Yes, I know. Another battery question?

SenorWickedStix

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I was looking the CNHL website about my batteries I’ve recently bought and what to charge them at. (6600 3S 120C racing series). It says don’t charge them over a 5C rate. If I’m reading the information I’ve found they’re saying don’t charge them over a 15 amp rate??? That seems nuts to me anyway. Is that math correct? I’m currently charging them at 4.7 amps.
 

QLynxer

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For a regular battery 1C 6600mah battery, you would charge up 6.6amps.

For a 5C 6600mah battery you can charge up to 33amps.

Higher amp would result in faster charging but reduced battery life.

I have 5C battery but my charger can only charger can only go up to like 6amps.
 

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I would stick to 1C (6.6A), maybe 2C (13.2A) if you're in a hurry. And if time is not a factor, go 1C.

There is diminishing returns on time, as you increase the current, since LiPo charging is done in 2 phases. Constant Current (CC), phase 1, until you reach your charged voltage. This is where the charger uses your set current. Then Constant Voltage (CV), where it reduces the current, to avoid exceeding the fully-charged voltage. It also balances the cells during this phase. But your set current is not used during CV.

The CV phase will take some time regardless, and will likely be a larger % of the total charge time, as you increase the charge current. A 2C charge takes a bit more than half the time of a 1C charge, since the CV phase usually doesn't really scale the same way, with current.

Think of a bit like filling an empty car tire to 30 psi, through the valve on the tire, from a large tank of 35 psi compressed air. At first you'll get a lot of flow (CC phase), but it will slow down at the end as you approach the desired pressure, without accidentally going over 30 psi (CV).

If you have time, and/or can start charging early enough, there is zero reason to "push it", IMO. Don't use 5C just because the manufacturer says they won't catch on fire :) It's in their best interest for your packs to wear out more quickly, requiring replacement, so they have an incentive to mention charge settings that aren't necessarily in the best interest of your packs.

If you want to charge multiple packs more quickly, the gentler approach is to charge packs in parallel, using a parallel board. For matching packs, at the same starting voltage, you can connect 2+ packs at once. And charge, say, 3 packs together at 19.8A, but each pack is only seeing 6.6A, or 1C. But, at the end of that charge cycle duration, you have 3 packs ready. And the only thing working harder is your charger, but it's not tougher on the packs. This is better, IMO, with matching packs, than doing three sequential individual charges at 3C. And it's likely also quicker than three individual 3C charges.
 
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Jon NC RC

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Ok. So I’m better off staying where I’m at for charge rate. Doesn’t matter to me if they take 1.5 hrs to charger or two. Longer life and less chance of failure is my goal. 😁 Realistically I’ll just buy more batteries if I want more run time. Lol.
Since you feel that way, I have always charged at 1C.....in your case with the 6600mAh would be 6.6 .....

typically takes an hour +/- at that rate.....

yeah, DEPENDING ON MANUFACTURER GUIDELINES (which can be sketchy most times)... you may/may not be able to charge faster, but

1) Im not in a hurry
2) Its safe
3) Batteries last longer most times
 
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