Shouldn't you already know the answers? After all, in your LinkedIn profile you say you're the Li-ion battery sales manager at the company you tried to promote in your very first post here.Carla Luo said:If i need a bike that is 25 kilometers per hour. I want to assemble it for myself. What kind of mid drive motor should I choose? What kind of battery is suitable? Is anyone the same with me?
Thank you for your professional answers,This is useful to me, I will always be concerned about you, I think I will learn more.spinningmagnets said:Carla, if the roads your customers are travelling are flat, then a direct drive motor can be cheaper and simpler, it can also run very quiet. For 25 km/h (16-MPH), it is easy. It can be done with 36V battery, a controller that allows 20A, and motor. There are thousands to choose from. Customers like a lower price, and then they complain that the battery and controller are not reliable and they die very soon, because they bought the cheapest kit.
In this situation, even though 36V X 20A = 720W is "adequate", a system that allows 48V X 25A = 1200W will make customers much happier, but of course it would be more expensive.
It is possible to have a lighter kit by using a geared hubmotor. Since the internal gear-set allows the motor to spin 5 times for each turn of the wheel, it is slightly more efficient. This means you can get the same performance from a smaller motor. They have a poor heat-shedding path, so they are not good for steep uphills. The demand for high and constant amps will make the motor and controller hot, and possibly even the battery. There are many choices that can provide 25-km/h.
A mid-mounted motor is usually the best choice for steep uphills. If the motor can use the bikes gears, then it can perform adequately in the lowest gear using 36V and 20A, like the BBS01 system. The BBS02 uses 48V and 25A, so it has more power, but the battery is more expensive.
For most people on flat land who need 25-km/h, they will choose a geared hubmotor and a 36V battery that can provide 20A. In this user-profile the Cute 100H and the Bafang SWXH seem to be popular, but...there are many other acceptable choices.
999zip999 said:All that being said the heart of an electric bike is the battery I mean a battery made with decent quality cells that can be verified Samsung 25r, LG, Sony ect. Not some generic junk or rewrap cells. Or junk bms as battery murdering system.
Seems a bit pointed given the context of this thread, haha. You can find decent generic cells that work perfectly fine and offer a better value in certain applications, the problem is when you purchase them from a platform like ebay where people try to resell garbage cells as something they aren't. Sellers on ebay know that most people will buy the highest number they can find for the lowest price. If they listed their 800mAh junk cell as 800mAh, they wouldn't be able to give them away, but if they say it's 4000mAh plenty of people are willing to take the bait for a couple bucks, and most won't have the equipment or experience to know the difference when it goes inside a flashlight.999zip999 said:All that being said the heart of an electric bike is the battery I mean a battery made with decent quality cells that can be verified Samsung 25r, LG, Sony ect. Not some generic junk or rewrap cells. Or junk bms as battery murdering system.
Kneelb4ZOD said:Seems a bit pointed given the context of this thread, haha. You can find decent generic cells that work perfectly fine and offer a better value in certain applications, the problem is when you purchase them from a platform like ebay where people try to resell garbage cells as something they aren't. Sellers on ebay know that most people will buy the highest number they can find for the lowest price. If they listed their 800mAh junk cell as 800mAh, they wouldn't be able to give them away, but if they say it's 4000mAh plenty of people are willing to take the bait for a couple bucks, and most won't have the equipment or experience to know the difference when it goes inside a flashlight.999zip999 said:All that being said the heart of an electric bike is the battery I mean a battery made with decent quality cells that can be verified Samsung 25r, LG, Sony ect. Not some generic junk or rewrap cells. Or junk bms as battery murdering system.
Something to keep in mind is Chinese cells have a huge range of performance and types. There isn't only 1 company making 1 type of Chinese battery. When buying something like an assembled battery pack for a moped or bike, the difference between a good generic battery and LG at 2600mAh is only going to be about 10-20%, but the price could be significantly cheaper. Plenty of people would rather spend the same amount of money to extend their range 50%, rather than get a battery with slightly better voltage drop characteristics.
Also, most Chinese manufacturers and trading companies who build or source battery packs buy both Chinese and Korean/Japanese cells to give their customers more options to choose from. I'm assuming Carla is working for a trading company and not an actual manufacturer, since most manufacturers would not bother to get an export license or deal with small foreign customers. As long as they are honest about the products they are selling, more choice is always best for the customer.
spiros said:I use both of batteries 18650 and rc lipos and I think that if the 18650 are not build at a really state of art they will not last to long the rc lipos will not last long but you pay less money for them I use 4 multistar 6S 16A from hobbyking and I like fast charging with my ICHARGER 4010DUO under surveillance and I store them into a military box that will not allow oxygen entrance in case of fire
Lithium iron phosphate is the main drawback in the low temperature environment can not work properly, there are lower voltage than the lithium battery, but he has a lot of advantages, such as the depth of the cycle of performance, safety performance is better, it can be considered battery A big breakMadRhino said:I use RC Lipo. They don't last long, they are not safe, but I need the power. Round cells would require to build a battery that is way too big and heavy, to supply equal power. Also, I like fast charging, and low resistance RC Lipo can be charged very fast. Fast charging is good for safety, because no one is tempted to leave a battery charging without surveilance when the volt meter is climbing as fast as a fuel gauge. :wink: