Alan B
100 GW
I'm collecting Lipo batteries and setting up my ebike. I'm starting with RC chargers and a simple balance tap paralleling board, but I would like to be able to monitor and collect data on my battery pack. Initially I thought I would use celllog's for this, and they are cute, but I just can't see myself dealing with the downloading of three or four of them more than a few times. I would also like to be able to experiment with some different charging and balancing algorithms, and have a readout that was easier to deal with on the bike. I want to learn more about what is really going on with these batteries. Eventually I want to have one-plug charging from AC.
My pack is still evolving but will probably be 18S4P of 6S 5AH 25C Turnigy packs, so 20AH total. So I'll have 18 sets of paralleled cells to monitor, charge and balance.
So what I want to do is more than a battery management system, it is a data acquisition and control system for batteries. So I'm looking at what that might be:
This leads me to something physically similar to Fetchter & GGoodrum's BMS boards - four JST-XH connectors for the balance taps, but with totally different electronics. Something that can be mounted in the little leftover spaces available in a compact ebike battery build.
Some questions:
Other considerations?
Thanks for your comments,
My pack is still evolving but will probably be 18S4P of 6S 5AH 25C Turnigy packs, so 20AH total. So I'll have 18 sets of paralleled cells to monitor, charge and balance.
So what I want to do is more than a battery management system, it is a data acquisition and control system for batteries. So I'm looking at what that might be:
Read each cell's voltage, display, store for later analysis
Measure temperature
Provide low voltage protection (probably ebrake or throttle control output)
Compatible with 5S and 6S Turnigy packs
Connectors for paralleling 4 balance connectors (JST-XH balance connector)
Small and modular to fit in the available bits of space, integrate with battery pack
Low standby current drain
Programmable for data acquisition and charge algorithm development
Cabling Minimization
Testing Port - for reading out cell voltages and doing balance charging with an external charger when needed
System must be self-testing, give some verification that it is actually working
This leads me to something physically similar to Fetchter & GGoodrum's BMS boards - four JST-XH connectors for the balance taps, but with totally different electronics. Something that can be mounted in the little leftover spaces available in a compact ebike battery build.
Some questions:
Cell Voltage Measurement Resolultion and Accuracy requirements? (is 10 bits adequate?)
Balance current requirements? (is 100 mA enough?)
Standby Current Drain requirements? (How much is too much?)
Other considerations?
Thanks for your comments,