power cables - confusion? 5v(PSP) / 5.4v??

equk · 09-06-05, 07:05 PM

I've just recieved a usb charger/sync lead from ebay, I was reading about the use of 5v rather than 5.4v in them.

Also there are loads of people suggesting using PSP power adapters. The PSP is 5v? not 5.4v.

After reading the threads where people have said not to use 5v to charge the x50v, I'm wandering why people are suggesting using PSP 5v adapters. I tried my USB lead earlier and it seemed to charge ok and it has a in-car adapter which I hope to use when I get GPS/tomtom.

Looking at the pinout diagram based on the vga/usb/serial cable, there are both 5v and 5.4v connections

What sort of damage could be done to the axim if you used 5v to charge it?

jimbo32 · 09-06-05, 07:19 PM

As for charging with 5V, there should be no problem, as long as your X50 is OFF during the charge cycle. If you try to use it during the charge cycle, the screen will likely flicker and your battery may actually discharge rather than charge. The issue is less the voltage than it is the amperage and since most 5V chargers are designed to mimic USB specifications, they usually only put out about 500mh, while the X50 seems to need more like 1500mh to both operate and charge at the same time.

As for the PSP adapter, I purchased a Pelican PL-6003 PSP car adapter and it does NOT support charging and operating my X50V at the same time without the screen flicker. The difference between my experience and what others have reported could be that I am using the 2200mh battery, which may require more mh to charge than the standard battery.

I have had some success with a USB car adapter that puts out 850mh, as long as the battery is nearly fully charged when I start out.

One of my pet peeves is that very few of these adapters disclose anywhere exactly how much voltage and amperage the put out, which makes it a guessing game as to which may or may not work. The Pelican I purchased doesn't say anywhere what the output is.

equk · 09-06-05, 07:30 PM

After reading through this thread I notice you can charge solely on 5v by disconnecting the 5.4v connection totally, altho I would guess the time taken to charge would be longer.

I think I might have to open up my new cable to check the connections.

If it's possible to use the PSP stuff, there are loads of adapters, external batteries etc that are a lot cheaper than the x50/x50v stuff.

*JakeRich* · 09-06-05, 07:32 PM

Before you go hacking into cables, why not read the facts about power and the X50v series. Might save you a lot of grief to have the facts first.

jimbo32 · 09-06-05, 08:25 PM

Originally Posted by JakeRich

Before you go hacking into cables, why not read the facts about power and the X50v series. Might save you a lot of grief to have the facts first.

JakeRich,

Exactly where is there a fact in that thread? That is one of the longest least informative threads on this web site. I can't believe anyone would reference that thread as a source for an answer.

bigbop · 09-06-05, 08:36 PM

There is absolutely nothing wrong with charging your X50 using a 5V power source that has an adequate current rating. I do it every day. It takes slightly longer to charge but I keep plugged in for a few hours anyway. I use a small 5v 2A wall supply.
The 5.4v input is specifically for charging the battery whereas the 5v input by the USB pins is actually used to turn on the PDA when it is connected to a USB host interface. Most PDAs actually have a 1K resistor from this pin to 5v. It is just by accident that the Axim charges via this pin - and takes a long time to do so because it's not really a power input.

equk · 09-07-05, 06:00 AM

Originally Posted by JakeRich

Before you go hacking into cables, why not read the facts about power and the X50v series. Might save you a lot of grief to have the facts first.

I have read 'the facts' as you put it

That thread was the reason for this one really. The fact that some say 5v works and others say it doesn't and will do damage to the device.

From what I've read tho I might buy a PSP 5v 2amp psu to use in the office/when on road staying in hotels.

Fobbing people off to threads which don't really have a definitive answer isn't really much help.

equk · 09-07-05, 06:27 AM

The 3800mAh Rechargeable External Battery For PSP looks interesting

extend your x50v?
Might be too good to be true but if it supplies 5v @ 2amps like the PSP power adapters it could be worth a go. They seem to be very cheap for Li-ion batteries aswell (£12incl postage) compared to Dell Axim X50 Li-Ion Battery Kit (2200mAh) £72.95

I guess almost everything for the PSP seems to be massively cheap compared to the x50/x50v accessories

bigbop · 09-07-05, 08:35 AM

Originally Posted by equk

The 3800mAh Rechargeable External Battery For PSP looks interesting

extend your x50v?
Might be too good to be true but if it supplies 5v @ 2amps like the PSP power adapters it could be worth a go. They seem to be very cheap for Li-ion batteries aswell (£12incl postage) compared to Dell Axim X50 Li-Ion Battery Kit (2200mAh) £72.95

I guess almost everything for the PSP seems to be massively cheap compared to the x50/x50v accessories

As long as it provides a well regulated 5V source, it will work without ANY issues.

Remember that a given device will draw a certain amount of (peak) current from the power supply. Power supplies don't 'push' current to a device. Therefore the power source must be capable of sourcing enough current or it's voltage regulation will drop. That is what people are seeing with the cheap automobile adapters that put out 500mA and the Axim is trying to draw over 800mA, causing the voltage to drop below 5V. The causes the Axim's internal battery charger circuit to shut down which reduces the input current and the adapter voltage goes back up to 5V and the Axim then tries to turn it's charging circuits back on - and the cycle repeats.

*JakeRich* · 09-07-05, 09:18 AM

Originally Posted by jimbo32

JakeRich,

Exactly where is there a fact in that thread? That is one of the longest least informative threads on this web site. I can't believe anyone would reference that thread as a source for an answer.

FACT: The Axim can draw as much as 2A when charging and running.
FACT: There are two sets of pins for power input, one for USB, one for External power.
FACT: The USB pins are current limited to protect the motherboard and USB ports from overcurrent conditions.
FACT: The USB pins only allow you to charge OR run, but not both.
FACT: When you don't provide sufficient current on the external pins, the Axim will constantly swap between external and internal power--usually causing the screen to flicker.
FACT: If your power supply is weak enough, you'll actually discharge the battery faster instead of charging it.
FACT: If you reconfigure a USB cable to provide power to the External pins, you have created a time bomb. Eventually you'll forget and attach that cable to a USB port and either blow the port or the MoBo.

I suggest you actually read the thread, there is a lot of information in it from actual measurements of the power consumption and connections. That's why it's a sticky.

*JakeRich* · 09-07-05, 09:38 AM

Originally Posted by equk

CLIP...
Fobbing people off to threads which don't really have a definitive answer isn't really much help.

What can be more definitive than this:

Quote:

What this means to you. Most of the direct sync cables and sync/charge cables made by third partys have the +5v from the USB port running to your +5.4v on the axim. While this will not damage the axim (it may damage the computer but should not). It is not correct ...

or this:

Quote:

The input slot on the Dell Axim has 2 pins to feed it power – 1 from your computer’s USB port (at +5 v) and 1 from the power cable (at +5.4v) that plugs into the wall outlet:

Cradle/Power Cable
Axim’s +5 v pin <== cradle’s +5 v pin <== USB cable (output +5 v)
Axim’s +5.4v pin <== cradle’s +5.4v pin<== Power cable (output +5.4v)

The cradle is setup this way and the Axim is smart. If you cradle the Axim without the power plug, it will only draw power from the USB port when the Axim is off. It knows that while the Axim is on, the +5 v from the USB doesn’t leave enough extra juice to charge the battery, except perhaps for a trickle charge. If the power cable is used, it knows it can operate and charge off the 5.4v of that line

The problem is third party USB sync/charge cables don’t use an external power cable. Instead, they channel any and all power from the USB port. The mistake is that they crossed the lead and feed the USB power (at +5 v max.) into a receptacle designed to eat +5.4v. Like so:

3rd Party USB sync/charge cable
Axim’s +5 v pin <== EMPTY (no cable pin, no power cable)
Axim’s +5.4v pin <== cable’s +5 v pin <== USB cable (output +5 v)

The Axim, when using a 3rd Party USB sync/charge cable, has a +5.4v appetite (pin) but only gets fed +5 v diet. If it sucks too hard, by needing juice to both charge the battery and run the Axim, it may zap the computer’s USB port or not eat enough to be full (i.e., charge the battery). The Axim doesn’t know to only draw power from this cable when it is off, as with the cradle and its two pins. It expects an ample (+5.4v) supply because it is coming in on the pin designated for the power cable.

Both are from the first page of the thread, so you don't even have to read the entire thread to see the problem. Later in the thread it is discovered that the real issue is not the voltage, but the current draw, but the analysis of the pins and impacts is otherwise correct. You can charge the Axim with 5v, but you must have 2 amps. Even at 5.4v, if you only have 500 ma, you cannot charge the unit--not enough current.

So, a charger that provides 2A at either 5v or 5.4v will work. But if you bypass the current limiters in the USB charging pins by cross connecting from the USB port's power pins to the X50's External power pins you put your power supply at risk. That's a major risk for MoBos and unprotected USB ports, and still won't work with car chargers if they don't provide the necessary current.

I didn't fob anybody off. I pointed to a thread where someone had done the engineering measurements to determine what was going on and provided the data backup to prove it.

equk · 09-07-05, 10:30 AM

Originally Posted by JakeRich

FACT: If you reconfigure a USB cable to provide power to the External pins, you have created a time bomb. Eventually you'll forget and attach that cable to a USB port and either blow the port or the MoBo.

I read thru the thread etc and everything you said I had picked up on appart from this quote. Altho the part of re-configuring the lead to provide +5v to the +5.4v pins seems strange.

Taking the theory that unless the +5.4v lines have power provided the x50v will only charge or sync, my cable already seems to do both at the same time. I've not noticed any problems yet, but I see the idea of the axim pulling more power than the usb can provide

. Which is why I said that I might change the configuration of my cable and buy a PSP power adapter

Parts of that other thread are misleading, like some people saying u must have 5.4v and not 5v etc. Whereas others are saying they are using 5v adapters already.

Does the standard x50v power adapter which comes with the axim provide power to the 5.4v lines? or just the usb lines?

I'd guess it would power the 5.4v lines, which would mean you would be powering 5v thru the 5.4v.

That other thread just got a bit misleading as it was more a debate than pure info. Thanks for the info

makes a bit more sense now, clearing up the fact that the problem is not with the voltage but with the ampage.

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