bill_n_opus

Originally Posted by Graham2456

I think everyone is getting too caught up with voltage. Voltage is not important, it is current that charges the battery. Voltage is only necessary to get the current flowing. The Axim battery is rated at 3.7 volts, therefore any voltage source above this level will cause current to flow into the battery (and thus charge it). The big variable is the amount of current flowing in which affects how fast the battery charges. The current flowing in is a function of the voltage driving it and the ability of the source to supply it. This is why USB chargers are not very satisfactory. Their voltage level is OK but their ability to supply current is very limited. Referring back to Ohm's Law, a higher voltage will cause more current to flow but unless the source is capable of supplying it the source voltage will drop (and the current along with it). The ideal would be a "constant current" source in a storage device (battery) but unfortunately they are not available. The nearest we can get is the NiMH so stick with them. I lived on a yacht for 6 years so if I got my charging wrong I sat in the dark.

There are battery packs out there that carry a much greater source of amps ... at a cost of course.

There's the Socket Mobile Power pack that rates at ~ 7.2 amps optimal at 5V ... and the Tekkeon MyPowerAll which comes in two amperage ratings. One is ~ 9A and the other is something like 13-14A or so rated at 5V. This is off memory so please be kind to me.

Of course, these products run at around ~ 90 bucks starting US dollars so they're not cheap. But they offer great flexibility in portable power.

I would buy the Tekkeon personally ... if I really needed it. I may still get the higher amp version if and when I get a new laptop and if the Tekkeon is compatible. That way I can charge all my portable devices including my cell phone, pda, converged device if I have one plus my laptop and pretty much anything that has an adaptor for it.

bill_n_opus

Just to update with my el cheapo 8 dollar pc-mobile 4xAA battery extender (basically a radio shack 4AA holder with the right cable) with 4 high quality Energizer (Sanyo MIJ) 2500mAh - charged my Axim with it's regular 1100mAh battery from ~ 23% to full with no problems. I even had the Axim on with medium brightness, wifi off, BT on .. and the extender changed the status upon startup from internal to external battery (ie: full brightness) before I shut down the Axim to do a full charge.

When it was green and I turned on the Ax to fool around a bit the extender still had capacity to charge some more at 97% when I tested quickly. I'm sure it would have had lots more capacity to charge but I ended up sticking the batteries back into my La Crosse bc-900 charger because I was interested to find out the charge capacity left.

Put the La Crosse in and selected the charge parameters with 4xAA at 1000mAh (or 1 amp) and when I came back it was reading ~ 1.45 volts charged for each battery at ~ 850mAh or so iirc.

Next time i'm going to drain my Axim down to almost zero and see what happens. I think my extender with fresh charged Energizers will still be able to charge to full. They may be able to expend much of it's amps to charge the Ax i'm fairly confident. Where that threshold i'm interested to find out.

Hope that someone got something out of that read.

bill_n_opus

Update again:

I ran my x51v down to zilch, zero, nada battery power.

I freshly topped up my MIJ Energizer (Sanyo OEM) 2500mAh NiMh batteries into my La Crosse bc-900 charger using the 1Amp selectable charge parameters. Final voltages after top up was ~ 1.45-1.47 or so.

Plugged the 4xAA into my pc-mobile.com battery extender, hooked it up via dongle to my Axim, turned on the extender and everything worked.

Turned on my Ax to see if it would use and charge at the same time and it did. Charge animation showed up, full brightness on, wifi off though, BT on.

Turned off the Ax and let it sit for awhile. I turned it back on awhile later and it showed 97% charged. Shut it off ... waited awhile longer and looked at the Ax again and it was showing green, fully charged.

Took out the batteries, stuck them back into my charger, selected the same parameters and when it was done it showed ~ 1150mAh charged on average which is about right.

So, what i've more formally learned is that you can charge your Axim from absolute dead to full if (and these are big ifs):

- you have top quality batteries (preferably very reputable brands and hopefully Made In Japan, although production of these batteries are now shifting over to China more and more - see Sanyo)
- have high capacity NiMh, mine being 2500mAh
- this test was done on the OEM 1100mAh battery. The 2200mAh and 3300mAh will most likely be more difficult to charge from such a depleted state. As for how far you could go and charge to full with a batt extender and extended batteries ... if anyone wants to donate such batteries to me i'll be happy to test! :)
- I used the replacement dongle ... with the full meal deal pinnage.

With capacity left over with my batt extender and good batteries I could probably charge the Axim from 50% to full ... but that's speculation, haven't actually tried it yet. May do that next time.

Hope this helped. PocketBrain ... are you reading this? Whaddya think?

jpp

Gomadic = Problematic

mmtbb

Hi,

Could you post a link to where you got this extender that works with the Axim x50v? Thanks