Voltage meter install

[Smurf2]

Hi.
I have Bafang rear hub 500w, 48v, 17.5aH battery.
Ordered voltage meter with two buttons and v/% messure.

Where is the best place to install it (connect to power) and with minimal damage? If cuttting, then somewhere water not go in.
-from display?
-from battery jack? cut wire or push wire in xt60/30
-bellow battery mount, where charging pins are

other ideas? where you will put?

I want isnstall that because my display 800S show just icon battery Bars.

Othet questions, is normally that battery when turned OFF on red button, gives all time around 3v? I think that is dangerous.

 

[docw009]

Most ebikes, even the simpler ones, have a battery circuit that goes live when turned on. I connect my handlebar volt meters onto that circuit. That way, the meter is only on when the bike is turned on. It also helps that I can see it when riding.

 

[E-HP]

Your display has battery level voltage going to it already via the red and black wires. If you're willing to open the display, you can grab the battery voltage from there and not run additional wires to the handlebars, then just duct tape the thing to your current display.

 

[Smurf2]

Your display has battery level voltage going to it already via the red and black wires. If you're willing to open the display, you can grab the battery voltage from there and not run additional wires to the handlebars, then just duct tape the thing to your current display.

That I'm looking for!
I thought that not full voltage goes to display. I thought that controller adjusts voltage around 5v, then that voltage goes to display!

Furthermore, I will check voltage on pins first, then I will see can I open it!

 

[Smurf2]

I tried to open 800S display, but after removed first cover, it looks that inside is glued very well.

 

[LewTwo]

Where is the best place to install it (connect to power) and with minimal damage?

If you have separate charging and power ports on your battery then you can usually read the current battery voltage on the charging port (assuming you do not have a charger plugged in when riding). Just get a matching connector for the charging port and wire your gauge to that.

 

[Smurf2]

I know that I can connect it down. There will be a long wires from bottom to the top of bike.

It will be grat if I can open that glued lcd screen.

From controller to battery I have xt60 or 30. Did you mean make something like this double connector and connect it in middle of this two? So will be 1 free for guage?

Or other idea is connect guage to connector bellow battery.

 

[Smurf2]

I opened!
It show full voltage on pins GND + IN+.
Now I just need solder that.

 

[Smurf2]

The tester wires (jumper) are bigger then wires in bafang display pins.
Can I solder first in bafang display tiny blue wire which I found ( because it is almost match and it is longer).
Then from tester jumper wires connect on this tiny blue wires? Will that work or be to hot?

 

[nicobie]

To monitor voltage, only small wires are needed. It's different for Amps and Watts unless using a shunt.

 

[Smurf2]

To monitor voltage, only small wires are needed. It's different for Amps and Watts unless using a shunt.

Yes, but tester have bigger wires (jumper cable) with connector installed already.
I will try like that, hope that will good messaure.

 

[TommyCat]

If you just want the new voltage display to work after you power on the main display. (IE with the bike’s system active) I would suspect the o_Bat terminal will have battery + power to it when the display is turned on. Verify first…


Regards,
T.C.

 

[Smurf2]

Yes, I was tried negative on GND, and positive on 0_Bat, but didn't work, nothing show..
So I soldered positive to In+.

Tomorrow just need to buy a hot gun to glue solder pins inside.

 

[docw009]

I also think 0_Bat probably goes to battery voltage when the display turns on. That's how I connect my voltmeters to the same 5 wires I find inside the display cables. There's battery, RXD, TXD, Ground, and the fifth wire will go to battery voltage when display turns on,

There's nothing wrong with having the meter always on. which is when you connect it between your IN+ and ground, if your battery has an on/off switch. Some of mine do not. and I don't want to see the LED's lit up at night in my garage,

 

[Smurf2]

That is my temporary voltage tester, and it not have power on/off button, maybe because that not working on 0_bat.
Another, better tester, with two buttons will come soon.

Now display shutt down slow, need about 1-2 min when any voltage disapears, but ok.

Hope that wires inside not be connect, otherwise battery will blow up

But, I not yet got answer why my battery, and other yours, when shutting power off, still have about 3.6v in circle? I want my bike left on my work but still afraid because battery stll not shut off full.. If you understand me.

 

[E-HP]

Now display shutt down slow, need about 1-2 min when any voltage disapears, but ok.

If you mean the voltmeter display, that's because it's still measuring the voltage from the controller as the caps discharge.

 

[Smurf2]

Now display shutt down slow, need about 1-2 min when any voltage disapears, but ok.

If you mean the voltmeter display, that's because it's still measuring the voltage from the controller as the caps discharge.

Yes, voltmeter display.