Thread: Low cost BMS
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Old 07-11-2011, 01:26 AM   #26 (permalink)
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Originally Posted by ianbartie View Post
Similar problems plagued the Volt Blochers (which is why I suspect they disappeared).
They had no form of fuse anywhere & they were permanently across the cells.
One of the two ICs it used was directly connected across the cell without a resistor divider. One particular brand of IC had a nasty habit of failing ON & then draining the battery to death as there was no safeguard to limit battery discharge & no indication it was happening either.
They also generated a LOT of heat from the TIP122 & the 5W resistor when they were shunting.
I still favour a system that disconnects the BMS electrically from the cells when the vehicle is off.
My current BMS has miniature relays on each board that switch off when the car is turned off.
Similar problems to what?
This BMS doesn't have any problems.
You can favour whatever you like but just read the title of this thread again. Your relays cost more than my whole board!
The shunt is 6R8 4 watts and made by series/paralleling 4 x 1 watt SMD resistors. The resultant surface area is large enough to keep the resistor temp below 6o deg.
Build one and see!
Sometimes I sits and thinks and sometimes I just sits.
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