how to limit dc current at 80A?

Dear Sir,
              I have a 48V 100Ah Lead Acid battery pack from which I have to power a electric drive train. I want to limit the current drawn from the battery to 80A & also short-circuit protection feature. Ipreferred MCB for this purpose but it  dint work out well. So I need an alternative for MCB, on searching over the internet I found that DC current limiter may do the job in my condition &. I am newbie in this field. Please guide me through the circuitry which may help me out.

Best Regards,
Rohit Patel.

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rickharris2 years ago

I assume you want to protect the motor. A car circuit breaker can be found at 70 and 100 amps for sure may be other amperage. These work fine in electric cars.

iceng2 years ago

What is an MCB going to do at 80A. The word miniature is diametrically opposed to your 3.8 KW (48V x 80A) control....!!! Try a 200 Volt 400 Amp MOSFET driven by a current sensing Op-Amp using a fan cooled heatsink.

Does such a Mythical Mosfet Exist?

If you have a link handy, without digging around google, that sounds like a Awesome peice of hardware !

Awesome !

Totally need to buy a pair of those to screw around with :D

On that note if you can source these (or something similar) That sounds like the way to go !

They are amazing and scary, I used to make a three phase H-bridge six devices to turn an IC engine using an inverted pm 400 amp starter motor / generator.

Now the ac unit would be placed in a rear wheel well and this ac machine was an extra inch between the transmission bell housing and getting rid of the front belt system streamlined the car profile for a whole new vehicle shape.

For the current limiting you can try some heating elements in parallel to get down to the 0.6 Ohm resistance.
For the protection check the so called "Fusable Links" in wrecked cars.
They are rated from 24 to 60V depending on manufacturer and car model.
Everythin aboue 24V max rating should work fine, the 12V ones won't stand the rated current for long on 48V.

kmossman2 years ago

a fuse/circuit breaker is your best solution

fuses are rather voltage independent, so the voltage the fuse is normally used in is not critical

motors have a high initial inrush of current, and a current limiter would interfere with this

Wired_Mist2 years ago

You will need a pre-made electric car controller. Even something for an electric Bike won't handle that much current !

Check out a DIY solution though !

After that a simple fuse works, otherwise you may be able to find a DC circut breaker too !

FarmerKJS2 years ago

A fuse would protect your system from over load.

I do not know how you would limit the current though