Efest 26500 flat tops are slightly recessed.

Joined
Jul 27, 2006
Messages
763
Location
Raleigh, NC
Just received my new efest purple 26500s. The flat top positive connection is ever so slightly recessed. They do not connect when pushed together in series. I don't feel safe with magnets between them and the literature Im finding says do not solder them. What's a flashaholic to do?
 

ChrisGarrett

Flashlight Enthusiast
Joined
Feb 2, 2012
Messages
5,725
Location
Miami, Florida
Just received my new efest purple 26500s. The flat top positive connection is ever so slightly recessed. They do not connect when pushed together in series. I don't feel safe with magnets between them and the literature Im finding says do not solder them. What's a flashaholic to do?

My two Efest IMR 3500s protrude a good millimeter, or two and make contact in series, so I don't know what to say, nor do I know if mine are typical, or unique in this regard, as they're all that I have in 26650s.

You can buy them with button tops, IIRC, or protected with button tops.

http://www.mtnelectronics.com/index.php?route=product/product&path=59_108&product_id=189

You need to know the light before you buy the batteries. If you have a reverse polarity protection, you'll need a button top. If you have a spring at the positive end of a light, you can get by with flat tops.

Chris
 

bella-headlight

Newly Enlightened
Joined
Jan 6, 2015
Messages
198
Location
South Wales UK
I used to be a fan of magnets & scared to solder blob the cell positive anodes.
However after getting a reasonable soldering station to replace my aged non temperature controlled 40 watt iron & gaining a lot more practice (& proficiency) at soldering I solder blobbed a few cells with no problems.
Then when doing some tail cap amp readings I noticed that 2 cells with a magnet for a button in series gave around 0.5A less than the same cells without a magnet when tested in the same light.
I took the cell with a magnet, took the magnet off & soldered a blob on & got about 0.5A higher reading than with the magnet.
This makes me think that the magnets I was using have a fair amount of resistance.
Now I don"t know if all magnets are the same, or if just mine are high resistance, but a combination of that & the fact that I now feel comfortable with solder blobbing cells means that I won"t go back to magnets (unless it was an emergency).
The other option if you don"t feel comfortable solder blobbing is to use one of these purpose made Jaxman cell connectors https://www.aliexpress.com/item/Con...lt&btsid=a2471e9e-91bb-487d-81d7-bd18affe490a
They are available in 2 sizes for both 18650 & 26650 cells, although when I bought mine there were only the 18650 ones which I used with 26650"s fine so I think either would work fine with 26500"s.
 
Last edited:

ChrisGarrett

Flashlight Enthusiast
Joined
Feb 2, 2012
Messages
5,725
Location
Miami, Florida
OP is talking about 26500 cells and not 26650

If you are using them inside D size barrel with plastic (PVC) tube, then using magnet is safer otherwise, globe of solder will solve the problem.

Thanks. Glossed over that one.

Not the first time I've misread cell numbers.

Chris
 

CuriousOne

Enlightened
Joined
Oct 14, 2012
Messages
813
You don't need any fancy soldering station to solder batteries, any 60W iron will do just fine. You just need special flux for battery contacts, because standard ones does not go well with batteries.
 

bella-headlight

Newly Enlightened
Joined
Jan 6, 2015
Messages
198
Location
South Wales UK
Yes I know you don"t need a fancy station to solder blob cells & at no point did I say you did.
What I was getting at was that before I had my station I never had the confidence to solder blob cells.
When I got the station I obviously started doing more soldering & this increased soldering practice (not the station) gave me the confidence to have a go at solder blobbing cells, which I am now comfortable doing.
I could probably blob the cells just as well with my old basic iron as there really is nothing to it.
 
Top