Current limiter : how does it work ?

[Fabien83]

Hello,
I discovered that some Victron BMS have a buit in current limiter on the alternator charging post.
Someone know how this works ? Is that made of variable resistors or similar components ? Does this produce heat ?

 

[SeaGal]

Is there a specific issue that you have and need to resolve? Or do you just randomly want to know how current limiters work, or want to know specifically how Victron have implemented a current limiting device?

The general principle is detailed here...

Current limiting - Wikipedia

en.wikipedia.org

And yes, any current flowing through a non-perfect conductor will produce heat.

 

[Fabien83]

Thanks for your answer. No issue at all for now. Just out of technical curiosity I wanted to know how this is implemented in the Victron BMSs and understand the consequence on voltage regulation.
If this generates a lot of heat, I understand that it is wasted energy.
I understand that it limits current while the battery is not fully charged but can it lower the voltage once the battery is full ?

 

[SeaGal]

I understand that it limits current while the battery is not fully charged but can it lower the voltage once the battery is full ?

No idea about Victron, but typically the circuitty would limit the voltage to ensure that no more than the specified current will flow. Once the battery reaches the full voltage, current will reduce accordingly.

 

[wpns]

Nowadays it’s almost certainly a switch-mode buck converter style circuit, so not a lot of waste heat to deal with.

 

[Fabien83]

Thank you for your answers. I had the idea that a BMS could only be ON or OFF and didn't know that some are able to limit the current instead of just acting like a switch.

 

[SeaGal]

Hmmm.. you were the one that said...

I discovered that some Victron BMS have a buit in current limiter on the alternator charging post.

But now you say...

I had the idea that a BMS could only be ON or OFF and didn't know that some are able to limit the current instead

So now I am confused