Advice on replacing/rewiring battery selector switch

[UncleTimmyBro]

1980 CHB Trawler with original battery selector switch. It is very unlike the newer 3 post switches (rotary?)
Any advice on switching it out/re wiring?
Currently 2 house 8D's to a start battery thru an Blue Sea ACR (fused)
All wired in series on a single circuit battery charger. 2nd side of batt charger unused.
Alternator wired to house batteries.
Edit; I guess I should add has anyone done this? Guidance..
To make a schematic I would just tear into it and do it
Thanks!

 

[Comodave]

Welcome aboard. Why do you want to change it out?

 

[wkearney99]

First post and it's an electrical one. Hang on, this might be a roller coaster ride.

It'd really help if you made a schematic of what's wired to where, and posted it. Because on an older boat you never know how far it's deviated from the original schematic.

 

[UncleTimmyBro]

Ha! Good question

Good question! It's old? I don't understand the wiring behind it? Where are the bus bars? Do I want start one 1/house on 2, etc? Or leave it 1 is all (house and start combined?

 

[UncleTimmyBro]

Well the first post could be motor mounts and busted bolts on the tranny/prop shaft coupler (letting the yard handle that) but where's the fun in that! Thanks guys!!!

 

[Comodave]

I had one of my engines out this winter. Not to bad to do after I built a crane. Changed the prop shaft coupler so I could use a split coupler. I replaced the drive saver with a spacer. I had to make 4 bolts out of all thread because of the new coupler design, but finally got it all done.

 

[AZ2Loop]

Welcome, UncleTimmyBro,
I'm not the electrical guru some of these folks here are, but I can offer this tip. Check out Jeff Cote of Pacific Yacht Systems' Youtube videos. He is very sharp and his videos are good. If he has one on battery selector switches and options to consider, it will likely be a good one that will be of value to you. Others on this forum will probably chime in and offer more information, too, but look through Jeff's videos and see if any cover the topic.

 

[mvweebles]

See attached schematic from BSS. Your "Charge" position should siwtch the 12vdc load from charger to batteries. Since battery chargers are now 'smart'/3-stage, this isn't really needed anymore

With your ACR, you should run the boat in "both" as it isolates the batteries - the ACR is essentially an automatic 1-2-both switch so you don't have to remember to manually switch. Getting line-of-site to the back side of the panel is likely difficult due to battery cables to rotary switch, so I understand your reluctance. Many users like to shut-down 12vdc while away from boat so going to OFF is an option. NOTE - Bilge pumps should be wired direct to battery with their own fuse to avoid being turned-off.

Best practice is to run alternator to engine start battery, though folks who have installed hi-output alternators often run to the house bank instead as they have relatively large battery banks. In theory, the ACR should mean it makes no difference. ABYC allows up to three cables on a lug, though having a bus bar/power post with a single cable led to the batteries sure makes life easier when servicing or replacing the batteries. .

What problem are you trying to solve, besides just figuring it out?

Peter

 

[Rated Aargh]

I know it’s OLD!

did you ever resolve this? Or did you just leave it alone?

 

[UncleTimmyBro]

I received no actual wiring advice so I left it alone.

 

[Rated Aargh]

Ok, well I’ll be looking into mine to see what I can find. If I figure anything out I’ll be sure to follow up with you.

 

[tiltrider1]

It’s hard to give good electrical advice with out seeing the entire boat system. Things that make sense on a boat with thrusters and household appliances won’t make sense on a boat that is only DC.

Now to complicate things are the needs of Li, AGM and FLA batteries.

 

[SlowRide75]

I have an 84 CHB with the same original switch. It is no,longer operational, I now has a three position main switch, a two position switch isolating the charger/inverter and an additional two position switch isolating the second larger alternator. I did not do the work, it was that way when I purchased the boat. If you’re ever up north in Channel Islands you’re welcome to stop by and take all the pictures and videos you want. Not sure if you can PM on this site but I would be happy to send you photos.