ledpocket

I am having a little issue with how my Gomadic sync and charge cable is working, and thought I would share it with you.

When I first got the cable it seemed to be working normally, but I had never let the battery get down lower than 80% or so before plugging it back in.

After a weekend of high wifi usage the battery was down in the 40-50% range, and I plugged in the sync and charge. For some reason I went to the battery meter to check it out, and it was showing that it was discharching at about 1% a second.

I then tried out my other battery, that was at about 98%, and it charged normally.

I put the discharged one back in and hooked it up to the dell cradle, and it began to charge normally. So I finished charging it up to 100%.

I then tried that battery again on the s&c cable, and it began to discharge. Removing the cable showed a steady climb back to fully charged.

I emailed gomadic, and they replied promptly, with the following:

"We have been running in to this problem some recently. Basically, the Dell
requires 5.4 volts of dc power and the USB port puts of 5.0. There is
always a +/- 10% buffer with these things, so it will work, but we're on the
edge a little. What we think is happening is that once you get below a
certain percentage of charge, the Axim tries to pull more power than the USB
port on some computers can put off resulting in it not charging anymore.

Things that you can do to mitigate this behavior is to turn off the Dell
while charging in order to re-establish a battery base above the required
threshold, minimize the use of other USB devices on the same port (if using
a hub), or turn down some of the power demanding components of the dell such
as the backlight settings on the screen.

If this is too much of an inconvenience for you and you determine that the
cable does not fit your needs, you may send it back at anytime for a full
refund.

Thanks,
gomadic"

So next time the battery was low, what I did was plug in the sync and charge then turn the ax off and let it charge a while. It charged to 100%. Then I turned the screen brightness down a couple of notches (it was set at 100% when connected to external power), and it doen't discharge anymore.

I hope this helps anyone who runs into this problem.

ledpocket

After a few days of dealing with this, it seems like anytime the battery is below 85% or so, plugging in the gomadic cable makes the ax start discharging (when the unit is powered on, about 50% screen brightness).

When powered off the ax charges pretty rapidly, so after a bit, I can turn it on and leave it on, and the level stays at 100% all day.

I wonder if anyone else is seeing results like this?

JakeRich

It's not really the Gomadic. It's the USB port. USB ports are only required to provide 100 ma of power at 5 v. The Ax consumes about 200 ma of power (1440 mah total in the battery/ 7 hours battery life). So, when connected to a USB port that provides 100 ma, if the Ax is powered on, there could be a drain of 100 ma, causing the battery to slowly decline. The fact that the Ax is also designed for 5.5v just adds to the dilemma, as Gomadic has pointed out.

Two things can mitigate this dilemma:

1) Some USB ports can provide as much as 500 ma. There is no guarantee any particular port will do that, but the spec does say that the port may provide that much. Some hubs do that if they are separately powered, but you cannot guarantee that they will just because they are powered. In short, you would have to read the spec on the particular card/hub/pc/pc card/whatever that is providing the port to see how much power is being provided.

2) Turn off the Ax. That stops power consumption and allows the 100 ma to catch up on the battery. You could also turn the brightness completely off, which should drop the power consumption even further, but then you would have to have a bright light to see the screen and if you did any heavy work that burdened the battery the gain in charge rate would be minimal.