Rewiring with ACR

[AusCan]

Now that the re-powering job is nearing completion; I am looking at rewiring the boat. I've moved the batteries to give me extra working space around the engine, and they will now be on the centreline fore of the engine.

The house bank consists of 2 x 105Ah AGM deep cycle batteries, and the start/windlass bank is 2 x 770 CCA AGM.

A/C battery charger is a CTEK M200, 15 amp.
I'll be using a Blue Sea Model 7610 Auto Charging Relay.

Below is a simplified drawing of the planned layout. Fuses & switches yet to be added.

I'm hoping this layout will be fairly idiot-proof. Alternator output is direct to the house bank rather than via a switch, so less chance of blown diodes.

With a small single diesel, I see no reason why I can't start the engine from the house bank. The start bank would be more of a back up bank. I may switch over to this if using the windlass for an extended period.

I'd appreciate any constructive criticism on the plan.

 

[FlyWright]

I like that your alternator is wired directly to the House buss and through the ACR to the start batt. This separates the charging current from the switch so the switch controls load only.

The only thing I'm having a hard time grasping is the C-1-2 switch. Is C the single common load connection so that house and start and windlass all get power from the battery as selected on the switch? I have 2 switches - one for start and one for house. They can be paralleled at the switches for emergency start. Otherwise, the loads are completely separated between house and start.

 

[Aquabelle]

Looks good but like FlyWright, I wouldn't go for a rotary 1-2-3 switch. Separate On/Off BEP-type battery switches with a Parallel switch in between: BEP Battery Switch Quad Incl VSR Electrical | eBay

 

[bglad]

1. I would suggest reducing the starting bank and expanding the house bank. Doing so would allow greater amp hours between charges. I wouldn't dedicate anymore power storage to intermittent loads than necessary.
2. Your house bank will have a number of loads that are not switched. Mount readily accessible manually resettable breakers that will also serve as disconnects so that if the @#$% hits the fan you can kill it all until you figure out what has happened.

 

[AusCan]

You're right guys. That switch setup didn't make sense.

I like that all-in-one VSR/switch combo unit, but my budget is already blown.

I re-tweaked my drawing to keep the start & house loads separate, while trying to keep it simple. I haven't drawn in fuses and single switches yet.

 

[ksanders]

I like your latest drawing. Good setup.

One suggestion if not incorporated is to provide a manual bypass to the ACR. This will allow you to combine batteries to help a weak start battery or keep the start battery charged in case the ACR fails.

I know you already provided for a failed start battery with the 1-2 selector switch, I would just add a combine function to that switch as well.

 

[FlyWright]

The way I read it, if you're on 1, you're powering the whole boat (house and start loads) on the Start batt. If you're on 2, you're powering the whole boat on the house bank. If you're on ALL, both systems are paralleled. You'll need to change that switch with every start and shut down. Inevitably, you will forget sometime and run one side down prematurely.

In my way of thinking, this is not the way to go. For the cost of a second switch, you can have complete separation of the 2 electrical system loads and never have to mess with the switches unless one side runs low.

Do you have a generator?

 

[DavidM]

I think that the last pdf is a very good setup to allow for automatic combining of the start and house batteries with an ACR.

The comments from the previous two posters confuses me:

KSanders- When the switch is set to all, the house battery will start the engine and the solar, AC charger etc will also charge the start battery, right?

Flywright- When the switch is set to 1 which it normally will be, it powers the starter from the start battery, nothing else. The start battery is automatically combined to charge the start battery from the house circuit (alternator, solar, shore charger) when the voltage gets up to 13+. It is a set and forget system, normally.

David

 

[FlyWright]

Yes, you're right, David. I saw the ACR leads as sharing load. My bad. They will share light loads when the charge voltage is up at 13+V, but will disconnect when the voltage drops below 13+/-V.

I would still advocate adding an ON/OFF switch to the house connection before the buss. If you need to remove house power, the switch positioned outside the ER is valuable. In fact, I'd position both switches outside the ER for easy and fast access. Got an ER fire? You don't want to have to go in there to shut off the electrical.

 

[Bacchus]

I think that the last pdf is a very good setup to allow for automatic combining of the start and house batteries with an ACR.
David

I agree w/ David... looks like a good & simple arrangement.
I believe most / all 1-2 Batt'y Sw include the All function that David mentioned - this should take care of combining house & start for problem start situations.

Only other questions I have... is there any need / advantage to have an on-off sw for the house loads not normally connected (bilge pumps, etc). I use my sw to kill loads like CO detectors & other parasitic drains when I leave the boat w/o being plugged in to shore power and charging.

Also - I have a similar situation to your windlass wiring (mine was thruster) and was concerned about the possible high Amp draw if/when the windlass (thruster) is powered and the ACR is connected - could it handle the amperage?

I talked to both ProMariner and BlueSea techs about charging both the engine start/house and thruster battys from the engine alternator. Results:

ProMariner (my original choice) cautioned against using their ProIsoCharge Isolator as the potential hi current feedback could damage the unit.

BlueSea recommended using one of their ML-ACR relays for this application. The Model 7620 is rated at 500A continuous, 700A for 5 min and 2500A for 10 sec and comes w/ a remote Sw that indicates when the relay is operating (combined) and allows both manual isolation and manual combine.
This is a litttle more $ than the ProMariner unit but the higher current handling capability makes it look attractive for the thruster application.

I ultimately ended up w/ a Sterling Power ProConnect Relay Series and specifically the ProCon CVSR-140 as they could handle very high current and actually reduces the current before disconnecting. Maybe this is overkill for your situation - I was concerned about thrusters and did some checking w/ the tech reps.

There is a Sailing Today article attached that does a good job of comparing the various combiner technologies.

 

[AusCan]

Thanks for the input, guys.

My electric needs are simple. No generator, no inverter. No major house loads, other than a small 35L fridge. Just lights, bilge pumps, fresh water pump, and electronics. A couple large built-in iceboxes handle the big beer demand days.

Don - Hopefully the ACR won't be seeing too big of an amp draw when using the windlass. The windlass only pulls 60 amps and has 2 start batteries to draw from. I do like those Sterling CVSR's though.

I'll continue to work out details for fuses and switches.
Al - I agree with having easily accessible switches which can be isolated in a hurry.

With this upgrade, I am moving all electrical components out of my engine "room".
Everything is going on the forward side of the bulkhead, under the salon floor. This area should be cooler, drier and more accessible than the engine "room". It will also give me a bit more wriggle space around the engine, with the old battery boxes gone.