12 volt system; two banks two alternators

[seayou77]

I had the pleasure of asking Nigel Calder about this best simple system, as described in his Mechanical Manual. Soon to be revised, 3 mos.
Twelve volt, Two bank Two Alternator system

I have found an Batt. combiner which makes this an unecessary upgrade. However I own the parts and want to fully understand the wiring in order to finally decide which to use.
The area I am concerned is the wiring of the house alt. directly to the house bank. He says just wire direct with the addition of a Zapp-stopper, to prevent ruining alt. if ever got shut off while running. The problem I have is that I imagine that the field wiring in the house alt. will allways be live, as if I left the ignition key in the on position. As the alt. excites automatically at a certain rpm. different from the smaller alt. the load will be spread out.
The alternatives are confusing to my crew, I want an idiot proof system. Thanks for input!

[kc8pql]

I have a two alternator set-up on my boat. The stock, internally regulated alt. charges the starting battery and a high output, externially regulated alt. charges the house bank. The three stage external reg. is controlled by the key switch so the field is not exctied unless the key is on, just like the stock alt.

Ken

[seayou77]

Thanks Ken, I will look into an external regulator. The battery combiner works great, I just can't see how all the charge travels thru a 14ga wire effeciently.

[kc8pql]

Originally posted by seayou77:
The battery combiner works great, I just can't see how all the charge travels thru a 14ga wire effeciently.Do you have a battery combiner or an echo charger? A 14ga. wire for a combiner seems very light.

[seayou77]

My battery combiner is a micro chip gizmo, bout the size of a match book, with three wires. One wire to each battery, the other a ground. It senses if a charge is present and opens a circuit to the weaker. Green lite when in use. Multiple batt. in each bank reccomend multiple combiners. $65 at waste.
I have a start batt. and an 8D house. Been known to pass out with the stereo playing. Hope to add a refridge.
The Balmar site has a dual alternator regulator "centerfielder" $165 at Defender. It is designed to field two alts on two engines. Alarms for charge peak or low, say if a belt slips off.
The Heart interface system adresses batt. mgt. but I don't think I need to rely on that $300 gizmo. Rather carry a couple of the $65 units as spare. Thanks!

[seayou77]

There is one option I considered, a solenoid in the field circuit connected to the ingnition. That would keep the circuits seperated while activating the alt. with the key. The house alt. is internally regulated.
Thanks Ken for your input, I hope to get this clear, a new engine box and insulation are awaiting. David

[seayou77]

Balmar sales staff set me straight. Take the field wire for house alt. directly from the field wire on start alt. Field is only chg. when key is on. Duh.

[kc8pql]

Yup, that's it. In essence, that's what mine does. Both fields are fed from the same terminal at the key.

[J. A.Tones]

There is a real easy fix for this problem and it can be expanded to as many altinators as you like.
Go down to your local big box auto parts store and get an oil pressure switch that has an isolated switching circuit in it. This is important because a lot of them are just switched to ground but you want one that will switch a separate circuit. Now run the field circuit for the extra altinator thru this switch and every time the engine is running and it has oil pressure, the alternator is energized. Need even more altinators, use more switches!

[seayou77]

Valid point! The current set up for one alt. is run thru such a switch. Believe there would be a small plumbing fixt. for the additional pres. switch. Good info. believe I visited this earlier in my learning process. Thanks, David