DNA 100C Wattage drop after 3 puffs. (Geekvape z100c p Coils)

[maximumsport]

I've been using the Geekvape DNA z100c mod with the P coils rated at 0.15 70-80W. After about 4 puffs @ 75 watts and the coil gets somewhat warn not HOT the wattage would drop down to 40 watts and give a weak vape.

I've updated the chip to the latest firmware. Some how the chip is dropping the wattage. Is there any way to disable this? I've looked in escribe but could not find a setting. I use the profile Watts with punch at 1. Nothing special.

Thanks.

[dwcraig1]

Use EScribe's Device Monitor to see the voltage drop during firing. 

Here on mine the problem was due to the battery not fitting tight enough for a good connection. Poor solder joints or a battery with low amp output could also be the problem.

Note if it drops below the Soft cell cut off the power will throttle down (2.75 volts in this case)

Included is a screen shot with acceptable voltage drop.

[BillW50]

This is common with not only with DNAs, but most mods as well. If it can't get enough power from the battery, it drops the wattage until it can. Likely suspect is the battery. You will need a battery that can do 30A to get that kind of power out of it. A poor battery connection can also cause the same thing.

[maximumsport]

Thanks for the info. I have a few new Molicel's I've been using the 45B ones. Molicel P45B 21700 4500mAh 45A and it happens.

I guess over 70 watts on a single 21700 in warm atmosphere temps cause the voltage drop? 

[dwcraig1]

Use EScribe's Device Monitor to see voltage drop. Your Molicel P45B 21700 would be good for way more than 100 watts. There is a poor connection between the cell and board.....for sure.

Here is my DNA100C with Samsung 18650 20S 30 amp cell with standing voltage of 4.0 volts firing at 75 watts.

Note that the voltage dropped to 3.23 volts. It would continue to fire @ 75 watts till the voltage drop hits 2.75 volts.

[maximumsport]

Thanks for that info. But I have 2 of the exact mods and they both do the same thing. What's chances of both having bad connections?

How did you fix your connections?

[dwcraig1]

In my case the problem was on two identical new mods. SXK DNA60 Ionboxes. Two different colors purchased from two different places.

What I did was to add a blob of solder to the positive contact on the cell. I did this for both mods.

This needs to be done quickly and with a high heat soldering iron 100 + watts. I used silver solder and acid flux, same as for house hold plumbing the filed down to desired length.

To see if this could be the problem with yours perhaps you could place a small washer between your cell negative and battery door and use Device Monitor to see if you get some improvement before proceeding to my method.

The two screen shots that I posted yesterday were from one of these mods before and after my fix. 

The added length here is 1.5mm.

[trucknuts]

Can't say whether it's the same issue but on my Z100C charging causes this issue which can persist for up to 30 minutes after charge is stopped. It's a temperature problem on the board that is distinct from the "Too Hot" condition and can present without charging, but the design of this mod causes it to be likely to occur during/after charging.

[BillW50]

@dwcraig1 also has a Z100C. Hopefully he will chime in here soon and mention if he has experienced this too.

[dwcraig1]

No problems here, I fired it more 10 times, the last 5 without air. The last three short ones was to catch the voltage reading.

[dwcraig1]

After charging, about 8 hits on it after charging completed.

Can you post a screen shot of Device Monitor with yours when problem is occurring?

[trucknuts]

Here is what mine looks like, there is a time gap between the hits (look at vbat jump) as the device is allowed to cool and it's charging during this capture.

I already reviewed it with support and verified the cause after pulling the board. What is still a bit of a mystery is why an edge case becomes so pronounced when the board is installed in the Z100C case. Best guess is 75% sandwich case design 25% silicon lottery, the relevant components are operating within specification to the accuracy I can measure.

 

 

 

Edited January 28 by trucknuts
image highlight different timestamps, plural to singular time gap

[Wayneo]

12 hours ago, trucknuts said:

.............. I already reviewed it with support and verified the cause after pulling the board.

And what did support say? What was the cause? Can you post screenshot of this profile, and describe the coil and atty please. 

[trucknuts]

Support indicated this was a safety feature when the boost buck overheats.

I can't speak to the specific criteria and thresholds used but can say on my board it is indeed components on the top-left overheating. The board could only detect this through an unexpected voltage being produced for a given input so I suspect it's a catch-all error that could be produced a number of different ways.

That recording is a Dead Rabbit Pro with 2 x 316L, 4.5mm, 5 wraps of 6 x 0.4x0.1 ribbon, 2 x 28 frames, 38 wrap but I reproduced it on a variety of attys and coils. The cause is a specific temperature condition which is really difficult to reproduce on the standalone board without adding external heat, Too Hot usually gets hit first. In the case though board temps can be barely elevated and this is decently reproducible.

The specific cause for me could be different for somebody else but in relation to the Z100C my testing shows it radiates very little heat (especially from the upper-front of the board) so time since prior usage (or charging) has a significant impact.

Profile below, at the time of that recording it was 450F and .101 Cold Ohms.

Edited January 29 by trucknuts
add ribbon width

[Wayneo]

38 minutes ago, trucknuts said:

Support indicated this was a safety feature when the boost buck overheats.

I would certainly agree with support as they have access internally with the designers and developers.

My main concern was with your puff screenshot. You're asking a whole lot from that single battery board with a boost buck converter. As you can see, your power (green squiggly line) plunges after hitting that 100 watt peak, never really leveling out. So it ends up being a weak puff after that initial burst of power.

Is your main reason/benefit for using TC to stop you from going over 450°F or for 'dry hit' prevention. Your current preheat parameters does nothing. 

If it's for specific, I can make suggestions for a better puff.
If it's for dry hit prevention I can help you with trying 'Replay'.

[trucknuts]

Yea for on-the-go devices I just want to get up to 420F+ from cold as fast as the device can then let it coast and only use preheat on at-home devices.

I've played around with replay a bit but never found it useful compared to what TC offers between temp and wattage inputs (at least not in SS). Definitely an under-explored feature for me though so if you have any pointers on better usage of it please do.

[Wayneo]

1 hour ago, trucknuts said:

I've played around with replay a bit but never found it useful compared to what TC offers between temp and wattage inputs (at least not in SS). Definitely an under-explored feature for me though so if you have any pointers on better usage of it please do.

Sure. First start off in the Replay profile, material 'watts'. Warmth set at 1, Punch at 5. Find the ideal watts you could vape all day. If you want it to ramp quicker/slower adjust that Punch value up or down. When you get a great puff, enable replay. You'll get a much fuller puff. Try that for a couple days and let me know what you think. Like TC, start with an ambient/cold coil. No material files to worry about or room temp.

EDIT: I've been told by a most respected source those 'P Coils' will ALSO Replay if under Mod->Safety you change that option to 'allow on unlikely' using the same parameters as above.