Samsung 20-R?

[MMcQ]

I've been looking into getting a couple new batteries and doing my research. From what I've been able to gather the Samsung 20-r is a decent mah (2000) 20 amp battery that according to mooch's latest chart shows pass on 40 amps. Not that I've ever had or will have any reason to go that high, I do have a friend who's into mechs that I would like to help out by finding a quality battery that would provide some safety if he were to have an autofire situation. Is there any reason why I don't see these batt's talked about anymore?

 

[sonicbomb]

Mooch rated it at 22 amps not 40, remember CDR is your safe value. The reason it's probably not talked about much is the 25R and the HG2 both offer better mAh ratings for a 20 amp CDR

 

[MMcQ]

I saw that but was wondering how it rated Max amps at 40 while the 25r and hg2 were only 25. I currently have 2 25-rs and 2 lg he2's. I guess my real question was why he rated it 22 amps cdr while it passed to 40. The only other battery i saw off his chart that came close was the hb2.

 

[sonicbomb]

Why don't you ask @Mooch

 

[Baditude]

I saw that but was wondering how it rated Max amps at 40 while the 25r and hg2 were only 25. I currently have 2 25-rs and 2 lg he2's. I guess my real question was why he rated it 22 amps cdr while it passed to 40. The only other battery i saw off his chart that came close was the hb2.

The difference is the "continuous discharge rate" vs the "pulse discharge rate".

That "max amps at 40" is the pulse rating. Big deal, its means absolutely nothing. For example, a nonspecific battery may have an advertised 40 amp pulse rating for 1 millisecond, but then the output immediately drops to an unuseable 6 amps. What good is that battery to you?

In vaping, we pay no attention to pulse ratings. They are meaningless to our purposes. There is no recognized standard for pulse ratings in the battery industry; however the continuous discharge rate (CDR) is an industry standard. Pulse ratings could be anywhere from a millisecond to a few seconds, and the manufacturer/vendor often doesn't publish what their pulse rating times are. So in effect, pulse ratings are useless.

There are no 18650 batteries with a genuine rating over 30A!

Battery pulse ratings are useless!

 

[MMcQ]

The difference is the "continuous discharge rate" vs the "pulse discharge rate".

That "max amps at 40" is the pulse rating. Big deal, its means absolutely nothing. For example, a nonspecific battery may have an advertised 40 amp pulse rating for 1 millisecond, but then the output immediately drops to an unuseable 6 amps. What good is that battery to you?

I understand that pulse ratings are completely worthless to our use but I asked mooch and the 40 amps max was a cdr rating. Unusable as it drained the battery too fast but it didn't vent and didn't get hot. Possibly shortening it's life and damaging it, I suppose. However from a safety standpoint for using in a mech I was looking for a battery that could handle an autofire, stuck switch scenario and that battery fits the bill. Not so much for out and about use, but home with his charger handy and some piece of mind if catastrophe happens.

 

[Baditude]

I asked mooch and the 40 amps max was a cdr rating. However from a safety standpoint for using in a mech I was looking for a battery that could handle an autofire, stuck switch scenario and that battery fits the bill. Not so much for out and about use, but home with his charger handy and some piece of mind if catastrophe happens.

Mooch rated it at 22 amps CDR, not 40 amps.

• At 30A the temperature rose to 89°C. This is too high a temperature for a cell operating at its CDR. There is significant voltage sag indicating that it's operating way beyond its rating.
• At 35A the temperature rose to 90°C. This is too high a temperature for a cell operating at its CDR. There is significant voltage sag indicating that it's operating way beyond its rating. The loss in capacity was significant.
• At 40A the voltage quickly dropped to a useless level. The temperature peaked only at 66°C due to the very short run time.
• Another discharge at 20A showed only a slight loss in capacity, indicating that the temperatures reached at 25A, 30, and 35A did not get high enough to do more than slightly damage the cell.
• I am setting a CDR of 22A for this cell since at this current level its operating temperature is at the average for a cell operating at its CDR. While operating any cell near its rated maximum current causes damage to the cell, I would expect decent cycle life from this cell at 22A.
• The cells never reached dangerous temperatures. At very high discharge current levels the voltage collapsed and significantly shortened the discharge time. This limited the temperature increase.

There is no piece of mind for any battery should conditions occur for it to go into thermal runaway in a mechanical mod. Things like a short circuit, putting a battery in backwards, or a stuck fire button will cause any battery to go into thermal runaway.

- Sealed metal tubes will probably explode if a battery vents violently
-The battery itself may physically block gas from escaping to the bottom of the mod
- Small vents at the bottom of the tube are useless, only very large gas vents near the top have a good chance of preventing an explosion

IMR/INR battery chemistry generally means a battery in thermal runaway will simply vent gas. However, in a mechanical mod with inadequate ventilation this could potentially be catastrophic. Vent holes in the battery cap are probably inadequate, as the battery may "swell" in size during venting, or otherwise physically block the pathway of the gas from escaping. Ideal location of vent holes are near the top of the mod, where the positive pole of the battery (where the gas escapes) is located.

Mech Mods with top venting holes?

Ideal location for vent holes in a mechanical mod

 

[MMcQ]

Sadly my friend purchased this mod without my input or I would've told him to spend the money on a better regulated mod. Its a FUhatten and does have two completely too small vent holes at the top where the atty would more than likely block them. Kick would only work with a 18500 as it's a fixed length. I understand that shorting ANY battery would cause it to go into Thermal runaway. I don't want to quote Mooch without his adding input into this thread on his own but he referred to the Max amps as being a Capability as opposed to a rating. If a battery loses the ability to function before achieving the temp necessary to go thermal than would that not prevent it from venting in an autofire situation? I probably won't be able to respond anymore as I got work but thank you for your input.

 

[Mooch]

Check out the Max Amps explanation at the bottom of the 18650 safety grades table.

 

[supertrunker]

Things like a short circuit, putting a battery in backwards, or a stuck fire button will cause any battery to go into thermal runaway.

Really?

Short circuit maybe, but the others?

My mechs don't care about the orientation of the battery.

T

 

[MMcQ]

Backwards battery with a tear in the wrap would effectively be a short once the button is pressed.

 

[supertrunker]

Good point, but any battery with a torn wrapper would put one at risk and regardless of the build or the CDR of the battery.

T

 

[MMcQ]

True but with battery orientation positive to pin it would create an autofire situation which should be more or less immediately noticeable. Then the cdr would come into play and the higher the cdr the less chance that thermal runaway could occur. Of course if you build above the cdr intending to pulse it could go thermal but if you build below it should just kill the battery. I believe... again I don't use mech's for this reason. My kbox 120 with its plastic battery sled just feels safer to me .