I was going to mention this as well, I have not had it nowhere near as bad as inspects but today was the 2nd time I noticed right before going to sleep my battery was already low but when I put it in the charger after sleeping it showed 2.46. Until you get a fix I will just remove my battery before I sleep, because when I'm awake it rarely leaves my hand.
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This is why I really didn't notice. I have 2 LBC Jrs, 1 with the Dna75 and one with the Dna75C each with a different juice; I use both of them about 20hrs a day. Gotta love graveyard shift coupled with insomnia... I never really noticed an issue I suppose due to my schedule/insomnia. Since this has been brought up I put a fresh off the charger battery in the 75 at 9pm and I'm letting it sit. At 9pm it started off at 98%, its almost 3am and it's at 93%. I will continue to test but it seems to be losing about 1% per hour so there is some sort of parasitic loss. I will take a body in to work Sunday morning and take some measurements with a megger (megaohmeter) that will allow me to test it up to 1000 volts. If it's slow I will read it with the infrared temp camera to look for hot spots. I haven't done any calculations yet but I would suspect a reading in the 8k-25k ohms range. If this comes back with a 100k+ reading I am incorrect and it's a board issue that I will be questioning Evolv about. Either way this has just gotten interesting. Who would have thought a single strand of carbon fiber in an insulator would be conductive enough to be an issue? Not me but here we are.
Same boat here only reason I noticed this week is I'm on vacation , when I'm working like you said it's in my hands for 20 hours and I usually replace the battery before my nap then it's off to work and and hammering away at the jr.
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Same here, I let JR sit on my desk for a couple days, was using LBC SR instead.
Stuck a battery in JR, I'll wait until it's dark to use the thermal imaging camera on the mod.
I've been feeling guilty lately my 2 SR and my xl proto have been getting neglected the jr has taken over the top spot and is not coming out of my hand, and I'm a flavor junky at home I easily on a daily basis have 15 mods I use since the jr maybe 6 and some days I don't even touch the others, I always took minimum 6 mods to work now 3 maybe 4 this damn thing is ruining me[emoji16] . There will definitely be at least 2 more Jr's coming my way. Finally got my BAM order in (sorry Tom I'm cheating on you , but turbos ultems look sic) now to give the vape budget a couple weeks to replenish and 2 more jrs will be headed this way. Just went thru my receipts for the 2 day Midwest vape expo over $500 in liquid alone [emoji23] and that's not all of it that was just day 2, They did a helluva good expo this year over 100 vendors lots of big names showed up very impressed especially after last year's was in a tiny area in the back of the jobs and family services building, this year at THE OHIO STATE fairgrounds.
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Tom, I used the TI cam on JR, I'm getting about a 8-10 degree difference in temperature at the bottom 1/2" of the mod. The very bottom of the board is the warmest by approx 10 degrees. I'll have to play with the images with FLIR software to clear things up. I'm not quite sure the emissivity of the body so that kinda screws the actual temps up some. I need to take some more images after I clean a little juice that was under the bottle. After I clean the juice up and allow it to dry completely I'll take some more pictures. But the heat is definitely coming from the bottom of the board.
That would make sense when it's in use. What you are seeing is the power side of the board taking in and processing the raw voltage from the battery. I'm more concerned with parasitic draw at idle. Measuring the temperature differential at idle should reveal a hot spot at the positive terminal and to a lesser extent at the negative and 510 where the negative is bonded to the actual body.
My test continues on my idle LBC jr (Production version) I installed a freshly charged battery and turned the mod back on. The test started at about 9pm Thursday night (@98%) and as of 10pm Friday night (25hrs) later it was down to 73% for a loss of 25% in 25hrs; not quite as bad as I had initially anticipated. At the current rate it would take a little over 4 days to reach 0% which is still 3.05v where I have the voltage cutoff set. My suggestion until I figure out the whole story and a fix would be if you aren't going to use the jr for 24hrs or more pull the battery or plug in the USB. The parasitic draw is far less than the half amp provided by the charging circuit.
I took the images when the mod sat idle for a few hours with the battery inserted, I didn't use the mod today. I was getting heat signatures from the bottom left of the board viewing the board from the back with the cover off, bottle out battery in.
Time for some math: Based on my readings so far:
Based on a 3000mah battery and a loss of 25% in 25hrs scales out to 30mah per hour of loss. If you look at the dna75 data sheet above you will see quiescent current (idle screen off current) is 7ma but what's especially curious is the 26ma screen on (idle with screen illuminated) data. I'm starting to wonder if the screen isn't completely shutting down.
Side note: Evidently the dna75 has a 1a onboard charger, not the 1/2a previously mentioned.
Tom, I'll try to take the mod to a fellow thermographer, who knows a LOT more about battery current and boards than myself. He also has a telephoto lens to peak into small spaces.
I have ended the test as of 2am Saturday after 30hrs and a final reading of 30% total loss in 30hrs which is consistent with my 25hr readings of 1% per hour. Phase 2 I will run the same test on one of my clear SLA printed prototypes which lacks the carbon fiber and should eliminate any chance of body conductivity.
The battery installed has been fully charged but sat on the charger for a few hours before beginning testing. Starting at 96% we will see how fast this battery discharges once the possibility of body conductivity is removed from the equation. (Glad to have my production mod back in service as well).
Upon further pondering I don't recall 18650s ever coming off the charger at 96% so the actual battery leveling out (or bleeding off) may be a contributing factor as well, just thinking out loud. Perhaps a call to Mooch might be in order.
The battery installed has been fully charged but sat on the charger for a few hours before beginning testing. Starting at 96% we will see how fast this battery discharges once the possibility of body conductivity is removed from the equation. (Glad to have my production mod back in service as well).
Upon further pondering I don't recall 18650s ever coming off the charger at 96% so the actual battery leveling out (or bleeding off) may be a contributing factor as well, just thinking out loud. Perhaps a call to Mooch might be in order.
Sorry, I didn't respond about the terminals. There were zero warm/hot spots at either terminal.
Just did my own test on the Jr. Full battery (well 98%) when I went to bed, checked it 8 hours later and it's at 90%. So basically 1% an hour. Not horrible, but not great. I've had my LBC sitting for like a week without using it and it's gone down maybe 1%. That is a guess because while it's at 97%, I can't remember if it was at 98% or 99% or even at the 97% that it sits now. So definitely not an issue with the LBC. LOL
Yep - this exactly ^^^
My Jr loses charge at pretty much the same rate while one LBC sat for 3 weeks without use (don't judge me) with minimal charge loss. I'll test with a Therion to maybe narrow the scope of debugging (ie, it's the same board, different bat, no cf in play).
Time to face the issue:
While the firmware may play a part in the draining issue I'm basing my solution on my research. Through digging through data sheet after data sheet I'm going to go ahead and call it. The issue is conductivity through the carbon fiber. From what I have read (and should have read before pulling the trigger on this material) this material is conductive at varying rates over the 3 axis of printing. This may also explain why I have such amazing conductivity from the negative to the board and even better to the atty. 3% battery life and full power at 60w.... Aluminum would struggle to achieve that but with plastic?
I have a few fix concepts in mind; I will retrofit one of mine tomorrow to test the conductivity and run the test again to compare it to the one without the fix and make a judgement wether it's viable or not. Fix concept 1 is relatively simple and involves a 1.5mm piece of peek epoxied into the slot where the contact rests and attach the contact to the peek.
Thinking back if I had just threaded the material at the board mounts instead of spec' ing hole big enough for a brass insert this would probably not been as much of an issue and the loss would be closer to 1% every 4 hours which could be easily explained. What I have essentially done is drive 3 ground rods in a semi conductor and dared it not to conduct. (Bad Chowderhead72) Tiny threads in plastic just seemed like a dumb idea for longevity so here we are. I have zero interest in leaving you guys hanging on this and I actually have a new material that I have been looking into for the future runs that I'm almost certain will amaze you. To be continued. This material is highly conductive.....
To the five folks that I have mods in construction for the solution will already be installed in yours so you will never have to deal with this.
While the firmware may play a part in the draining issue I'm basing my solution on my research. Through digging through data sheet after data sheet I'm going to go ahead and call it. The issue is conductivity through the carbon fiber. From what I have read (and should have read before pulling the trigger on this material) this material is conductive at varying rates over the 3 axis of printing. This may also explain why I have such amazing conductivity from the negative to the board and even better to the atty. 3% battery life and full power at 60w.... Aluminum would struggle to achieve that but with plastic?
I have a few fix concepts in mind; I will retrofit one of mine tomorrow to test the conductivity and run the test again to compare it to the one without the fix and make a judgement wether it's viable or not. Fix concept 1 is relatively simple and involves a 1.5mm piece of peek epoxied into the slot where the contact rests and attach the contact to the peek.
Thinking back if I had just threaded the material at the board mounts instead of spec' ing hole big enough for a brass insert this would probably not been as much of an issue and the loss would be closer to 1% every 4 hours which could be easily explained. What I have essentially done is drive 3 ground rods in a semi conductor and dared it not to conduct. (Bad Chowderhead72) Tiny threads in plastic just seemed like a dumb idea for longevity so here we are. I have zero interest in leaving you guys hanging on this and I actually have a new material that I have been looking into for the future runs that I'm almost certain will amaze you. To be continued. This material is highly conductive.....
To the five folks that I have mods in construction for the solution will already be installed in yours so you will never have to deal with this.
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