charging faster means more power! (wut?)

from rc guys here

uh… wut? myth right?

maybe… just having warmer pack?

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A hotter cell will have a lower IR and output more power (I think) but it is minimal and obviously lowers the cycle life.


Yeah what he :arrow_up: said


That whole post is all kinds of confusing. What do they mean by “1C” and “2C”? Did they actually mean to put 1 A and 2 A and just decided that the existing unit of an amp for current doesn’t matter anymore.

The real formula for power in relation to current is P = I^2 * R (I is squared to be clear) so in reality more current means you can deliver more power to the battery. Whether or not that is healthy for the specific battery is a different issue.

1-2c is the c-rate

so if you have a 1000mah pack you can charge it at 1c=1A


traduction : a perfect balanced pack to 4,200 per cell will give you a better signifiant performance , you never charge a warm lipo pack above 40 degree , or you can get serious problem , its better to wait so the pack can have a rest and then you charge it at room temperature

C rating is Amps per Amp-Hours

So a 9Ah pack with a 100C rating can discharge at 900A

Or a 9Ah pack charging at 2C charges at 18A


Ah that makes more sense. It is one of those variables that someone made up without looking at all the other established ones already. (Upper case C was already well established for capacitance.)

As for this guy claiming that charging your battery at a faster rate will result in more power being able to be delivered by the battery, that is just absurd. I think he might be getting confused with the fact that some BMS will allow more current to be pulled from a fully charged battery than it will allow the controller to pull from a battery at half capacity or less. I’ve seen that happen with my BMS that doesn’t have a discharge by pass. Also RC car batteries all have the BMS built in unless the hobby shop near me just sells abnormal RC aimed batteries

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Not quite, it’s a marketing speak rating, it’s based on established units but obfuscates the true specs.

Premade packs almost always have a BMS built into them, even cheap china packs.

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What? All I’ve ever seen are bare pouches, that’s why they come with JST plugs to plug into a balance charger, which will handle the balancing. Because of that, they’re really easy to overdischarge if you don’t pay attention, hence why lipo alarms are a thing.


Oops I missed the LiPo part, I was referring to Li-Ion packs.

I don’t think Li-Ion cell packs are common in the RC space. Not enough discharge and too heavy for most uses. When I think of hobby batteries I always go to the rectangular pouch cells.


To be fair, I tend to just get more upset when I see people not respecting all the well established physics variables. Adding more meaning like that makes it even more difficult for the average person to understand which is always bad for science. Unfortunately tech companies are not science companies though and they don’t care so long as they sell their products.

My bad, I was just going based on the fact that all the employees didn’t know what a BMS was when I asked if they had any. One claimed it was built in to the batteries already but I never bought any to confirm that. I think I did see at least one Li-Ion pack there though, but I could be wrong.

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c-rate for charging is not the same as the output c-rate


Yup, that’s it…all of it.
The rest is just making it confusing.


I think the reason they didn’t know what it was is that they don’t use what we’d traditionally consider a BMS. To save weight inside tiny lipo powered RC cars/planes/drones, they tend to use a balancing charger which has a similar effect to a BMS. It can’t do any monitoring during discharge (because you left it at home) or disconnect the battery from a load so it’s not a 1 to 1 equivalent but it’s similar

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C is “per hour” in much the same way that Hz is “per second”.

So 3C on a 5Ah battery = 5Ah · 3/h = 15Ah/h = 15A


C rating is “per hour” units.

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Yeah I see that now, I was just one simplification away from that.

A/Ah = 1/h

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This is true to some extent. SOME. Lithium batteries (especially LIPO) have a certain temperature range they’d like to stay in. At that range, as Kevin mentioned, they have a lower IR which allows for better peak performance. But note that this is almost entirely unapplicable to our applications, since we almost never run our battery packs at their peak, especially with varying loads.