From: Marty Goodman Subject: [BC] Li Ion system info Date: Thu, 21 Nov 2002 17:46:31 -0800 Message-ID: <0.700001764.716078194-1463747838-1037929617@topica.com> Kevin asked: "Hi Marty I'm ready to do Li Ion. I tinker but at a lower level. I suggest you list a recommended combination of charger, battery, regulators and so forth. I need a complete suggested system for everything but the load. Consider my load 12v halogens you will probably set about 13.7v or so. Vendor website, part numbers and price is appreciated. I am close to Action electronics and Marvac in Santa Ana, CA, and have the Digi-Key catalog in my bag. I have the load; the lights. I like running 2 lights for I like redundancy. Keep it simple, and I have to mount all into the bike light system and the charger needs to fit on my counter. " Kevin, I don't have the time to provide the exceedlingly detailed "how to" info you asked for above in all details you requested, but I can provide what should allow you to proceed: (1) Li Ion chargers: I buy mine from Span Inc. I use the FCM2 model on my headlamp batteries. These cost about $90. They are high quality, microprocessor controlled chargers. You must specify the number of cells in your battery, and the charging voltage you require per cell (4.2 volts per cell for the kind of batteries I use, 18650 shape Li Ion batteries made by Sony and others, salvaged from Laptop and Cell Phone battery packs). Look for them on the web. (2) I get my batteries by taking apart laptop LiIon batteries sold on Ebay. The Bat 30IL for the Dell 7000 is a nice 12 cell pack (be sure to only buy those that are rated at 5400 mah... there are poorer cpacity varients being sold!). Or for the Dell Extensa 5000i (9 cell packs). Price is around $5 to $8 per cell when bought this way. I personally test the cells on my battery tester for capacity, to make sure I'm not building up a pack with a bad cell. (3) I use the Power Trends PT 6304 DC to DC converter module to regulate voltage. This can be purchased for about $20 or so from Digikey. You need a data sheet for it to be able to use it, but it's pretty easy to impliment... not all that muchharder than using a simply LM317 linear regulator, tho you do need to buy LOW ESR electrolytic capacitors to use with it. (4) I designed my own low voltage cut off device to protect my battery, that can be set anywhere between 5 and 20 volts to disconnect the battery from the load when the voltage gets too low. You can feel free to design your own, or you can contact me to buy one of mine (I did a run of PC boards). I'd want about $20 for a built up PC board (which you can package as you wish, or in an external box available from Radio Shack). My design is simple, can be easily modified by the user, but provides NO warning that the battery is about to get cut off. I find I don't need a warning circuit, because I am so conservative in choosing big capacity batteries for all rides I do. I use a system that incorporates these items to power my NiteRider Blowtorch, and am about to use it power my CatEye Stadium as well. At a setting of 14.5 volts output. (I use a 21.6 volt nominal, 6 cell Li Ion battery as the input to the regulator... and charge that battery as two separate 10.8 volt 3 cell Li Ion batteries.) But this is NOT a HOW TO project! You have to know what you're doing, know the characteristics of Li Ion batteries, and be VERY careful to make up your battery pack SAFELY with proper protection against short circuits! NightSun is about to be selling their combo charger, Li Ion battery, and regulator for $200. The output will be 12.5 volts. I do not know if you can adjust the output... it's possible you cannot. In any case, NightSun DOES NOT wish to support modifications of its product... it's only for use with NighSun systems. ---marty