Batteries, Battery Options Options

[wsuetholz]

Hello,
Would this type of battery work? If so, then could the battery be integrated into where the hinge is? I realize that this is probably not workable, but, cheap batteries, and the possibility of simplifying the system board layout by not putting the battery in the middle of it, ok, to one side.

2700ma AA rechargeables

[Da_Blitz]

i dont think that making a model that runs off AA battries would be too hard, it would require a diffrent charger IC so it might be worth ronsidering putting an 8 bit micro in thier to handle charging. that way we wouldnt need a diffrent hardware rivision.

the only thing i can see wrong with AA battries is that they are quite high. but i think my Z's battrey is a bit higher

where this would work well is in the sidekick gull/wing type design where we could put the battries right at the edge and leave all of the middle just for PCB

i am considering the battry placment to be off to one side or if we use AA at the back

[BarryW]

Has anybody looked into the sony video camera batteries?? Would be kinda cool, if you had to be away from power for awhile just pop in one of the really big ones.

[Da_Blitz]

i belive someone mentioned that, guess it all depends on the case, which seems to be having a huge impact on this project (more than i would have thoght)

[Ferret-Simpson]

I think digital Camcorder batteries are the best option. Chaging over a USB connector?

We're looking at 2 USB ports. . . I vote we make one an OTG port with that lovely little connector and use that to charge, like on the Universal, and my Abacus. That could be the one on the back for stacking with expansion packs? Makes a docking cradle as simple as a usb cable connected straight to a 5v line (via some sort of regulator and switch to autoselect between power from USB cable and power from Mains Charger) and from the USB cable's data lines. Just mount that on a moulded or formed aluminium base, stick in a blue LED to look cool and away we go! Then just use the USB cable as a network to your linux box (Because Windows 5ux><0RZ, naturally!) and away we go! Suddenly you have a bluetooth, Wifi and 3G access point for your aged pre-wireless Vaio.

Ok, that's SLIGHTLY off topic. . . but yeah, Camcorder battery.

[daniel3000]

Having AA batteries (optionally rechargeable) would be awesome!
Imagine batteries are empty on the go, and you can simply go into the next shop and buy a pair of new ones for a few dollars.

That was one of the big advantages of the HP 200LX (sorry to mention that again! ;-)

Also, a buffer would be good so that the device doesn't have to be rebooted on battery exchange. Tat's one thing I don't like with the Zaurus.

daniel

[Ferret-Simpson]

Yeah, but how many mAh does a normal AA hold? E.G. A Duracell Ultra. . .?

It's a goo idea to be able to do that, but Not all batteries are the same. . You'll find yourself suddenly going dead. . .

[desertrat]

Yeah, but how many mAh does a normal AA hold? E.G. A Duracell Ultra. . .?

NiMH batteries goes up to 2700mAh at least, I suspect alkalines (or other non-rechargeables) will do quite a bit more. Using AA batteries will make it "future-proof", ie you can instantly take advantage of any advances in that technology, eg my first set of NiMH AAs were rated 1300mAh, my latest at 2700mAh.

-- cheers

[Da_Blitz]

actually from what i have seen alkalines only do about 1000maH but the battery discharge curve is diffrent which for some applications means it gets a longer life

basically an alkilines charge can be worked out from the voltage because as the charge goes down so does the voltage, with the rechargables its at about 90%-100% voltage until you hit 80% capacity, at which point the voltage drops throgh the floor

now if you have a device that requires x volts and is sensetive to changes then you can see that an alkaline would dip past there sooner. however wether or not this would effect s would have to do with the chipset i use for charging, and a bit of testing however i am inclined to use li-Ion due to the weight/capacity advantages

one other thing to note that 1 3.7v litium ion battery @ 1000maH is equal to 3x 1.2v NiMihs @ 1000maH (you cant jus mach maH you have to match the power (power = voltage x current/maH)) so even if the NiMih is 1000mah, i have to pull tricks to bump that up to 3.3v and 5v (cpu IO and USB and perhaps 2.5v) but to do so i have to consume extra current

i am tired at the moment so there may be a mistake in the above statment but basically you dont get somthing for free

[zedkatuf2]

Yeah, but how many mAh does a normal AA hold? E.G. A Duracell Ultra. . .?

NiMH batteries goes up to 2700mAh at least, I suspect alkalines (or other non-rechargeables) will do quite a bit more. Using AA batteries will make it "future-proof", ie you can instantly take advantage of any advances in that technology, eg my first set of NiMH AAs were rated 1300mAh, my latest at 2700mAh.

-- cheers

The "energy density" ie [mAh x Voltage]/mass for NiMh batteries isn't so good (ie it's smaller) compared to Li-ion or Li-polymer batteries.

I've not been following this thread, but generally it seems that Li-polymers are the best approach (more expensive, but worth it IMO)

zedkatuf

[Ferret-Simpson]

http://www.mobilefun.co.uk/product/11276.htm

Beat THAT for a PDA battery!

3200mAh, and although it's not the smallest battery ever, it's not worldbeatingly huge. It's a standard accessory for the HTC Universal phones, so they're a commercially viable option. I can't see how we could feasibly get a higher capacity battery, of an acceptable size, for the same price.

Opinions? Gotta love the Universal. . .Solving so many problems. . .

[Ferret-Simpson]

Does No-One have an opinion on this?

[zedkatuf2]

Does No-One have an opinion on this?

Looks good

[Da_Blitz]

i havent had a chance to look at the link 9still on the command line with links here and will be for a couple more days) however if its anything like the mega backpak for the xda2 form li-ion.com (i belive thats the link) then its worth looking into

hopfully we can get a rectangular square battery, i do like nice flat ones instead of a thick brick as it gives me more horizontal board space and makes the board easier to route

an unexpected side effect is that we can take a nokia battery and stack several side by side meaning we get the magical "hot swap" ability, just dont pull all the battries at once, anyone got any idea what the maximum capacity for one of those batteries are, hopfully its 1Ah and we can get 2 side by side, if we can get 3 then 800mAh should be enogh

anyway i should have my new Xen setup running in the next day or two so i can do experiment with the pcb stuff in windows in a virtual machine (got to love the new x86s)

[Da_Blitz]

forgot to mention the obvious however nokia or mobile phone battries should be easy to get so they work out well, in fact they are litterly off the shelf items happy hunting