Lawrence, I'm certainly not a charger expert. The way the bq2003 is used in the Tropica charger (oh I'm out on a limb here)is as a controller for a buck converter. It turns on a FET sending current through an inductor and then the batteries. When the current reaches a programmed threshold it shut it off. Current is regulated by adjusting the pulse width. There's really no output that can turn off a charger. When 2003 senses the threshold voltage, it just quits turning on the FET. I'll let others explain the details of a buck converter.
My problem is that it looks to me like in this configuration, it just keeps pumping out 12 amps until a threshold voltage and then shuts off. This doesn't sound like a valid charging method for lead acid. Is this why everyone I know of with a Tropica has replaced the charger? Steve In a message dated Mon, 7 Oct 2002 11:41:57 PM Eastern Standard Time, [EMAIL PROTECTED] writes: > > > The charger chip that senses current and voltage is a nice feature. Can > these chips be added to a charger like the B&W or maybe a variac bad boy. > It seems that that chip and a relay would be all that is needed to shut down > any circuit. Lawrence Rhodes... > ----- Original Message ----- > From: <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Monday, October 07, 2002 9:12 AM > Subject: Tropica update > > > > Last Thursday we went to DMV to start the "adventure" of getting our never > registered 1995 vehicle registered. I had pretty low expectations for this > first trip based on the experience of others. Well, I was wrong (again)and > we came home with a red temp sticker good through year end after just an > hour! Next it's off for a CHP inspection. Last Friday I was able to drive it > to work, about 14 miles each way. I can charge at work so it got a drink > before going home. > > > > Speaking of charging, I've got the schematics for the Tropica charger. > Thanks Matt! I was looking over it this weekend and it's "brains" are a > BQ2003 which seems to be a NiCad charger. If I understand the options they > have it wired for, it does a constant current charge of 12amps to a set > voltage and then shuts down. That doesn't sound like a good plan for lead > acid does it? I looked at another part from Benchmarq, the bq2031, which is > designed for lead acid. It has a constant current bulk charge followed by a > constant voltage charge and terminates on hitting a min current or a delta > voltage. The parts look close in the support they need but certainly not pin > compatible. Any comments on the wisdom of replacing the > 2003 with the 2031? > > > > thanks, > > Steve > > > > > >
