KeepingItLight, do you think the batteries I posted a picture of above will be safe to use in the Acebeam K70?.
Sorry to say, I am not really the right person to answer this. I do not own the
Acebeam K70, and I don't know much about it. I own only one flashlight that uses more than one 18650, the
Nitecore P36, so I have limited experience with multi-battery flashlights like the K70.
That said, I had some fun trying to learn about the issue.
According to the
Acebeam product page for the K70, it uses a "4S battery carrier" and has a working voltage of "12V-17V." So the batteries are in series. The input current used by the driver, therefore, will be the same as the current flowing in each battery. Presumably, the driver is some sort of buck driver.
I could not find an Acebeam spec for this current.
CPF member kj2, who is an experienced reviewer, reports being told by Acebeam that the K70 draws 7A. He also asked, and then answered, the same question you have about batteries.
Out of these two batteries, LG INR18650-MJ1 - Sanyo NCR18650GA, which would be the best choice for the K70?
I know both are very similar, but have read the Sanyo's are a slightly shorter. Could that cause connection issue with the K70 battery carrier?
Acebeam told me, the K70 draws about 7A from the batteries so think the Sanyo's are the way to go.
Note that kj2 did not consider the Samsung 30Q in his question. Assuming that the current draw of the K70 is indeed 7A, then, performance-wise, I doubt the Sanyo/Panasonic NCR18650GA would be as good as the Samsung INR18650-30Q. They both can handle the current safely, but, at 7A, the 30Q probably sags a little less under the load.
Using
HKJ's battery comparator, I was able to verify this. The NCR18650GA I chose for this comparison was the protected KeepPower 3500mAh battery.
The Orbtronic 3500mAh may provide performance similar to the KeepPower 3500mAh. That, however, is not the battery you purchased. You have the Orbtronic 3400mAh battery.
If we again assume that the 7A figure is correct, I do not think the Orbtronic 3400mAh battery is a good choice for this flashlight. That battery is built around the Panasonic NCR18650B. Orbtronic has the NCR18650B incorrectly spec'ed at a maximum continuous discharge of 6.8 amps. The manufacturer, Sanyo/Panasonic, posts 4.875 amps in its battery specification.
Orbtronic posted its own "derivation" of the maximum continuous discharge current for the Panasonic NCR18650B battery. Evidently, Orbtronic did not have access to the manufacturer's specification for this battery. That is why it made its own "calculation."
Based on an assumption that the maximum continuous discharge current is 2C, Orbtronic incorrectly obtained a 6.7-amp maximum. The datasheet cited by Orbtronic, however, never explicitly states that the maximum continuous discharge is 2C.
Below is an excerpt from the manufacturer's specification showing the actual maximum to be only
4.875 amps. Note that the datasheet cited by Orbtronic is a different one that does not explicitly provide the maximum continuous discharge current.
Unfortunately, I do not know which protected 18650 batteries use the three-MOSFET protection circuit mentioned by Acebeam.
I wish I could help more, but this is about all I could find.