MOB+ power, off instruments?

[DSW]

Hi,
I'm installing a MOB+ and where should I pull the power from? The closest instrument is the fuel gauge.

Parker 2110. Yamaha 175 Salt Water Series II carb. There is yellow 12v+ I can get to on the back of the analogue tack or fuel gauge. These are the only two instruments so I'm guessing not a lot of load there already.

The MOB+ specs say: fuse 1-3 volts, use wire 20 AWG, and Recommended Wire the xHUB to a circuit with a power switch to avoid battery drainage. The xHUB has a power draw of 30mA in idle mode while connected to a power source.

I have an open switch on the panel and could go there. Seems like an extra step to turn on the panel switch and then turn the key. Any suggestions or reasons I should not daisy chain power off the instruments? That's the closest open tap point after the key on the Yamaha harness. Then MPB+ has power at engine start up (I know I'll have to turn the key, connect the Fob, and then turn key to start), and when you turn off the engine you turn off the MOB+. Seems logical, anything I'm missing?

Thanks

 

[warthog5]

Don't pull power off of gauges.....Pull power off of a CB in the switch panel. You will probably need a jumper.

IE: Has a Female spade and 2 male spades.

You pretty much will NOT find a 1 or 2 amp ATC style fuse in your town....3amp yes.

I have to order 1 & 2 amp fuses.

By taping a CB power will be shut of to your instrument when the Master switch is shut off.

 

[pelagic2530]

Don't pull power off of gauges.....Pull power off of a CB in the switch panel. You will probably need a jumper.

IE: Has a Female spade and 2 male spades.

You pretty much will NOT find a 1 or 2 amp ATC style fuse in your town....3amp yes.

I have to order 1 & 2 amp fuses.

By taping a CB power will be shut of to your instrument when the Master switch is shut off.

Warthog, is there any reason that jumpering off a CB on the switch panel would be better than hooking it up to an empty circuit on a house battery fuse block, if one is available?

Also, is 20ga wire appropriate in this situation? I was under the impression that all marine wiring needed to be 16ga or larger to be in compliance with ABYC, with the exception of pigtails <7" in length.

 

[warthog5]

Warthog, is there any reason that jumpering off a CB on the switch panel would be better than hooking it up to an empty circuit on a house battery fuse block, if one is available?

Also, is 20ga wire appropriate in this situation? I was under the impression that all marine wiring needed to be 16ga or larger to be in compliance with ABYC, with the exception of pigtails <7" in length.

My answer was assuming all circuits were in use....By all means if you have a empty circuit....Use that.

The smallest marine tinned wire you will find is 16ga. I use it on stuff like LED courtesy lights.
You'll be fine with it....There are situations where the components have as you say...20gauge...22gauge on them.

Your statement about 16ga is correct.

 

[DSW]

Thanks for all the input.

To clarify I have three options for powering the MOB+

A) off the yellow 12+ from the Yamaha key harness via the instruments with an inline fuse - Warthog said not to do this.
B) off fuse block, but I have two batteries and a Blue Seas off, 1, 2, 1+2 battery switch and I don't think that isolates a house battery other than by careful operation.
C) off FB that has a switch with inline fuse.

I thought you wanted a switch in the circuit to turn the MOB+ on and off after the main battery switch, so I was looking a A or C. I didn't think you wanted it left on all the time if the main batteries were on and the motor was off.

Waiting for mail order connectors bullet connectors so it will be a couple of days before I finish this.

 

[pelagic2530]

Thanks for all the input.

To clarify I have three options for powering the MOB+

A) off the yellow 12+ from the Yamaha key harness via the instruments with an inline fuse - Warthog said not to do this.
B) off fuse block, but I have two batteries and a Blue Seas off, 1, 2, 1+2 battery switch and I don't think that isolates a house battery other than by careful operation.
C) off FB that has a switch with inline fuse.

I thought you wanted a switch in the circuit to turn the MOB+ on and off after the main battery switch, so I was looking a A or C. I didn't think you wanted it left on all the time if the main batteries were on and the motor was off.

Waiting for mail order connectors bullet connectors so it will be a couple of days before I finish this.

From the unit's specs it looks like it pulls 2.4W at 13.8V. That's 0.17A, which is a very low power draw (the 30mA looks like it's the power draw of the battery operated "fob", rather than the hardwired boat unit). Over the course of a day of boating, it's not something you'd likely need to be concerned about being powered on. It's definitely something that you want to be able to power off when the boat is in storage though.

 

[warthog5]

WOW! I'm learning how misunderstood electrical is to people.

I don't want you connecting it thru the motor wiring....That would mean it was only powered up when the motor is running....IE: Ign key ON.

I want it wired so when the main battery switch is turned ON....In your case Position 1,2 or ALL it is turned ON.

That way when the battery switch is turned OFF at the end of the day.....The unit draws No power.

You seem as well as others to want to have things where you turn the Master switch ON......Then you turn a switch ON that is on the dash.....Then you pick up the unit and hit the ON button on that.

You see how crazy that is to turn something ON?

When you walk in your bedroom.....you don't have to turn 2 switches ON to turn the light ON.

 

[DSW]

Warthog and pelagic2530,

Ok got it:
Powering MOB+ hub off fuse block, switched by main battery switch.
Draw is negligible, did the math for that and my LED anchor light and plenty of capacity for a possible overnight

Will be safer for others to use the boat if the MOB+ powers on with the main battery switch too, no fumbling around looking for why it's not working.

I was lead astray by two things. I've been using other's boats for a long time and most everything is lead thought the CB panel, and second the MOB+ instructions that say make sure it's switched. I usually ignore the main battery switch in my thinking, time to get past that.

Thanks for all the help, this year's upgrades of MOB+, Backbone, and Garmin FS 10 almost done. Just waiting for bullet connectors to be delivered and I'll be finished.

Thanks for all your help.

 

[pelagic2530]

WOW! I'm learning how misunderstood electrical is to people.

I don't want you connecting it thru the motor wiring....That would mean it was only powered up when the motor is running....IE: Ign key ON.

I want it wired so when the main battery switch is turned ON....In your case Position 1,2 or ALL it is turned ON.

That way when the battery switch is turned OFF at the end of the day.....The unit draws No power.

You seem as well as others to want to have things where you turn the Master switch ON......Then you turn a switch ON that is on the dash.....Then you pick up the unit and hit the ON button on that.

You see how crazy that is to turn something ON?

When you walk in your bedroom.....you don't have to turn 2 switches ON to turn the light ON.

Wart, just mulling this over. Is there any reason to have the MOB+ unit running when the motor is not running? If the purpose of it is to kill the engine if the fob gets too far away, seems to me that there's no real reason to have the unit energized if the motor is off. Maybe just to prevent it from having to "pair" with the fobs every time you start the engine? I'm not familiar with the specific operation sequence of the unit.

 

[warthog5]

I guess you could dissect this to the tenth degree.....BUT...Here is my thinking.

If your on the boat.....Master Power is on and everything is available.

If your Not on the boat ...Master Power is shut down and everything is off so no current drains....EXCEPT...
The bilge pump....It is powered directly off the battery and not thru the Master Switch.

This is keeping in line with the KISS method...."Keep It Simple Stupid"


Now....lets go back to that bilge pump. Those automatic..All in one's....I have a bunch of them thrown out here in a old tote. They draw milliamps....as they sit on the trailer....They turn on..test to see if there is any resistance....and stay on to pump water...or turn OFF if no resistance. You cant test them either unless you fill the bilge.

So thats why I yank them out.

Then install a Rule A Matic PLUS - thats the one with the cage....not the one that looks like a duck bill.

and a 1500 standard Rule pump as a primary.....Another Rule A Matic Plus raised a little higher hooked to that is a 2000 standard Rule pump and a High Water alarm.

The theory there is if water got high enough for the alarm to go off...The main pump system has failed and you have a serious problem.....

 

[DSW]

Finished!