WARNING on USB Charging Ports!

[Frozen001]

Just wanted to post a warning to everyone who has the built in USB charging ports on their camper/RV. We have a 2017 Grey Wolf 29BH that has 6 of these through out the camper, 3 of which are in the bunk house where my children sleep. So for two of them have failed. The first on is the one located near the couch on the slide. This win I had my smartphone plugged in charging when I unplugged the cord from the socket I noticed if was HOT to the touch. I immediately pulled it from the wall as cut the lead 12V supply lead, and was going to replace it when I had time. Now this weekend I used the port by our bed to again charge my smart phone. Unplugged the cord completely, and all was good. An hour or so later I go into the trailer and smell burnt electronics. After searching around and getting to the are where it was the strongest I touch the USB port that I used to charge my phone (no cord was it all) and it was HOT. I immediately pulled it out of the wall and clipped the power to it.

We got home yesterday and I opened up the two failed USB ports to find this.

USB Port Internal pictures

There are three photos. The one with the circuit board in my hand is from the latest failure. The other two are the first failed port. The earlier port is not as bad, but you can see signs of overheating on both the board and components.

Beware.

I am in contact with forest river and will report back their resolution.

[mike-s]

Frozen001 wrote:
The biggest problem with the design is that it does not follow the USB Charging specifications. That specification requires different voltages present on the D+ and D- lines that allow the phone to determine how much current it can draw.

It's not clear what you're referring to. There is no "USB Charging" specification. There's a "USB Power Delivery" spec, which requires intelligence on both sides. But, that would add cost where it's not needed.

The charging ports would follow the "USB Battery Charging Specification 1.2", found here.

Note that the spec defines a "USB Charger" as "a device with a DCP, such as a wall adapter or car power adapter."

1.4.7 Dedicated Charging Port
A Dedicated Charging Port (DCP) is a downstream port on a device that outputs power through a USB connector, but is not capable of enumerating a downstream device. A DCP shall source IDCP at an average voltage of VCHG.
A DCP shall short the D+ line to the D- line.

Also see section 4.4. A DCP is by far the easiest and cheapest USB compliant port to make - 5V (1.5 A min for maximum charging, 5 A protection limit) on the power lines, short the data lines (with up to 200 ohms).

There's nothing in the spec about a USB charger pulling the data lines to different voltages for charging. That's all non-standard proprietary stuff. There are chips out there which can recognize and support devices which use such non-standard methods.

[joebedford]

XLsemi website

Chrome can translate the chinese.

[Frozen001]

Since I am going to replace these anyway, I am going to do some load testing one of the "good" ones to see what they can actually safely handle.

The biggest problem with the design is that it does not follow the USB Charging specifications. That specification requires different voltages present on the D+ and D- lines that allow the phone to determine how much current it can draw. These devices in the trailer do not have any of that circuity. all it is is a buck switching regulator made by XLSEMI (part number XL2010E1) (which has no website BTW, all I can find is datasheets from xlsemi.com, but I f try to go to a home page I get a DNS error. I am assuming they have just poorly copied a TI or linear design).

[1320Fastback]

MrWizard wrote:


Personally i think Forest River and the RV industry, just bought the cheapest 100ma Chinese USB charger, the could find, and did not give a second thought about it

That pretty much sums up the entire RV industry in general for all parts and pieces.

[GordonThree]

Counterfeit is using the term USB but not adhering to anything in the standard.

[toedtoes]

MrWizard wrote:
I think the word 'counterfeit'
Is the wrong word,
Cheap poorly designed that can not limit current is the correct description

Now if they were mfg and labeled and sold as 3 amp device at 3 amp prices,
That's counterfeiting

Personally i think Forest River and the RV industry, just bought the cheapest 100ma Chinese USB charger, the could find, and did not give a second thought about it

I would think the latter would just be a ripoff.

Counterfeiting would be putting an Apple logo on a non-branded (or other brand) charger and selling it as an Apple brand charger.

[MEXICOWANDERER]

CHINA!
I love it!
Diagnosed an ENTIRE PALLET of clothing irons. No work.
Troubleshooting.
Disassembled enough irons to diagnose the circuit boards were sealed without having the circuit component devices soldered to the circuit board.

Chopped the nice long silicone plug and wire from the irons. Nice cord.

Forklift the pallet up onto the flatbed. Sent north as "chatarra" scrap.

[MrWizard]

I think the word 'counterfeit'
Is the wrong word,
Cheap poorly designed that can not limit current is the correct description

Now if they were mfg and labeled and sold as 3 amp device at 3 amp prices,
That's counterfeiting

Personally i think Forest River and the RV industry, just bought the cheapest 100ma Chinese USB charger, the could find, and did not give a second thought about it

[Ralph_Cramden]

D.E.Bishop wrote:


I would also consider reporting the failures to RVIA, they may not really have any power over manufacturers but they do try and keep the overall quality reasonable

LOL. That sticker they already slapped beside the door says the OP's rig already is certified by the "manufacturer" to meet standards for recreational vehicles per the NFPA. The RVIA certifies nothing, they simply provide a decal, a name, and a load of BS all skewed towards the manufacturers, not the consumer. That sticker means your USB port and LED lights will likely melt, your plumbing will leak, your fridge will never cool below 50, and your furnace will likely fail the first time its needed.

OP, our 17 Rockwood had the USB port meltdown also. Likely the same as yours. I replaced it with a standard 12VDC accessory socket. Our LED cieling fixtures also melted the lenses and made visible yellow burn marks in the cieling panels from heat. Forest River sent me new ones, the exact same junk. I found some replacements online for the lights that operate almost 70* cooler according to the tell tale IR gun.

[pnichols]

GordonThree wrote:
USB 3.1 gen 2 power transfer gets really complicated, as power transfer is reversible, the device can power the host, example docking your ultrabook to a large format monitor via USB-C connector, and the monitor backfeeds power to the laptop. Those circuits are crazy with buck-boost or SEPIC topology on both sides, and fancy chips out the whazoo to figure it all out.

That's exactly the kind and amount of circuitry that shouldn't be buried within the combustible-material walls of RVs - unless enclosed in metal boxes as is the case with receptacles in the walls of houses.

[2DHoop]

Had one burn up in a vehicle and later found out there are several recalls on a variety of different adapters. Probably similar inferior components among all of them.

CSPC:
https://www.cpsc.gov/recalls?combine=USB%20charger&page=1

[mike-s]

Frozen001 wrote:
IC looking like a counterfeit from an manufacture with no website (www.xlsemi.com)

You gonna keep us in suspense, or tell us the part number, and what they're counterfeiting? My suspicion is that it's a simple switching step-down voltage converter chip.

To others:

(this is for USB 2):

Responsibility for the current drawn is principally placed on the device drawing current. The source is supposed to enforce a limit, but it "cannot exceed 5.0 A" per USB 2.0 spec, which is more than any reasonable device can be expected to draw (it's more than the 1.5 A the common Type-A connectors are spec'd for) - it's to provide a fail safe and cover simple non-USB spec devices people will plug in which don't do anything but draw power, like fans, lights and coffee warmers (!). Baseline is a proper USB device can only draw 100 mA without doing anything else.

Next step is negotiating more power, which requires negotiating over the data lines - then the device can draw 500 mA. Most chargers don't have the intelligence to do that.

Then, there's the USB Battery Charging spec, which many chargers do use. It's pretty simple to do - short the data lines together (with 200 ohms in the most recent 1.2 spec) on the charger, which tells the device it can draw up to 1.5 A. There are other methods, a charger can be able to provide more, but any USB compliant powered device isn't allowed to draw more than 1.5A.

Beyond that, there are non-standard proprietary methods of negotiating more voltage and/or current - Qualcomm Quickcharge, Apple, Samsung, etc. Note that anything drawing more than 1.5A (including Apple iThings) is drawing more than the connector specifications allow. And even those expect the device drawing power to limit their power draw to a maximum.

USB 3 adds more methods, which allow higher voltages, and therefore more power, but the negotiation becomes more complex (and expensive), and devices and chargers are at the front of the bell curve. Current (common) RV USB ports certainly don't support USB 3 methods.

[GordonThree]

bob_nestor wrote:

wa8yxm wrote:
As I recall the "Standard" for USB ports is 500mA or 1/2 amp

My phone can suck 2 or more amps off a well designed charger/adapter via the USB cord..

NOW. a WELL DESIGNED USB port WILL limit the current... but the key word is WELL DESIGNED.. Not ever designer even knows HOW to limit current (i do but hey. I paid attention in DC Theory)

For USB 1.x and 2.0 the power is 0.5A; for USB 3.0 it is 0.9A.

And that's only after the device asks the host nicely. IIRC the initial current is 100ma or some such low number.

The USB PD protocol (power delivery) allow for up to 100 watts delivery, I believe it' 24 volts at just over 4 amps, but again, that's for the device to request and the host to say yes or no. Devices that support PD usually do 9v at 3a for safety regarding the battery.

The Qualcomm QuickCharge protocol allows for 36 watts, 12v at 3a, which most newer LG and Motorola mobile devices support.

There's other protocols out there, too numerous to mention.

USB 3.1 gen 2 power transfer gets really complicated, as power transfer is reversible, the device can power the host, example docking your ultrabook to a large format monitor via USB-C connector, and the monitor backfeeds power to the laptop. Those circuits are crazy with buck-boost or SEPIC topology on both sides, and fancy chips out the whazoo to figure it all out.

[Frozen001]

brulaz wrote:
http://shop.pkys.com/Marinco-SeaLink-Dual-USB-Charger-Receptacle_p_6752.html

Blue Sea also makes quality products.

Those look nice I am also considering these:

Powerwerx USB panel mount