USB and charge current limiting characteristics of DNA 200

[Mad Scientist]

Have seen some questions asked about the current draw on a USB port when charging so wanted to get the solid scoop. My understanding of the specifications is that DNA 200 USB current draw is specified to limit at 500mA if data lines are detected and 1A if not (assuming USB current limit is set at 1A in escribe). So to the question: if a DNA 200 draws significantly more than the 500mA and 1A as specified in the respective operating conditions as set forth above, what is the explanation? As a general proposition, operating outside of specification is a malfunction but can more light be shed on what is likely going wrong in each circumstance. Thank you.

[VapingBad]

It can draw over 500 mA with data lines present if the computer has a USB power setting, later versions of Windows don't so it is mostly 500 mA.

I would think that over 1 A would be a fault with the DNA, not seen this happen though.

[Jaquith]

Mad Scientist said:

... So to the question: if a DNA 200 draws significantly more than the 500mA and 1A as specified in the respective operating conditions as set forth above, what is the explanation? As a general proposition, operating outside of specification is a malfunction but can more light be shed on what is likely going wrong in each circumstance. Thank you.

The stock Evolv USB charger on the DNA 200 is 1A and it will indeed supply the full 1A to the balancer IF the supplied Voltage and Current is sufficient for 1A charging. 

Charging or Testing (Case Analyzer) from a PC are a problem if using USB V1.x~V2.x or if the USB 3.x is non-native plus different power variants. Only the revised high power power variants of USB 2.0 / USB 3.0 Battery Charging Specification (Version 1.2; December 2010) and USB 3.1 (1.5A). So to remedy this problem either requires a: USB 3.x Card, Powered USB HUB, or in some rare instances BIOS/UEFI and or software/driver enabling. In the case of USB 2.x with higher e.g 1.5A you lose data transmission.  

Personally, I don't find charging off your PC an 'ideal' solution for many reasons. My preferred solution is USB 3.x either as a native solution or as an add-on IF 1A requirement is important.

Hope that helps. 

[VapingBad]

The 1 A refers to USB current not the current to the battery, it can not supply 1 A at 9 - 12.6 V to the charge chip from a 1 A 5 V supply,

[Jaquith]

VapingBad said:

The 1 A refers to USB current not the current to the battery, it can not supply 1 A at 9 - 12.6 V to the charge chip from a 1 A 5 V supply,

Who said it did? What?? USB with type D connector has a 5V limit. Evolv limits the voltage to the Cell's capacity not the series voltage; balanced charger...

[VapingBad]

Jaquith said:

[QUOTE=VapingBad]The 1 A refers to USB current not the current to the battery, it can not supply 1 A at 9 - 12.6 V to the charge chip from a 1 A 5 V supply,

Who the said it did? What?? USB with type D connector has a 5V limit. Evolv limits the voltage to the Cell's capacity not the series voltage; balanced charger...[/QUOTE]

I thought you did

"The stock Evolv USB charger on the DNA 200 is 1A and it will indeed supply the full 1A to the balancer"

But I confess I am not sure what you mean by the balancer as it balances by taking current from the high cells.  But the the charger can not supply 1 A because the board only get a max 5 W from the USB and the min charge voltage being about 9 V the max current would be about 555 mA if it were 100% efficient voltage conversion.

[Jaquith]

VapingBad said:

I thought you did

"The stock Evolv USB charger on the DNA 200 is 1A and it will indeed supply the full 1A to the balancer"

But I confess I am not sure what you mean by the balancer as it balances by taking current from the high cells.  But the the charger can not supply 1 A because the board only get a max 5 W from the USB and the min charge voltage being about 9 V the max current would be about 555 mA if it were 100% efficient voltage conversion.

Imagine what you 'think' I know multiply it times 50 and then maybe more. It's getting rather annoying! 1A * 5V = 5W; Watts = Volts * Amps 

You are the only one saying a damn thing about 9V!?

USB Power specs https://en.wikipedia.org/wiki/USB#Power

[VapingBad]

I really don't understand what you mean Jacquith' I am trying to help you, the charger mainly works in series not on a cell by cell basis.   The charge current across all 3 cells for most of the charge cycle is via the thick wires and the same for each cell, the balance taps are only used to monitor the cell voltages and drain high cells when balancing and never for charging, they do not carry over 40 mA.

[Jaquith]

VapingBad said:

I really don't understand what you mean Jacquith' I am trying to help you, the charger mainly works in series not on a cell by cell basis.   The charge current across all 3 cells for most of the charge cycle is via the thick wires and the same for each cell, the balance taps are only used to monitor the cell voltages and drain high cells when balancing and never for charging, they do not carry over 40 mA.

I'm referring to the USB output, you can use the Balancer to charge and plenty of chargers do but I never suggested directly from the USB. You can increase voltage through a boost / DC-DC. What I'm referring to particularly is the various USB outputs by type.

[Mad Scientist]

I think this discussion might be helping to refine the questions, and I think maybe it has been answered. So if I'm understanding the answers correctly . . . if the DNA 200 detects data lines, it will still negotiate with the hub for up to 1A of charge current? As a result, it is not necessarily malfunctioning if it draws 1A charge current from a PC that is capable of supplying 1A or more? If the DNA 200 draws more than 1A of charge current it is malfunctioning?

[VapingBad]

Mad Scientist said:

I think this discussion might be helping to refine the questions, and I think maybe it has been answered. So if I'm understanding the answers correctly . . . if the DNA 200 detects data lines, it will still negotiate with the hub for up to 1A of charge current? As a result, it is not necessarily malfunctioning if it draws 1A charge current from a PC that is capable of supplying 1A or more? If the DNA 200 draws more than 1A of charge current it is malfunctioning?

Yes, conceptually the DNA tells the PC that it would like up to an Amp then the PC should provide the closest it can't get, later versions of Windows do not have the power setting on the USB driver so provide only 0.5 A.  I am no expert, but there a few methods for USB devices to tell the host what current they require and Apple have added non standard ones into the mix.

If I feed my DNA200 with a 5 V 1.7 A supply they never draw more than an Amp, but a dirty supply may damage the the DNA and cause this to be exceeded.

E:
The simplest method of requesting more current used by many charging cables is to short the data lines & IIRC ther is a variant with a resistor across the data lines that requests a specific max current.  

A largest concern with USB supplies is a power spike on the mains earth which is normally used for 0 V, these are caused by lots of conmen appliances like refrigerators and should be filtered out by the USB supply.

[Jaquith]

The standard DNA 200 draws 1A @ 5V or less whether it's connected to a 2.5A USB supply. However, there are modded boards like those used in the Vapor Shark DNA 200 that can draw up to 2A @ 5V. The idea is no different than a 40W bulb drawing 40W from a plug capable of a much larger supply of power. The PC's are moving towards USB 3.1 with a backwards compatibility with its 100W supply capacity. So a DNA 200, typical, should not exceed 1A, but as I mentioned there are exceptions.

Charging, a 2A charges 400% (4 times) faster than a 0.5A 'typical PC supply' and 200% (2 times) faster than a 1A supply.

Vapor Shark DNA 200 (2A)