Electrical System Update Recommendations

[Notyetsinking]

I have just finished installing a new Balmar 100amp alt with mc-618 regulator on my Boat, and naturally I discovered the wiring was horrible. I was a bit concerned when I discovered the alternator on it was likely a 5amp prestolite unit, but came full circle when I had finished everything with the install and the engine didn't start. The replaced alternator had only 2 wires connected to it, so I had assumed the non-current wire was the excite wire connected to the key switch. Imagine how shocked I was when I turned on the house batteries and, all of a sudden, the regulator came on and the engine was able to start

The start battery(Group 24 AGM) essentially acts as the central negative, with the alternator output, start battery, and 2 house batteries(Group 27 AGM) connected to a west marine 130amp battery combiner model 134108. The 2 house batteries are connected to a 1/2/both switch, but for some reason also connected in parallel. I have included a quick diagram to somewhat show what is going on.

I want to put the house batteries, alternator and victron Orion Tr Smart 12/12 30amp input on a common positive bus, with the output going to the start battery. The voltage sense of the mc-618 will then output dependent on the voltage of the house battery, and the TR smart should be getting more than enough to top up and maintain the start battery. What are peoples thoughts on this setup?

[Stu Jackson]

The AO should go to the house bank. The combiner then feeds the start bank. The battery sense wire MUST go to the bank being charged by the AO, not the other one.


Being surprised by a wire connection is not good. When I did my upgrade I drew detailed wiring diagrams, like this, so I knew what to expect and was not surprised:


Alternator Regulator Wiring Diagrams - all three http://c34.org/bbs/index.php/topic,4548.0.html

[Notyetsinking]

Originally Posted by Stu Jackson

The AO should go to the house bank. The combiner then feeds the start bank. The battery sense wire MUST go to the bank being charged by the AO, not the other one.


Being surprised by a wire connection is not good. When I did my upgrade I drew detailed wiring diagrams, like this, so I knew what to expect and was not surprised:


Alternator Regulator Wiring Diagrams - all three http://c34.org/bbs/index.php/topic,4548.0.html

The combiner is going away and is being replaced with a victron DC-DC converter as referenced in the second diagram. In the new diagram, the alt will be feeding the house bank. My question is if putting the alt, house bank, and dc-dc converter on a common bus is acceptable?

I understand the value of diagrams but that was not the issue here; I failed to confirm the origins of the excite wire. Lesson learned.

[goboatingnow]

Surely the alternator should feed the biggest battery bank and the dc dc handle charging the starter. That’s what I do.