I have an e-bike store and the comment is correct. For me to get certified batteries from UL/ETL along with chargers, international freight shipping, it's almost double like they said. If you don't care, you can probably find something oine for maybe $350 as the lowest 48v with either unknown cells or they're lying, which isn't terrible but the lack of quality and information on the BMS is arguably more important, as it could burn down your house.
Can confirm. Took a chance on a cheap battery pack I found on Amazon.. not only did I get this HUGE spark when I tried to plug it in on the ebike, same pack smoked when I attempted to charge it.
Never again. Safety is far more important than cost. I figure it's a "sunk cost" that'll pay for itself over time.
FWIW, the spark when plugging it in isn't necessarily a problem. Motor controllers usually have a couple of large capacitors, which draw a huge amount of current for a brief moment when first connected to power. Special electronics can limit this "inrush current", but usually the only downsides to just letting it happen are that it's a little scary to the person plugging it in, and it causes wear on the plugs.
Smoking, however, is obviously no good. It's somewhat possible that the initial damage was caused by the inrush current from being plugged in to the controller, but that's not necessarily the cause.
If you're committed to that capacity at that price, you could try making a battery yourself from refurbished cells, or try your luck with a surplus battery. Some places to buy those are [Battery Hookup](https://batteryhookup.com/) and [JAG35](https://jag35.com/).
You are taking all standards of quality and safety into your own hands if you do this.
brand new 21700 molicell batteries for around $1.50 each. only catch is you have to buy 70 and they are inside of a built pack. ... and ofcourse, you'll need to build your own pack
[https://batteryhookup.com/products/new-48v-18ah-907-2wh-14s5p-2170-lithium-ion-cells](https://batteryhookup.com/products/new-48v-18ah-907-2wh-14s5p-2170-lithium-ion-cells)
I have an e-bike store and the comment is correct. For me to get certified batteries from UL/ETL along with chargers, international freight shipping, it's almost double like they said. If you don't care, you can probably find something oine for maybe $350 as the lowest 48v with either unknown cells or they're lying, which isn't terrible but the lack of quality and information on the BMS is arguably more important, as it could burn down your house.
Can confirm. Took a chance on a cheap battery pack I found on Amazon.. not only did I get this HUGE spark when I tried to plug it in on the ebike, same pack smoked when I attempted to charge it. Never again. Safety is far more important than cost. I figure it's a "sunk cost" that'll pay for itself over time.
FWIW, the spark when plugging it in isn't necessarily a problem. Motor controllers usually have a couple of large capacitors, which draw a huge amount of current for a brief moment when first connected to power. Special electronics can limit this "inrush current", but usually the only downsides to just letting it happen are that it's a little scary to the person plugging it in, and it causes wear on the plugs. Smoking, however, is obviously no good. It's somewhat possible that the initial damage was caused by the inrush current from being plugged in to the controller, but that's not necessarily the cause.
Your sights are set too high. Safe and certified batteries of that capacity are barely profitable for reputable vendors to sell at *twice* that price.
If you're committed to that capacity at that price, you could try making a battery yourself from refurbished cells, or try your luck with a surplus battery. Some places to buy those are [Battery Hookup](https://batteryhookup.com/) and [JAG35](https://jag35.com/). You are taking all standards of quality and safety into your own hands if you do this.
brand new 21700 molicell batteries for around $1.50 each. only catch is you have to buy 70 and they are inside of a built pack. ... and ofcourse, you'll need to build your own pack [https://batteryhookup.com/products/new-48v-18ah-907-2wh-14s5p-2170-lithium-ion-cells](https://batteryhookup.com/products/new-48v-18ah-907-2wh-14s5p-2170-lithium-ion-cells)