which I understand) and limit throttle/punch on my ESC to have more consistent control and operate within system capability. Could you elaborate a little on what you mean by "limit throttle/punch on Esc?

Reply
QuadifyRC
1/3/2021 09:23:09 am

Sorry for the late response, I'm having notification issues. This should explain: https://www.quadifyrc.com/rccarreviews/better-brushless-esc-control-budget-program-card-for-racerstar-surpass-goolrc

Reply
Paul Van den bogaard
1/3/2021 07:48:56 am

Im running on stock motor with a stock 2200mah batt. If im gonna buy a lager batt with a higher c rating. What mah/c-rating should i get to run without problems? For example a 4000mah 50c?

Reply
QuadifyRC
1/3/2021 09:26:43 am

Hi Paul

I assume you are talking about the 124019 or 144001? In that case size is limited by physical dimensions - what will fit in the tray under the body. My recommendation is that the 2200 battery from the 124018 and 124019 is actually very good and has the right connectors - just get more of the same.

Remember if you were able to get your wish of a massive battery and long runtime, the motor and ESC will get that much hotter. Best way to get longer runtime is a lightweight brushless setup but that is quite a commitment.

Reply
Samuel Scholey
23/11/2021 09:44:48 am

Hello, I have just ordered the parts for your cheap 144001 brushless upgrade.
-DumboRC X6
-Surpass 35A ESC
-Surpass 2445-3600Kv Motor
-Surpass 17G servo
-15T gear

Im very new to RC and its sometimes a lot to take in from the articles. Can I upgrade my battery and what battery is best? Will this damage the ESC if I don't get the correct one. (I'm going for 2S)

Reply
QuadifyRC
10/12/2021 12:48:11 pm

Awesome! To be honest your stock battery will do just fine here as this brushless motor is way more efficient. You will have a lot of fun with this setup. If you really want you can go to the 124019 2200mah battery for a bit more runtime but I have a car setup like this one you have here and it is brilliant with the stock batt.

Reply
Iain Langley
18/2/2022 09:21:55 pm

Hi,
Great write up.

I am about to buy a HBX 901a. They come with a 1600mah 2s, no idea what the stock battery C rating is though. The stock ESC shows as 35amps on the product spec page.

I was going to buy of these 2 1600mah 2s 35c lipos from Amazon, https://amzn.to/3rYuaba, which I assume will suit the car fine? (please tell me if i'm wrong).

Would I be able to run 2 of the above lipos in parallel using an adapter, giving me (in theory) a 3200mah 2s?

What affect on the amps does running them in parallel have? 1 of the above batteries looks to provide 56 amps, so would running them in parallel then provide 112amps? If so, would this be safe in the 901a?

Thanks and sorry for the huge pile of questions! Keep up the great work.

Reply



Leave a Reply.

    Archives

    November 2022
    October 2022
    September 2022
    August 2022
    July 2022
    June 2022
    May 2022
    April 2022
    March 2022
    February 2022
    January 2022
    December 2021
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020

    Categories

    All
    104001
    104002
    104009
    104072
    1/10
    124016
    124017
    124018
    124019
    144001
    144002
    144010
    16886
    16889a Pro
    184016
    284131
    4s
    4 Things
    Anti Roll Bars
    Balance
    Basher
    Battery
    Brushless
    C24
    Charging
    Cogging
    Crawler
    D22
    D32
    Diatone
    Diatone Q25
    Drift
    Drop In
    Dumborc
    Eachine EAT14
    Eachine EC30
    Eachine EC30B
    EMB-MT
    Ex07
    Ex16
    Flyhal
    Flysky FS-G7P
    Flysky Noble Pro
    FMS
    FPV Car
    Goolrc
    Guide
    Gyro
    HBX
    Hbx 901a
    HS10422
    K989
    LC12B1
    LC Racing
    Lipo
    Metal Parts
    Micro
    MJX Hyper Go
    Monster Truck
    Mx-07
    Pinion
    Preview
    Program Card
    Project WLCRacing
    Q33
    Racerstar
    Radiolink RC6GS V3
    RC Boat
    Review
    ROCHobby
    Setup
    Sg 1602
    SG 1603
    SG 1604
    Soldering
    Spectre
    Speed Run
    Stance
    Surpass Hobby
    Timing
    Transmitter
    Tuning
    Tyres
    Upgrade
    Vinyl
    Wheels
    WL916
    Wltoys
    WL Toys
    Wpl
    Zd Racing

    RSS Feed

Thanks for visiting QuadifyRC.com Follow us on facebook below to get all the latest updates
  • RC Cars
  • Car of the Month
  • Quad Reviews
  • Quad Mods
  • COUPONS AND DISCOUNTS
  • Long Range
  • About & Contact