George S.
Well-Known Member
Is This Battery for Real??
shorturl.at/suIOQ
I ordered this battery the end of March. It arrived last week, around May 13th. The package simply showed up with a DHL label on it. There was never any tracking. The cost was about what the ad states, plus sales tax. I guess Ali is enough of a monster that US states make sure they pay tax.
The battery pack contains 13 cells, but they are a larger 21700 cell, not the standard 18650. There are 13 cells in series and 3 in parallel. The claimed capacity of these relatively large cells is 5,000 mah, or 5 Amp. With 3 sets, this is a 48 volt and 15 AH battery. This works out to around 650 watt hours. Since 48 volts is a little high as an average useable voltage You shouldn’t just multiply amp hours by the nominal voltage. The watt hours will also depend on the low voltage cutoff point in the specific BMS you have. For the test I ran, the BMS cut at 42 volts, which is not the end of the battery, exactly. I use a watt hour meter, watt meter, and precision voltmeter on my bike. This is useful information to judge your battery as you ride.
In the initial rundown test, the battery was charged to 4.2 volts per cell, which is the normal standard for this type of Lithium cell. Most chargers will list 54.6 volts as the terminal voltage for a 48 volt pack. The rundown test used a 48v inverter connected to a 200 watt load. The test ran until the LVC on the inverter shut the inverter down, around 42 volts. The total watt hours at the end of the test was 626 watt hours. The voltage recovered to 42.5 volts or so. It’s hard to get useable amounts of power as the battery drops to 43 volts or so. Worrying about these garbage watts is not worth my efforts. If you were riding an ebike you would be drawing 200 watts, a useable amount of power, until the capacity was depleted. All of this is based on a few test cycles, which were consistent. This battery could supply 700 watts, full legal power, with a fresher charge. That’s all I tested. There are a lot of nuances to using a battery on an ebike. You need a cell that can supply the legal 750 watts. As the battery depletes, you need a cell that still provide useful voltages and amps to the end, or the practical end. These cells do the job.
Conclusions
1. The 21700 cell allows for a small pack and a very useful form factor. This pack, 600 wh, is the standard for more premium ebikes, but the new cell saves some space.
2. The cell that LK is using seems to be fine for standard ebike uses. It may not be a high power cell, but I don’t test for that.
3. There is no way to know how long the pack might last. There are safety measures that can be incorporated into any ebike pack, and it’s unlikely this pack is much more than robotic spot welded cells with a BMS. At some point I might cut the pack open but I doubt it. It’s a very nice looking pack. I do all my charging outside with solar.
4. There seems to be no way to trace where these cells may actually come from. Some say this 21700 is a re-wrap of Tesla cells, probably cells that graded below what Tesla wants. Tesla makes batteries in China. When people say not to buy Chinese cells, it’s meaningless. Is an LG cell made in China inferior to one made in Korea. As Joe Biden said, the Chinese want to dominate the EV battery market. The ebike market is a rounding error, in all this. China will develop this kind of cell and they will perfect the manufacturing. If this isn’t the breakthrough ‘Hundred Dollar Pack’ it doesn’t matter. You can pick up stuff from Battery Hookup or Jag35. You can buy LFP on Ebay. Certainly if you DIY and spot weld you can get a great cheap pack for low dollars.
In some ways, China is laying down a marker with this pack. They are saying they can make a nice, perfectly usable ebike pack for $100. Maybe this pack shows what they will do or maybe it shows what they can do.
They can sell it directly. They did this with large prismatic LFP cells starting a year ago. Their position has only gotten stronger. That was EVE, and now EVE is supplying to Tesla.
www.aliexpress.com
shorturl.at/suIOQ
I ordered this battery the end of March. It arrived last week, around May 13th. The package simply showed up with a DHL label on it. There was never any tracking. The cost was about what the ad states, plus sales tax. I guess Ali is enough of a monster that US states make sure they pay tax.
The battery pack contains 13 cells, but they are a larger 21700 cell, not the standard 18650. There are 13 cells in series and 3 in parallel. The claimed capacity of these relatively large cells is 5,000 mah, or 5 Amp. With 3 sets, this is a 48 volt and 15 AH battery. This works out to around 650 watt hours. Since 48 volts is a little high as an average useable voltage You shouldn’t just multiply amp hours by the nominal voltage. The watt hours will also depend on the low voltage cutoff point in the specific BMS you have. For the test I ran, the BMS cut at 42 volts, which is not the end of the battery, exactly. I use a watt hour meter, watt meter, and precision voltmeter on my bike. This is useful information to judge your battery as you ride.
In the initial rundown test, the battery was charged to 4.2 volts per cell, which is the normal standard for this type of Lithium cell. Most chargers will list 54.6 volts as the terminal voltage for a 48 volt pack. The rundown test used a 48v inverter connected to a 200 watt load. The test ran until the LVC on the inverter shut the inverter down, around 42 volts. The total watt hours at the end of the test was 626 watt hours. The voltage recovered to 42.5 volts or so. It’s hard to get useable amounts of power as the battery drops to 43 volts or so. Worrying about these garbage watts is not worth my efforts. If you were riding an ebike you would be drawing 200 watts, a useable amount of power, until the capacity was depleted. All of this is based on a few test cycles, which were consistent. This battery could supply 700 watts, full legal power, with a fresher charge. That’s all I tested. There are a lot of nuances to using a battery on an ebike. You need a cell that can supply the legal 750 watts. As the battery depletes, you need a cell that still provide useful voltages and amps to the end, or the practical end. These cells do the job.
Conclusions
1. The 21700 cell allows for a small pack and a very useful form factor. This pack, 600 wh, is the standard for more premium ebikes, but the new cell saves some space.
2. The cell that LK is using seems to be fine for standard ebike uses. It may not be a high power cell, but I don’t test for that.
3. There is no way to know how long the pack might last. There are safety measures that can be incorporated into any ebike pack, and it’s unlikely this pack is much more than robotic spot welded cells with a BMS. At some point I might cut the pack open but I doubt it. It’s a very nice looking pack. I do all my charging outside with solar.
4. There seems to be no way to trace where these cells may actually come from. Some say this 21700 is a re-wrap of Tesla cells, probably cells that graded below what Tesla wants. Tesla makes batteries in China. When people say not to buy Chinese cells, it’s meaningless. Is an LG cell made in China inferior to one made in Korea. As Joe Biden said, the Chinese want to dominate the EV battery market. The ebike market is a rounding error, in all this. China will develop this kind of cell and they will perfect the manufacturing. If this isn’t the breakthrough ‘Hundred Dollar Pack’ it doesn’t matter. You can pick up stuff from Battery Hookup or Jag35. You can buy LFP on Ebay. Certainly if you DIY and spot weld you can get a great cheap pack for low dollars.
In some ways, China is laying down a marker with this pack. They are saying they can make a nice, perfectly usable ebike pack for $100. Maybe this pack shows what they will do or maybe it shows what they can do.
They can sell it directly. They did this with large prismatic LFP cells starting a year ago. Their position has only gotten stronger. That was EVE, and now EVE is supplying to Tesla.
145.6US $ 30% OFF|Liitokala 48v 15ah 21700 13s3p High Power 1500w Electric Bike Battery E-bike Battery 48v15ah Lithium Battery With 30a Bms - Battery Packs - AliExpress
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