Epoch 5000mAh 10A unwrapped

Batteries and Chargers Rechargeable Batteries
21

Yeah they probably could. Can we gather enough people for a 500 minimum group buy? I’m in for 4!lol

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22

That would certainly be THE DAY! :rofl:

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23

I unwrapped the vapcell F58 and I didn’t find anything underneath. I reached out to vapcell asking if it’s a rewrap or their own battery but I don’t think they understood the question because there response was “no tricky”.

On my fist cycle the discharge was 5087mAh’s, very disappointing but I will do another cycle and see what we get.

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24

Hey @ToddZiegler1024, thanks for the report.

Agreed. A few suggestions:

  • if you’re checking that on a charger that gives you full control (like the MC3000), please consider checking the battery datasheet and programming its charge and discharge parameters exactly like the datasheet states; things like discharge current, cutoff discharge voltage, rest period, charge current and charge termination current can have a large effect on the battery capacity.

  • keep an eye on the room temperature, the battery datasheet specifies the temperature their batteries capacity are measured at (usually 25C), much lower or much lower or much higher than that and capacity will be affected.

  • give it a couple of charge/discharge cycles more, usually the battery capacity improves after a little use.

Please keep us posted :+1:

25

I don’t have the MC3000. I have an opus BT C3400 and liitokala lii-m4s. My first cycle was on my opus and I am doing the 2nd cycle on my liitokala.

I will check the data sheet.

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26

Can you please tell me what .2C means? How do I convert it.

27

I’ve heard good things about Opus chargers (don’t remember if it was the BT C3400). About Litokala, not so much (at least as a brand).

Re: the BT C3400, I just googled and I think I found its manual: https://images-na.ssl-images-amazon.com/images/I/51TCfcbvBaL.pdf; gave it a cursory read and it seems not many parameters can be programmed (eg for discharge, only the discharge current can be set, and even so only at fixed values with large intervals among them).

There’s also the matter of precision, not sure how precise these chargers’ measurements are as (at least the for BT C3400) it seems the manufacturers do not indicate that.

Please let me know if you need assistance with interpreting it, it would be my pleasure to help.

28

Sure! It means a fraction of the battery capacity, which is indicated by the letter C. In that case, supposing the battery capacity is indeed 5800mAh (but please use the exact value in the datasheet), 0.2C would be 0.2 * 5800 = 1160 mA.

29

For testing purposes what should I set the mA at? 200?

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Let me have a look at the datasheet, will try and find it, and get back to you.

31

I want to make sure that when I report the values of a battery test, that I’m giving the best results I can based on my equipment and knowledge. Which are both lacking but much more in the knowledge category.

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32

Presuming I’m correct and the battery model string is indeed INR21700M58 as indicated in this photo, it seems Google itself can’t find a datasheet, at least one in PDF format:
https://www.google.com/search?q=“INR21700M58”+filetype:pdf

:frowning:

@ToddZiegler1024, where have you got the “0.2C” number from?

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34

Don’t despair, we’re here to help! :+1:

Presuming an official datasheet for the MJ1 can’t be found, I would try and use the values that the rewrapper (Vapcell) indicated for its F58 battery: https://www.vapcelltech.com/h-pd-174.html, that is:

  • Nominal capacity: 5800 mAh;
  • Maximum capacity: 5800*1.2= ~7000 mAh (in case your charger allows you to set that – for safety purposes during charging);
  • Cut-off voltage during charging: 4.2V (see below)
  • Cut-off voltage during discharge: 2.5V (a little too low for my tastes, but that’s what Vapcell indicates – I would employ it for testing but not for regular use).
  • Continuous Discharge current: 1.2A (from the notes after the first graph in the above page, the red line where it indeed reached 5800mAh during Vapcell’s testing; these same notes also confirm the cut-off voltages above);

I can’t find anywhere a spec for the charge termination current, but presuming it’s the same as my LG MJ1 (different size but same manufacturer and apparently the same or similar chemistry as per the “INR” prefix, so I think this is a reasonable assumption), it would be 50mA .

Which of these parameters can you set in your chargers?

35

Perfect, that’s what I used in my message above.

36

So with my equipment, would I set the discharge/charge at 500mAh’s to get the most from the battery?

37

On the BT C3400, presuming the manual I found for it is correct and the current can only be set at 200, 300, 500, 700, or 1000 mA, I would try with 1000mA, which is the one closest to the 1.2A the Vapcell spec page indicates.

38

I have had good luck with my liitokala lii-m4s. However it does tend to get warm and it doesn’t have a but the batteries don’t get hot. I keep an eye on it with my IR gun.

1 Thank
39

That is what I thought to. With the help you all gave me, I was able to read the graph and understand it.

I was surprised and pleased that it did so well at 1.2mA.

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40

Glad to be of help! Let me know if you need anything else.

You certainly mean 1.2A, not mA :wink:

And yes, I agree: this capacity at 1.2A constant discharge is a very good number, my 3500mAh LG MJ1 for example, is specced at 680mA (about half of that, and with a larger-than-half C) for optimum discharge.