with vtc5s harder to Come by, What is the BEST, SAFEST choice for subohming
- Thread starter Spencer87
- Start date
- th_trl_thread_readers 0
- Status
Perhaps not but the performance at that drain is shown on the data sheet.
That's a start.
So how did Sony accomplish 30 amps continuous on its vtc5 to publish it? And what temp do they record the cell increasing by?
I've always wondered how Sony could publish a CDR of 30A when the cells get hotter than the max they suggest running it at. IMO the LG HE2, the Samsung 25R and the VTC4 and VTC5 should probably be rated very similar for CDR, with the HE2 losing out a bit at higher discharge rates.
The Powerstream site has temperature data on the Sony's. They also say this:
"Maximum discharge current is somewhat arbitrary, you can always get more amps if you can accept a lower voltage and don't let the battery get too hot. The current we list here is the highest that the manufacturer (LG or Sony) supplies discharge curves for. Look at the charts listed below to see the voltage drop and temperature rise."
It's too bad they don't give temperature data on the HE2, but I bet they get just as hot as the Sony's at high rates of discharge. Here's some data including the Samsung 25R at high discharge rates.
Last edited:
Probably on a bench load tester, and the max for the VTC5 is 80c. I believe 30A is just the number they reached when fully discharging the cell and just hitting that temperature at full discharge.
80 Celsius or 200 amps? What c are you referring to?
I believe enough of us have looked up the vtc5 and sonys temp ratings to know along with independent testing and the vtc5 data sheet that the vtc5 exceeds it's temperature rating at a mere 2/3 of its continuous discharge rating. That is to say above 60 deg. Celsius at 20 amps.
Might I add these are numbers actually portrayed on the graphs on the vtc5 data sheet.
I'm personally not going to rely on conjecture to justify sonys over rating of these cells.
Now what do you suppose was the equipment involved in this "bench load tester" you speak PROBABLY of?
For the record, a bench load tester can be anything. I can probably come up with a dozen or more ways to configure one out of items I have in my garage for example.
# anticipates very simple explanation that professional equipment is different and expensive under the guise that it's relevance is substantial... or can possibly add anything useful to the discussion.
Last edited:
80 celsius, which is the discharge maximum for sony VTC cells. seems for most of these high spec batteries, the manufacturers max cell surface temps run 75-80c.
Bench is the operative term there rather than load tester, the important part is being able to test the battery in a standard ambient temperature (23c)
edit: believe me, I would like nothing better than to be able to say the vtc5 is in the same class as the 25r and he2 batteries, I have real financial incentive to be able to say that. but the truth is it simply isn't. it's slightly better, and the difference is at very high discharge rates (near 20A and beyond).
for comparison, the samsung 25r at 20A hits 95c(!!!)
Last edited:
80 Celsius huh?
Where... http://www.intaste.de/community/dtf/technical_information.pdf
Not there. Not in the lithium literature I've read through from Sony anywhere. Please produce the literature to back your statement.
Please note; performance @ 30 amp drain inherently missing from data sheet.
Where... http://www.intaste.de/community/dtf/technical_information.pdf
Not there. Not in the lithium literature I've read through from Sony anywhere. Please produce the literature to back your statement.
Please note; performance @ 30 amp drain inherently missing from data sheet.
Last edited:
https://docs.google.com/file/d/0Bx9io5ZhKnhhRDFZSlFKd3dSZG8/edit
At 7.2.4.4
For comparison, the LG (75c) one is here:
https://docs.google.com/file/d/0By-7aw3qPc-oZXUwSXV5bmVOeHc/edit
At specification 2.9
EDIT: Let's not lose sight of what's being discussed here, we're trying to determine whether the CDR is inherently meaningful, and whether CDRs can be compared directly. generally they can; if a cell performed better than its counterpart with a higher rated CDR there's no reason a manufacturer would underrate CDR.
EDIT EDIT: It is a little curious that sony does not show data from the VTC5 at 30A. Given the data presented, it seems like it would perform similarly or a bit better than the VTC4, which does show 30A data. Almost makes you wonder if the rating of the VTC5 really is 30A, though performance metrics back up a rating at least as good as the VTC4. so I guess in this case we have to work with the data sony does provide us in the datasheet.
Last edited:
Actually, temperature checks out. At least by the data manufacturers provide.
Looks fine. The VTC4 and VTC5 perform very similarly respective to their capacities, and significantly outperform a 20A rated cell, the Samsung 25R.
- Status
Similar threads
- Locked
