mini-master relay ?

[shiney]

In my plan, my always hot batter bus is located in the sub panel near to my m-bus and e-bus. This is some 24 inch from the Battery so exceeds the Z-11 6 inch wire length recommendation by some way. My idea to fix this is to put in a current limiter near to the battery so I sent an email to Bob Nuckolls to ask his opinion, Bob has replied;

" If the battery bus is not located next to the battery then legacy conventions call for adding a mini-master relay to disconnect for crash safety"

Is this in place of a current limiter, has anyone else done this and how does a mini-master relay work ? How have other builders solved the problem of the battery bus being a distance from the battery?

Martin

 

[az_gila]

Why not move...

..your "always on" fuse block/battery bus?

There should only be about 3 or 4 items on this bus, and then the "always on" feed line will be kept short as Z-11 recommends.

I realized this, and moved mine to the front of the firewall instead of placing it with the other two major busses. In my case, it removed an "always on" wire from penetrating the firewall, where it might be hard to inspect.

 

[shiney]

battery bus

Thanks Gil, I appreciate your valid point. I'd like to be able to access my battery bus without taking off the cowl so I think I'm going to go wih the current limiter, it seems to be the most simplistic method

 

[az_gila]

If it's crash safety...

Thanks Gil, I appreciate your valid point. I'd like to be able to access my battery bus without taking off the cowl so I think I'm going to go wih the current limiter, it seems to be the most simplistic method

...as Bob N. mentions, then a current limiter is not the best idea.

It is just a fancy word for a big fuse... ...and in a crash situation, the wire from the battery would still be live and powering various items.

Access to the battery bus should not be a big deal since none of the fuses on it could really be called critical. The most critical is the E-bus feed, and that is a back-up, not a primary feed.

However, a fusible link (is that really what you meant by current limiter?) right at the battery, and a 24 inch length feed that you originally mention should be OK if the 24 inches is easily inspectable. If it has to penetrate the firewall, just add an extra sleeve around the wire for safety.

Remember to periodically check that the Alt Bus Feed switch is actually working...

 

[shiney]

Change of mind

Hi Gil,

Thought you'd like to know, I changed my mind and put the battery bus 6 inch from the battery,saves more work!

Martin