Well currently I use a dynamo (this is a very old bike, 20-30 years or = so) and it has filametn bulbs front and rear, what I would like is a = constanst light output no matter how fast I bike, which is not the case = atm, and light when the bike isn't moving, in case you have to stop for = traffic or something. One idea would be to have the light on for about a minute after the = dynamo stops charging. I was browsing maxim earlier for those battery ICs, found a few, most = were programmable by an SMB bus, I'd rather keep this as simple as = possible. Thanks for the info though, Patrik ----- Original Message -----=20 From: "Jinx" To: Sent: Tuesday, July 10, 2001 6:31 AM Subject: Re: [EE]: LED bicycle headlight > > What is a gel cell, and I can I charge it with a dynamo from a bike? >=20 > A sealed lead battery. The 6V 3Ah I buy is around NZ$22 (US$9). > One thing you need to keep a careful eye on is charging voltage > and limiting the discharge voltage. Go below a certain voltage and > not charge it PDQ and you'll permanently stuff it. Maxim will have > details about battery mangement ICs, which I'd recommend for > getting the best lifetime. I have a smart charger for gel cells so > haven't needed to look into it and can't supply details, sorry. As > for using the dynamo, I've never measured the output of one but > I guess it must be a few volts. If it isn't enough to directly charge > a battery you may need to build a voltage doubler and then regulate > it. It's all sounding very complicated but it isn't really. The money > you'll save over disposable batteries and the piece of mind gained > from having a second source of power will be worth it >=20 > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu >=20 >=20 -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu