Help re Rechargable 18650 Batteries

[Benfool]

The easiest way would be to measure them with some calipers. If they're bigger than 18mm in diameter and 65mm long then they're probably protected. Also protected cells tend to be button tops, non-protected flat tops (but this isn't always true).

I think you'd struggle to tell via measuring rhe voltage.

 

[The Old Ruminator]

The seller has ignored my request for a refund as he says he has posted the batteries. I CBA to argue over the £15 I paid for them so will give them a try and charge them in the garden.

 

[Cantclimbtom]

The easiest way would be to measure them with some calipers. If they're bigger than 18mm in diameter and 65mm long then they're probably protected. Also protected cells tend to be button tops, non-protected flat tops (but this isn't always true).

I think you'd struggle to tell via measuring rhe voltage.

My two are 26800 and fat and slightly over length, the over length made me wonder (actually spoke to the supplier by phone and they didn't know!! as they had to send a slightly different product and wanted to check) but very expensive so nervous to risk killing them.

Sorry to hear you got stuffed for £15 O.R.!

 

[traff]

The easiest way would be to measure them with some calipers. If they're bigger than 18mm in diameter and 65mm long then they're probably protected. Also protected cells tend to be button tops, non-protected flat tops (but this isn't always true).

I think you'd struggle to tell via measuring rhe voltage.

Whilst this is generally accurate, please don't measure the length with calipers unless they are cheap plastic ones and thus insulated. Otherwise you are shorting the cell, which if it is unprotected, will result in a suprise.

 

[andrewmcleod]

The seller has ignored my request for a refund as he says he has posted the batteries. I CBA to argue over the £15 I paid for them so will give them a try and charge them in the garden.

Just keep clicking 'refund' on eBay and they will end up giving you a refund. eBay is a buyers' market, and this listing is against eBay policy.

 

[Cantclimbtom]

Whilst this is generally accurate, please don't measure the length with calipers unless they are cheap plastic ones and thus insulated. Otherwise you are shorting the cell, which if it is unprotected, will result in a suprise.

But surely that'd allow someone to distinguish between the protection circuit popping in a protected battery and incendiary runaway of a non protected battery?

 

[ChrisB]

The seller has ignored my request for a refund as he says he has posted the batteries

These days all the payments go through eBay, and eBay have told you

If you can't reach a resolution, or the seller doesn't fulfill their return policy, you may be eligible for eBay Money Back Guarantee.

So ask eBay for the refund

 

[paul]

ChrisB is correct - I recently won an auction for a high-valued item and paid promptly but had no communication from the seller at all - not even delivery. I informed eBay and my payment was refunded a few days later by eBay.

 

[mattsccm]

Am I right in thinking ( my wife says stop there) that those with a button top are protected and the flat tops, as used in vapes are not? Not a sure fire way of quality though as some I have from Chinese head torches have this protection.
Note. I have Trustfire torch which has lasted a good 8 years and it and the original 18650 battery are going strong. It gets used hell of a lot. Just bought a Trustfire head torch that is darn close to the popular Fenix ones but way cheaper. I do wonder if Fenix have their own factory or are they just rebadged as so much is nowadays and none the worse for it.

 

[Bob Mehew]

I'm afraid I have not come across a simple way to tell whether the safety protections are installed except by stripping the battery apart. Reputable manufacturers can install safety protection and then offer different means of outlet (i.e. button / lead / terminal). Which I appreciate is of little help.

 

[The Old Ruminator]

The batteries have arrived. Charged OK. 7800mAh 3.7v. Li-on. Low discharge rate, no memory effect,. Short circuit and over current protection and discharging protection.. Crucially it does not say where they come from just the words Bai Chaun Ultra Fire . Although they have managed to spell it Uitra Flre. That says it all I suppose. Will advise if anything goes wrong.

om Wikipedia, the free encyclopedia




Beijing Baichuan Intelligent Technology Co., Ltd.

Native name	北京百川智能科技有限公司
Company type	Private
Industry	Information technology
Founded	April 10, 2023; 19 months ago
Founder	Wang Xiaochuan
Headquarters	Beijing, China
Number of employees	170 (2023)
Website	www.baichuan-ai.com

Baichuan AI (Baichuan; Chinese: 百川智能; pinyin: Bǎichuān Zhìnéng) is an artificial intelligence (AI) company based in Beijing, China. As of 2024, it has been dubbed one of China's "AI Tiger" companies by investors.

 

[Cantclimbtom]

UltraFire, UitraFire, SureFire, TrustFire should be good
HouseFire, CarFire, InsuranceFire were never as popular brands and best avoided

 

[Fulk]

Hi TOR, are these '7800mAh 3.7v. Li-on.' batteries single cells or packs of 2 or 3? 7800 mAh sounds a high capacity for single cells.

 

[andrewmcleod]

That mAh rating is definitely nonsense

I have a little gizmo that can read the actual mAh of a battery (some chargers can do this as well). Basically you charge the battery and then discharge it into a big resistor, and the gizmo reads the total energy extracted. Of course that was also cheap off eBay, so accuracy not guaranteed!

 

[The Old Ruminator]

Hi TOR, are these '7800mAh 3.7v. Li-on.' batteries single cells or packs of 2 or 3? 7800 mAh sounds a high capacity for single cells.

Normal size battery as goes straight into the torch.

 

[ChrisB]

OR, if the supplier is claiming that a normal sized 18650 battery (18mm diameter, approx 65mm long) holds 7800mAh, they are lying to you, and you shouldn't believe anything else they tell you, e.g., about protective circuits. The best non-specialist 18650 cells are about 3600mAh, Vapecell have one called the H40 which does 4000mAh but at the expense of a lower maximum current. 7800mAh is so far beyond what's possible that it cannot be genuine.

 

[Cantclimbtom]

I have been irritated by battery manufacturers quoting numbers like 7800 and when you look carefully that's the mW (milliwatts) so maybe it's a 2,000 mAh battery labeled as 7800 to catch the unwary. Keep looking and you'll see examples!

 

[The Old Ruminator]

Its a wicked world. Now even my honey I have for breakfast is not all real.

 

[Trek]

18650 cell Database

This is a really helpful battery database for reference

 

[Fulk]

Well. There's so much information on there . . . seriously, if I wanted to check the credentials of a battery on some random web-site how would that database help?