USB sync/charge cable warning - Page 5

02-17-05, 11:55 AM

oh and i forgot to ask....what does all this have to do with percent of power left in the battery. Is there a differential on the needed amperage to charge a battery at different levels of charge/discharge?

zim2dive · 02-18-05, 01:49 PM

Ok, some added info...

AFAICT, the Axim A/C power pins are not driven out, so the reverse charge should not be occuring over those. Using the Dell AC -> Cradle connector, I measured 0V across the connector.

Next, I put the Axim in the cradle, and disconnected the USB from the computer so I could measure it. With the AC power connected to the cradle, I saw 3.86V on the USB power pins. With the AC disconnected, it dropped slightly to 3.77V.

So it would appear to me that any reversal must be happening on those pins...

From this I offer a hypothesis to be considered... if one were to take the USB sync/charge cable, and disconnect the USB power pins, then there should not be a battery reverse drain scenario. The only "problem" area would be if the connected source could deliver enough current on the AC power pins.... (what happens if it cannot, is it a problem, or just a slower charge?)

Somewhat unrelated, I found that the Axim would accept down to 4.5V on the AC power connection and still charge (using a variable power supply) and the AC -> Cradle connector. I did not test for a VINmax (being unsure what protection circuits might/not exist).

Edit: and/or if one were to disconnect the USB power on the cable (pin 21 according the the charts), and insert a 0.3V Schottky diode, that _should_ prevent the reverse problem too.

Thoughts?

Mike

molgo · 02-23-05, 01:09 PM

while we're talking about these technical issues, does anyone know what the real life risk is of using a 6.5V car adaptor that puts out a 2A max with the axim which requires 5.4V and supposedly about 1A.

KennyX50 · 02-23-05, 01:10 PM

Hello kenban,

Can you verify the power pin layout for the 5.4VDC and 5VDC the input on the USB sync/charge cable? This pin layout was posted by other Aximsite member under the title "X50V pin layout?". It said Pin 1-4 are for 5.4v and pin 21 for 5v. Following is the link to the pin layout picture. Thanks,

http://www.aximsite.com/boards/attac...achmentid=6461

back of x50v
______----________________________----______
| 1 17 19 35|
| _-_-_-_-_-_-_-_-_- _-_-_-_-_-_-_-_-_- |
| 2 18 20 36 |
-------------------_____--------------------
front of x50v

02-23-05, 08:27 PM

Originally Posted by KennyX50

Hello kenban,

Can you verify the power pin layout for the 5.4VDC and 5VDC the input on the USB sync/charge cable? This pin layout was posted by other Aximsite member under the title "X50V pin layout?". It said Pin 1-4 are for 5.4v and pin 21 for 5v. Following is the link to the pin layout picture. Thanks,

http://www.aximsite.com/boards/attac...achmentid=6461

Will try to look at my notes and see if I can verify this. But it looks good to me.

KennyX50 · 02-24-05, 06:12 PM

Hello KenBan,

I am confused because it takes 4 pins (pin1 to 4) to supply +5.4V base on the pin layout. I thought X50 only needed one pin to supply the +5.4V.

02-24-05, 07:28 PM

Just to make sure I took my cradle apart. Its quite easy only 4 screws under the rubber feet on the bottom. Yes those are the correct pins.

molgo · 02-24-05, 08:49 PM

with that being said, how do you explain the fact that I have owned both the seidio sync and charge cable and the boxwave directsync cable. From multiple hubs and usb ports with both, the seidio cable only discharged and never charged, while the boxwave cable has for the most part charged the axim. From a powered hub, the boxwave always charged my pda regardless of how low the battery was, even at like 5%.
And kenban, since it seems you're one of the few who really knows the technical issues, do you think it's safe to use a 6.5V usb car charger with the axim? I tried it last night and it seemed to charge fine, even at low battery, wifi on, max processer, and full backlight. I'm not positive it's 6.5 but it's either 5V or 6.5V giving out 2A max. The label on the charger and the box say two different specs

JakeRich · 02-24-05, 09:16 PM

The protection circuits in the Axim won't let 6.5v get through, so the charger is probably 5v. At 5v/2A, you've got plenty of power.

ocharlies · 02-24-05, 09:27 PM

I am also using a usb sync/charge cable and it seems working fine charging battery and axim being used at the same time. One example is one night I fell sleep while listening to mp3 audiobooks. The battery was drained out and the Axim went to sleep too. The next morning when I woke up I plugged the usb sync/charge cable to my Dell 700m's usb port. The Axim immediately woke up and continued playing mp3 files. At the time battery was shown as completely empty. A couple of hours later the battery was full with the green light on. All the time the Axim was playing mp3 files with the usb sync/charge cable connected to the laptop. It seemed the usb sync cable was able to charge the battery while the Axim was being used.

molgo · 02-24-05, 10:42 PM

with that being said, how do you explain the fact that I have owned both the seidio sync and charge cable and the boxwave directsync cable. From multiple hubs and usb ports with both, the seidio cable only discharged and never charged, while the boxwave cable has for the most part charged the axim. From a powered hub, the boxwave always charged my pda regardless of how low the battery was, even at like 5%.
And kenban, since it seems you're one of the few who really knows the technical issues, do you think it's safe to use a 6.5V usb car charger with the axim? I tried it last night and it seemed to charge fine, even at low battery, wifi on, max processer, and full backlight. I'm not positive it's 6.5 but it's either 5V or 6.5V giving out 2A max. The label on the charger and the box say two different specs

zim2dive · 02-24-05, 10:58 PM

Originally Posted by JakeRich

The protection circuits in the Axim won't let 6.5v get through, so the charger is probably 5v. At 5v/2A, you've got plenty of power.

Jake, are you saying overvoltage is not an issue? (they have protection diodes?)

Not that a good design wouldn't have such protection, but I've been hesistant to test that myself.

Mike

zim2dive · 02-24-05, 11:03 PM

Originally Posted by molgo

with that being said, how do you explain the fact that I have owned both the seidio sync and charge cable and the boxwave directsync cable. From multiple hubs and usb ports with both, the seidio cable only discharged and never charged, while the boxwave cable has for the most part charged the axim. From a powered hub, the boxwave always charged my pda regardless of how low the battery was, even at like 5%.

If one cable connects to both +5 and +5.4 then that could be a difference. Also, how long is each cable? Even a 3' cable with wire that is to small (high gauge) could drop enough voltage to become ineffective given the current draw required, altho my measurements showed that the Axim was will to charge as long as the input was >= 4.5V.

Mike

02-25-05, 02:09 AM

Zim2dive is correct the gauge of the wire can have some effect. Although I don't think thats what the differance is. At this point on this is pure guess time :) but you commented that the one cable will sync and discharge while the other cable works correctly someone pointed out earlier that only the 5v pin for USB is driven out and you get 0v on 5.4v pin if nothing is connected to the axim. Well that does mean you can only be discharging through the 5v pin and not the 5.4v pin. It might be that the Seido cable has the power run to both the 5v and 5.4v pins but the Boxwave only runs the power to the 5.4v pin. (pure guess I don't have either cable and really have just been trying to help out in general I use the dell sync/charge cable and it only charges if the axim is off which for the few times I actually need to charge with USB is fine with me)

But you said you tried multiple hubs and USB ports and the Seido cable has never worked for you. Makes me wonder if something is wrong with the cable beyond a design flaw.

I almost hate to bring this up because I don't want people to get in their head that x sync and cable cable works while y sync and charge cable does not. But then all I am really trying to do is warn that if you get one of these cables it might not work and why it might not work. Maybe we should do a poll that lists the major brands of sync and charge cables and you can vote if your x cable works, x cable discharges axim and just an other problem field at the end as a catch all.

One last comment tonight. Something a lot of people seem to forget. There are a lot of electrical fires every year. If you draw too much current from a transformer that does not have any current or temp protection it can melt down and catch on fire or cause a fire somewhere else due to the huge current draw. Recently the power cords on ALL xbox's made before October 23, 2003 and in europe before January 13, 2004 were recalled in the US alone thats 14.1 MILLION power cords. So far according to microsoft fewer then 1 in 10,000 has had a problem. I know we are dealing with a totally differant situation here to a point but some individuals use these cables with wall adaptors. Then there is the whole issue on the cradle killing peoples USB ports on the computer.

EDIT: Totally forgot part of the point of the xbox story is this comment on the FAQ on xbox's site "In almost all instances, any damage caused by these failures was contained within the console itself".

jnguy · 02-26-05, 02:32 PM

I think I'm understanding everything. I actually recently had a problem where I plugged the sync cable into a battery dead axim... and the axim didn't for for 2 days, or something like that. Anyone care to explain whether or not http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWN:IT cable would work... so much for cheap ebay cable.