Current limiter for battery charge

Thread Starter

Remco

Joined Nov 30, 2013
1
I'm not an electrician, so excuse me if I might ask a maybe very simple question...

The case is that I would like to limit the available ampere on a 230AC connection to 4, 6, 8 or 10 Amp without loosing Voltage and without disconnecting the current.

This way, a device like a battery charger that normally uses 16 Amp can be refused to use this power and make an other fuse (limited to 8 Amp) disconnect the current.

The solution should be able to fit into a small box like a cup of thee, and should not cost more the few dollars...

Who can help me? What do I need?
 

MaxHeadRoom

Joined Jul 18, 2013
28,576
This was typically done in the past with a current transformer and a current meter with a settable trip.
Not sure if the electronic versions are available now, but quite possibly?
But it has to either have something that ignores inrush, or is employed after the fact.
Max.
 

#12

Joined Nov 30, 2010
18,224
Your question is a bit vague. Do you want to install an 8 amp fuse? Do you want to reduce the maximum current the battery charger delivers?

Basically, you can't limit current without reducing the voltage unless you use some smart methods. You can't just tell a light bulb to be dim by putting a smaller fuse in series with it.
 

t06afre

Joined May 11, 2009
5,934
Also what kind of battery are you going to charge. Most kind of cells are not so forgiving as the lead acid cell type.
 

MaxHeadRoom

Joined Jul 18, 2013
28,576
The idea I got from the OP was to disconnect power if the demand was over a set limit?
I have done this with items such as furnace coal conveyors using the CT method.
Max.
 

bountyhunter

Joined Sep 7, 2009
2,512
Power supplies do this by monitoring line current using a current transformer then having a relay that trips open and "times out" for a period of time then resets and keeps opening and timing out until the overload is gone.

Impossible to do this for a few dollars.
 

inwo

Joined Nov 7, 2013
2,419
The way this is handled in the real world is with keyed plugs. Like twist-locks. tm.

Good battery chargers check for conditions (polarity and voltage) before enabling the load.

Theoretically an AC supply could check the same way.

Not simple, universal, or inexpensive.
There would have to be a unique need to even consider it. IMHO
 

inwo

Joined Nov 7, 2013
2,419
The idea I got from the OP was to disconnect power if the demand was over a set limit?
I have done this with items such as furnace coal conveyors using the CT method.
Max.
Furnas makes some really neat devices for this. Self contained and self powered.

Used one to sense overload in a silo unloader. Time out reverse, time out reverse.

The real reason I like them is that I've a bin full.:)

Believe op's idea would require soft start or current limit.
 

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