Current limiter and VP-X

High_Flyer · #1 09-28-2015, 02:34 AM

Good morning,
I'm starting my electrical system (RV-7).
I'm installing a VP-X (plus a full Dynon panel).
I have seen that some builders are installing a current limiter on the firewall between the alternator and the VP-X. I can't see (or I missed it) anything in the VP-X manual about this.
I would have thought that the VP-X could handle all electrical malfunctions, including over-current.
It would be nice to have a few opinions on this.
Thank you.
Alain (in France).

Sylvainsting · #2 09-28-2015, 05:30 AM

I am in the same case. I would like to build a simple system, so if it is aredundant information...

Sylvain

DanH · #3 09-28-2015, 07:42 AM

The current limiter (a big fuse) isolates the alternator B lead from the battery in the event the B-lead is shorted (insulation cut, broken ring terminal, etc). Battery cable current does not pass through the VPX or a standard main bus; neither can serve the function of a B-lead current limiter.

airmel · #4 09-28-2015, 07:45 AM

Try pages 26-27 of the VP-X manual. There is an "ANL" fuse which is a current limiter for the alternator. It shows it going to the switched side of the battery contactor which is also wired to the power input of the VP-X. This protects the B-lead wiring. (The item not needed when using the VP-X is a shunt as the VP-X will provide this information without the need for a shunt.)

High_Flyer · #5 09-28-2015, 10:52 AM

Yes I now see it on pages 26-27 of the VP-X manual.
Thank you very much.
Alain.