openinverter forum

Since this is folder to publish BMS related stuff i am adding this DIY BMS originaly made by Neville Harlick of NZ and changed a bit by me.
It was intended to be used for Low level balancing after a long drive, but software was adapted to support High level balancing.
Balancing is not initiated everytime however. It can be switched on by user. Primary function of BMS master is to reduce charger current and shutoff charger itself at end of charge.
BMS was intended for LiFe cell chemistry, but software was changed again to support LiPo cells.

Cell modules use Pic12F chip to sense voltage and act as transponder for master. Voltage is sensed by LM285 ref diodes through R divider. There is also thermistor on each module.
Master is controlled by Pic16F chip which polls comms and makes decisions. If comms would fall out watchdog trips the chip and everyting is disconnected, red LED is lit and display starts flashing.
The Project file is the oldest with original drawings. Rest of files are updated and redrawn version with additional functions.

If someone is interested, we have made some progress with serial and CAN charger control. However CAN would require a redesign of Master board. First of all i would use Pic18F with CAN controller integrated and second i would design I/Os so relais are incorporated on board.
Everything is drawn in Designspark.

EDIT: Some past forum links
http://forums.aeva.asn.au/viewtopic.php ... w+cost+BMS
https://sourceforge.net/projects/low-cost-bms/

I decided i need to have some form of control over my Jaguar cell voltages. So i went to dust off my old BMS plans.
Since it is daisy chain i will need one Pic12F chip and LM285 reference for each cell. But in return i will get good voltage reporting and temperature reports as well. I went on and made a design for 16S board. Since i have 96S i will need 6 of them.
They will be connected to each other with twisted pair for noise suppression and each pair will end in master board.
Now master board will be something for me to play with. My intention is to make a new master using a Pic18F chip with CAN bus module. This way it will be able to send telegram to charger and cell voltage reports to CAN LCD display i intend to have in my car in the future.

After i finished one board i tried each module individually and only when i was sure they work i connected twisted pairs. When wires are joined Pic12F programming is inhibited. Then i connected complete board to my cell block. I use Molex Minifit connectors.