i'm not sure it's the app's version, but maybe the bluetooth stack used on oreo maybe?
I think you might be making a few wrong assumptions. Since this BMS runs at 16S or 20S, that's realistically 66 volts or 82 volts. I think you are going to see many years of in place use before the BMS drains the pack.izeman wrote: ↑Feb 19, 2018 7:21 amanyone got any information about STANDBY drain? i realized that the 12v rail for the BT module is "always on". so the processor and other stuff is "on" as well. i read that standby current should be around 0.2mA w/o BT connected. but at what voltage?
voltage of the pack? can't be. those BMS range from a few cells to 30 cells in series. if they all had 0.2mA (multiplied by voltage) the wattage would differ a lot. if it was 0.2mA of the whole pack it would drain the whole 30Ah pack in 30.000 * 5h = 150.000h = 17 years. i could live with that
but how could i measure the voltage drain? the BMS itself is powered by the balance leads, and i guess it takes the PACK's voltage to power it's logic board, as the cells drain evenly. i could just connect the first and last balance wire and see what happens. that way i could measure the current going over one of the wires. would this fry the board? it should NOT do any harm, but who knows?!
I think the electronics are powered by the entire pack voltage and you said that can't be the case. I think those 6 transistors and some other components make up a linear regulator that runs at pack voltage, but I'm not 100% sure...yet. A regulator would operate at a wide range of input voltages and still output 5 volts.izeman wrote: ↑Feb 19, 2018 1:32 pmwhich assumptions are wrong? i don't see you say anything different than i do.
my BMS is 15s so around 50-60V. and something has to power the 12V for the BT module, and i guess the atmel is always on as well (i should be in sleep mode though). i will need to measure that.
still i see some voltage drain over 24h. i'll do some long-term test now. user merlin stated, that his bms (the very same type we two have here - different cell numbers, but otherwise it's the same i guess) drains the pack by 100mV over 2 weeks time.
this would mean that a fully charged pack is empty quite quickly.
Best mosfets for anything...
That's not the case, you can connect them in any order so long as you connect the correct tap to the correct cell input port.
Check out this video where he measures the standby current. The BMS goes into sleep mode at which it only draws 0.5mA, it jumps up to 5mA periodically to scan for activity on the UART. There are some errors in other parts of the video however.
Where is this K1? I have the 16-20S BMS and I don't see it anywhere. Can you post some pic's please?izeman wrote: ↑Feb 18, 2018 12:49 pmYES!!! i works!
just connect a latching switch to K1, enable SWITCH in eeprom (windows software) and voilá! you can switch the BMS on/off with it.
if you DISABLE the SWITCH checkmark in the software it will be ALWAYS ON.
edit: it's a bit strange: i can easily connect with my redmi note 3 android, and i could connect with my mi mix2 an nougat firmware, but it's not working with oreo. any ideas why this could happen?
Ignore the charge side mosfets. You only care about the discharge side mosfets. I wouldn't bother with mosfets that are rated higher than 100 volts. The BMS can't handle more than that anyway if yours is 20S or less. The IRF4110 or AOT290 will work well for this BMS.flippy wrote: ↑Feb 18, 2018 3:27 pmwould the IPP048N12N3G be a better alternative? (4.8mOhm)
https://www.infineon.com/cms/en/product ... 48n12n3-g/
i still plan on putting like a dozen on the board to replace the chinesium mosfets to get decent current capabillty.
Thanks ElectricGod. That is the same version of the app that I am using. I will try turning GPS off and on. Otherwise I'll have to wait for the seller to come back online.ElectricGod wrote: ↑Feb 19, 2018 1:52 pm
The latest software can be found here.
https://www.lithiumbatterypcb.com/smart ... -download/
Are you saying I can connect cells 3, 11 and 20 and NO other cells and the BMS will survive? That seems unlikely. Each channel on the board is part of a much larger voltage divider. No one channel "sees" more than it's small portion of the whole pack voltage (the voltage of the one cell it monitors). Connecting random cells and leaving others disconnected would mean that the voltage at those connected channels could be significantly higher than that of a single cell.Fionn wrote: ↑Feb 19, 2018 2:11 pmThat's not the case, you can connect them in any order so long as you connect the correct tap to the correct cell input port.
If you connect a higher voltage cell (say cell 8 at 30V) to a lower input position (say cell 4 - which expects about 15V), you will burn out the 150ohm precision resistors that form the voltage divider on the inputs.
I thought I had a lot of scrounged laptop cells. He's definitely been at it a while longer than me!Fionn wrote: ↑Feb 19, 2018 2:11 pmCheck out this video where he measures the standby current. The BMS goes into sleep mode at which it only draws 0.5mA, it jumps up to 5mA periodically to scan for activity on the UART. There are some errors in other parts of the video however.
Well cool...teach an old dog a new trick! I'm always careful to plug in from lowest to highest or to disconnect from highest to lowest.