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On 11/08/2013 05:00 PM, vordoo wrote:
Hi,I would have to recommend against doing this yourself unless you want to make a significant investment in equipment and open a small business. Here is why: 1) You need to buy batteries in bulk (hundreds) then charge and discharge them with calibration equipment, then select enough batteries with equal characteristics to fit the pack being rebuilt. Just picking 6 to 9 random batteries from a batch does not work, they charge and discharge in groups and have to do that equally or they will overheat. In that case, tripping the alarm at the controller, rendering the pack unusable, is the lucky scenario. For other scenarios, see "soldering" below. 2) Soldering the batteries together will not work, for three reasons: I) Each one has a fuse/vent on top that cannot withstand high temperature. II) The cells degrade, rapidly and irreversibly, when heated with a soldering iron above 50C. Typical soldering occurs at about 225C. III) Further heating causes an oxygen breach and fire at least, though explosion is a very, very possible outcome for cells of this capacity. YOU DO NOT DO THAT. NO, SERIOUSLY, DON'T. (If you still decide to do that, please do share the story here, both as a warning to others and for our sick entertainment, once and if you get out of the hospital) You will need a spot welder station, but not just any spot welder but one that does not breach batteries when welding them AND have the contacts on a small enough distance that allow actual welding on area of about 5mm AND making the welds that are able to pass the current required. Yes, this is the station with electronic charge/discharge control, about $2200 used. OR YOU CAN BUILD ONE AND BLOW UP YOUR HOUSE. Welding the pack together is done with a nickel strip which you'll have to buy in bulk. No, cold connectors will not work. 3) Repacking batteries changes the overall characteristics of the pack, you have to re-flash the controller with factory settings and actual cell data to have any kind of accuracy during charge-discharge cycles. The software to do that (UBRT, for example) is expensive (albeit it's available on per-battery license basis) 4) Usually the pack controller chip burns the controllable fuse on the pack's control board when something is wrong with the battery to prevent damage to the notebook. The restoration is possible, if you're good with electronics and a soldering iron, but there is no guarantee that the restored fuse will burn out the next time it's needed and the batteries won't overheat trying to burn it. The right way to do that is with Wood's alloy, which is much more toxic than regular solder, which is "throughly wash hands after touching, don't breath in vapors, only use in a well-ventilated area" toxic. Or you can buy a thousand of new fuses from China. Did I mention that different batteries, even of the same brand, have different fuses? My own experience: During my last trip to Russia I've used repacking services there (Moscow): Case (1): The pack for my Lenovo W700, the cost was 100 roubles more than buying a new brand name, official, original battery, which I also did. The restored pack works well, in fact, I'm using it right now to write this email, however, I had to re-do the controllable fuse restoration myself because the soldering job was terrible and dangerous, basically a huge drop of solder shorting the fuse and the fuse cover is now missing. My rework is somewhat better, I'm not very happy with it now, I did what I could, and was very satisfied with it, only later realizing that it was only a partial success and even that was more a matter of luck than skill in this case. I also had to re-glue the pack's plastic case together, because the glue job was ever worse than the soldering. But I have to thank him for that, I guess, otherwise I would not discover the fuse. Case (2): The pack for an old laptop that does not have a replacement original battery available anymore. The work was done in a establishment different from the first one. It works very nice, just like new. Glued together well too, no idea what surprises are inside though. I hope my field laptop won't blow up one day. My advice would be buying a new original battery from a trusted supplier unless it is not available anymore. In that case, I've heard there is a lab in Netanya that does the "battery repair" (no idea about the quality of the nature of the work). Or ask someone who's going to Russia/Ukraine to repack a battery for you there (the turnaround of the service is usually about a week). The best forum dealing with battery repair is www.avalon.co.ua, you can find where the repair labs of the members are located. It is in Russian, but some people do manage to have a conversation there using online translation services. -- Sincerely yours, Michael Vasiliev |
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