Alternator Upgrade on 1985 Mercruiser 260 (and 3rd Battery?)

[DeepImpactFishingTeam]

Bruce: Just wondering why not mini? The switch is rated for 300 amps continuous, and the ACR is rated for up to 65 amp alternators, my alternators are 55amp each.

Also, good call on the two house batteries together, maybe I'll split the panels up so noncritical circuits off the port (like interior lights, downriggers, etc.) and critical and frequently used (nav lights lights, auto pilot, chartplotter) run off the other battery.

 

[bruceb58]

According to Blue Sea, the mini is for outboards and small gasoline engines. You can pull a lot of current starting your 5.7L engine. The bigger switch is not that much more money.

As far as the ACR goes, you mentioned the possibility of going to a bigger alternator which is why you would want a bigger ACR as well.

 

[bruceb58]

Are you going to be adding battery chargers to charge your batteries? If so, you going to get a couple 2 bank chargers or a 4 bank?

If you are, I have a suggestion for how to hook up your ACR differently if you don't want the ACR to combine while you are charging the batteries, put the ACR across the output of your switch. That way, when the switch is off, the ACR will be out of the circuit.

 

[DeepImpactFishingTeam]

I actually called Blue Sea, their techs confirmed the mini being suffice for the 55amp alternator.

Also for charger, i plan to run two, 2 bank battery Chargers (pro mariners)

 

[bruceb58]

I actually called Blue Sea, their techs confirmed the mini being suffice for the 55amp alternator.

Also for charger, i plan to run two, 2 bank battery Chargers (pro mariners)

What did they say about the switch? So you shelved your plans on upgrading the alternator to higher current?

I would do what I suggested and have the ACR on the output of the switch. That way the ACRs are not combining with the chargers on.

 

[DeepImpactFishingTeam]

I shelved the alternator upgrade...the switch holds 300 amps continuous .. and i will have one switch for each engine, so i am more than set there. I anticipate that since i replaced the corroded terminals, will have 4 fresh batteries in the boat and split house loads between two dedicated group 27 deep cycles (isolated from each other/each alternator) i should be set.

Thanks for the guidance everyone - feel cautiously optimistic i should have this solved.

Robert

 

[bruceb58]

Did you ever do the voltage drop test I recommended in post #10 for both the positive and negative side?

I would still buy the larger switch.Did you tell them what size engine you had?

 

[DeepImpactFishingTeam]

Yes i supplied all info to blue seas...they said mini is fine, alternator is rated 10 amps under the ACR's.

I can't really test as you suggested, it's winter here in WI, batteries are out of boat, and the boat is only accessible through the access hole in the shrink wrap. I'll have to wait to spring to see if the issue exists still after fixing the things i can over winter (corroded wires, bad cell in battery, using proper wire to supply house to new panel (replace old, uncovered fuse panels, etc.)

 

[bruceb58]

I sent BlueSea a tech request asking them what they though about using the E vs M battery switch with a 5.7L engine. This was asking about the switch, not the ACR.

This is how they responded:

[FONT=&quot][FONT=&quot]Bruce,[/FONT][/FONT]
[FONT=&quot][FONT=&quot]Thank you for the question. The M-Switch is a great little switch, but if you have the room for the E-Switch it is little bigger, has higher ratings and is a little more robust in design.[/FONT][/FONT]

[FONT=&quot][FONT=&quot]Best Regards,[/FONT][/FONT]

[FONT=&quot][FONT=&quot]Kevin Patterson[/FONT][/FONT]
[FONT=&quot][FONT=&quot]Blue Sea Systems[/FONT][/FONT]
[FONT=&quot][FONT=&quot]ABYC Certified Electrician[/FONT][/FONT]
[FONT=&quot][FONT=&quot]Technical Support Specialist[/FONT][/FONT]