REQ(US): MobilePro 900c AA Battery Adapter (Can it be done???)

thanks

i'll let you know if i get some information about the batts.




oh i know / read about a lot of people who want AA's there are rechargeable versions as well so it is not very costly.

anyway, 2 nimh AA's with the highest capacity, i.e. 2600 mAh (only rechargeable nimh would be really practical imo), are able to store about 6.2Wh energy, the original 1500 mAh li-ion battery 10.8Wh. not so bad.
of course a rebuilt li-ion battery (2600 mAh) will have three times the capacity of the nimh's 18.7Wh.

the above was about the jornada.. the nec 900 has a 2200 mAh battery by default, 15.84Wh and it still lasts less than the jornada on its original 1500. also the nec 900 has some problem with the suspend time, it'll last 1 week or so... =(however 900c will last 2 weeks) with the 2200mAh. two AA's would be a disaster there. though as i said it could be able to house 4 AA's... that makes it sound a little better.




if it once really lost capacity, you don't have much hope to regain it. maybe recell it
if you want to keep as much of it as possible, don't let it fully discharge too often. a few times a year, that's enough.

Edited by cmonex 2006-11-15 8:19 AM

One question that comes to mind when we talk about using rechargeable AAs to power the Jornada is: Would the standard power supply charge the AAs while they are in the Jornada?

Edited by CE Geek 2006-11-16 5:16 AM

No it wouldn't. You'd have to plug the Jornada into the AC (Or swap in other batteries) to prevent the memory from being erased, then charge the AAs in a standard charger.

Yet again I wonder why you'd want to buy rechargable AAs that give you 5 hours and need an external charger when you could buy li-ions for 14+ hours and charge it in the Jornada.

i don't need rechargeable AA's but believe me many people would love them. they are always available, not proprietary and when needed, you can put in AA's that are available anywhere. some people buy nec mobilepro 700's because they can be taken for hiking in places where you wouldn't have a way to recharge the li-ion battery. true, the nec 700 would still have an advantage, i.e. it can run 30 hours off two AA's, so less pricey.

Yet again. . . ah bollocks, see my earlier post.

"No it wouldn't" is slightly off since yes it could is the right answer. If we're already adding a voltage boost IC, we'd might as well add in a second one to charge with the Jornada's integrated circuitry. We're removing the Li-Ion charging IC; we can replace it with one that charges NiMH. Cmonex, any ideas on those pins yet?

I'd be willing to CAD something together as far as the casing goes. Anyone wants to kick in for components, feel free.

We could apply the same circuitry to other devices, too. Thoughts?

No, Jax is correct in this case, since I was asking if the standard HP power supply would charge the rechargeable AAs. You're talking about building a different power supply.

The battery doesn't contain much hardware outside of the batteries themselves. Making the Jornada charge AA batteries would probably involve motherboard mods.
Have fun with that. Your winning personality won't make many people want to help you.

Somebody better get the fire extinguisher - I see a flame war coming.

All this talk about batteries is giving me a head ache

Can I fix my battery somehow without frying my J720 but make the device hast longer then 3 hours?

I was scrolling through this, and just could not wait to see the retort from Jax.

Cmonex: 2600mAh nimh cells give less power than 1500mAh lithiums? Why?

Edited by ProgramSynthesiser 2006-11-16 11:06 PM

Ni-Mh cells are 1.2v. Li-ion is 3.6v. 3x the total watt-hours if the capacity is equal.

As for the person who just wants his battery to work again, you can send it to me and have the cells replaced with new high capacity ones. Or if you're good with a soldering iron you can try it yourself. Just remember that an overheated lithium battery will try to explode, and a lithium fire can't be put out with water.

yes, 1500 mAh li-ion has more energy, 10.8Wh vs 6.2Wh (ni-mh). 1.5Ah x 7.2V vs 2.6Ah x 2.4V (if we're talking about two cells for both)

yes, if you are confident with soldering, you can recell the battery, batteryspace.com has 2400 or even 2600 mAh cells

alight.. pretend like your talking to a complete n00b with power (witch isn't very far from the truth)

can I take apart my battery and make it work better? what would I need?

(im just concerned I'll get the wrong voltage and fry my poor little Jornada)

You need two Li-Ion cells, size 18650. Get the 2400 mAh or the 2600s if you feel like going all you. The ones with solder tabs already attached will make it easier.

Hold the Jornada's battery in both hands and attempt to twist it apart. There's a good chance the two halves will begin to seperate, at which point you can pull the case completly apart.

Now you can carefully remove the guts of the battery. It's held together with a weak black glue.

Once out, carefully break the leads off the existing cells and solder the new ones in place. Make sure to get the polaity right. You should probably leave the new cells in the fridge overnight before soldering, so that they won't overheat internally so easily.

After that, just glue it all back together and use.