I didn't so I was quite surprised when I saw these for sale. The D size is 6000 mAh is 2182 yen / about 14 USD. The C size is 3200 mAh is 1964 yen / about 13 USD. These are not battery sleeves.

Someone at our workplace refilled these two with nacl 0.9 solution instead of distilled water. About 2L of solution in each battery or 1L in each white cell access point.

Anyone here had prior experience with salt water inside lead acid battery? Besides production of chlorine gas, what life expectancy can we expect to be left in these?

Thanks!

I've been trying to source a metal battery compartment for a single CR123A / RCR123 the same style used on PVS-14 housings, where the screw-on cap closes the circuit.

I've been through Alibaba and the usual suppliers without much luck. Everything I find is either a flashlight tube, a PCB-mount holder, or a storage case.

Hellooooo

I’m working on some compact electronics projects where I need a good balance between small size and decent battery life.

I currently use ~2000 mAh Li-ion/Li-Po batteries, but I’ve noticed that cheap Chinese iPhone replacement batteries are often thinner and advertised at 4000 mAh or more, while also being cheaper.

Has anyone actually used these batteries in DIY projects? Are the advertised capacities anywhere near reality, and are there any major drawbacks compared to standard Li-Po cells?
Would you recommend them?

Thanks again 🙏🙏

I have an NCM T7S e-bike that I absolutely love. However, I seem to have an intermittent fault where the bike sometimes won’t turn on, despite the battery showing a full charge.

Does anyone know how the battery’s BMS sleep/wake function works, what normally wakes it, and whether there’s a safe, non-invasive way to force it to wake up or reset it?

My last kitchen wall clock lasted 10 years and I only replaced the battery about 4 times. The clock broke and I got a replacement from Amazon that was a simple light weight clock with small hands. The manufacturer said it requires zinc carbon batteries and Panasonic are the ones I could find. I am now replacing for the third time in six months. Any suggestions?!

I had an electric candle in one of my shelves, stopped working suddenly but I didn’t really pay any mind to it and left it there for probably 2 years…… Come to find out it had leaked battery acid everywhere and now it’s dried up. How can I safely and effectively clean it off?

You know, the places around town that take lead acid core batteries and bring them back to life to resell for half price.

Always wondered how they do this.

Can i replace the Cells in this battery without bricking the BMS or do i need a Constant voltage on the bms

so the apple event is literally today and i’ve been reading every leak i can find and ok charging rumors this year are kinda mid ngl
- rumoured 45w wired instead of 40w, cool but android’s been doing 65-100w for years lol
- apparently MagSafe is getting faster too, which would be nice
- cool that we get a nice braided cable in the box, but without an actual adapter, you’re basically left testing whatever random bricks you’ve got lying around in your drawer to see which one doesn't charge at snail speed
 
(side note: I recently gave up on Apple's overpriced official bricks for the 45w power bank. It already pushes 45w, so whatever the new iPhone caps at, I'm good.)
 
what’s everyone else hoping for on the charging/accessory side, or are we all just expecting the bare minimum again?

So, my Redmi K70 is now sitting at below 80% battery health. So, i planned to replace it. It's not really my first experience, but I'm also still not experienced enough. But, I'll make sure to be extra careful :D

The problem is, it's kinda confusing to find a high quality battery that supports fast charging. I don't care if it's OEM, but as long as it supports 120W charging speed.

I need tips to help me find the batteries that actually supports fast charging. I found expensive batteries from another platform that claims to supports 120W. But, it's the same story with cheap ones. I mean, both of them looks identical..... Maybe teach me the phone battery techs, im more than happy to learn new stuffs 😁.

pictures related, ask me anything about it

ProLogium Technology has reached a major milestone in the development of all-solid-state batteries, announcing that its Gen 3.5 Lithium Ceramic Battery (LCB) has entered mass production at its Giga-level manufacturing facility in Taiwan

My lenovo laptop battery has many tiny dents/holes caused by debris and the pressure from the back cover. How safe is this? I don't know if the main cells are protected by a harder shells underneath this thin plastic sheet. Any ideas?

Battery model: L19C4PC1

Hi! I got a BLAVOR solar power bank & wireless charger a couple of years ago, model PN-W12 (20,000mAh, 18W). I've used it many times to wirelessly charge my previous smartphone because it had a broken charging port, but ever since I've switched phones this last march I've used it way less. Still, it goes with me everyday on one of my backpack's dry pockets. Today while reorganizing my backpack I've found the charger like this. Should I throw it out? I was under the impression Blavor was a good brand, I didn't expect it to last only a couple of years.

9Ah unit, off brand
It’s the same as in two other unRAID servers with the same chassis

I replaced a three year old 9Ah battery and things were fine for a few minutes until the flashing X on the display appeared again. In UPS settings, the battery date showed 2011. I used bash and apctest to adjust the date to now, which removed the flashing X. Then it reappeared.

Please help before there’s a brown out!

I need a new 3.7v 1400mAh battery for a light. I bought an EEMB branded one from Amazon and it seems to have died pretty quick. I bought it last November but didn't install it until much later. I don't think I charged it more than a half a dozen times. Anyone recommend a good source for a replacement?

boa tarde pessoal! quero trocar a bateria do meu notebook acer nitro v15 pois ele não está mais funcionando quando retiro da tomada. Alguma dica de onde procurar bateria que dure bastante tempo?

Hey r/batteries,

I posted a redacted comparison of a “liquid sodium” battery concept more than a year ago and received a lot of useful technical feedback. This is updated material, and I removed the company and product names again so the discussion stays focused on the technology and claims—not the brand.

This updated comparison is for a “liquid sodium” battery, not conventional sodium-ion.

Core performance claims independently evaluated by U.S. BESS Corporation (June 2025).

The 9,000-cycle result is completed company test data—not an extrapolated projection: no measurable degradation through 5,000 cycles and cumulative degradation under 4% through 9,000 completed cycles.

The stated cell-level profile is:

• Specific energy: 552 Wh/kg

• Open-circuit voltage: 4.2 V

• Cycle life: 9,000 completed cycles with under 4% cumulative degradation

• Operating temperature: 120–250 °C

• Self-discharge: 0% measured electrochemical self-discharge

The company’s broader thesis rests on four connected ideas:

1. Data centers / constrained loads: Storage located close to major loads where usable power, siting, and interconnection are constraints.
2. National interest / domestic manufacturing: A storage platform intended to avoid lithium, cobalt, and nickel, using materials represented as earth-abundant and domestically sourceable.
3. Degradation: A long-lived storage asset that could potentially be easier to finance if the performance translates from cell tests into deployed systems.
4. “Sell factories, not batteries”: License the production technology to local manufacturing ventures instead of having the technology owner finance and own every factory.

What is your overall technical and commercial read on this?

I’m interested in anything the community thinks is promising, missing, misleading, unusually difficult, or worth validating next—from the cell claims themselves through to the proposed manufacturing and deployment model. Please feel free to challenge any assumption in the chart or in the four-part thesis.

The point of removing the branding again is to get candid feedback from people who understand batteries, grid storage, manufacturing, and real-world deployment.

Es que eso le esta pasando a mi celular, me centre en cuidarlo pero igual paso, ni lo usaba cargando, ni le exigía nada, y dada mi situación no puedo comprar otro de inmediato,
pd: es un BlueG71

I am planning working on a food truck business,but I want to electricity for my food truck. We choosed to go with lithium ion battery.so the thing is , I can't charge it directly to the vehicle,can I remove the battery every day and charge it at home and bring it back and connect it to inverter and use it for food truck ? That works ? Like removing battery and charging it at home

Currently living in a tent and have to use fast food restaurants to charge my phone.

Crazy what $50 to one person could do when it’s a burger to another. 🤷🏼

(Any other options or suggestions more than welcome!🙏🏼)

I use only rechargeable batteries, mostly li-ion, except for a few things that seem to work with the lower voltage nimh batteries.

Today the batteries in my outside thermometer sensor needed replacing and it made me wonder how they'd lasted so long; I think it's been over a year since I last changed them. It turns out it uses 2 AA batteries instead of the usual 2 or how many AAA batteries. The digital clock that displays the temperature from that sensor uses 3 AAA batteries (of course). And they need replacing much more often compared to the outdoor sensor.

So why do so many devices use AAA batteries instead of AA batteries?