Hey 2850Bounty Rick. Have another electrical question for you, Or anyone here-gctid810560

[Guest]

I am trying to isolate my helm electronics. Attached is a VERY ROUGH diagram of my setup. Where would I put in another ACR and battery combo if that's what I need? The problem is whenever I start my boat, the electronics shut down/reset and I don't want to kill the electronics. I read that the electronics should be isolated via ACR and dedicated battery (if I have the space for another battery. How can I reconfigure what I have so that my electronics are isolated?


Attached files

[CptCrunchie]

"billfnh" post=810560 wrote:
I am trying to isolate my helm electronics. Attached is a VERY ROUGH diagram of my setup. Where would I put in another ACR and battery combo if that's what I need? The problem is whenever I start my boat, the electronics shut down/reset and I don't want to kill the electronics. I read that the electronics should be isolated via ACR and dedicated battery (if I have the space for another battery. How can I reconfigure what I have so that my electronics are isolated?

I'm confused by your question. You have two engines with two alternators. I would connect one alternator to the start battery and use it to start either engine. I'd connect the second alternator to the house battery. Then I'd put all your electronics on the house.

I'd also start the engine connected to the starter battery first.

[Guest]

Im not following? both engines to 1 battery? You don't use a sep battery for each engine?

[CptCrunchie]

"billfnh" post=810583 wrote:
Im not following? both engines to 1 battery? You don't use a sep battery for each engine?

If you have 3 batteries, sure. But you only need one engine to start, because you don't start both engines simultaneously. Once it is running, you should be charging that battery. Moreover, depending on how you wire your systems, you could add a cross-over solenoid to connect the house and starter battery in the event you drain the starter battery.

Rick and I have agreed to disagree on this. I - like you - want independent systems for my electronics. I've even changed my current boat to two systems because I want the starter separated from the electronics, one reason is with your OP with my alarms going off and my electronics restarting. The second reason is that I have no desire to go to the MBSS switch every time I shut down the engine when fishing to save the starter battery. A third reason is that I want a completely separate system for the house and starting batteries, with the ability to charge both when the engine is running.

My last boat was a 33' Chris Craft with twin 327's. To simplify things, I took the existing two batteries, wired them in parallel and used them as starter batteries. Then I added a big deep cycle house battery. One engine alternator charged the start battery, and the other (a 118A stepped alternator) charged the house battery.

Since you already have two MBSSs, separating them should be easy.

So let me ask you, since you have twin engines, are both alternators connected together (or would they be with using an ACR), or are they independently connected to each battery? Either way, as soon as you select 'BOTH' on your MBSSs, that's what they are doing anyway. From your diagram, if you add an ACR as you show, you can stop the electronics from taking the hit if you switched both MBSSs to an individual setting. Otherwise, IMHO, you will have to separate the systems into house and start.

[GearGuts]

I too have a single start battery for my two engines and a separate house bank with the alt outputs going to the start and house. All my navigation and radios run off the house bank. This way eliminates loss of essentials if the start battery became drained due to "issues", which usually happen shortly before you need your radio... I would however check out your power supply to your equipment, If the battery draws down to less than 10 volts while cranking it may be getting tired or you could have a bad connection somewhere which would likely drop your voltage at the helm below the shutdown threshold of your electronics ? Worth a look IMO.

[Guest]

So currently I have 2 MBSS, one for port and 1 for stbd. I have an ACR between the 2 so for all intent, if I lost 1 alternator, the other alternator would run both. I am also able to charge with 1 alt in this configuration. My plan was to use what I have and add another ACR and another battery and wire the house stuff on this battery, and use the ACR to allow for charging but not starting.

[CptCrunchie]

"billfnh" post=810612 wrote:
So currently I have 2 MBSS, one for port and 1 for stbd. I have an ACR between the 2 so for all intent, if I lost 1 alternator, the other alternator would run both. I am also able to charge with 1 alt in this configuration. My plan was to use what I have and add another ACR and another battery and wire the house stuff on this battery, and use the ACR to allow for charging but not starting.

That would work, .....but you'd have to add another MBSS and rewire all your house supply needs and electronics to that. While that may seem simple, there are better ways to separate your systems.

I'm not sure where I found this, nor who I should be giving credit to, but IMHO, this would be easier to do.

[attachment]36771 wrote:
schematic-f.jpg[/attachment]

[MonteVista]

"billfnh" post=810560 wrote:
I am trying to isolate my helm electronics. Attached is a VERY ROUGH diagram of my setup. Where would I put in another ACR and battery combo if that's what I need? The problem is whenever I start my boat, the electronics shut down/reset and I don't want to kill the electronics. I read that the electronics should be isolated via ACR and dedicated battery (if I have the space for another battery. How can I reconfigure what I have so that my electronics are isolated?

There are many different ways to wire a boat with twin engines and multiple batteries. I shall not get into that because your problem has nothing to do with that. I have solved that problem on my boat and here is how it works.

1 - Electronics should be wired DIRECTLY to thje +VE post of the HOUSE battery. This way, when the START battery (or any of the START batteries) is used to crank the engine, electronics does not suffer a voltage drop.

2 - Step 1 solves the main problem but creates another; Electronics remains ON even if the MBSS is switched off. This problem is solved using a small (12v) control relay as follows:

2.a - The 12v relay coil receives GND (i.e. battery -VE) and the COMMON output from the MBSS. Thus, the coil receives 12v only if MBSS is ON (either 1, 2 or 1+2 setting).

2.b - The 12v relay terminals are connected to the HOUSE +VE and feed the electronics.

2.c - An optional dashboard switch can be installed to turn electronics OFF from the dashboard even when the MBSS is ON.

Figure attached.

[attachment]36772 wrote:
elect.jpg[/attachment]

Enjoy!

[2850Bounty]

Bill, can you be more specific regarding your symbols and battery cable terminating points?

In other words, when you show a battery switch icon, please show the terminals and/or whether it is a BS or an MBSS.

BS = Batt Switch..... ON/OFF only.

MBSS = Main Batt Selector Switch...... OFF/#1/ALL-BOTH/#2

Feel free to make the necessary changes to this image below.

That will help determine what is existing.


Attached files

[Guest]

Sorry Rick,

I didn't have the graphics. I put the 1, 2, both and off on the circles. They are indeed MBSS switches.

[2850Bounty]

Here's another example of a schematic that is like a road map that's missing some of the city or street names on it!

These need to show the actual terminals so that the on-looker can determine which does what, etc.