Author Topic: Custom battery pack (Read 16484 times)

V-Man · « **Reply #15 on:** October 25, 2004, 10:30:11 pm »

Good grief! Your are much more ambitious in your experimentation than I am. Keep up the good work and let us know how your stuff works out.

Thanks
V-Man

Mahoro · « **Reply #16 on:** October 26, 2004, 12:05:11 pm »

I wish you can post the photo of you Zauri along w/ your battery pack

aka1nas · « **Reply #17 on:** October 27, 2004, 12:30:14 am »

Quote

Recharge time is possibly explained by the following: (provided that the Z uses a standard three stage charger)

1. Bulk charge. Amperage is high and voltage is high. Somewhere around 70-80% of charge is delivered this way
2. Forgot what this stage is called. Voltage rises, and amperage is low as the battery is fully charged.
3. Float charge. Voltage and amperage are stablized at a point that compensates for the battery selfdischarge.

Note: I know the above for 12V lead/acid and NiCd and NiMh works well. Not sure about lithuim though. If the above is true, the bulk charging stage is providing enough current to charge both batteries in approximately the same amount of time. The second stage (absorbtion?) is where the time difference comes in. Of course, I could be completely wrong .

V-Man

I think Li-Ions are similar, but they have less of a voltage rise during charging than NiMh batteries.

This project looks really neat. I would like to try something like this as well. I do have one question. I noticed that the stock battery has 3 terminals instead of just two. I don't have it in my hand at the moment, so I was curious what the third terminal does and what if anything, you would have to wire to use another Li-Ion cell.

Shdwdrgn · « **Reply #18 on:** October 27, 2004, 07:58:35 pm »

The third terminal is used as a battery sensor, and I believe is used to detect how much charge is left. In the case of this project, the external batteries I purchased only have the + and - terminals, so that is all I have connected. Due to the batteries all being hooked in parallel, they will all discharge at a similar rate, therefore the remaining charge reported by the original internal battery is nearly accurate for all batteries together. This may become a problem as the batteries get older, if I get a dead cell or have a cell which discharges faster than the others, but as long as all batteries are functioning correctly there should be no problems.

Jumphog · « **Reply #19 on:** November 02, 2004, 11:50:20 am »

Interesting stuff, but theres something you may want to think about with adding extra batteries. If you have the 3 batteries all connected in parallel then as they run down the two higher capacity ones are going to discharge differently to the 900mah sharp battery, possibly even discharging through the smaller battery.

Id guess that after a while you will find that the two li-polymer batteries will have a similar capacity to the sharp battery. The problem with having batteries in parallel like this is that when one of them fails it brings down the other with it - this can be a 'bad thing' especially with lithium based batteries which can burn up if treated improperly.

Have you tried just using the two li-polymer packs without the sharp battery? The battery on my 5500 is pretty weak and after reading this thread I might consider replacing it with some of these if the zaurus will work without the sharp battery in it.

Shdwdrgn · « **Reply #20 on:** November 03, 2004, 06:00:14 pm »

Hmm that's an interesting consideration, and no I hadn't thought of that. My internal battery is also pretty weak, but I have not done any testing without the internal battery. The problem is that the Z will not turn on without the internal battery, even if it's plugged directly into AC. I'm not sure how to get around that problem?

By the way, the batteries I got are 1300mAh, include their own internal charge monitoring circuitry, and were only $5.95 each. They can be purchased at http://www.allelectronics.com/cgi-bin/cate...T-42&type=store

Jumphog · « **Reply #21 on:** November 03, 2004, 06:25:02 pm »

Z not turning on without bettery: Id guess that the 3rd terminal on the sharp battery is used to talk to a battery monitoring chip or perhaps a thermistor. Has anyone got a dead battery that they could take to peices and have a look at? Perhaps you could end up taking the actual battery out of the plastic case and just having whatever is connected to the 3rd terminal left in it,with the bigger batteries hooked up outside.

I might have to see if allelectronics will ship to the UK, thats a good price...

V-Man · « **Reply #22 on:** November 03, 2004, 10:05:34 pm »

You also might check to see if the Z will turn on with just the external battery (without the internal battery in) connected since you are using the internal battery connections and not the external power port.

V-Man

caunt · « **Reply #23 on:** November 12, 2004, 11:27:35 pm »

Just to answer the question about running the Z with only external batteries...
I pulled out my battery, connected leads to the internal connections and to the battery, and it's a no-go. Whatever is being passed through the middle lead of the sharp battery is required to turn the machine on.

macz · « **Reply #24 on:** November 15, 2004, 04:39:37 pm »

Just wanted to let you know that I was able to connect this battery as the only one to my Z5500.
There are 4 wires: 1red, 2red, 3black, and 4black. I used 1red as a plus (positive terminal), 3black as a middle contact, and 4black as a minus (negative terminal); 2red is not used. Then I made a sandwich: "Fake" battery on the bottom, 3M mounting tape in the middle, and Sony/Palm battery on the top.
For the "fake" battery:
Using piece of balsa (for weight, can be found in a crafts store like Michael's or A. C. Moore), I made a "copy" (dimension-wise) of the original Sharp battery;
To reproduce the original battery's contacts, I pushed three U-shaped, 10 mm-long pieces of 24-gauge solid conductors (the only ones I have) into the wood.
Then, I ran the three wires under the Us and pushed the conductors further into the wood to secure the wires.
My Z works as it should with this battery for a couple of days now and it does not look bad aesthetically.

woverin · « **Reply #25 on:** November 22, 2004, 09:07:16 am »

macz, Can you post some pix about your Z5500 battery pack ?

macz · « **Reply #26 on:** November 22, 2004, 11:40:19 am »

I attached the picture to this post. If it is not shown then I will provide a link later today.

semen · « **Reply #27 on:** November 22, 2004, 09:45:07 pm »

Bah. No other battery threads are alive, so...these "Battery Extenders" don't screw up Sharp's Li-Ion charging mechanism in the actual battery ? I've seen them selling on eBay (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...5733164071&rd=1) and being the uber-suck and soldering, I was wondering if they are safe to use.

V-Man · « **Reply #28 on:** November 22, 2004, 10:07:33 pm »

I have heard good reports on the stuff from "PeakCloudy". That said, I have no personal experience with him though. The chargers/battery extenders should work with no problems. I use 4-AA NiMh batteries in my homemade packs. The alkaline batteries could put out too much voltage and you risk damaging your Z. I did use alkalines a few times before I broke down and bought the NiMh batteries. I would reccomend the rechargable NiMh because the cost (over time, the initial cost is higher) will be lower than replacing the alkalines constantly. Also the NiMh batteries have a peak voltage (when fully charged) of approximately 5.34V. That should be well withing the tolerances of any Z. I have used my external battery packs for several years with no problems (both on my Z and on a iPaq).

V-Man

semen · « **Reply #29 on:** November 23, 2004, 08:56:03 am »

Ah, thanks. So I guess my Duracell NiMH 1.2V/1800mAh will work fine. Thanks. How much extra time do you pull from yours ? I would imagine adding 7200mAh would beef it right up a few hours ?

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Author Topic: Custom battery pack (Read 16484 times)