100C Wattage Drops

[trucknuts]

In Watt Boost and Watt profiles after several hits the device becomes limited to ~42W. Correlates to board temperature and not getting near cell soft cutoff (2.75).

Might be on the wrong track with temperature because it's not the exact same temperature each time and is around the odd figure of 47C. In support of something temperature related if I short fire and keep it above 40C it keeps firing in a restricted wattage for ~60s. If the board temperature drops below 40C before 60s then it fires normally.

Any ideas on what is causing this or troubleshooting steps to try? It's 100% consistent to reproduce but the time until it starts firing normally is a bit spotty.

Edited November 30, 2023 by trucknuts
add cell soft cutoff

[Wayneo]

When the mod starts limiting the watts, can you feel the battery, and is it hot or anywhere on the mod hot?
How long has this been happening

Can you tell me the battery details.
Can you tell me the firmware version on your mod.

For future DM screenshots, can you do a full one (it would have shown firmware), and you only need volts, power, power set.

[trucknuts]

New device today (Hadron Mini) and it's operated like this since first boot.

Running SP55.1 and just checked SP46 and the same behavior is experienced. If it is temperature related it occurs at a few degrees lower on 46 than 55.1 (~114F vs ~116F).

The mod case heats up to 85F and the battery to 76F but nothing is hot to the touch.
Have not checked the board for hotspots so let me know if that is a possible issue (awkward to check but doable).
The board temp (from sensor) is ambient +6.5F after 1 hour idle and the room temp (from sensor) values are often are not sane (ambient -10F, ambient +20F, etc.). Nothing else seems notable on the topic of temperature.

Have tried Samsung 30T, 40T3, and Molicel P28B with no change between them. Initial screenshots were between a 30T and 40T3.

DMing full screenshot of a mostly charged 30T where it does dip very low, but not to cutoff.

[BillW50]

What troubles me is why are you firing a DNA100C for 60 seconds? This isn't what the rest of us are accustom to using our DNA100C for. And to handle such abuse, you're probably going to need heatsinks and possibly fans.

[trucknuts]

Longest fire in testing has been 3 seconds but typical is ~1.5s.

EDIT: ~60s is the idle time before it resumes normal power levels.

Edited November 30, 2023 by trucknuts
60s clarification

[BillW50]

Sorry, so you want to fire at 100 watts and have to wait for the board temperature to fall below 40°C (104°F) between firings and then it works perfectly right?

Edited November 30, 2023 by BillW50
Sorry

[trucknuts]

Yup, as long as the board temp is below 104F when firing everything works perfectly. The hi/low temps of 116F/104F are not always exact but very close.

Just did a watts profile @100W and it did 2 normal hits, then 1 at 40W, then waited 35s (until 103.7F) and it hit at 100W again. Alternately if I keep hitting it at 40W after 60s somewhere around 109F it will start hitting at the set power again.

Doesn't matter whether it's 50W or 100W (other than how quick the heat builds up), same behavior. Ex. 2@100W, 4@70W, 6@50W before it drops the wattage.

It sure looks like it's based on board temperature to me but I can't find any reference to a thermal limit on the board and 47C is a really weird cutoff point.

[trucknuts]

Then whenever I think I get the limitation it works different. Just had the same behavior when it hit 112.4F which other times definitely doesn't trigger the lower wattage hit.

Feels like there is some other piece of the puzzle going completely over my head.

[BillW50]

Ok, I'm going to try duplicating this on one of my DNA100C.

[BillW50]

Does it happen at 50 watts too? Chain vaping here at 50 watts I got the board reading over 130°F and power out is solid. The battery is only a 15A battery (so 50 watts is pushing it) and the battery is at a low charge and the battery voltage drop is at 2.9v (not surprising) when firing. Running SP55.1 here.

[trucknuts]

Phew, that's a relief in the sense that I did not fundamentally misunderstand the DNA board specs. The downside is I definitely have a problem and am fresh out of ideas. Thanks for checking that!

In watts profile @50W the 5th fire dropped to 42.5W with the lowest vBatt @3.64v and highest board temp @ 108.9F.
Battery is slightly warm (<80F), case is warm (<90F). EScribe shows good voltage so the connection is solid unless there is something happening far faster than the program polling interval. No error or warning messages come up on the display or indicators in EScribe so that should significantly limit the potential conditions...and also possibly make this voodoo/fault territory otherwise there would be some kind of indicator?

 

[BillW50]

I'm running the International firmware version, same for you? I'm trying to think of a reason for your experience outside of a problem with the board itself. But everything externally looks fine in your screenshots. A faulty board could cause this i.e. temperature sensitive faulty chip or a cold solder joint. In either case, it needs to be replaced or repaired. Is it less than a year old? If so, Evolv covers it under warranty.

[trucknuts]

Yea, I'm on 1.1 SP55.1 INT.

This is a 1-day old vendor mod (Hadron Mini) so I guess the retailer is going to be the right channel to address.

Interestingly 0.37 coils are working fine so whatever the problem is only affects driving lower resistances. 0.15 ni80 is far within the safe zone going off the 75C and 250C datasheets so sounds like it's just a short straw situation. Only two other posts on the forums sound vaguely similar to this and both of those never answered what their voltages were dropping to.

[BillW50]

When a DNA gets too hot, I'm pretty sure that is set to 100°C. And it doesn't lower the wattage, but just displays Too Hot error and refuses to fire.

Oh works fine with .37Ω? Oh I tested with a .4Ω Kanthal coil. I don't have anything built right now at .15Ω (which is weird since I commonly do). But I am positive I have many times even on a DNA100C and its not a problem. But that does tell me the problem is at the final stage on the board (which is no surprise really, as there was better than a 50% chance it was there anyway).

I'm glad you found out everything you did. Because that really narrows it down perfectly. Bummer getting a faulty board though. That is super rare.

[Wayneo]

While the retailer should be the one to address this, I'd really suggest you open a Help Desk ticket, and let Evolv guide you. Like Bill, everything looks somewhat normal with decent brand batteries. 

10 hours ago, trucknuts said:

... and not getting near cell soft cutoff (2.75).

All the cell soft cutoff does is say what voltage to generate a 'Weak battery' warning, letting you know the 'check battery' will be coming soon.

2 hours ago, trucknuts said:

EScribe shows good voltage so the connection is solid unless there is something happening far faster than the program polling interval. No error or warning messages come up on the display or indicators in EScribe

The polling interval for device monitor was ~4 times per second, on the mod it is always reading everything live and at a much faster rate. There are no warnings or errors on escribe Device Monitor, only your mod.

You think it's heat related, BIll thinks it's the board, I think it could hardware, firmware, or an over taxed battery(even though it wasn't hot). Hence, my suggestion to contact the Help Desk (link in my signature line)

[trucknuts]

I ended up doing an RMA on the device (mod not board) and the new one does not have the issue. Can't say what the culprit was but from the perspective of the purchased unit it was some kind of defect.