I've been using the Digipower pack for a few weeks now. I don't think I have even used the supplied Dell AC adapter or cradle charger. I just take the battery to work or on travel with me - I can get more than enough charges out of it. I have noticed no negative consequences - the Axim is still charging and discharging at the same rate as before. So I believe it is safe.
The only problem I have with my home-made 5v regulator is that it acts like the USB charge cable ... when the main battery is around 70%, trying to use the Axim and charge at the same time doesn't work. I have to shut off the Axim to get a charge.
I measured the output voltage under load and it was down to 4.83. I'm going to put two regulators in parallel to see if that helps get the output closer to 5.0v.
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Mike, can I ask why you don't regulate the voltage to 5.4V, since that's what the AC adapter puts out? Not having much electrical know-how, I'm guessing that it might be a difficult thing to do.
beachbrian, I'd still be inclined to charge with the AC adapter as often as possible. You might not see short battery life now, but who can say a few months or a year down the road? Why test fate when you don't have to?
Love to if I could. The regulator I used (7805) is fixed at 5v. I'm exploring the possibility of using an adjustable unit, the LM317, but I read that it has a 1.2v voltage drop. With a 6volt pack, that still gives 4.8 output.
I was trying to keep it simple, but there are lots of more complicated regulator circuits that may be better. Still looking.
For now, this works for emergency charging in the field as long as the Axim is off. $35 invested.
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Just agreeing with Beachbrian, i also have
used my Digipower quite a bit with
no negative affects... How ever I do
charge it with the Dell power when
not in use....
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Mike C: Further down in the regulator link you provided there is a way to use two resistors or a zener diode to make an adjustable power supply:
"It is possible to increase the output voltage of a Regulator circuit using a pair of 'voltage-divider' resistors (R1 and R2 in the diagram below), or a zener diode. It is not possible to obtain a voltage lower than the stated rating. ie you could not use a 12 volt regulator to make a 5 volt power supply, but you could use a 5 volt regulator to make a 12 volt supply.
(Diagram did not copy)
Some regulators are designed to produce a regulated voltage as low as 1.7 volts, for example the LM317. This type of regulator is ideal to use in 'variable' power supplies able to provide 1 amp regulated DC at voltages ranging from 1.7 to around 40 volts.
The interfaces described on this site are based on either 5 volt, or 12 volt integrated circuits. They use either LM7805, or LM7812 regulators."
Check it out. Let us know what you think. I may get one of those batteries (DPS 9000) for my Olympus camera and use it for my Axim also.
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Someone out there should have enough electrical know-how to read the specs and make a call. Does the thing work as presented in the original message, without me pulling out soldering irons and electric manuals? If there's a doubt... then I'd agree it's best not to chance it. But if an elec-tech can examine the specs and say, "I can't see what the danger could be"... then that's a very neat thing.
Question... is the unit used only for charging or can it be used as an auxilary battery supply if the unit battery is getting low on power (ie, can you use it to power the Axim during live usage)?
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I skipped over that part at first, about increasing the voltage because it didn't give specs for the voltage divider, but I figured out what I need to do and I'm cutting a pcb right now.
I'll take some pictures this time in case it works.
The LM317 could work with a higher pack voltage than what I have, like for a car charger, but those are already available for purchase ready made.
Wayfinder,
The trouble is, there are no specs to examine, and no ckt diagrams available that I'm aware of. The biggest problem with using an external pack is that it actually starts to drain the Axim battery if the supply voltage falls below a threshold. Too much voltage could burn something out, or over-volt the main battery (very bad).
If someone knows the specs for the charger ckt, by all means let me know.
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Mike
Yeah, the diagram apparently was for illustration purposes only. I suppose one could figure the R values for the voltage divider with a little math. I am looking forward to seeing any pictures you post for the PCB and the assembly.
Originally posted by Rustle beachbrian, I'd still be inclined to charge with the AC adapter as often as possible. You might not see short battery life now, but who can say a few months or a year down the road? Why test fate when you don't have to?
If we were talking about Ni-Mh batteries, then I would have some concern. However, the absolute flexibility offered by Li-ion batteries (which the Dell battery, and the Digipower battery are) means that we should not be prone to memory loss, voltage fluctuations over time, etc. There was a link earlier in this thread to a great article about batteries that offers a lot of information. The Li-ion technology really means risk-free usage. At least that's what I believe.
Quote:
Originally posted by Wayfinder Does the thing work as presented in the original message, without me pulling out soldering irons and electric manuals?
This thread is really discussing 2 different battery options now. The original post about the Digipower doesn't require any home-made voltage regulator, so to answer your question, yes it does work out of the box. The alternative that Mike C offered is a different (even more inexpensive) Ni-Mh solution, and he is working on the voltage regulator for that battery pack. So the conversation might be confusing but just realize that we are not all talking about the same battery pack. :hide:
I was so excited to hear of the DPS-9000 usage. I ran right to the Best Buy even though all they now list on their web site is camera specific DigiPower batteries.
Sure enough, it appears they aren't going to carry the DPS-9000 anymore, but there was an open package one that was remarked for $19.95, geez.
It works with my Nikon 995, will work with a future Nikon 5700, works slick with the Axim and my life is complete. Even if you have to get the Ritz Camera one at $69.95 or the CompUSA one at $79.95 it's still a great buy, compared to the Dell at $129.95.
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