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Correct batteries for my RC truck

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Correct batteries for my RC truck

Old 01-02-2021, 08:14 PM
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Asuarez23
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Default Correct batteries for my RC truck

Hello,

I have a Redcat Volcano EXP PRO and I purchased these batteries for it (100C 5200mAh 7.4V LiPo Battery 2S Deans Hardcase for RC Car Truck Helicopter). Are they okay to use in my stock RC?

Thanks
Andrew
Old 01-05-2021, 01:30 PM
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jester_s1
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If the battery fits in the truck, it will be fine. If the truck has a slipper clutch, I'd make sure it's loose enough to not break anything. That battery is going to add significant weight and some extra power to the truck, both of which stress the drivetrain more.
Old 01-06-2021, 02:06 PM
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If the battery fits in the truck, it will be fine.
That's a good start.
That battery is going to add significant weight and some extra power to the truck, both of which stress the drivetrain more.
Weight? Yes. Power? No
The stock battery is a 7.2v (2S) LiPo and it's being replaced with a 7.2v (2S) LiPo, so there will be no additional "power".
But, the 5200mAh pack will get you longer running times due to the extra capacity (5200mAh vs. 3500mAh). Keep in mind that due to the extra weight of the 5200mAh pack, it may not be as much extra running time as you expect.

The capacity of a LiPo is like a gas tank in a car.
A 5.2gal gas tank will take your car farther than a 3.5gal gas tank when they both start out full of gas.
But the extra gas in the full 5.2gal tank adds weight. And the extra capacity in the tank does nothing to make the car faster.

The C-rating of the battery is pure BS.
And even if the "magic" 100C LiPo pack was capable of delivering 520A of sustained current, it is up to the ESC and motor to be able to use it.
So, assuming the supplied 3500mAh 15C pack isn't hot to the touch after a run, you are not stressing that 3500mAh 15C battery anyway and you gain nothing with a "magic" 100C 2S LiPo in terms of adding performance.

Also keep in mind that as in any racing application, lighter is always better.
With LiPo batteries, "lighter" generally equals lower capacity (and shorter running times). But the a lighter truck will accelerate faster, stop shorter and corner better with a lighter battery. And, a lighter truck doesn't sustain as much damage when running around and crashing.
However, while you will get longer running times with the 5200mAh pack, it may become a pig on the course.
Are they okay to use in my stock RC?
Sure. I hope you don't pay too much for them while also expecting a big upgrade.

Last edited by ticedoff8; 01-06-2021 at 02:26 PM.
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Old 01-09-2021, 09:22 AM
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jester_s1
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If the new battery has less internal resistance, there will indeed be a power increase. The new battery both has more capacity and is a better quality battery, which means it will hold voltage under load better and therefore increase the power output of the motor. Some of that power will be used to accelerate the heavier weight of the truck, so the driver may not see a performance increase. But the drivetrain will most definitely see more torque and more stress, hence my recommendation to check the slipper clutch adjustment.
Old 01-10-2021, 11:09 AM
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If the new battery has less internal resistance, there will indeed be a power increase.
That is not accurate.
That's why I had this comment:
The C-rating of the battery is pure BS.
And even if the "magic" 100C LiPo pack was capable of delivering 520A of sustained current, it is up to the ESC and motor to be able to use it.
So, assuming the supplied 3500mAh 15C pack isn't hot to the touch after a run, you are not stressing that 3500mAh 15C battery anyway and you gain nothing with a "magic" 100C 2S LiPo in terms of adding performance.

#1 - There is no RC hobby grade LiPo battery sold by any distributer that can deliver 100C.
Read this thread on RCG: "
Battery Load Test Comparisons UPDATED 12/2020" It has (literally) 8 years of research and data on RC hobby grade batteries and their actual, real life, tested capabilities. There are only some that come close to their labels and none of them are labeled "100C"
Fundamentally, IR is the prime factor in determining the pack's ability to get close to the labeled rating.
IMHO: If a distributor labels their 2S 5200mAh pack as "100C" (520A) - it is pure BS and I would assume their IR is so high that it would test out as a 10C or worse discharge rate.

#2 - On top of that, if the truck's existing ESC, motor, transmission, diff, tires (etc) were capable of pulling close to 52A (3500mAh x 15C), then the stock 3500mAh LiPo pack would be hot at the end of a run. If it is cool to the touch, that means the drive system is pulling much less than 52A out of the pack.

So, again: IMHO, the "magic" 100C 5200mAh packs is not worth the weight or the money.

Last edited by ticedoff8; 01-10-2021 at 11:12 AM.
Old 01-12-2021, 08:33 AM
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jester_s1
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It's true no system pulls that kind of power. It's also true that C ratings don't mean much. They can be a way to compare batteries within a brand, but that's about it.
I'll stand by the advice to make sure the slipper gives a little when he punches the throttle.
Old 01-14-2021, 11:42 PM
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The C rating is important when comparing packs, but the real problem is that manufacturers (mostly those of the economy packs) overstate it's meaning for marketing purposes. Many people pay more attention to the C rating without considering the total amperage or wattage that battery can supply. I don't buy that the battery the OP listed is a true 100C constant. A burst rating maybe but even then that's gimmicky.

Old 01-15-2021, 09:52 AM
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At an actual amp draw of 100C, the battery would be fully depleted in just a tick over 30 seconds. No one uses their battery packs that hard.
Old 01-16-2021, 02:31 PM
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Hello, thanks to you all for your answers and explanations, it personally helped me a lot.
Old 01-16-2021, 08:38 PM
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Even as hard as anyone could push their vehicles I don't believe that any RC power system could draw 520A. That's what starts your car in the morning.

All I'm saying is that it's best to know the wattage of your motor and be sure you have enough available power from your battery to feed it. Often times manufacturers don't list the wattage; they'll state Amp draw. Most hobbyists don't consider motor power or current draw. They think "I need at least a 25C because that's what I heard you need." If you go one step further and check the specs on your motor and find its current rating then you can size your battery based on the known current demand of the motor.
Old 01-19-2021, 08:26 AM
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jester_s1
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As stated above, C ratings can be useful in comparing battery packs within a manufacturer, but there's nothing absolute about them. If I'm buying some Gens Ace packs, their 45C will give me a few more amps than their 20C pack does for the same capacity. But a high quality 20C pack will probably outperform a cheap 60C.
Old 01-22-2021, 02:29 PM
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If I'm buying some Gens Ace packs, their 45C will give me a few more amps than their 20C pack does for the same capacity. But a high quality 20C pack will probably outperform a cheap 60C.
Why do you make either one of those assumptions?
Gens Ace / Tattu don't post their independently verified C-Rating test results for each of their batches of battery packs they distribute.
I test every pack I get with a LiPo ERS Meter Mark II. Either this one or the Wayne Giles LiPo ESR Meter are pretty much the gold standards for "at home" reading of the real C-Rating for any LiPo back. I've never had a battery whose C-Rating tested better than what was printed on the label.
That includes Gens Ace 6S 3300mAh "60C" packs (real C-Rating < 20C) and generic 2S 2200mAh 20C receiver packs (real C-rating < 10).
If you accept that the C-Rating printed on any label is a lie, then you have to accept that it is useless for comparing batteries.
Old 01-22-2021, 05:02 PM
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That's what I was suggesting in my earlier post that it seems to me that the C rating is overemphasized for marketing. Meaning that not only can a manufacturer sell a battery of higher capacity for more money but, also a battery which has a higher C rating on it's label. Unless you have equipment to bench test a battery there is no way to verify how accurate its rating information is. I hear stories of people buying really cheap LiPo packs on Amazon or eBay; say a 6000mAh pack but they experience no great increase in runtime. Maybe they aren't truly 6000mAh or possibly of inferior quality.

In my experience when I run a battery manufactured by a "popular brand" like Dynamite, Venom, ProTek and TrakPower I generally felt that the run time of same sized packs was greater than a "cheap brand." Maybe I'm lucky but I have 10 year old Dynamite and Venom packs in my collection that work very well and have not swelled; but I've had 2 Turnigy packs and an unknown brand puff and eventually stop holding charge which were less than half as old as the Dynamite and Venoms.
Old 01-25-2021, 11:58 AM
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hat's what I was suggesting in my earlier post that it seems to me that the C rating is overemphasized for marketing. Meaning that not only can a manufacturer sell a battery of higher capacity for more money but, also a battery which has a higher C rating on it's label. Unless you have equipment to bench test a battery there is no way to verify how accurate its rating information is. I hear stories of people buying really cheap LiPo packs on Amazon or eBay; say a 6000mAh pack but they experience no great increase in runtime. Maybe they aren't truly 6000mAh or possibly of inferior quality.

In my experience when I run a battery manufactured by a "popular brand" like Dynamite, Venom, ProTek and TrakPower I generally felt that the run time of same sized packs was greater than a "cheap brand." Maybe I'm lucky but I have 10 year old Dynamite and Venom packs in my collection that work very well and have not swelled; but I've had 2 Turnigy packs and an unknown brand puff and eventually stop holding charge which were less than half as old as the Dynamite and Venoms.

You may have a misunderstanding of what "C Rating" vs "Capacity" means.
Or, I may have misunderstood your reply.
If the battery is labeled "6000mAh" that is capacity. Capacity is basically "How much fuel is in the tank" and translates (all things still being equal) to how long / how far you can go on each charge.
EG: A fully charged (4.2v LiPo per cell) pack rated at 6000mAh (milliamps per Hour) will support a 6A load (6,000milliamps) for 1 hour before the cell's voltages drop into the "unsafe" zone (about 3.3v per cell). That is literally "1C" and that is something that is pretty easy to check.
In general, cell manufacturer's spec sheets will be relatively accurate regarding capacity. And, the pack distributors know that capacity is something they will easily get caught cheating on, so they tend to stick to the manufacturer's spec sheets on that.
EG: If you buy a 6000mAh pack and repeatedly only get 4000mA out of it, you will ask for a warrantee replacement.

However, C-Rating measures how quickly the cell can be discharged without permanent damage (overheating, chemically breaking down and thermal runaway (aka: Exploding)). A truly higher C-Rating would not change the run time (all things being equal).
C-Rating is also something that is hard to measure by us hobbyist, so it will be much less liking to result in a warrantee replacement.
And, how would you prove it? It's a literal "Catch-22" (watch the movie - it is awesome). The only way you can tell a distributor lied about C-Rating is to pull more current out than the pack is designed for and destroy the battery. Then the distributor denies the warrantee replacement because you destroyed the pack ("Destroyed" = "Abuse").
The tell-tale sign of this scam is that pack distributors will not publish their pack's Internal Resistance or ESR values for the pack's they sell. This is because IR / ESR are easy to measure. Then, they would have to be more honest about their labels.
It would mean that if they are selling crap-packs, they couldn't charge premium prices because they would quickly go bankrupt with all the packs that get returned.

Last edited by ticedoff8; 01-25-2021 at 12:08 PM.
Old 01-27-2021, 06:53 PM
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I think you misunderstood me. But no worries.

I agree with verification of the ratings; it's sort of a "one-time" event.

The other half of the "C" rating that people don't always understand its that it's a multiplier value that works with the amp-hour rating of the battery. I've seen within the specs of various vehicles that a "25C minimum rating is recommended." But I have also seen others that better explain and say something like "20C 4000mAh minimum." So, if an unknowing hobbyist went online to order batteries rated 25C then they're only considering half of the equation. By the math, a 25C 4000mAh 2S pack will supply the same amount of current as a 20C 5000mAh pack. If they were looking for inexpensive batteries they could buy a 25C rated 2200mAh 2S pack. That would only be able to supply about half the current of the other 2. Depending on what type of vehicle they're going to run they could be setting themselves up for failure.

I generally prefer to purchase batteries with higher C ratings when possible to give myself a margin for current draw. That way the battery will likely never be pushed beyond its limit and they will hopefully last longer.
Old 01-28-2021, 07:06 AM
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It's rare that at Lipo does from being worn out. Far more common is deterioration caused by time.
Old 01-28-2021, 09:43 PM
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I mean last longer as in a longer lifespan. I've made the mistake of using an inadequate battery for an application. By doing so I stressed the pack past it's limit, it puffed slightly. I continued to use it for a short time before eventually storing it. I came back to check it months later and a cell had dropped below 1V. It was done. But had I used a more robust pack with higher specs I likely wouldn't have damaged it to the point that it would fail prematurely.
Old 02-19-2021, 02:30 PM
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I have nothing technical to add. Buy Zeee batteries - they're cheap-ish and are very good quality.

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