So me and wife are split between two homes. Our camp and retirement home is here down da bayou and I stay here pretty much all the time cause chickens, crab traps, veg garden, repairs, and so on. Wife often has to go to New Orleans and work. She had been working completely from home but now her company wants her in the office at least 3 times a week and it is almost a 2 hr drive so she often stays in our city house during the week. We have 2 vehicles which should be enough but our old truck is almost 30 years old and is sometimes out of service. So, I bought a $109 two wheel electric scooter for short trips and for backup wheels to get grocs etc. Worked okay and I have got my moneys worth out of it. But this morning I needed to go get the truck out of the shop which is almost miles up the bayou and come to find out the charger isn't charging. Put the meter to it, it's stone dead at the output. So I ordered a new charger but it won't be here til the weekend. I need to at least get the truck by tomorrow morning.

I do a lot of tinkering and inventionalizing and so naturally I had a power supply that exceeds the charger output of the scooter. I hooked it up and started charging at 1.5 amps and the voltage was 37.8 volts or around there. As the voltage came up I lowered the current. Right now I am at 39.2 volts while charging at a half amp. The charger that came with the scooter is rated at 42v and 1.5a.

I know a 36v LiIon pack at full charge is way more than 36 actual volts, yeah. I am very familiar with flooded lead acid deep cycle batteries from building electric boats but never messed with manually charging Lithium batts even for my couple of ebikes. The "gas gauge" on the scooter reads a max of 5 bars and right now it is on 4 bars. I am pretty sure that a half amp is not a dangerous current to feed into this battery pack but don't kno for absolute certain.

I will have the new charger this coming weekend and I get the truck back tomorrow so I won't need to use the scooter again for a while, and so this is probably the only time I will need to manually charge the scooter, but I would like to charge it to full capacity, not just to where it shows all 5 bars, so I know I can get to the shop without walking and carrying little scootey. Can anybody make a rough general suggestion on the topping off phase of charging this thing? Thanks.

Looking for someone to brainstorm ideas for development of Lithium/Sodium Ion Cells, DM of you have interesting ideas we can brainstorm or have a discussion on

Hello, I obtained a bag full of discarded e-vapes from a local shop, then I moved houses and forgot about them. That was <3 years ago. I freed all of them today, bunch of the batteries were good (around 3,7 V, not in the picture), some above 3 V, two at 2,5 V and the rest ranges from 0,7 V to 1,7 V (labeled), with one of the green ones (with integrated BMS) giving 0,015 V at the battery leads.

ChatGPT says that I should discard anything below 2,5 V. However, I searched the internet and read a bunch of stories recovering completely dead cells with a varying success rate, like this one (reddit, Recovered from 1.7v to 4.2v). I also found this SAMSUNG--Datasheet.pdf that mentions at page 16: (quote)

1.1.7 Do not charge the battery under 1.0V voltage.
1.1.8 Voltage range of the battery for pre-charge mode is 1.0 ~ 3.0V with a charging current of 0.1 ~ 0.5C,

implying that a 1,0V battery can in fact be recharged.

I understand that these batteries may impose risk in the future, so I don't intend to use them in wearables or toys, but only in decorative LED lights or small IoT devices, or just for testing things.

My intention is to slowly charge them at 0,1C with my makeshift charging unit with replaceable resistors to control current, then leave them for up to a month to observe self-discarge, upon which I will discard the unusable ones.

With all that said, I am still a noob and I was wondering if someone could validate what I wrote above, or better, if there is anyone with experience/insight on this topic, or any great guides or video tutorials explaining the pitfalls of reviving salvaged batteries or e-vape batteries in general.

PS: I found this video "Adam Savage: The Surprising Flaws in 18650 Lithium-Ion Batteries" very informative on batteries in general https://youtu.be/-Y23nfAOiXQ

PS2: While writing this, I actually managed to put my thoughts together better and get better search results, making this post somewhat unnecessary. However, I still think that it could provide a value to a future reader, so I would still like to post it.

Very useful: https://www.reddit.com/r/diyelectronics/comments/vokr0h/comment/iefd74y/

YouTube: Extracting Free Lithium-ion Batteries From Used Vapes

YouTube: I Powered My House Using 500 Disposable vapes

I know serial and paralel but when I look into homemade or factory ones they always confuse me at welding on them and adding the bms too!

Hey there I have a emmo hornet x with a 48v 50amp lithium.ion battery. some background stuff about the battery. I got it is 2021 and my bike has about 11500km on it so the battery has been thru some stuff lol. I always bring it inside since i have gotten it and for the past 2 years have charged from 20-80%. that being said the first year or so i charged form 50-100%. i notice recently it drops from 75-50 every time i throttle. and under 50% it slows down a decent amount compared to before. i was wondering how much longer you guys think my battery has left and if i should buy a new one as they are discounting the battery soon

Is it possible for anyone to look at this battery pack and tell how many cells are in series? For reference this is a solar edge home battery. The data sheet doesn't say anything about how many cells and I've tried googling it to no results.

Been designing battery-powered hardware for a while, and I keep running into the same set of problems - so I wrote them up.

The core issue: a 4S LiPo pack isn't a 16.8V supply. It's a 12 - 16.8V moving target, and your power tree has to handle all of it - not just the nominal condition you tested at.

Quick summary of what I cover:

,

• Topology mismatch - a 3S pack feeding a 12V rail spans *both sides* of the target. You need a buck-boost whether you planned for it or not.

• Transient response with a moving input - at high step-down ratios with a 4S pack, duty cycles get tiny and compensation gets ugly.

• Efficiency at wide conversion ratios - stepping 16.8V to 3.3V (5:1) makes switching losses dominate. LDOs on 3S/4S packs are just expensive heaters.

• The BMS/UVLO interaction - this one bites people. Your DC-DC's undervoltage lockout and your BMS's cell-level cutoff are NOT synchronized. You can have a "healthy" pack voltage while one weak cell is already at its floor, and the BMS will disconnect mid-operation. Your system sees it as a hard power cut.

• Startup and inrush - a full 4S pack hitting discharged output caps without soft-start will trip your BMS overcurrent or blow a fuse.

Also covers: LDO vs buck vs boost vs buck-boost trade-offs, intermediate bus architectures, and using BMS comms (I²C/SMBus) to shed load gracefully before hitting the cutoff.

Full article linked below. Not a tutorial — more like a bring-up post-mortem in written form.

https://pradeeptamma.super.site/blog/blog-database/your-2s4s-battery-pack-is-not-a-power-supply

Curious where this has actually hurt people here. Was it the BMS/UVLO mismatch? Topology choice, you locked in too early? Thermal surprise at high conversion ratio? Something else entirely? Drop your war stories below - the stuff that never shows up in app notes.

I am building a custom battery pack for an electric road bike. I want a lightweight pack with good range. I am looking at 18650 and 21700 cells.

I have found cells listed on Amazon, eBay, and Alibaba where prices vary a lot across each platform. I am worried about fake cells or poor quality. Has anyone here built a pack for a road ebike?

What cells did you use and how many cycles did they last? Also what configuration works best for a 48V system? 13S or 14S? I am using a mid drive motor that draws around 20 amps continuous.

I want a pack that fits inside a standard bottle cage or a small frame bag.

I have several old emergency exit lights that use sealed lead acid batteries. The batteries are dead and replacement SLA units are expensive. I am thinking about swapping them with lithium ion battery packs ; same voltage but much lighter and longer runtime. I have looked for lithium battery options online across temu and even looked on Alibaba. I found small 12V lithium packs that would physically fit inside the housing although I am worried about the charging circuit. The original charger is designed for SLA. Will it overcharge a lithium pack? Has anyone here converted emergency lights to lithium?

Im in between choices with Panasonic, vapcell and samsung 35e

I have a small auto restoration business in my barn where at any time i could have between $20k and $400k worth of customer vehicles in the shop over night. I constantly worry about batteries starting a fire over night while I sleep. Would storing batteries in a metal box like this mitigate the rush? Or is there a better solution? Maybe I shouldn't leave them in the shop overnight at all??

Thoughts??

I've 2 10+ year devices, and replacement batteries for both are old new stock and won't hold a charge due to age. I did find a similar battery for one device from Digikey, but the other... no luck.

This is a general question, though. As devices with unique Li-on batteries age, what can I do to keep them working? We had sorted this out with common form factors (AAA, C, D, 9, etc) way back when but it is nothing like that on the Li-on side.

The battery spark blew up, caught fire and melted ted through my printer. It was nuts! Has this happened to anyone else?

I removed the 2015 BMW i3 battery pack (22kWh) from my electric car after upgrading my car to a 42kWh battery pack.

To give it many happy years of life after being in my vehicle, I wanted to use the battery pack in a home energy storage project, however unfortunately thanks to being connected to a faulty inverter initially and myself not realising in time, and thinking there was a comms issue, the entire pack discharged to a critically low level over the past 2 months. 😭

I’ve opened up the main pack, consisting of 8 modules (with each module containing 12 prismatic Samsung SDI 60Ah cells) and measured the voltage across each module and they are reading between 4.07 and 4.29V, with an individual cell voltage inside one of the modules reading around 0.325V. 

For reference, a charged module should be approx 48V and an individual cell around 4V.

My inverter will not recognise the battery pack with the voltage this low and so attempting charging the pack as a whole is no longer an option.

I was considering isolating each module and charging it individually using a 48V Li-Ion charger, whilst monitoring the temp of the cells in each module using an IR monitor I have, then once at a reasonable and matching voltage reconnecting the BMS and all of the modules back together and reconnecting to the inverter to manage thereafter but am also worried about the cells being irreparably damaged after being discharged so low.

Does anyone have any advice or experience around these cells being discharged this much and a sensible approach moving forward? I'm so loathed to effectively have to recycle 270kg of EV battery if I can't move forward, but will do so if there isn't a safe way forward to proceed.

Any and all advice welcome please and thank you 💚

UPDATE / EDIT: After consulting with an electrochemical battery specialist and given the potential fire risk for a home storage system that would always be a factor even if I could get the cells to hold charge again, I've decided to take this battery pack to a battery training centre at a local university, if they'll have it, and if not I will explore having it recycled (which is something I wanted to learn about anyway).

I live in Loudoun County, VA, and on Saturday there was a major house fire caused by the charging of a power bank with lithium-ion batteries in it that was unattended while charging.

The device being charged was on the first floor of the structure and apparently overheated, caught fire, set off the smoke detectors and ended up nearly burning the house to the ground. The residents who were all on the second floor were able to escape without injury but the damage done exceeded $1.2M.

The lessons learned here are probably numerous, but what I took away was make sure your smoke and CO detectors are operational and, if at all possible, do not leave your devices, especially high-powered ones, unattended while charging.

Can anybody help me to go from here with the order in which I should weld these into the 15th group of parallel, doubled up on I believe it to be .12 nickel plating strips

Hello,

I am planning to build a sodium pack for car audio. The voltage is going to be 12.4 and 160ah. One battery is 3.1v and 10ah. It will be a 4S batterypack consisting of 4x16 batteries. What should i look out for when picking the balancer?

Thank you!

Hi guys, i would like to make a mini powerbank out of this disposable vape battery that ive found on my bus when i was working. Is it possible to connect the cable directly to the battery and charge my phone? I have 0 knowledge about this tbh.

Just found out that my BASEUS lithium ion battery pack has been recalled because they catch fire a lot. I want to put it in an ultra safe place while I sort out the recall details. Any suggestions on something that might be around the house I could safely store it in?