Permanent live (Webasto loom?)

[catlotion]

Hi everyone,

We've decided to treat our boat to a new car radio at the nav station. However, being a new-fangled digital type we need a permanent live to preserve radio settings. I'd rather not run a cable from the batteries as the routing is a nightmare and the bilges are full of conduit already.

We do have a Webasto Evo 3900 control there though which I assume has a permanent live (the heater is wired directly to battery bank via an inline fuse) - does anyone know if it's possible to take a live feed off this plug? Or is this a bad idea?

cheers,

Toby

 

[pcatterall]

Cant see any major issues, just ensure that you protect the radio with another smaller fuse and remember that you will loose your settings should you have to disconnect the heater.

 

[David2452]

Not so sure, the EVO is a relatively new model with sophisticated control options some of which have more than one live feed for different purposes, remember that that feed you tap into will then have a permanent return where it is not supposed to have a permanent return Another consideration is that an EVO, being a relatively new model will more than likely be still under warranty, if for instance an ECU fault developed you may have an issue. If you give the control module number I will check which if any live you can certainly use with impunity if any. However, my choice would be to route a 0.5mm2 fused cable from the "live" side of the switch that supplies the main power for the radio, that's what I do as its simple, safe and is easy to route as you are already running the main power supply for it.

 

[catlotion]

if for instance an ECU fault developed you may have an issue.

Good point - it's brand new so I'd like to protect the warranty. Will go with your suggestion. It's just that we normally turn off batteries at isolators between visits.

 

[David2452]

Good point - it's brand new so I'd like to protect the warranty. Will go with your suggestion. It's just that we normally turn off batteries at isolators between visits.

If you wish to continue that sensible and safe policy the only real option is a bit more work taking a feed from the live side of the isolator then, unless there is a permenant live fuse panel dedicated to bilge pumps, alarms and the like.

 

[lw395]

One possible alternative is to feed the permanent live from a local sealed battery.
One boat I sail on has a 10Ah (?) yuasa which is intended as an emergency VHF power supply. If the drain on the memory supply to the radio is low enough it might be an option.
You might even be able to use nicads or something, you may find it remembers settings with a lot less than 12V?
Probably only really needs a little lithium battery like on a PC motherboard, shame they don't build it in!

OTOH, a permanent feed for a few things like Navtex and enough LED lights to find the main switch has its uses.

 

[David2452]

Probably only really needs a little lithium battery like on a PC motherboard, shame they don't build it in!

Actually some do, Fusion Marine units for instance, oddly enough I am fitting one of those to a commercial in the morning, but as this is PBO I assumed a dedicated marine spec unit is not on the cards.