.

[Timpo]

Delete.

 

[AHicks]

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]

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.

 

[Volt_Ampere]

I would never go above 1C on 18650 cells. That should charge in under an hour.

 

[J.R.]

For those new to all this and would like to know about "C-rate", here's a good source.

https://batteryuniversity.com/learn/article/what_is_the_c_rate

 

[tomjasz]

Dictated by the BMS used. The battery supplier should know what the BMS is rated for. IME seldom more than 5A.

 

[tomjasz]

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]

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?

 

[MarkF]

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.

 

[tomjasz]

So what would happen if I use 6A charger on a battery that comes with 5A BMS?
Would it just limit it to 5A?

You’d potentially fry the BMS. What if you used a 24v battery in your car?

 

[tomjasz]

I wouldn't have a problem charging my 10ah battery at 8 amps

Hopefully you didn’t buy a battery I have to warranty. Charge at 8A at your own peril. NEVER charge at a rate higher than the BMS specifications. Jeez. How is it we are suddenly are smarter than the battery builders?

 

[AHicks]

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

 

[tomjasz]

oh ok so basically, whatever the possibility, it won't be good.

Very simply put, charging the batteries we use a 2A rate is the most beneficial.

 

[tomjasz]

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.

 

[tomjasz]

Quoting them,
"
Do you recommend Fast Charge?

Only if you really need it as it wears the cells faster"

SO! Only the 52V have BMS capable of 8A, and they don't recommend it. At least that's how I read it.

 

[MarkF]

And yet they sell a charger that goes to 8 amps to anybody that wants to buy it, juice even sells it for all there bikes. Where's the BMS you talk about Thomas that can't be charged to 8 amps. Why does Luna sell a higher amp charger, if it can't be done because your going to fry your BMS. Show me 1 BMS that will fry if you use a Satiator at 8 amps. Do you think they would even sell a charger that goes that high if it even fried 1 BMS on the market. If your BMS limits the charge to say 5 amps then it still will not hurt to use an 8 amp charger would it since your BMS would be governing the charge rate. Keep your insults to yourself Thomas and try to refrain from spreading false information on batteries. If 1c is a safe charge rate and 8 amps is less then 1C on a battery pack, then 8 amps is a safe charge rate. Do your math before insulting me.

 

[tomjasz]

Keep your insults to yourself Thomas

Nsults, yikes my friend, where are there insults? Suggesting customers use parameters outside of a products recommended specifications is something a seller just can’t do.

Why does Luna sell a higher amp charger,

Because their BMS is capable.

Do you think they would even sell a charger that goes that high if it even fried 1 BMS on the market.

my Satiator can charge a 48v battery, but I wouldn’t use the 52v option.

it still will not hurt to use an 8 amp charger would it since your BMS would be governing the charge rate.

Seriously? You trust cheap Chinese BMS to protect you.

Where's the BMS you talk about Thomas that can't be charged to 8 amps.

Nearly every BMS I own has a 4-5A limit in the specifications. Battery university and others address the advantages and disadvantages of faster charges. The average Joe here will prolong battery life and increase cycles by charging at lower rates. Clearly Juiced reccomends NOT charging at 8A, and specs only suggest 52v batteries be charged at 8A. “But not recommended”.

I don’t agree, however my intent was not to insult. If you read my comments as an insult, I owe you an apology. And I do apologize.

 

[tomjasz]

From your charger seller,
“
BMS Limits and charging fast:
Commercially sold ebike batteries such as the Luna Cycle packs have some kind of BMS (battery management system) that protects the pack. One of the things the BMS does is limits how fast the pack is allowed to charge. If you plug a 10-Ah battery into a 5-amp charger, and the battery does not charge, the BMS might be refusing the charge.

Most lithium BMS’s have a limit of around 7 amps as the limit on how fast they will charge. Also, the BMS is in charge of balance chargingyour cells to further ensure you packs safety and longevity.

 

[ctbaz]

I set my satiator to charge my 52V pack to 85% (~56.3V) and am noticing when I put the battery into my bike, the bike is reading the voltage at 55.4. Anyone else have this issue where the satiator and your bike aren't reading the same voltages?

 

[Gfmucci]

Having used a number of different lithium batteries and chargers, my basic understanding is "speed kills". Not necessarily instantly but sooner than consistent slow charging would. Sure, you can occasionally charge at a 6 or 8 amp rate on some systems, and the higher capacity chargers allow that safely with the right battery. And some of us might occasionally need a quicker than usual charge. So it's there for the times its needed. But as a routine, I understand that the slower the charge rate, the better it is for the life of the battery. And the less often you take advantage of the max charge rate, the better.