Hey Blair,
ISSUE 1:
To follow up here, weāre actively working through battery optimizations (one of our developers did a seriously awesome study on battery usage!) that are going to be rolled out in new firmware releases.
(for reference) Rapid battery drain
ISSUE 2:
May be hardware related, Iāll have to escalate this one as Iām not sure.
ISSUE 3:
When charging that is the case. When I remove my device from the charger, I get a time estimate. Could you confirm please?
Dan
about issue 3: yes I can confirm
throughout charging it states remaining time -1
as soon as removed from power supply it states remaining time 119 minutes (for example)
probably the confusion (at least for me) comes from the next line ācharging?ā yes/no
I read this the first times as both lines as remaining charging time. 
Just for info: Last night I switched it of with 97% left. After now round about 9 hours I have 90% left while in the meantime it was switched off.
I also had this issue.
I charged my device Friday and turned it off, started the jumpday Saturday with 96%
I connected my device with the DZās wifi and I didnāt turned my device off between jumps, but was also not playing a lot with it.
After 4 jumps, the icon showed a half battery and when I went up for the 5the jump, when I was waiting for boarding next tot the plane, I got a warning tune out of the device. (On that moment there is no chance anymore to change altimeters. I checked my device: 13% of juice left. I went up with it and around 10000 it was empty.
A friend I was jumping with has also a Dekunu, also logged in on the local wifi network and also left on between jumps. Fully charged by the beginning of the day. When mine went black- he still had 36% (with the same jumps done).
Sunday, I also started with a full battery but didnāt connect to the DZās wifi. For the rest the same. It went black after 6 jumps and I had to power it up in between.
An average jumping day is around 8 or 9 jumps. So I hope the battery life will improve huge with the next FW update. IMHO it should be able to last at least one full weekend with a little bit extra for comfort, no?
Iāve noticed that the device uses more battery when it is inside a building and unable to locate a GPS signal. Iām going to make a guess and say that the device boosts the GPS receiver signal in an attempt to get a satellite lock?
If I leave the device near the hangar door, it locks GPS signal and seems to last a lot longer.
Iām not able to say how much more battery it uses, but it was noticeable this weekend.
I guess for anyone having battery issues \ battery life over a weekend, this might be something to consider.
Also - see other thread regarding known issue of device not giving correct battery reading after being charged when powered off.
Inside the hangar, my device had every time the best gps contact of whole the day (circle full white), so I donāt think thatās the issue here.
Both the devices were about the same time in the air and in the hangar. 
I think itās indeed with poor gps contact inside the plane. He was sitting right behind me: I had no gps signal and he had around 8 sats signal. Probably my device was searching more indeed.
But then: why do I have bad (or even about 5 jumps no) signal and the person right behind (or sometimes in front of me) not.
Youāre lucky
The camera room where I am has thick walls and several layers above it - at the download station I canāt get a GPS lock (which is normally where I would leave my gear between jumps)
@Tracy Does the device stop looking for a wireless signal (one that it was connected to previously) if it goes into plane mode? I pair mine to a phone, so it stays with meā¦
@stirre maybe next weekend one person try pairing to a phone, and the other use the wireless network - might give reveal a differenceā¦ Not sure if I can think of anything else that might help you at this point tho 
@SkydiveNow I believe it is the GPS not the wifi, sitting under the wing of the plane etc. can affect that too.
Fingers crossed the update will be rolled out prior to this weekend of jumping 
New issue, not mentioned yet I think.
This morning I checked my Dekunu (standard OFF). Batt indicated 95%, so I turned it off again. This evening I heard the noice of the dekunu and the screen indicated the round D-symbol. I turned it on: low battery level.
It is now already a few hours plugged in. It went from 0,0% - > 21%. But after that (although it is plugged in) - my battery capacity isnāt charging anymore, but is going down (now 19,5% and still plugged in). On the screen, I see the battery symbol + green loading flash next to it and the Dekunu led is still greenā¦
And now, after several hours chargingā¦ Only 53%ā¦actually, with such behavior, it makes me āafraidā to jump with it without my normal visoā¦
Never rely on it if you do not feel save. Take your Visio with you on the other arm, wait for the Battery update, sell your Visio, enjoy the blue skies!
I would check how many amps the plug is that you are using. I donāt remember how many amps are the minimum for Dekunu to charge, but I bought an Anker power plug that outputs 2.4 amps per each USB port.
Half charge wonāt last long so I would definitely use a backup alti. A portable power bank is a good investment in my opinion, (good for keeping a phone from dying too!)
Donāt know. Just the USB-port of my laptop. The strange thing is: I used it already a couple of 5 or 6 times to charge the device before without any problem. And nowā¦half a battery after more than 5 hours charging and indeed, it died after only 3 jumps.
Iām lucky I can charge it at our DZ without any powerbank, what works fine and fast.
I guess you gave the answer on your own. At the DZ it works fine you say. I assume you do not use your laptop over there to charge.
Why is that the explanation that charging with the same laptop went well for 5 or 6 times before?
Charging via USB isnāt just black and white.
Three things that could be your problem; USB Version, Cable, Charge Source
There are different USB versions (USB 1.1, USB 2.0, USB 3.0 and USB 3.1) and these different versions of USB (notably 3.0 and 3.1) have different power delivery capabilities.
Basically, the later versions can deliver more power to the device. So if youāre using a USB 2.0 connection you can charge the device with 500mA, USB 3.0 can do 600mA - Now things get complicated as there is a charging specification which allows significantly more power to be delivered.
There is also the cable itself - the cheap chinese cables often have a thin gauge cable made of steel inside, the really good ones have a thicker gauge of copper (less line resistance)
I have a crappy chinese cable that I use to show people the difference - same charge port, same device but the crappy chinese cable take 4 times longerā¦
Another one is that the cables might be power only cables (red and black wires) which I believe means the smart charge devices canāt use the battery charge specification by pushing power down other linesā¦ obviously makes charging slower.
Lastly, the ports on a laptop are not always equal. You might have a mix of ports (USB 2/3) and you may also find that there is a software controller inside the laptop that limits a port or ports power output - so one port might be permitted to deliver more power than the others (unlikely but has been witnessed in the past)
Your laptop might also be in power saver or balanced mode - even if plugged into the mains. Check to see if there are any power saving options whilst in AC mode.
Iād suggest;
Get a decent cable (the one supplied seems pretty good)
Charge via a mains powered 2.1A smart charger rather than a laptop.
Hope it helps
But stil bottom line is: We all wait for the battery management update, should have a possibility to charge in between the jumps, and if that does not give enough confidence, then I would wear a second alti until it is fixed.
And thanks @SkydiveNow for the explanation.
Basically you say: my laptop fluctuates a lot in port supply of the USB, because I only used the dekunu cable (every time) , I was using the laptop all the times while charging and I used every time the same USB port of the 3 and it worked fine until this week.
I think most computer/laptop USB ports are pretty inconsistent with charging. They are primarily designed for transferring data instead. Anytime Iāve tried charging my cell phone from my computer it takes way longer than when plugged into a decent wall charger.
If you want to charge while mobile Iād highly recommend buying a power bank. I bought this power bank and itās great, not just for Dekunu but also charging my cell phone which usually is getting low at the end of the day.