Does anybody have experience with this set-up?

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Oct 8, 2007
Vessel Name
Moon Dance
Vessel Make
1974 34' Marine Trader Sedan
After taking a "Marine Electrical Systems Basics" course a few weeks ago I now realize the PO had some unusual ideas about rewiring a boat. The worst offenders that I see right off are the use of welding cable from the batts to the engine (jackets already soft) and a strange paralleling technique of the 4, 4D batteries.

Replacing the welding cable is a no-brainer.

I'm going to reroute the cables to parallel the batteries correctly, another no-brainer.

But I'd like to get a little more modern than my "OFF-1-2-ALL" switch and reconfigure the system to the one in the link below.*

Right now, I'm not sure all the batts are being drawn from nor charged!* More investigation required.

I have a 1974 Marine Trader 34' sedan.* Single Lehman 120, small alternator, no genset, no need for super fancy, digital fixes!* KISS.

Does anybody have any experience with the Blue Sea setup in the link? Positive, negative, words of wisdom?

It is a good system. You say you have 4 four D's? How are*your banks*made up? Two separate two battery banks? What size alternator and what type of charger?

-- Edited by Gamekeeper at 14:18, 2008-12-22
I have to admit, it's been 12 years since purchasing my current boat.* Right after purchase, I replaced the battery & charging systems including new*primary wiring.* It hasn't missed a beat for 12 years,*and does not include any 1-2-ALL switches or*charging relay switches with starting isolation.* (It does have one on/off switch to combine the house/engine start banks for emergencies)

However,*time marches on, and maybe the Blue Sea*is a better system.

But it's hard to argue with simplicity:* Dedicated alternators to each bank, basic 3-stage temperature compensated regulators, and a good battery monitor.* The first house bank of (10) 6 volt wet cell golf cart batteries went 7 years and produced around 250,000 amps of service life.* I am expecting at least 12 years from the (10) 6 volt gel cell batteries that replaced them.

I really like the Blue Sea gear, but the key to a simple system is to*get a 2nd alternator added to your ME.
We had a discussion about this a year or so ago.* I personally like the ACRs like the Blue Sea.* Hook it up so that the alternator charges the start bank first, and when the voltage gets high enough, the ACR bridges the house bank in and it charges.* The shorepower charger can hook to the house bank, and again, when the voltage gets high enough, the start bank gets charged.

I like the fact that you can never forget to disconnect the banks when you anchor, or reconnect them when you are on shore power.

I think it was FF that made the point that a basic solenoid to parallel the batteries whenever the engine ignition switch is on does the job pretty darn well for a lot less money.

The second alternator route is pretty sweet, too - but it seems that there isn't any real clean way to do so with the Lehman.* Most installations that I've seen require the use of a field-built bracket that attaches to the stringer side of the motor mount.*
Don't tell my brother he will have trouble mounting another alt on a lehman. He hung a 5000 watt Seapower unit on his and still kept the regular Alt. And yeah he had to build a custom bracket for the unit. Has been working great for about 10 years now.
WE use 2 rotaries and a simple system.

A large rotary selects engine start batt (which moves Alt output ).

A second rotary selects battery bank for all loads.

Since we use a deep cycle as starts , its very simple.

Anchoring , turn the engine rotary off after shutdown , and select either batt for house service that evening.
The oil pressure sensor is hot wired to the selector output , so it is silenced by turning off the start power.

On start select the HOUSE batt , to assure it has not been over discharged.

Over 30F its enough to start a 6-71 . The hotter batt is reserve if required .

If she is slow to start the batt selected gets 2 hours of direct charge .

Combine the batts after start (or 2 hours after a 3 day layover)and both get charged together with no effort.

A digital gage allows knowledge of how the charge is proceding.


-- Edited by FF at 05:09, 2009-01-02

-- Edited by FF at 05:11, 2009-01-02
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