How fast can you charge the battery?

Timpo

Well-Known Member
As many of you know, AliExpress has different ebike charger for different charging rate.

Some of them are basic 2A charger, but some of them can go up to 10A, 15A, 20A... and so on.
Apparently charging rate is called "C" (if you don't know what it is, please research on Google like I did).

Anyways, my question is, after doing massive research, I got different answers all over the place.
Many people said the modern Lithium Ion can handle 1C charging rate, whereas some people do not recommend going up that high.

I have a 4A charger from AliExpress (yes, I was playing safe), but is it true that you can really go up to 1C? Have you ever tried it?
Btw my Reention battery comes with 2.1mm x 5.5mm DC connector, so nobody makes higher than 5A, but just wanted to know for the future if I end up getting a different bike or battery.

https://www.aliexpress.com/item/Global-Certification-54-6V10A-Charger-48V-Li-ion-Battery-Smart-Charger-Used-for-13S-48V-Li/32822242043.html?spm=2114.search0104.3.10.52706b34o8IFnQ&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_10130_10547_319_10059_10884_317_10548_10887_10696_321_322_10084_453_10083_454_10103_10618_10307_537_536,searchweb201603_52,ppcSwitch_0&algo_expid=ffced22a-64df-4d2e-b522-02893382e687-1&algo_pvid=ffced22a-64df-4d2e-b522-02893382e687
https://www.aliexpress.com/item/48v-12A-charger-2-12A-Adjustable-current-smart-charger-3A-4A-8A-9A-10A-11A-12A/32886864766.html?spm=2114.search0104.3.45.52706b34o8IFnQ&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_10130_10547_319_10059_10884_317_10548_10887_10696_321_322_10084_453_10083_454_10103_10618_10307_537_536,searchweb201603_52,ppcSwitch_0&algo_expid=ffced22a-64df-4d2e-b522-02893382e687-6&algo_pvid=ffced22a-64df-4d2e-b522-02893382e687
 

AHicks

Well-Known Member
Timpo, when messing with charging rates you need to factor balancing and heat issues. As a rule, as charge rates go up, so should the user's experience level.
 

MarkF

Active Member
1C is the safe rate for lithium Ion. Higher than 1C is where it gets fuzzy. I would not worry about going up to 1C as far as charging goes. We use up to 5c with hobby lipos all the time with no problems.
 

Timpo

Well-Known Member
That's interesting how everyone says about 1C is okay for moder lithium ion. Not limited to this forum but everywhere else too.

I don't know why virtually all ebike manufactures list their battery charging limit as 3 or 4A.
It doesn't matter if it's 48V 8.8Ah or 48V 16Ah, the limit for these batteries are both 4A.

Maybe the ebike companies are playing safe? I don't know..
 

Timpo

Well-Known Member
Dictated by the BMS used. The battery supplier should know what the BMS is rated for. IME seldom more than 5A.
The topic of BMS comes up often here on EBR and I'm still a bit in the dark about it.
https://en.wikipedia.org/wiki/Battery_management_system

So I guess the BMS regulates the charging rate?
What if you use 15A charger from AliExpress? Does the BMS not allow you to charge it or will it regulate it down to 4A (or whatever it is programmed to do).
 

Thomas Jaszewski

Well-Known Member
The topic of BMS comes up often here on EBR and I'm still a bit in the dark about it.
https://en.wikipedia.org/wiki/Battery_management_system

So I guess the BMS regulates the charging rate?
What if you use 15A charger from AliExpress? Does the BMS not allow you to charge it or will it regulate it down to 4A (or whatever it is programmed to do).
My understanding, with the BMS i use, is the BMS LIMITS the rate. On my packs I can use UP TO 5A rate. The charger needs to match the BMS rating. I never considered anyone would try and use a 15A charger, if one exists. There are a lot of BMS makers and battery builders. Your best source of information on the limits of your battery is the seller!
 

JohnT

Active Member
Charge rates are like discharge rates, and going higher might stress the battery and reduce its life. The question is how high can you go without a significant negative impact. I hear 0.7 to 1C for charging, but shouldn’t that vary, just like safe discharge rates, depending on the cells’ specs?
 

Timpo

Well-Known Member
My understanding, with the BMS i use, is the BMS LIMITS the rate. On my packs I can use UP TO 5A rate. The charger needs to match the BMS rating. I never considered anyone would try and use a 15A charger, if one exists. There are a lot of BMS makers and battery builders. Your best source of information on the limits of your battery is the seller!
So what would happen if I use 6A charger on a battery that comes with 5A BMS?
Would it just limit it to 5A?
 

Timpo

Well-Known Member
Charge rates are like discharge rates, and going higher might stress the battery and reduce its life. The question is how high can you go without a significant negative impact. I hear 0.7 to 1C for charging, but shouldn’t that vary, just like safe discharge rates, depending on the cells’ specs?
hmm okay so sounds like 1C is like generally safe range for charging an ebike battery. I'd go a bit lower just to be on safe side I guess.
 

MarkF

Active Member
Timpo
Say a cell is rated at 2500 mah. At 1c that is a 2.5 amp charge rate. Now parallel 4 of these and you get a 10 amp charge rate. 15 amps at 6 in parallel. So your chargers that do 2 or 4 amps are well under 1c charge rate. I wouldn't have a problem charging my 10ah battery at 8 amps as that is still less than 1c. I think these low amp chargers are just cheap to make and they probably worry about battery packs made with garbage cells, so why not keep the charge rate low as an insurance policy. Today's better battery packs are being made with better cells now so i think the worry is unnecessary about going to a higher charge rate. Having said that, I would not use a cheap charger (ali express) that claims 8 amps or higher until they prove themselves. I would feel safer using a Satiator charger for 6 to 8 amp charging. A good charger will be a smart charger in that it would turn off the charge if a cell got out of wack. I don't trust the cheap ones to do that. I don't know how much influence a BMS has in the say of things and we don't really know which BMS we have in our bikes. So probably best to not go cheap here.
 

AHicks

Well-Known Member
Mark, when thinking of using acceptable practices often used in RC, you have to factor in the BMS here in the bike world. RC batteries have no BMS as there are not enough cells to make that practical. With all of the cells in the typical bike battery, and the need to balance them at least occasionally - you pretty much have to install a BMS. It's going to determine who gets what amount of power for how long to get the job done. -Al
 

Timpo

Well-Known Member
Very simply put, charging the batteries we use a 2A rate is the most beneficial. We start reading all those threads where the 60v and 72v fellas write about their 20s10p packs and somehow get the idea we should be able to charge at their workable rates. I have a couple of small 10s2p and 14s2p packs I drag along for a buffer and keep my batts fully charged the entire season. No reason to rush if I plan a bit. I’ve a couple of batteries I babied and one I beat on. The well managed packs, always charged at 2A and usually 80-90% are my strongest packs. But even a 4 year old abused pack still gives me good service. Just don’t remember exceed the BMS specs.
I don't even know my battery pack's BMS specs to be honest. But my AliExpress 4A charger has been working fine.

I knew that lower charging rate will be better so that's why I got the 4A.
I almost considered getting 8A since Juiced sell this 8A satiated charger so I thought it might be fine.

But at the same time, typically ebike manufactures say so not go over 4A so I kinda went to the safer side.
 

Thomas Jaszewski

Well-Known Member
I don't even know my battery pack's BMS specs to be honest. But my AliExpress 4A charger has been working fine.

I knew that lower charging rate will be better so that's why I got the 4A.
I almost considered getting 8A since Juiced sell this 8A satiated charger so I thought it might be fine.

But at the same time, typically ebike manufactures say so not go over 4A so I kinda went to the safer side.
They sell the Satiator with the capacity to charge up to 8A. But that in no way means they suggest you do charge at 8A. 5A is a common limit so you’ve had no issues.