Estel | # 1491 | 2013-03-16, 02:08 | Report

Even if it would be possible, every cycle (even when no re-calibration done), updates capacity for a 1% or so lower one. It's build-in hardware chip.

May I ask why you want to avoid recalibration? It sounds quite counter-productive, unless you swap batteries of different sizes, every cycle.

/Estel

impeham | # 1492 | 2013-03-16, 19:37 | Report

i do

i sometimes use a dual battery and sometimes single and i have scripts to display battery level in both modes (the device is calibrated for the dual battery, and my single battery script uses the same as the dual, but cuts the values by half).

i want to avoid recalibration by accident when using the single battery.

bogdanov_s | # 1493 | 2013-03-18, 06:04 | Report

Hi everybody .i'm new here i make something you talking about 9600mAh battery on my nokia n900 .. for just 20 dolars .when finist project totally i'll take photos

impeham | # 1494 | 2013-03-18, 08:53 | Report

sure you are

independent | # 1495 | 2013-03-18, 09:27 | Report

Hello. I mentioned several pages back I had one of the new nokia bl-5j batteries that come with newer Nokia phones (this one from an X1-00). I've had it I most a year I suppose. Not done major duty except trying to get the built in chip to stop registering at 2044mAh.. Using bnf and the bq scripts for battery monitoring. Anyway, just to say got 1415mAh discharge for what is reported as a 1430mAh cell. So, guess it comes above reported..

EDIT:

I say it comes in above reported mAh because it is an old battery ie most of a year old and having been used during that time. Using the bq27200.sh script and fully discharging the battery without charging after reaching "VDQ 1" gives me a measured discharge of 1415mAh.

I would like to add, getting from the 2044mAh registered charge level (takes 3x calibrations with a normal battery) is not easy as sometimes (yes following all of the guidelines) the phone turns off before the voltage goes below 3.248v. That said, bnf and the bq27200 i2cget scripts make for a truly fantastic tool and once calibrated bnf is a deceptively simple, very accurate battery "tank" level tool. Thank you Estel and everyone else (shadowjk, et al) who made it possible!

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Last edited by independent; 2013-03-19 at 21:36. Reason: Because I tested the battery after using it for a year and this was not clear in the post

Estel | # 1496 | 2013-03-19, 10:29 | Report

Yesterday, I was building new dual battery from 2 scud bluedream cells, as my 1st dual-scud was getting really worn (~2100 mAh reported, as opposed to original 3100+ mAh). I've made it usking cells, that dr_frost_dk sold me looong time ago - time goes fast so I'm not sure about exact date, but surely, it was more than a year ago.

I've kept that cells between 20%-80% charge - to be precise, from times to times, I've charged them to 4.200 mV (without saturation phase, aso as soon as it hits 4.200 mV with 500 mA charging, I stopped charging, to not stress battery - what I did on this phase is called "fast charging" in Li-Ion world), then, discharged them to 3.800 mV, and kept them this way in dark place, room temperature, for next few months. After that, I did same as above.

The result is, that finished battery report 3010 mAh when discharged to 3000 mV at constant 300 mA rate. It means, that during variable rate discharge (real-life N900 usage), relative capacity will be much higher, 3100 mAh at least, or even more (thumbs held).

Conclusion - those cells, when properly stored, virtually doesn't lose any capacity at all. While I suspect that they were quite fresh at time dr_frost_dk bought them, it's still nice, how well they keep capacity during storage.
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I've took many photos during assembly, and I'm preparing some nice things for (wanna-be) battery constructors - I think both absolute newbies, and experienced dual-batt creators may benefit from it much. Stay tuned for Estel's N900 workshop, issue 1

/Estel

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Last edited by Estel; 2013-03-19 at 10:33.

sjukfan | # 1497 | 2013-03-19, 13:05 | Report

Maybe he's using three 18650s?

dr_frost_dk | # 1498 | 2013-03-19, 18:04 | Report

ill put a link in post #2 when you make a guide, and sorry to everybody for my abstinence lately, have been doing alot of things an in the process of building the next EV-Moped (google "electro DM50") and also messed up my back in the last days so have been laying down most of the time... really hate my "health"

I should really get in gear and remake a dual scud for my N900, i have been using a single Polarcell for some time and for the most of the time it is good enough but sometimes i almost run out of juice and my "stand" on the XL cover is better ten original cover

bogdanov_s | # 1499 | 2013-03-19, 21:26 | Report

this is what i made
9600mAh battery !!!

Attached Images

  

handaxe | # 1500 | 2013-03-19, 22:05 | Report

Not pretty but thats a lot of juice.

So whats your run-time - 6 days?