Samsung 25R vs. VTC4

[SmokingAStogie]

I called illumination supply and was told that the official CDR for the Samsung 25Rs are at 20A CDR but have been tested up to 35A CDR while the VTC4s are at 30A CDR. Has anyone ever used a Samsung 25R battery on a mech mod at .2+ohms?

 

[Baditude]

Has anyone ever used a Samsung 25R battery on a mech mod at .2+ohms?

Nope. 0.5 is the lowest I've ever built for my Samsungs. If you are going to be building that low of resistance, use the proper batteries. A Samsung 25R should only be used with 0.4 ohms or higher. You want to have a couple of 0.1 ohms headroom for safety. We put too much faith into cheap ohm readers.

o1.0 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

Explain it for the dumb noob: Ohm's Law calculations

Others may differ, but I go only on the continuous discharge rate amps, not the pulse discharge rate. Pulse ratings are meaningless to me.

Continuous Discharge Ratings vs Pulse (Burst) Discharge Ratings

The "continuous discharge rating" in amps is the standard specification for amp limits within the battery industry. It is a determination made by the manufacturer and represents the amp limit a battery can be safely used before it will fail.

The "pulse or burst" discharge rating is not a specification standard within the battery industry. Every manufacturer or vendor seems to have their own definition of what the pulse rating is.

A pulse discharge rating is any use above the continuous discharge rating. It is never safe and not within the intended operating parameters of the battery. You should not operate your device above the continuous rating if you can help it. The pulse rating is a condition in which the battery is on basically a buildup to failure. It is exceeding the sustainable and intended discharge rate of the battery. It is inappropriate for a consumer device to operate in the pulse range of its battery.

Which would be why we shouldn't rely on any pulse rating. Any failure, mechanical or electronic, that fires the mod will operate in the 'continuous' mode. If your setup relies on a pulse rating, it's instantly over spec.

If your amp draw is safely in the continuous discharge range, your coil could act almost like a fuse and burn out before the battery is stressed. If you are already running the battery at the edge of it's limits (pulse), there is no margin of safety.

 

[SmokingAStogie]

Nope. 0.5 is the lowest I've ever built for my Samsungs. If you are going to be building that low of resistance, use the proper batteries. A Samsung 25R should only be used with 0.4 ohms or higher. You want to have a couple of 0.1 ohms headroom for safety. We put too much faith into cheap ohm readers.

o1.0 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

Explain it for the dumb noob: Ohm's Law calculations

Others may differ, but I go only on the continuous discharge rate amps, not the pulse discharge rate. Pulse ratings are meaningless to me.

Continuous Discharge Ratings vs Pulse (Burst) Discharge Ratings

The "continuous discharge rating" in amps is the standard specification for amp limits within the battery industry. It is a determination made by the manufacturer and represents the amp limit a battery can be safely used before it will fail.

The "pulse or burst" discharge rating is not a specification standard within the battery industry. Every manufacturer or vendor seems to have their own definition of what the pulse rating is.

A pulse discharge rating is any use above the continuous discharge rating. It is never safe and not within the intended operating parameters of the battery. You should not operate your device above the continuous rating if you can help it. The pulse rating is a condition in which the battery is on basically a buildup to failure. It is exceeding the sustainable and intended discharge rate of the battery. It is inappropriate for a consumer device to operate in the pulse range of its battery.

Which would be why we shouldn't rely on any pulse rating. Any failure, mechanical or electronic, that fires the mod will operate in the 'continuous' mode. If your setup relies on a pulse rating, it's instantly over spec.

If your amp draw is safely in the continuous discharge range, your coil could act almost like a fuse and burn out before the battery is stressed. If you are already running the battery at the edge of it's limits (pulse), there is no margin of safety.

I never build anything lower then .2 ohms, thats my limit. I guess VTC4s are my best bet then. Thanks for the info!

 

[brekec88]

For mech mods go with Sony. In regulated devices I get way better battery life with LG or Samsung.