Description of Bill Dube's and others modular charging attempt. 120 volt input and a 10 amp output, waterproof,two status lights, isolated switcher-type,10 amp constant current to trigger voltage then constant voltage until current drops to an amp or two then constant-voltage float charge. John Wayland dat1200@europa.com and Lou Tauber ecar@europa.com are working with the manufacturer on units modified especially for Optima yellow tops. Search the EV List Archives for more info. This scheme was eventually abandon because without system management and charge fault detection it was easy to drive off thinking all the batteries were charged but a charger malfunction left one or more batteries undercharged compared to the rest of the pack - a severe pack imbalance. Driving with the pack in this condition depletes undercharged battery first. After it's depleted the rest of the pack continues to force a current throughout, charging it in reverse. This causes the cells in the battery to reverse polarity, permanently damaging them. This condition can easily result in a catastrophic battery failure with a battery acid steam explosion the reversed battery due to the intense heat from reverse charging. Not Good.
Charger type equalizers add additional charging current to low batteries.
Shunt type equalizers divert charging current from charged batteries so they are less likely to overcharge while low batteries continue to charge.
PICs are cheap and effective microcontroller chips. They come in many flavors, but in general they can have multiple A/D converters, serial I/O, and control lines all on one chip. They can be programmed using assembly language and a Windows 95 PC. They come in sizes from 8 pin surface mount to 32 pin DIP. Their potential applications are endless, and they will probably be the chips that eventually go into everything from toasters to alarm clocks to ham radios. PICs represent a new paradigm in automation and micro control.
Our MooRocco telemetry system utilizes multiple remote PICs to gather data from everything from the batteries to the brakes. These remote BABY PICs all report via fiber optics to a BOSS PIC, which will format the data for transmission via amateur packet radio.
Our batteries, 10 in the back, 6 in the front, are monitored by what we call our Bottle Cap PIC Project. We have these (plastic) bottle caps with an little circuit board inside. We have a PIC (a _very_ small and limited microprocessor) in each bottle cap with two connectors connected across the terminals of each battery. It checks the voltage across the battery and the temperatures of the two leads. That way if your battery terminal is a little bit loose and it starts to heat up, we can see that. They communicate with a "Boss PIC" through fiber-optic cable, so we don't have to worry about the battery voltages leaking -- it keeps everything separate and isolated." They have heard of terminals getting very hot and causing problems, so they figure their system can warn them long before a loose terminal overheats and starts a fire. The Boss PIC communicates with an onboard PC and over ham radio to the chase vehicle.
more _much_ later...
On the expensive side, hard to find but VERY clean and compact.
