determining continuous amp rating

[eyerhere]

does any body know how the continuous discharge rating is determined? When ever I see graphs it is always showing Mah. Personaly I am always more concerned with safety than longevity.
there has got to be a better way of verifying than sticking it in a mech and seeing if it heats up.

 

[Stosh]

The continuous amp rating should be included in the specifications of the battery on the vendor's website.

For the most popular batteries there's a list here http://www.e-cigarette-forum.com/forum/blogs/baditude/4848-9-battery-basics-mods-imr-protected-icr.html with the continuous amp rating, (pulse ratings are meaningless)

 

[eyerhere]

Yes but what I was wondering was how it is determined what that rating is. Manifacturers have been known to exagerate, purple efest as an example.

 

[Froth]

Yes but what I was wondering was how it is determined what that rating is. Manifacturers have been known to exagerate, purple efest as an example.

Efest doesn't manufacture their batteries, they're re-branding a cell from LG or Sony or whoever with their Efest wrapper. That's why EFest gets a bad rap from many folks on here, because you DON'T know for sure because they do not manufacture their own cells.

I do not purchase Efest batteries at all any more due to this, you can buy the same exact battery without the purple Efest wrapper for $2-$5 cheaper. For instance, the Efest purple 2500mah "35A" is actually an LG 18650 HE2 battery cell, which has only a 20A constant drain rating, they have a 35A pulse drain rating which Efest puts on the wrapper but fails to mention it's a pulse discharge rate. Dangerous.

Edit: To actually answer your question, they don't make the cells and then go figure out what discharge rating they have. They design the battery with the discharge rate already in mind, so before anything is even put together they have a very good idea of what the drain rating will be, they only test them afterwards to confirm that they designed the cell to specification.

 

[wonner]

...they only test them afterwards to confirm that they designed the cell to specification.

And I believe the OP is asking how that test is performed.

If any manufacturer or distributor claims a specific continuous or pulse discharge rating, what test is used to verify it?

 

[Stosh]

A manufacturer that claims a specific continuous discharge rating is supposed to be following a very specific industry standard set industry wide, I believe it's the IEC but not certain.

These standards are only set for continuous discharge....pulse discharge ratings are made up by the individual companies or distributors and may have little scientific basis.

 

[eyerhere]

And I believe the OP is asking how that test is performed.

If any manufacturer or distributor claims a specific continuous or pulse discharge rating, what test is used to verify it?

Yup you nailed it that is what I am looking for.
Rephrased: how would an outside testing lab confirm the manifacturers continuous discharge rate?

 

[Froth]

Yup you nailed it that is what I am looking for.
Rephrased: how would an outside testing lab confirm the manifacturers continuous discharge rate?

How is the test done and how to read the charts

It's a lot to read, but it's way better than anything I can type in response.

 

[eyerhere]

I dont know why you could not type all that
Thank you now all I gotta do is see if I can make sense out of it all. Love a challenge.

 

[supertrunker]

Fascinating read - thanks.

T

 

[sk4477]

Unfortunately lygte-infos excellent post on how to do battery/cell measurements doesn't actually answer the OPs question: "how to verify the continuous discharge rate of a cell". I, too, thought: "Oh, theres probably an IEC for it, but had no luck finding one. Or maybe Underwriters Labs, they are big into testing and certifying cells, they surely test if the claimed max continuous discharge rates are legit? Well.. no.. no they don't. They not even mention it.

It's actually worrying me a bit, since we all rely so heavily on a supposed spec, that seems to lack specification.

 

[Ryedan]

Unfortunately lygte-infos excellent post on how to do battery/cell measurements doesn't actually answer the OPs question: "how to verify the continuous discharge rate of a cell". I, too, thought: "Oh, theres probably an IEC for it, but had no luck finding one. Or maybe Underwriters Labs, they are big into testing and certifying cells, they surely test if the claimed max continuous discharge rates are legit? Well.. no.. no they don't. They not even mention it.

It's actually worrying me a bit, since we all rely so heavily on a supposed spec, that seems to lack specification.

I agree sk4477 and I've also not been able to find any information on standards in the battery industry for determining continuous discharge ratings.

Sony VTC batteries get up to around 100 deg C at 30 amps discharge. OTOH their 30A discharge curve looks quite good compared to slower rates. Samsung 25R and LG HE2 are in about the same boat at 20 amps and get a bit hotter at 30 amps but still look pretty good.

It really would be nice to know how these specs are calculated. I think there are no accepted industry standards for this otherwise they would be published somewhere and/or at least a reference to them would turn up when you look for the standard. Battery industry players must understand how things work though or there would be a lot more battery incidents than there are.

 

[Froth]

Unfortunately lygte-infos excellent post on how to do battery/cell measurements doesn't actually answer the OPs question: "how to verify the continuous discharge rate of a cell". I, too, thought: "Oh, theres probably an IEC for it, but had no luck finding one. Or maybe Underwriters Labs, they are big into testing and certifying cells, they surely test if the claimed max continuous discharge rates are legit? Well.. no.. no they don't. They not even mention it.

It's actually worrying me a bit, since we all rely so heavily on a supposed spec, that seems to lack specification.

While it may be worrying it's not the only time you go through life dealing with a "supposed spec" that you must simply trust to be accurate and true. For instance when you buy a car you're told it has X amount of horsepower but to actually verify that for yourself requires some very expensive specialized equipment, furthermore there is no real standard for the way horsepower output is measured between different manufacturers. Some manufacturers use different methods than others but most all of them post a horsepower number for the masses to see.

When you begin to push the envelope(with anything really) you have to also begin to trust outside information and listen to theoretical possibilities, the key is to get that outside information from reliable and trusted sources who have experience.