Rules and thoughts on main batt switch placement

[FF]

>The harder the starer has to turn the higher the amp draw goes up.Most starters are rated at unloaded amps.<

Larger ones are rated at 9.5V as the starter mfg are in the real world.

 

[Tdot]

Amperage will no doubt go up as load does as well, I was just noting that a really fried starter motor is unmistakable when pulled from the block.

Brian, nice rig, I like the buss bars between the relays and switches. I am looking for the same thing, the rocker at the helm, as well as an indecator that the relay is kicking in the House batteries as well.

Some part of me wants to wire straight from the starter batteries to the starter for maximum oomph, but the professional in me lets me know that that's moronic and unsafe.

 

[rwidman]

I
Parallel wires between the batteries and the starter if needed to keep Vdrop under control.

Unless the cables to be paralleled are the exact same length and gauge and the connections have the same resistance, the current in the cables will be unbalanced because of resistance. A better plan is to use the necessary sized cables in the first place.

 

[rwidman]

Tdot
You are getting onto the right track with Blue Seas gear. Use the RBS but also have the manual switch at the helm.

You can isolate by manually turning the yellow switch in the ER, or flicking the rocker switch at the helm. Also use an ACR.

First pics is my ER config for 2 start batts and house bank, then the auto parallel & isolate at helm, and lastly the RBS and ACR components

I see that these relays only cost $160 or so. I think I will get one for my starting circuit which came from the factory (it's been nearly fifteen years) without a switch for the starting battery. Adding a manual switch would be difficult without a lot more cable.

 

[FlyWright]

When adding a switch to a starting circuit, give thought to access during a runaway starter-induced fire. I've learned of several instances of a fried solenoid/relay engaging the starter autonomously and causing a fire. The only way to stop it is to remove electrical power from the start circuit. That could be hard to do if you need to enter a burning ER to do it.

You can't always do it easily by going forward or aft of the batteries, but sometimes running the cable up to a cabinet in the saloon or galley will work.

 

[Art]

Batteries in the engine room will not last too long as 120F+ of the engine room is not good for them.

The 180F next to an operating engine is even worse!

I've often had batts in engine compartment. Currently all our batts are in there. Never noticed an appreciable reduction in batt life as compared to batts away from engines. Admittedly all batts are not right up against engine. But, they all are confined in containers (very breathable containers) on lower levels of the ER.

 

[rwidman]

When adding a switch to a starting circuit, give thought to access during a runaway starter-induced fire. I've learned of several instances of a fried solenoid/relay engaging the starter autonomously and causing a fire. The only way to stop it is to remove electrical power from the start circuit. That could be hard to do if you need to enter a burning ER to do it.

It can be even harder if you're away from the boat.

I have never heard or seen firsthand of a runaway starter or a starter operating by itself, but I suppose it's possible.

I'm thinking more and more of adding the remote switch. I'll check the boat this weekend for a good location and the cable size so I can order the correct lugs.

 

[Capthead]

A bad starter might be my problem with my port engine. It has started becoming harder to start over the past few years and won't start with the starting battery. Starboard spins and starts quick. I have to add the house bank to get the port going. I've cleaned and checked cables, even added another ground and nothing seems to help.

I'll pull the starter and have it checked.

Great thread guys, I'm learning from TF and that's a good thing.

 

[Tdot]

15 years of wrenching on diesels has taught me that the starters go bad sooner than a well kept engine..... I was taught way back when: "most carburetor problems are electrical", true for gassers, but still pertinent for starting and charging systems....

Art, thats good to know for temps.... I have to take exception to the rig I have now, where the PO jammed a piece of asbestos between the port cylinder bank exhaust riser and the batteries!!!