I have designed & assembled a digital battery pack monitor
A Tri-Quad - 3 meters/displays that provide (4) different readings
It consists of an Amp/Volt meter, to display the total battery pack voltage & the amperage being drawn by the motor (load)
…& also, (2) voltage meters, to display the voltage in each 1/2 of the battery pack
I got the Tri-Quad mounted on the bike & everything connected
Double checked ALL connections before final hook up (plugging the BMS plug in to the battery)
Everything is a "go"
Plugged 'er in
...still looks good
Went to turn the key on to "power up" the system & turn the meters on
…& noticed Balance Monitor Meter #1 is kinda flickering
(how can it do that? they should be off) Weird/NOT GOOD
Then, I turned the key on & everything worked, as designed
...the Amp/Volt meter "lit up" & displayed 45.9V
...the battery balance meter #1 "lit up" & displayed 22.5V
...but, meter #2 didn't do nuthin', nuthin', nuthin'
I went thru everything (3) times
...WTF everything looks "right"
So, (as a test) I got out (2) other Volt meters & connected them in place of the (2) meters that are GLUED IN (what was I thinkin') to the Tri-Quad
…& it seems to work "as designed"
I think, I burned out balance monitor meter #2
While connecting the wiring harness that goes from the Tri-Quad to the battery pack, I was thinkin'
The Amp/Volt meter is switched on/off thru it's 12V power wires
...but, the (plain) voltage meters are powered, thru the monitor wires, right from the "source"
We gotta add a switch, to be able to turn the meters on/off
So, I added/wired a relay into the "center tap" connection
...I figured that by breaking that single connection, would turn both meters on/off
(This way I could use the bikes 12V system to switch the "higher" voltage stuff (24V - 48V) on/off)
Now, I'm thinkin' that, ...IDK really?
Basically, I had the (2) meters wired in series
...maybe with the "center tap" connection off (disconnected)
...instead of ~22V goin thru each meter, there was the whole "pack voltage" (~45V) goin thru them
They should of been able to handle it
...the specs say DC5.0V - 120.0V (input voltage limit 132.0V)
Here are the ones that I used
But, when I look at other voltage meters
...like this one
I notice, there is no decimal point (like on mine)
The packages are not labeled so, (maybe) did they send me "smaller" meters?
...how could I tell?