Lithium Ion battery fault  - Page 1
Forum section: electronics / general

author: Hein1976
author_rank: Newbie
timestamp: May 24, 2020, 08:02:03 am
content: Good day. I hope someone can help me here. I have a electric scooter that the battery show good power. This are the 12amp 60V battery. When you drive it about 200 - 500m, the power just go out. It look like that the board on battery maybe have a crazy time. How do i fix it or is there a setting that a person can do? I have 2 videos that i recorded on this problem. How do i upload it?

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: May 24, 2020, 08:06:43 am
content: Most likely a faulty battery. The charge indicators typically show the voltage of the battery as charge indication. It does not measure the actual capacity. Check if the battery is over heating during the charging cycle. This can be an indication of a failed battery. Then check for any bulges on the battery. you may have to open the battery pack to check individual cells.

author: SolarMan
author_rank: Contributor
timestamp: May 24, 2020, 10:09:07 am
content: You can upload a video to YouTube and then link to it here. Perhaps you can also mention the make/model of the battery/scooter?I agree there could be something wrong with the board on the battery. For lithium batteries, the board is generally referred to as a "BMS" for "battery management system". Here's a video showing the replacement of a BMS:Perhaps you could measure the voltage across the battery while it's connected to a load?

author: tunk
author_rank: Super Contributor
timestamp: May 24, 2020, 11:17:21 am
content: The battery most likely has 15-16 cells in series (and a few in parallel).It could be a unbalanced battery, open the battery and measure the cell voltages before and after.

author: Chalcogenide
author_rank: Regular Contributor
timestamp: May 24, 2020, 02:15:44 pm
content: A friend of mine brought to me a 10s 8Ah pack from an electric bike that measured a whopping 200 mAh after less than 3 years of moderate use, even with a balanced BMS (confirmed to be be working after my autopsy). Open the pack and check the balance status, but it might just be that some cells are just dead.

author: Hein1976
author_rank: Newbie
timestamp: May 24, 2020, 07:42:08 pm
content: Here are the videos on YouTube.https://youtu.be/XWgJ043ap44https://youtu.be/IuElrcgHmLA

author: Hein1976
author_rank: Newbie
timestamp: May 25, 2020, 05:04:21 am
content: Are the YouTube videos available to see that I have uploaded?

author: SolarMan
author_rank: Contributor
timestamp: May 25, 2020, 07:57:26 pm
content: Yes, the video links are working fineThe voltage drops very suddenly after a few seconds. If you have a degraded cell on your hands then it must be seriously knackeredHas the range of your scooter gradually declined over time? (suggests cell degradation)Or is it a problem that appeared suddenly? (suggests a BMS fault)Would you be comfortable opening up the battery module to do some tests?

author: Jeroen3
author_rank: Super Contributor
timestamp: May 25, 2020, 08:35:02 pm
content: If you decide to open it, please make sure you have a plan to act on when the battery goes in thermal runaway or otherwise starts spewing fire.You will need it! A normal extinguisher will not work. And it will keep exploding until all cells are open. The only way to stop this is to use a lot of water, or submerge the rechargeable battery.Beware, lithium battery fumes are toxic. Hydrogen fluoride etc...But it indeed looks like one of the cells is dead. Or the BMS throws the towel. The latter one is a bit weird though, the voltage will usually die quicker when that happens.Do not use water onnon-rechargeable lithium batteries, these contain theelementlithium and will show you an alkali-metal explosion.

author: trobbins
author_rank: Frequent Contributor
timestamp: May 27, 2020, 12:15:02 pm
content: Does the battery voltage level show the voltage rises in a normal manner whilst charging? Does the voltage get up to max indicator level?Do you have an operating manual for the scooter, and does it describe how to maintain the battery/charging and talk about equalising? If the BMS had an equalising capability, and the cells were being just protected from low voltage, then long duration equalising may provide an improvement path.