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Fast charging the Kingsong 16X

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On 8/6/2019 at 9:25 PM, chrisjunlee said:

So if I understand this correctly, the current would be distributed over 6 parallel. Or 1.7 A . That's a fast charge value I'm willing to accept. 

For those reading that don't have much experience with 18650 batteries, it's easy to reduce these discussions to black and white thinking, which become dogma without context.

FWIW, these are the conditions I would personally use, given the tradeoffs I've chosen:

  • slow charging: 1.5 A stock charger (1.5A / 6 = 0.25 A per cell. Incidentally, this is precisely the lowest most 18650 chargers go to)
    • use case: overnight, I don't need the wheel for the next 12+ hours
  • regular charging: 5.0 A rapid charger (5.0A / 6 = 0.83 A per cell, which is below the 1.0 A regular charging threshold)
    • use case: topping off at work, daily commuting 
  • fast charging: 10.0 A or two rapid chargers (10/6 = 1.67 A per cell. 2.0 A is considered fast, so 1.67 is a bit under that)
    • use case: those rare summer days when you need to charge between long epic rides

For posterity, the tradeoff is overall battery cycle life. The lower you stress the cells, the longer they last. But, charging is just one aspect of that: discharge rate is something I never see being discussed. What good is it to baby your batteries with a 0.25 A charge load, when you're ripping uphill pulling 10 A per cell?

Again, this is my just perspective, with the values and use cases I've chosen. I believe it is a reasonable set of choices to maximize your riding time, and thus your utility/enjoyment of your wheels.

Hi chrisjunlee;

 

I just noticed I have only the stock charger, which is 1.5A, and it seems when I return from work and would like to go out for a ride, i still have to wait 1-3h to charge it from 50% to 100%. Then I return from the ride with 50-70% and let it warm up to home tempature, but thats late night and im going to bed. As I dont want to charge it overnight without my watch, I return the next day from work and again I have to wait 1-3h to charge it from previous day to 100%.

 

I want to keep maximum lifetime of my batteries, so I don't want to fast charge, as it creates heat and heat kills batteries (or maximum charging cycles). So My idea was - allright, when I need to charge the battery just little faster, can I use 2x slow charget 1.5A instead of buying the 5.0 A rapid charger, or 2x rapid chargers (10 A) ? I feel like going this way, i can use only one 1.5A so the batteries charge slowly and I keep maximum lifetime of the batteries, or when needed, I will use 2x 1.5A and safe few minutes/hours, yet it's not "too much"

 

Thanks

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8 minutes ago, Ddolik said:

I want to keep maximum lifetime of my batteries, so I don't want to fast charge, as it creates heat and heat kills batteries (or maximum charging cycles).

There are no "fast" charging possibilities available for our EUCs.

Regular chargers are for the usee LiIon cells (as good as) always "very very slow" chargers.

Some of the sold fast chargers could come up to regular charging (~0.5C) for EUCs with smaller battery packs...

Assuming a 4p (4 cells in parallel) configuration and 3.5 Ah per cell 4*3.5/2=7A would be normal/regular charging with 0.5C!

1.5A for this configuration would be just 1.5/(4*3.5)=0.1C charging...

However, most/many used connectors, the EUC wiring and/or the battery packs BMS input protection are not really designed for higher currents. So just about everything below 5A could be considered as "safe" (if one has at least 3 3.5Ah or 5 2Ah cells in parallel and one wants to stay below 0.5C)

8 minutes ago, Ddolik said:

So My idea was - allright, when I need to charge the battery just little faster, can I use 2x slow charget 1.5A instead of buying the 5.0 A rapid charger, or 2x rapid chargers (10 A) ?

Some wheels like Z10 and KS16X have charge current limitations!

The Z10 just does not charge with currents over some ?6-9?A, the KS16X starts continously beeping above 5A (or did it afair with some firmware revision)

8 minutes ago, Ddolik said:

I feel like going this way, i can use only one 1.5A so the batteries charge slowly and I keep maximum lifetime of the batteries, or when needed, I will use 2x 1.5A and safe few minutes/hours, yet it's not "too much"

As long as one stays below this 0.5C for charging (for some cells 1C are specified from the manufacturers) other conditions like storing the cells fully charged (especially) at higher temperatures has much higher impact on lifetime.

I have never read something about increased lifetime of liion cells by (very) slow charging compared to 0.5C charging. Would be interesting if there are some reliable sources for these rumours.

PS.: A good source for LiIon cell knowledge is www.batteryuniversity.com

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If you're charging while using both ports, do both chargers need to be the same? Or is there no problem to combine for example a 1.5 A and a 5 A charger?
 

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Because I still didn't get any 10A fast charger, I have now charged several times with the 5A fast charger from 1radwerkstatt and the original King Song 2,5A fast charger.
Since both are not calibrated very exactly, both chargers together give 8A. Me and my 16X are still alive, I can't say more.
The annoying alarm at 5... A I have interrupted by switch.

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7 minutes ago, buell47 said:

Because I still didn't get any 10A fast charger, I have now charged several times with the 5A fast charger from 1radwerkstatt and the original King Song 2,5A fast charger.
Since both are not calibrated very exactly, both chargers together give 8A. Me and my 16X are still alive, I can't say more.
The annoying alarm at 5... A I have interrupted by switch

Ok, thank you! :)

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