Charging battery faster

scootergrisen

scootergrisen

100 W
Joined
Feb 26, 2018
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154
I have an electric scooter with 48V25Ah lithium-ion battery.

It takes 6 hours to charge the battery with the charger (its called C300) that came with the scooter.

The charger says:
input: 200-240VAC 3.0A
output: 54.6V 5A

I have measured the usage with a cheap meter on the 240VAC side and it says it is using 2A and about 288W when the battery is charging at the highest.

54.6 x 5 = 273 watt right? So i guess the charger is running as full capacity.

But i dont understand if the meter says 234 voltac 2 amp 288 watt at the same time.
Because 234 x 2 is not 288.
Does that calculation with voltage x amp = watt not work for AC :bolt: ?



I would like to know what decides how fast the battery can charge.

The charger is called C300 (48V5A).
There is another charger called C1200 (48V20A).
So will the battery charge 4 times as fast with C1200?
Or how can i know what charger to get?

Can i damage something if i connect the C1200 or other charger with higher A to the battery?

The battery have two connectors.
Can perhaps one charge the battery faster then the other?

Here are some links with pictures.
Battery: https://scootergrisen.org/forum/viewtopic.php?f=3&t=3612
C300 charger: https://scootergrisen.org/forum/viewtopic.php?f=3&t=3601
Meter: https://scootergrisen.org/forum/viewtopic.php?f=3&t=3615
 
The charger's output in volt*amps, to the battery, determines how fast the battery charges.

Your charger probably has a crappy power factor (wikipedia power factor) which would explain the mismatch in readings.

If you did want to get a better charger you could charge that pack at up to 25 amps or over 1kw. Big improvement!
 
The meter says powerfactor 60.

I am guessing i cant just get a 1800A charger and charge the battery in 1 minute.
I am guessing the BMS might control how fast the battery is charged.
So how do i know if the C1200 charger would charge the battery faster?
 
1C is standard max charge rate for lithium (number of amp hours > amps) so your 25ah battery can take 25 amps.

Who knows what your BMS tolerates but probably ~1C.

More powerful charger will charge your battery faster, other things equal.
 
So lets say i get a 25A charger and that is the maximum the cells can tolerance and it works fine.
What will happen if i get a 100A charger?
Is the BMS not designed to protect the cells so they will not get charged at 100A?

The BMS says 13S-P Joydo.
So that means 13 series of cells right?

Seems there are 10 cells in each series.
If the battery have 20 cells in each series or 1 cell in each series does this affect how fast the battery can be charged?
 
scootergrisen said:
So lets say i get a 25A charger and that is the maximum the cells can tolerance and it works fine.
What will happen if i get a 100A charger?
Is the BMS not designed to protect the cells so they will not get charged at 100A?

The BMS says 13S-P Joydo.
So that means 13 series of cells right?

Seems there are 10 cells in each series.
If the battery have 20 cells in each series or 1 cell in each series does this affect how fast the battery can be charged?
Click to expand...

No - cells will be charged at maximum current based on data. For example - i have panasonic 18650BD cells. Their standard charging current is 900mA (i guess i can go higher but its not needed). So i need about 3-4 hours to charge 1 cell. I have 10 batteries in parallel and i can charge it with 9A charger (900mA x 10 cells).
I can use 100A charger but cells will drain only 9A.
I think every BMS can handle 1C (in your case this is 2,5A) so no need to worry. Maybe your cells are not that good as datasheet shows? Try with better charger - use 10-15A so you can be sure.
Be aware - faster charging will destroy your cells faster. 6 hours is ok time i guess. If you need battery asap - buy one more battery 😁
 
How do i calculate what charger to buy?
I guess the more A the charger have the heavier the charger is so i would also like a charger that is not more heavier then needed so i dont drive around with extra weight pulling down range.

Does faster charging always mean it destroys the cells faster?
Or how do i know what current is best for cell life?

I already have 2 batteries since having just 1 battery seems to make the scooter not so usefull.
Even tough 50 km range for one battery sounds ok if i want to get back i can only drive 25 km out.
Unless i want to wait hours for charging some place.
If i can find a plug to charge at all.

I have two chargers. Can i combine them and charge one battery with two chargers?
I think i read the S5000 charger contains two S2500 charger.
 
Your battery datasheet shows 1C charging current. In your case its 2,5A. You have 10 cells in parallel in your battery pack so its 2,5x 10 = 25A. You can buy some quality 25A charger but you should try first. Find charger from some friend and test your battery.
Im not sure about two chargers-maybe if you have same chargers. Not sure about that.
 
My battery have 2 connectors on the outside.
It seems to me i can charge using both connectors.
And that one of them is just there because its a more common charger connector.

The charger the came with the scooter can only connect to the connector that only have - and +. It does not use the earth pin.

But the other connector (the round one) have 2 thick wires, 1 medium and 5 small wires.
The 5 small wires are connected to the BMS.
So i wonder if i get a charger that can use the round connector if the charging could be faster and if perhaps the charger can communicate with the BMS to select how much AMP is to be used etc. or maybe its for showing data on a display outside the battery.
 
Ah(of battery) divided by amp output of charger (with appropriate voltage ) equals time in hours to charge.
Ah/a=t
(but in reality it's more bc of the cv phase)
Power of charger = v x a... eg. 48v x 5 amp = ~250w
Regular charging a 1c is pretty stiff, it will age your batteries faster. 0.3c (3hr charge rate) is much better for your cells. You'll need a (roughly ) 8amp charger or 400w for this.
 
So my 5 amp output charger can charge a 25 Ah battery in about 5 hours (6 hours in real life).
So a 25 amp output charger can charge a 25 Ah battery in about 1 hour.
And a 150 amp output charger can charge a 25 Ah battery in about 10 minuttes.

How do i know what rate i can charge the battery without it being bad for the cells?
Are there an optimal rate that the cells can be charged at that is the fastest and does not damage the cells quicker?

Lets say i wanted to build a new battery for my scooter the can be charged in 10 minuttes but without damaging in the cells.
 
A 150A charger @ 54V would probably cost more than the whole scooter.
But if you really want to know what cells can be charged within 10min without having their cycle life completely destroyed then you can look into Lithium Titanite batteries, they have really low capacity/weight compared to lipo though.

The second fastest thing would be HEv Cells that can be fast charged to 80% in under 30min.
The two I am familiar with are Lg Chem and Samsung SDI, but not easy to get your hands on and the Cells don't come in a 18650 form factor.

How do i know what rate i can charge the battery without it being bad for the cells?
Click to expand...
By looking at the spec sheet posted above.
 
So where is says:
Standard Charge
Constant Current 0.5C (1250mA)
Click to expand...
Are there any reason to charge slower then that?
So i would need a 12.5 amp output charger to get that level of charge right?
So if my 5 amp output charger takes 6 hours now the 12.5 amp output charger should be 2 hours 24 minutes.
Which is kind of a big difference.

Will the switch from 5A to 12.5A be bad for the cells?
What if i switch to slower charging from 5A to 1A will that be better for the cells?
 
I might not want to buy a 150 amp output charger but i just want to know what it takes to get fast charging.
Suppose i or others wanted to make a charging station to charge scooters quick then maybe it could be used for that and then each user can pay for the charger.
It would not be bad if you could ride your scooter and charge it in 10 minutes or 1 hour.
It would be much more useable then the 6 hours it takes for my scooter battery at the moment.
 
scootergrisen said:
I might not want to buy a 150 amp output charger but i just want to know what it takes to get fast charging.
Suppose i or others wanted to make a charging station to charge scooters quick then maybe it could be used for that and then each user can pay for the charger.
It would not be bad if you could ride your scooter and charge it in 10 minutes or 1 hour.
It would be much more useable then the 6 hours it takes for my scooter battery at the moment.
Click to expand...

General safe guidance using a charger around 0.2(C/Capacity) (means at least 5 hours of charging to get full 1C/Capacity)
so for 25AH you can safely use up to 5A charger with the same voltage

Standard battery usually around 0.5C max charge (sample spec for panasonic) chinese battery usually lower
Panasonic NCR18650GA specs:
Capacity (Ah): 3.5 Ah ( 3500mAh)
Charging Voltage (V): 4.2 V
Max. Charging current: 2 A

2A (2000mA) / 3500mAh = 0.57C

Can you use higher current/Amps? yes you can, but must below the Max charging current (around 0.5C) which means your 25AH maximum is 12.5A (assuming you are using very good quality of battery) so you'll still need 2 hours of charging time

But you need to know as well, the faster the charging, generate more heat to the batteries, and lowering the cycle rate (age of battery)

Higher than 0.5C and generally you'll blew up the battery
 
The links says Refer to 6.2.1 and 6.2.2 on the page but i dont see it on the page.
Where do i read about 6.2.1 and 6.2.2?

Does the cells really last twice as long if i discharge it each time 80% compared to discharging it 90%?

What about the scooters that might be out there that can be charged very fast if they exists.
Do they just accept that the batteries will last shorter and replace them more often or do they use other types of cells?
 
If you want your batteries to last longer you should avoid to charge to 4.2 - 4.1 is good enough. Also dont discharge them bellow 3.2v. Keep charge and discharge current as low as possible. With this you can prolong your battery life 2 or 3x. Imo you need 8-10amps charger. 3-4 hours is not long time for charging. At least for me.
 
How do the people that make scooters decide when charger comes with the scooter?
Why did they decide that my scooter should come with a 5A output charger and not a 3A or 8A?
 
scootergrisen said:
How do the people that make scooters decide when charger comes with the scooter?
Why did they decide that my scooter should come with a 5A output charger and not a 3A or 8A?
Click to expand...

3A charger is much cheaper than 8A or 10A. Also smaller batteries (less cells in parallel) often comes with 2-5A chargers.
 
So why did they not sell my scooter with the cheaper 3A charger?

Does number of cells in series/parallel have anything to do with how fast the battery can be charged?
 
anyone seen a graph of how fast-charging effects lithium cells at different voltages? Samsung 30Q have a stated max charge rate of 4 amps but I believe that's a conservative number based on the limit of charging while at the highest states of charge and at lowest state of charge the current could be done higher with no detriment. Maybe it wouldn't even diminish cycle life. Maybe it would be explosive at some point. can you judge both by the cell's temperature increase?
(assuming fast charging a cell that starts at a typical temp)
 
Fast charging is about 30~50% responsivle for wearing out a battery.

Considering the cost of batteries you need to take into account that killing off your battery twice as fast means you need to replace it much sooner. Prehaps even within a year if you use it as a daily driver.

Ask yourself if this is worth the cost or you just need to get a bigger battery so you dont need to fast charge or even fully charge (stop at 4.1v or lower) so your battery can last a decade.
 
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