Help re Rechargable 18650 Batteries

[The Old Ruminator]

Currently I have 3,000 mAh batteries in my torches. Suddenly all four went dead at the same time. So question one is why should this happen ?

I can get these again from Amazon but I thought that I would try higher mAh batteries readily available from eBay. I see they go up to 9,000 mAH but I ordered ones at around 6,000. I then get conflicting emails from ebay and the seller.

no.reply@ebay.com​ ​

Thu, 7 Nov, 19:40 (13 hours ago)

to me

Hello -----
We take product safety very seriously. We’re reaching out to you because an item you purchased may have been recalled or pose a safety hazard. We recommend that you stop using this product. If you have questions about the item(s), please reach out to the seller or the manufacturer. Item details are listed below.


Due to product safety concerns, the sale of 18650 and 21700 batteries or battery cells being sold individually are not permitted on eBay unless they are built into a product or accessory and can't be removed or directly handled.


If you have any problems, we recommend that you contact the seller from your Purchase history and try to reach a resolution. 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.

The sellers response -

Dear Valuable Buyer,

I hope this message finds you well. I am reaching out regarding your recent order from my store. I wanted to inform you about eBay safety email, eBay has sent you an auto email by mistake. So please ignore this. Our item absolutely 101% authentic ang highy quality performance.
it has been tested many times and gone through many testing stages then we start selling this product. fell free and use this item. This is safe for you. we already contact the eBay team about this email. We try to solve this issue quickly as soon as possible.​

 

[The Old Ruminator]

Now all this reaching out has left me utterly confused. I am not even sure if I will get the batteries now. If I do are they safe to use and charge or will my torch explode and knock somebodies ruddy head off.

 

[JasonC]

The response from the seller does not inspire confidence. I'm no expert on batteries, but the word 'bargepole' leaps to mind...

 

[Benfool]

As far as I know, the maximum capacity of 18650 cells currently is 3600mAh - anything more than this is a lie. Only buy cells from a reputable seller and only buy reputable brands.

My personal recomendation is either

www.ecoluxshopdirect.co.uk/
or
www.nubattery.co.uk

And I would tend to stick to the following brands
Panasonic (NCR)
Sanyo
Sony
LG

Anything with the word Fire in it (TrustFire/TrueFire/TrustMeThisReallyWillSetOnFire) is chinese crap and is definitely to be avoided.

I'd personally return the cells you've bought from eBay (the distance selling act is your friend) and buy something proper. The fact that he's claiming that they are 101% authentic should be a dead giveaway!

Determining why your cells are dead is going to be hard without firther context. Were they all used in the same device? In series or in Parallel? Are they protected? And how were you charging them and at what rate? The first thing I'd do is check the voltage on them - if its less than 2v then they have been deep discharged and cannot be recovered.

Hope that helps!

 

[Benfool]

Actually, there does appear to now be 4000mAh batteries available - they're reasonably expensive and not brands that I would generally buy. I would stick with the above brands at a capacity of 3500mAh or 3600mAh.

B

 

[Samouse1]

Actually, there does appear to now be 4000mAh batteries available - they're reasonably expensive and not brands that I would generally buy. I would stick with the above brands at a capacity of 3500mAh or 3600mAh.

B

I was about to link to Fenix, they've got a 4000mah battery out now. Curious as to why you don't include them in the list, it's a brand a lot of cavers put a lot of trust in!

 

[Benfool]

Fenix aren't a manufacturer, they rebrand cells for they're own use - that's why they are substanally more expensive than others. I suspect they're now using some of the 4000mAh cells on the websites I quoted above.

The fact that fenix are rebranding them is a good sign that they are reliable.

 

[Bob Mehew]

Still looking into this topic, as I understand it Li ion batteries can be built with various safety features to reduce the fire risk, so this has resulted in cheaper Li ion batteries being sold without these safety features. The suspicion is that many of the e-scooter battery fires which have recently occurred are due to the owner replacing the supplied batteries when they fail with more cheaper ones which don't have the same safety features. Hence ebay resorting to the ban on selling of individual batteries but permitting the selling of kit which contains such batteries on the presumption that the kit will some how mitigate the impact of a Li ion battery fire.

Ben is right in saying only go for batteries from reputable manufacturers via reputable dealers. Although I can't cite an example, I have the impression that one can get batteries with a nominal voltage of 3.7v and much higher capacity than 3700mAh because they contain several Li ion cells rigged in parallel rather than in series.

 

[snebbit]

Regardless of whether the seller thinks the items are safe/authentic etc., they've still broken eBay policy by selling them. It's not a recent policy change either so they can't use that excuse. If they contest a refund, go to eBay direct and they'll recover the funds for you I'd have thought.

 

[Benfool]

Ben is right in saying only go for batteries from reputable manufacturers via reputable dealers. Although I can't cite an example, I have the impression that one can get batteries with a nominal voltage of 3.7v and much higher capacity than 3700mAh because they contain several Li ion cells rigged in parallel rather than in seseries.

A 18650 by definition would be a single cell, so would have a nominal voltage of 3.7v and max capacity of 4000mAh.

Many devices including caving lights, laptops and eBikes would have a battery pack made from several 18650s in series and parallel.

 

[Trek]

Another reputable UK supplier is https://www.fogstar.co.uk/

 

[ChrisB]

So question one is why should this happen ?

One possibility is that your charger is broken and failed to charge them but still showed that it had.

Are they used singly or together?

 

[Space Doubt Caver]

With old batteries, like NiCad, NiMH, you had to make sure you emptied them (used all the power) before recharging so they didn't lose their power memory, if it even had 5% charge left in them, if you charged them with 5% still in them without draining all the power.

Then when you brought them upto 100% charge, it would read as 100% charged, but in actual fact you will have lost that 5% of power memory the battery had, even though it told you it was at 100% after a charge.
To keep your old batteries as long as possible you always made sure you used all the power and then charged them when 100% empty.

With Lithium Ion Batteries whether it be 18650 or any other model, their power memory is kept by ensuring you leave 5% of the power in the batteries, if you where to use that last 5% of the battery even unknowingly, it will lose it's power memory, and then will no longer charge from that point on.
If this happens with just 1 of the lithium ion cells, it spreads to the rest of them depending if they are connected in series or in parallel, if they are in series then it does move to all of them and eventually they degrade but at a much slower rate.

If they are connected in parallel then that would mean if they had used that last 5%, that all the batteries had at the same time then all together they would have lost substantial power memory and recharge capability in all of the cells as a whole.

Usually applications such as headtorches will be in series, as not to over power the LED's, and to give you more time.
and sometimes it can be the power management system, (Circuit board in the battery casing) that's the problem but this is very rare.

If you get new 18650's and want to install them, go to a certified electrician who is insured for such work.
Better safe than sorry.

SDC

 

[The Old Ruminator]

One possibility is that your charger is broken and failed to charge them but still showed that it had.

Are they used singly or together?

No fine with other batteries. All four came out of the torch and all four would not recharge. I dont recall running them flat but the torch could have knocked on in the box.

 

[mikem]

Most torches toggle down to a lower setting as the batteries drain, so it would have to not be checked for a long time to totally flatten them

 

[Stevie]

I used these guys. Uk based. Easy to speak to on the phone. I selected the batteries I needed to fit into my Duo and they wired them together and shrink wrapped leaving the tail with the connector I specified sticking out. Been using them 18 months now and not had a problem.

LiIon Batteries UK | 3.7V 1S LiIon Battery Packs | Overlander Batteries

3.7V 1S Lithium Ion (LiIon) battery packs for a variety of applications. Constructed in the UK with custom options available.

www.overlander.co.uk

 

[Cantclimbtom]

Not sure if the higher capacity batteries have less charging cycles? Let's see if wormster or another regular here who works with batteries can enlighten on capacity etc...

For 4 batteries (in same torch?) to go dead at same time sounds like they were non protected batteries and over-discharged?

 

[The Old Ruminator]

Not sure if the higher capacity batteries have less charging cycles? Let's see if wormster or another regular here who works with batteries can enlighten on capacity etc...

For 4 batteries (in same torch?) to go dead at same time sounds like they were non protected batteries and over-discharged?

The only answer really. Thanks

 

[Benfool]

Put a multimeter on the cells and you can easily check - if under 2v then they are deep discharged and are ruined

B

 

[Cantclimbtom]

Put a multimeter on the cells and you can easily check - if under 2v then they are deep discharged and are ruined

B

Question for you and others about protected batteries, If I had 2 li ion batteries and didn't know if they were protected or not, is it possible to tell without opening them up? Such as fully charged immediately out of a charger and look for a slight "missing " voltage?

Edit: and if I add my own and accidentally "double" protected them, will I lose and significant capacity?