JesseW
1 mW
I took a leap of faith and ordered a battery through aliexpress. The seller is listed as "Sky Technologies" or their store banner reads "Shenzhen Sky Battery Technology Co., Ltd". They advertise "48v 1000w battery 48v 20ah electric bike battery 48v 20ah lithium battery pack use LG cell with 30A BMS and 54.6V 2A charger". It was $443 with shipping to Washington state. Just wanting to share what I've found to help others who are looking to order from an aliexpress vendor.
I've received this battery and used it for several discharge cycles on my ebike. I've taken the cells out of the case and inspected the construction and the cells. I've also hooked it up to a DROK digital multimeter and tested using a full discharge using a heater to consume the current.
Here's what I've found:
The cells have the marking LGGBF1L18650 on them matching the claimed LG F1L 3.4 ah cell that is supposed to be used in the pack.
The cells are well connected with 4+ spot welds on the end of each cell connecting them to the metal tape that runs between cells. The tape is silver color, I can't tell if it's nickle or what but no corrosion is visible.
The block of cells wrapped in heavy adhesive paper, not the best or most durable material, I may put plastic shrink wrap around them in the future.
There is a fuse in the case but it is not connected to the circuit so it's technically not protected unless there's something in the BMS that acts as a fuse which I don't know about.
The key switch acts as a fuse as I found out when I accidentally short circuited the battery. The key switch is wired in line instead of a relay as on some other silverfish batteries I've inspected which is poor construction but easy to fix if I want to. As it is the key switch actually acts as a fuse by failing when I accidentally short circuited the battery. I do like this key switch because unlike some other silver fish cases the key can be removed from the lock in both the off/unlocked and the off/locked positions. The lock pin was in a slightly different position from my other silverfish battery (from my '16-'17 Rad Mini) and so I had to drill out the lock pin hole on the mounting strip and dremel off some plastic bumps on the bottom of the battery to make it fit with my Rad Mini, not a big deal though.
When I tested the battery after a full charge with the drok multimeter and a 5 amp draw it put out 17.9 amps at avg 48v, or 848 watts, before the BMS shut it off when it reached 35v. Looking at other tests of the LG F1Ls online (thunderheart reviews) it seems like a pack of good F1L cells should have a 19.2 amp output before reaching 35v. That may be because these cells are slightly inferior, maybe B grade, or it could be my testing setup which isn't high quality. At any rate it's close so I DON"T think they're a low quality counterfeit cell.
Everything arrived well packaged and just like pictured with first test of performance within about 5% of what I expected so I'm quite happy, especially since the price is quite good. You can read more about my ebike project on the Endless Sphere ebike forum.
Check out the photos, I tried to put them in the post here but if they're not viewable see link to album below. I'd be interested to hear what you all think about the quality of the cells, the BMS if anyone recognizes it from the pictures (how likely is it going to burn my house down?), and my testing technique, the Drok multimeter seemed like the best way to do it for <$20, I'm not interested in spending the money on a high quality meter at this point.
https://photos.app.goo.gl/uQ38oRwrHGwrrNzH9
I've received this battery and used it for several discharge cycles on my ebike. I've taken the cells out of the case and inspected the construction and the cells. I've also hooked it up to a DROK digital multimeter and tested using a full discharge using a heater to consume the current.
Here's what I've found:
The cells have the marking LGGBF1L18650 on them matching the claimed LG F1L 3.4 ah cell that is supposed to be used in the pack.
The cells are well connected with 4+ spot welds on the end of each cell connecting them to the metal tape that runs between cells. The tape is silver color, I can't tell if it's nickle or what but no corrosion is visible.
The block of cells wrapped in heavy adhesive paper, not the best or most durable material, I may put plastic shrink wrap around them in the future.
There is a fuse in the case but it is not connected to the circuit so it's technically not protected unless there's something in the BMS that acts as a fuse which I don't know about.
The key switch acts as a fuse as I found out when I accidentally short circuited the battery. The key switch is wired in line instead of a relay as on some other silverfish batteries I've inspected which is poor construction but easy to fix if I want to. As it is the key switch actually acts as a fuse by failing when I accidentally short circuited the battery. I do like this key switch because unlike some other silver fish cases the key can be removed from the lock in both the off/unlocked and the off/locked positions. The lock pin was in a slightly different position from my other silverfish battery (from my '16-'17 Rad Mini) and so I had to drill out the lock pin hole on the mounting strip and dremel off some plastic bumps on the bottom of the battery to make it fit with my Rad Mini, not a big deal though.
When I tested the battery after a full charge with the drok multimeter and a 5 amp draw it put out 17.9 amps at avg 48v, or 848 watts, before the BMS shut it off when it reached 35v. Looking at other tests of the LG F1Ls online (thunderheart reviews) it seems like a pack of good F1L cells should have a 19.2 amp output before reaching 35v. That may be because these cells are slightly inferior, maybe B grade, or it could be my testing setup which isn't high quality. At any rate it's close so I DON"T think they're a low quality counterfeit cell.
Everything arrived well packaged and just like pictured with first test of performance within about 5% of what I expected so I'm quite happy, especially since the price is quite good. You can read more about my ebike project on the Endless Sphere ebike forum.
Check out the photos, I tried to put them in the post here but if they're not viewable see link to album below. I'd be interested to hear what you all think about the quality of the cells, the BMS if anyone recognizes it from the pictures (how likely is it going to burn my house down?), and my testing technique, the Drok multimeter seemed like the best way to do it for <$20, I'm not interested in spending the money on a high quality meter at this point.
https://photos.app.goo.gl/uQ38oRwrHGwrrNzH9
