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DNA75 can't show USB charge current? And a few other ?s


vapesmooth234
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just got a DNA75 Hcigar VT75 nano. Tried to set up in escribe to show the USB charge current on screen. But unlike my old DNA200, I see no option on the dropdown menu to show "USB CURRENT", only "Current" which apparently isn't USB current, whatever "current" is, it stays at 0.00A while charging. I just like to see what Amps the usb is charging at. Max is 1.0A on a DNA75, correct?

But DNA250 max USB charges at 2A, correct? But then how come my new Hcigar vt250s DNA250 is only showing max .95A when using a 2.1A wall adapter? The USB cord I'm using can't supply 2A or something?

 

 

One last thing for now,  Under MOD tab I have my old DNA200 triple 18650 mod set to the following which I think someone told me in the past to do:
Battery
capacity: 33 Wh 3 cell
Soft Cell cutoff: 2.8V

Charging Mode: max recharges (instead of max puffs).

Should I set my new DNA250 and DNA75 mods also to Capacity 33 Wh, and set soft cell cutoff to 2.8V? I know what max charges and max puffs means, but not sure about 33Wh is. At default the DNA250 is 9wh. the DNA75 doesn't even show anything there for Wh. And soft cell cutoff at default is 3.09 V on the DNA250.

 

I'm using dual sony vt6 3000 mAh in the DNA250 by the way, and a single 18650 3000 mAh LG H2 in the DNA75. And I plan to only ever charge these via the MOD's USB.

 

It's just safer to make soft cell cutoff lower than the default 3.09V, but it's kind of like max recharges vs max puffs in that you don't stress the batteries as much and therefore get more months out of them vs more puffs between charges? Don't these cells charge to 4.2V on an external anyway? Why is default 3.09V so much lower than that though?

 

 

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"But DNA250 max USB charges at 2A, correct? But then how come my new Hcigar vt250s DNA250 is only showing max .95A when using a 2.1A wall adapter? The USB cord I'm using can't supply 2A or something?"

 

Once the DNA250 mod got down to about %30 battery life, it DID charge at somewhere around 1.35A with the 2.1A wall adapter. My DNA200 (when charging worked) did something similar, it would reduce USB current A as it started to get towards %100 battery life, I guess it's safer this way. Maybe though I was only getting 1.35A and not 2A to the DNA250 because it was a USB 2.0 instead of 3.0 but I doubt that. As long it's over 1A I'm confident in it not being something I needed to set in escribe or something.

Still wondering about all the rest ?s though is anyone knows. thanks

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The 250 limits current to 1 A if there is a data connection on the USB, lowering current in the last phase of charging is when the charging changes from constant current to constant voltage mode and all lithium battery charges do this for safety and efficient charging.  Charge current will also lower if the board temp is high, again for safety. 

Only 200s & 250s have a balance charging controller that the board can read the current from, the 75 & 75C have a simpler charger chip which does not provide that info, but the board can stop or start charging, the 60 can't do that as the charger is a separate board.

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Super fast and easy way to find out if you're using a USB cable capable of carrying 2.0 amps from wall-wart to mod - If you go into EScribe / Screen Tab/ and select "USB Voltage" "USB Current" in the drop down menu, then upload settings to mod. Unplug USB cable from PC and plug into your wall-wart or USB charging hub. Wait for charging screen to appear on mod and take note of USB voltage shown on mod while charging. If the USB voltage is 4.27 or below, the DNA board will back off on charging current.(ex: less than 2 amps). On a typical DNA 250 with a quality USB cable connected to a power supply capable of supplying 2 amps or better with a quality cable, you should see a USB voltage of around 4.43v - 4.83v. You need sufficient voltage headroom to allow the DNA 250 to draw it's 2 amps capability. 

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