Idiot mistake or common? Shunt connection

Pugwash69

Full Member
I installed a battery monitor with a shunt on the -ve cable a few weeks back. After charging the battery up to full I calibrated the 100% level and thought it was all working fine. I've had my charger on this week and noticed the monitor is showing a small drain, instead of a charge. Although the voltage looks fine it's saying I'm down to 89% charge.

I've connected the battery charger directly to the battery instead of the -ve lead going through the shunt!

Carry on
As you were
 

wildebus

Full Member
I installed a battery monitor with a shunt on the -ve cable a few weeks back. After charging the battery up to full I calibrated the 100% level and thought it was all working fine. I've had my charger on this week and noticed the monitor is showing a small drain, instead of a charge. Although the voltage looks fine it's saying I'm down to 89% charge.

I've connected the battery charger directly to the battery instead of the -ve lead going through the shunt!

Carry on
As you were
Opps :)
 

Pugwash69

Full Member
Yeah sort of what I said. My solar charge controller also straight to the battery. I didn't read the instructions.

I found this diagram today that would have been helpful.
A_Battery_Monitor.jpg
 

wildebus

Full Member
What would happen if the negative busbar was also wired to the vehicle (neg) body?. Would the current flow still be measured?
Pugwash's diagram doesn't show it, but that is how the wiring would be done in 999 out of 1000 cases (at least). As long as the shunt is the only battery negative connection one side, and all the grounds/chassis/0V/Negative (whatever you like to call them) are on the other, current flow is measured (y)
 
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