Why aren't there quick chargers for ebike?

[Timpo]

Why aren't there quick chargers for ebike?

I was looking at cell phones, and some of the largest smartphone companies like Xiaomi and Vivo have introduced quick chargers that can be charged 0% to 100% in 13 min to 17 min.
Somebody here on EBR said that RC cars, boats or airplanes can be charged from 0-100% in 15 minutes. (give or take)
Tesla can be charged 0-50% in 20 minutes. (0-80% in 40 min. and 0-100% in 75 min)

As far as I know, ebikes typically take hours to charge, you can't just drop by at coffee shop and charge it for like 15 min (like people do on cell phones and laptops) and go.

I know there are "quick chargers" for ebike, but that usually means your 6 or 7 hour charge may become 3 hours. (0 to 100%)

 

[rich c]

If cell phones and laptops had the size of battery pack your eBike does, they wouldn't be a quick charge either. The Tesla charger you refer to is a 220v input charger. Want to carry one of those to the coffee shop?

 

[Johnny]

Why aren't there quick chargers for ebike?

I was looking at cell phones, and some of the largest smartphone companies like Xiaomi and Vivo have introduced quick chargers that can be charged 0% to 100% in 13 min to 17 min.
Somebody here on EBR said that RC cars, boats or airplanes can be charged from 0-100% in 15 minutes. (give or take)
Tesla can be charged 0-50% in 20 minutes. (0-80% in 40 min. and 0-100% in 75 min)

As far as I know, ebikes typically take hours to charge, you can't just drop by at coffee shop and charge it for like 15 min (like people do on cell phones and laptops) and go.

I know there are "quick chargers" for ebike, but that usually means your 6 or 7 hour charge may become 3 hours. (0 to 100%)

The short answer is probably weight and price.

The long answer:

It is all about the capacity of your battery. Li-x batteries can be charged 5c(means 5 times the capacity of the battery hence around 12 minutes in the case of 5C) or more if needed (not all but the higher quality ones can be).

1. Output/Weight: The RC planes/cars etc. the batteries are usually small batteries which have significantly less capacity compared to what you have on an ebike. a 3S 4ah pack has close to 50wh capacity for example so if you want to charge it in 15 minutes you need at least 4c which is 200w of output for each of those batteries.

For an average 500wh ebike battery you need a charger capable of at least 2000W to charge it around 15 minutes. Now, we even have RC chargers (which are more capable then your average ebike charger) that have 2000w+ output(on the field you want to charge it fast to keep on flying your rc plane etc.) but these chargers are heavy. For 2000w just the AC/DC power supply will be 8+ pounds.

2. Price: The higher output you like the more expensive the charger will get. For 2kw I'd say at least 300$ and probably much more.

3. Battery life. When you exceed 1C your battery will degrade faster, at 4C the battery life cycle will take a very significant hit. Ravi on the forum is probably the best person to elaborate on this.


Even the Cycle Satiator is only 360W but it decreases the charge time significantly and I think for portability and cost 350-500W output is a good target for ebike chargers.

Side note, when the manufacturer does not let third party batteries or chargers you are stuck with their decision, in this case for example unless Bosch decides to make a higher output charger you are stuck with their standard one. 4A (an output <150W) is not bad but on the road one can definitely use 300W+.

 

[6zfshdb]

There have been quite a few threads here on EBR discussing charge rates. The "C" factor is one consideration but there are others. Heat is the enemy of any lithium battery. They get warm at a normal charge / discharge rate and can get quite hot when charged or discharged rapidly. Some batteries dissipate heat better than others due to their design. Quick chargers may work fine for some but could cause damage to others.

The BMS in some batteries will limit the charge rate or shut down completely if the temp gets too high. This can reduce the effectiveness of a quick charger. This problem can be worsened if you try to quick charge a recently depleted battery which is already warm from use.

Tesla eliminates this problem by using an internal cooling system which ebike batteries lack.

As mentioned by @Johnny, Ravi Kempaiah is our resident expert. He put a lot of time & effort into a post he made last year on lithium batteries and I refer to it often:

E-Bike Battery Guide

This thread is dedicated for helping new E-bike owners to understand and maintain their batteries in the best possible way. There is a lot of confusion for any new E-bike owner as to how one should treat their batteries: Shop owners may say one thing, online resources may another thing, someone...

electricbikereview.com

 

[Ebiker01]

8 or 10amps is possible. That can be about 45min. For a 500wh pack.
But the pack needs to have at least 16amps .

 

[Ebiker01]

Yes. But with a 6-700wh pack you don’t need >80% on road. 30min. Is enough for 300wh @6.2amps.

 

[Johnny]

Do cell phones and RC cars have battery cooling system though? I don't think they do..

I agree that heat is a big factor to consider in charging.

Smartphones do have cooling, it is not only the battery but the chipset also needs it(cooling).

For Rc planes (same for other rc vehicles too), most of the time the cells only have a shrink wrap and connectors for charging and balancing because of weight constraints. When charging you can use a probe to monitor the temperature for added safety.

The RC batteries are also discharged at high rates (for planes 5c+ on average and 20c+ in bursts is very common). For planes we make holes, vents on the body so that the circulating air cools the battery , speed controller etc.

In rc packs there are not many cells and they(the cells) are somewhat exposed so ventilation is easy. On an ebike battery lots of cells are packed together and sealed so cooling the cells in between is harder. On the other hand ebike batteries are not stressed as much as RC batteries, usually you are discharging them below 1c (even at bursts it seems to be below 2c). So you must not be fixated on this RC battery comparison too much, different applications different requirements...

yeah I know battery life can be an issue, but still doesn't explain cell phone's fast charger.
0-100% in 15 min for example, means 0-80% in probably 10 min.

Also Tesla's Panasonic cells do last pretty long time as far as I know.

Again @Ravi Kempaiah knows the best on this topic but I believe both in cell phone batteries and the new Tesla batteries fast charging still decreases cycle life. But I may be mistaken.

 

[MarkF]

The satiator does pretty good at 8 amps but BMS systems can cut that down to 5 amps. So whats the point if your system can't take it. I've said before many times the packs can take a higher charge than whats being done. I'm sure price has something to do with it also as a higher amp chargers will cost more. Look at what they want for an 8 amp satiator charger. I would never consider those cheap chargers on Ali express either.

 

[MarkF]

Because of the garbage chargers that customers have bought from them that turned out bad. Not saying they will all be bad but I wont recommend them unless there supported in the US. Lipo fires are real and no sense in rolling the dice on cheap crap. Just my thoughts on the matter.

 

[FlatSix911]

Again @Ravi Kempaiah knows the best on this topic but I believe both in cell phone batteries and the new Tesla batteries fast charging still decreases cycle life. But I may be mistaken.

You are correct... Fast DC Charging with a High C rate will definitely shorten the lifespan of the battery.

Tesla actually limits the Supercharging rate after a number of DC charge cycles to protect the battery capacity.

Tesla battery expert recommends daily charging limit to optimize durability

Like owners of gas-powered cars, electric car owners can adopt driving and ownership habits to prolong the useful life of...

electrek.co

Tesla explains why it limits Supercharging speed after high numbers of DC charges

The Tesla community had another small technical/communication controversy this week that was not unlike the controversy around Tesla’s undisclosed performance...

electrek.co

 

[Stefan Mikes]

I noticed a D-Power charger here. It is used with the Lovelec e-bike I own, actually I have got two batteries and two chargers. All works as expected but the charging current is only 2A.

 

[slayer1962]

I would buy a second battery charge the first while riding e bike with second if this was a concern for me. I normally do 3-5 miles and pedal some so no issues for me

 

[AHicks]

Timpo,
I think maybe Marks point has more to do with buying a Chinese charger with little knowledge of the charge manf's reputation, being able to digest the charger's specs (assuming they are even close to what you get with the charger), especially if buying on price point alone. Although willing to buy direct, I am definetly more suspicious of the product I receive. There's little doubt I would be monitoring the first few charges closely with a digital VOM for sure!

 

[6zfshdb]

I have 3 bikes and 3 chargers which were made in China. Two failed within the first year and were replaced under the bike manufacturer's warranty. The warranty has now expired. The same charger is available on AliExpress for half the price charged by the bike company but what about the warranty? It certainly doesn't match that of the bike maker.

Rather than continue on this cheap charger route, I bit the bullet and spent the $$ on a Grin Satiator. It's a US made product with excellent customer support. At the present cheapo Chinese charger failure rate, it will pay for itself in the long run.

Reliability is also a big factor for me. I frequently travel with my bikes and a charger failure on the road could be costly and very inconvenient.

BTW: This isn't intended to be a plug for Grin Technologies. Any quality charger would address this issue.

 

[MarkF]

The grin charger is the best we have for the amp rating it does. Bosh and others are slowly coming out with higher amp chargers. None are cheap though but there is a reason for that. Quality components are costly and considering what a fire can do to your home, I don't want to risk saving money here on the unknown.

 

[Ravi Kempaiah]

Thanks for tagging me on this thread.
One of my upcoming research projects for 2020 is to reduce the charging time for next-gen EV batteries. So, I can comment on this.

Quick charging is a hard scientific problem, especially for EVs.

It reminds me of what Guy Kawasaki, one of earliest Apple Investors said... " wireless charging and quick charging are superb ideas and anyone who solves that at commercial scale, would become a billionaire"

Phones can be charged at fast rates because they only offer 1yr warranty and after 500 days/350 cycles, the phone battery capacity sucks but people can afford to replace it.
But, it's quite another thing to replace an EV battery.
It is easy to design batteries that can be charged in 20 mins but the cycle life takes a hit and EV owners don't want that. In an EV, you want very long cycle life.

It is safe to charge at ~ 0.5C and anything more, you would want thermal management and as folks alluded here, weight and cost are limiting factors to implement that on an E-bike. I am sure we will better chargers in the coming years as E-bikes become mainstream.

A large number of 2A and 4A chargers are not built for long-term usage. Among all E-bike chargers, Grin Satiator is one of the very best.

 

[Ebiker01]

Bosh and others are slowly coming out

Bosch already has a 6amp Charger ,althoughis for Eu only ,but at 150$ is better to just get the very best mentioned above.

 

[MarkF]

Ravi

Over in the RC world a German student did a good article on lithium batteries. Do you see anything wrong with what they are saying here. He talks about the packs needing to be warm if you want to charge at a higher level. It's a long read but I would like your expert opinion on this article if you have the time. Or if you can point to anything wrong with what they wrote.

 

[Shane(NZ)]

Its something that bugs me also,we have 3 E-bikes in the family,Trek lt9 4 amp, giant Trance 6 amp and a budget commuter bike 2 amp.
when charging the mtb batterys which I do inside(both 500 wh) there is no temp change in the battery from start of charging to end,
those same battery cells come out in many other products with higher charge rates. power tools etc
Most E-mtb come with a 4 amp charger as std, you think they would offer a fast charger(10+ amps) at a crazy price of cause.

Greyp make a G12 elect moto/e-bike with a 2000 wh battery which charges fully in 80min from 0%, that charges alot faster than there std type E-mtb with a battery 3 times smaller(4 amp charger same as the rest) the e-bike industry has a long way to go in the charging stakes.

 

[6zfshdb]

I think we've all learned from this thread and others like it that lithium batteries can be charged at rates well above 2 - 4 amps as long as certain precautions are taken. Bike makers have no idea of the conditions under which their batteries will be charged. You could likely charge an already warm battery on a hot day in the sun at 2 - 4 amps without a problem. At 8 amps or higher, maybe not.

Sure, 2 - 4 amp chargers are cheaper to make but an e-bike brand could gain a significant competitive advantage by offering a fast charge option. Certainly it would be worth the extra charger expense. However, just one battery fire that makes the news or getting a reputation for short lived batteries would cost them that advantage and perhaps a lot more. Charger cost is just one factor. Safety is another. In today's litigious society, it pays to be conservative.

The much talked about Grin Satiator has an 8 amp max charge rate. For the price, they could have easily made it 10 amps or higher if they thought it feasible to do so. The Satiator also comes with an extensive user manual which includes many safety warnings. There is a lot to know in order to use it safely.