"Batt down" at 60% charge

[Gnostical]

Hi, I've been using my DNA100C every day for about 9 months now, but lately, in the last month or 2 I've been getting this issue where the battery charge indicator isn't even down halfway and starts getting weak puffs and says "batt down." I figured the batteries were dying, 2 Samsung 40T's, both do this on this mod. I don't have another 21700 mod to test. I just picked up 2 more Molicel P45B's and they do this too at around 60% charge despite being completely new. If I immediately change batteries it's fine until I hit that dreaded 60%.

This wasn't an issue when I first got the mod, it might start saying batt down at 5% or 10% charge at first, but it's starting to do this sooner and sooner despite having plenty of charge left. What could be causing this? The mod is a ViciousAnt Primo. Thanks

[dwcraig1]

I would be looking to the battery cap for a poor connection. Try cleaning the groves on the battery cap and the groves on the mod for the cap with a cotton swab and alcohol. Does that screw adjustment on the battery cap come apart? Clean it's threads as well. Does the battery fit tight enough in the mod when the cap is installed?

[Gnostical]

I just cleaned it as thoroughly as possible with cotton swabs and 99% iso alcohol on both ends that the battery touches. I adjusted the screw on the cap to fit as tight as possible. I was poking around the escribe software and the cell soft cutoff range was I think around 3.5V default and the type is set to 18650 and it won't let me click it to change to 21700. I just moved the cutoff to 2v, would that help at all?

[dwcraig1]

The correct setting would be 18650 and cell soft cut off at 2.75 volts (default)

[Gnostical]

Why 18650 if I'm using a 21700? I'll set it back to 2.75, but what would happen if it was lower? Oh also, and I'm using it single coil 0.20 ohm at 35w. Typically chain a few puffs then set it down for 5-10 min. The battery goes into low batt mode after an hour of usage.

[dwcraig1]

For what ever reason the board isn't receiving enough power from the cell (amps) do to a bad connection, could be cell fitment, bad solder joint, ect

Use EScribe's Device Monitor to see your voltage drop while firing. Here is one of mine that has a poor battery to board connection. The voltage drops to 3.37 volts when fired at 45 watts. If it drops to soft cell cutoff of 2.75 volts it will throttle down the wattage. Check yours with Device Monitor.

[dwcraig1]

Here's a DNA100C with 40T firing at 45 watts, this voltage drop appears as expected.

[Gnostical]

Thanks for the help so far, after cleaning the contacts and re-adjusting the battery cap, it stayed until 25% battery before dropping off. Not perfect, like how I used to get it to 10% before dropping but still, good enough that I'm happy with how it is now.

Here's it with the battery at full charge

and here it is at 25% when it started saying batt down. I noticed it kept climbing in charge when not using it to the point of gaining almost 10% charge within minutes, then taking a couple puffs, it quickly drops back to what it should be. Not overly concerning but just something odd. It was having a lot of difficulty reading the battery charge correctly compared to before

Edited April 21 by Gnostical

[dwcraig1]

" I noticed it kept climbing in charge when not using it to the point of gaining almost 10% charge within minutes, then taking a couple puffs, it quickly drops back to what it should be."

Pretty normal behavior especially when charge is on low side. It is better to note actual standing voltage than to use the estimated percentage as it is just that (estimated).

Here is a CSV for battery curve from my DNA250C, save yours first then give at a try if you want. It may be the same as yours or maybe different. 

Battery curve only changes percentages and battery bar, doesn't change how the mod works.

 

DNA100C battery curve.csv

[dwcraig1]

Your last screen shot shows it throttling down from 34 watts to 29.38 watts. With the cell that you are using and firing at 34 watts that looks like there is still a problem. You seem to be on the right track to solving it. Is your adjustment screw on the battery cap at the end of it's adjustment? Meaning do you feel it may need to be holding to battery tighter?