Battery Current Monitoring Relay

Do you need to monitor it or just have it cut out? What type of speed controller is on the vehicle? If it is an electronic speed control some have pots that enable you to set a thresh hold current. It will trip out on over current. Some reset after taking your foot off the accelerator petal. Some reset by placing the vehicle in neutral.

Vehical having a fix speed of 10kmph which is driven through curtis make DC drive having max acceleration time 3.8 sec At starting current drawn by vehicle : 23-25 Amp In normal running current drawn is : 16-18 Amp But in case of any jamming/overloading due to improper break release or failure / worn out bearings of load wheels vehicle draws 40-50 amp which results in failure of DC drive Thus, i want to provide indication / tripping at overloading

What model Curtis controller? Several of their models have current limiting pots that are accessible and can be set for your needs.

If you put a Thermistor in line with the motor drive, it will not allow the motor to draw more than the desired current.

A cheaper solution is thermal overloads on the motor contactor. The motor draws too much current, the overloads overheat, and the circuit is broken. After a set time, the overloads reset and the circuit is made, until mechanical failure occurs.

The downside of the overloads is they don't allow the battery to be drawn down (usually .8) low enough to drop the supply voltage.

It is a challenge; because, as the supply voltage drops, the required current increases, the motor gets hotter, the contactor overloads heat up....

An electronic circuit with a few transistors and resistors could be put along with your existing motor which would in turn sense rise in current drain of more than 25 amps and trigger the tripping contact. mann935