LG HD2C 20A 2100mAh 18650 Bench Test Results...a 25A/2200mAh battery, better than the HD2
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Ahhh...thanks! Yes, my math was wrong.
There are reasons why LG uses a particular temperature. But it's not a hard safety limit where damage occurs above it and the cell is fine below it. These cells experience damage every second they exist after being manufactured. Their capacity drops and their internal resistance increases. As the temperature rises the pace of this damage accelerates. But unil you get up to around 125°C there aren't any real physical changes to the battery caused by the high temperatures. Below that you just get an accumulation of this temp-related performance damage. The 70°C spec was chosen by LG either in response to customer requests or as a result of their tests determining that it's the temperature you can run the cell at and still get a decent number of cycles (number of charges/discharges) before the capacity drops, or internal resistance rises, above a certain number. It's not the point at which safety is suddnly compromised.
If a customer is willing to accept a drop in cycle life down to, let's say, 100 cycles before the capacity drops a certain percentage then they can operate the battery at a higher temperature. This is done in a lot of severe environment applications where the ambient temperature is very high.
My ratings are to be used to directly compare the performance of different batteries without worrying about the different criteria that each manufacturer uses to rate them. If one battery runs cooler than another for me then it can get a higher current rating to allow direct comparison of their performance. For example, if your setup draws 15A and you can choose a 20A or 25A battery you could choose the 25A one knowing that in my tests it would run cooler than a 20A one.
My ratings, or any rating for that matter, aren't recommended operating conditions. They're just ratings to be used to compare performance. For the HD2C, no one is going to get near its ratings in use. Even at 70°C the battery is too hot to hold and the user of that mod will stop.
You have gotten me to take another look at my data though and I now realize I gave the HD2C an unfair advantage. I think I was too focused on the HD2's 25A rating and used the upper limit for an acceptable CDR temperature instead of the average temperature, as I would for a rewrap. In my tests the HD2C's reached 74°C at 20A. This is hotter than LG's test results considering their 20A rating but that's completely acceptable considering the difference the setups and, possibly, the ambient temperature. If I rate the HD2C with the same critical eye I would use for a rewrap I would rate it at 22A. This results in a 79°C temperature, the average for cells at their CDR in my tests. But, lower than what I normally see from LG's run at their published ratings, which is typically 82°C-83°C in my tests.
My 22A rating would result in a 79°C temp in my tests. With the 4°C diference in our setups that would mean that the HD2C would reach 75°C in LG's tests. This is very close to their test results and would never be seen when vaping except perhaps by vaping competition participants.
I'll update my test report to reflect the new rating. It's only a small change but even that is still important to me. Thank you for your time regarding this!
What were your concerns regarding my Aspire test report?
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IMPORTANT UPDATE
I gave this battery an unfair advantage, giving it a continuous discharge rating (CDR) of 25A, when it should really be rated at 22A. I allowed this battery to reach the upper limit for a battery operating at its CDR instead of using the average temperature as I would for a battery I did not know the rating for.
When I use this average temperature limit the HD2C must be rated at 22A instead of 25A. Its performance has not changed, just the way I interpret the results. Sorry for the confusion!
I am unable to update my original post but the ratings table has been updated with the new rating.
CAUTION: If you discharge the HD2C at 22A continuously or vape at 50A or higher down to below 3.0V then you could bring the HD2C's temperature up over the 70°C rating that LG gave it by several degrees. If done consistently this will result in a shortening of the battery's life. And vaping above my 30A maximum continuous amp (MCA) rating can result in some some cells possibly venting (not thermal runaway) if there is a mod malfunction or accidental button press.
I gave this battery an unfair advantage, giving it a continuous discharge rating (CDR) of 25A, when it should really be rated at 22A. I allowed this battery to reach the upper limit for a battery operating at its CDR instead of using the average temperature as I would for a battery I did not know the rating for.
When I use this average temperature limit the HD2C must be rated at 22A instead of 25A. Its performance has not changed, just the way I interpret the results. Sorry for the confusion!
I am unable to update my original post but the ratings table has been updated with the new rating.
CAUTION: If you discharge the HD2C at 22A continuously or vape at 50A or higher down to below 3.0V then you could bring the HD2C's temperature up over the 70°C rating that LG gave it by several degrees. If done consistently this will result in a shortening of the battery's life. And vaping above my 30A maximum continuous amp (MCA) rating can result in some some cells possibly venting (not thermal runaway) if there is a mod malfunction or accidental button press.
With all things said and done regarding this battery, would you still say it's a better performer than the pink LG HD2? I just purchased a single 18650 mech and I typically build between .22 and .3 ohms.
I am torn between the LG HD2C and the LG HD2.
Thanks for all of your hard work, Mooch!
Another quick question - the build that I have running in my rda is .18 ohms. Steam Engine calculates that I am drawing 20.56 amps from the battery. I am using the LG HD2C in a mech. This should be OK right as long as I'm not running the batteries down too low? So far I have been changing out the batteries once they hit around 3.6 to 3.7 volts.
You're exceeding the amp rating of your batteries so it can not be called safe. You're not exceeding the rating by much so you shouldn't be in too much danger, but still... A coil that low in resistance... I wouldn't do it. If your ohm reader is off by a little you might be drawing way more amps.
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LG HD2C 20A 2100mAh 18650 Bench Test Results...a 22A/2200mAh battery, better than the HD2
* Coil amp draw from Ohm's Law calculations for Mechanical Mods:
1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
0.0 ohms = dead short = battery goes into thermal runaway
You're pushing that particular battery too hard in a mech, IMHO. Increase your ohms, or use a true 30 amp battery.
Everyone is free to set their own parameters, and I can only say what mine are. I try to never exceed 50% of the CDR (continuous discharge rating) of a fully charged battery (4.2v). So with a 20 amp battery, that 50% would be 10 amps continuous -- a 10.5 amp draw from a 0.4 ohm coil.
The reason that I place a 50% limit is because as a battery ages the mAh of the battery degrades, as the mAh degrades so does the batteries c rating (amp limit). So down the road, your 20A battery may only be a 10A battery.
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Hey Mooch. I love what you're doing. Amazing stuff. I hate to bother you with questions you probably receive constantly, but I'm having trouble deciding.
I'm running a .27 ohm buld on a series mechanical. Voltage under load is 6.5 with fully charged HD2s. I want a new pair, and I'm thinking either HD2C or VTC5A. What are thoughts and recommendations?
I'm running a .27 ohm buld on a series mechanical. Voltage under load is 6.5 with fully charged HD2s. I want a new pair, and I'm thinking either HD2C or VTC5A. What are thoughts and recommendations?
I haven't compared them directly but you can check my discharge curves to see which sags further when pulsed at the current levels you're vaping at.
@Mooch would you still consider the hd2c better than the sony vtc4 and hd4? Im using a asmodus minikin 2 (180W) and it's a 2 battery mod. I can't decided which batt to choose. I dont vape beyound 90, usually in the 70-80 degree range. But i want the ability if i choose to vape up to 100W. What do u think about the sony vtc5A?
A touch better, yes.
The VTC5A is a bit better than all of them, especially since its capacity is higher too.
Thank you sir for ur response.. appreciate ur indept research on all the batts.. you sir, are the real MVP
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