Alternator connected to starter WTH

[mitiempo]

That makes more sense.

You still have 2 switches one of which is not necessary. All it does is add connections with voltage drop and possible failure points.

The 60 amp alt should go to the start battery positive and the larger alt should go to the charge bus with the solar output.

[Charlie]

I bought some time with Maine Sail. Worth every penny I spent. After speaking with him I came up with a less expensive cleaner and more robust rewire.

Remove the two 1-2-Both switches. Replace with On/Off switches

Add a third on/off switch to be used as an emergency switch to use the house bank to start the engine.

Run all charging systems to the house bank on the battery side of any switches (protects the alternator)

Install a VSR to charge the reserve bank.

Simplicity. You want to turn the engine on? Turn on the engine switch.

You want to turn on the house bank turn on the house bank switch.

Emergency switch allows for combining both banks to start the engine or to use either bank individually.

[Wotname]

^^

[Charlie]

Step one was easy. I was able to change my batteries from two banks of series/parallel to one bank. Just had to move a couple of jumper wires around. Next is to get the alternator wire in place so that it goes directly to the batteries without a switch to interrupt it.

[Stu Jackson]

Glad to hear you're making progress, i.e., understanding "How It Works."
While you now know that MS has his own website with great info, here's another resource:




Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html

[osprey877]

Originally Posted by Charlie

Step one was easy. I was able to change my batteries from two banks of series/parallel to one bank. Just had to move a couple of jumper wires around. Next is to get the alternator wire in place so that it goes directly to the batteries without a switch to interrupt it.

Be careful about running a heavy wire directly from the alternator to the battery. The positive post on the alternator is an insulated post that is electrically connected to the stator ring. It is a relatively fragile connection and will not survive the constant vibration it will be subjected to if you connect it to a large inflexible cable that is affixed to the boat in such a manner that the cable cannot move freely as the engine and alternator vibrate (especially on starting) and thus puts a physical load on the positive terminal (Don't ask me how I know this) The technician at the marine electric shop I took my broken alternator to had a couple of suggestions as to how to avoid a repeat performance: 1) Affix the cable to the engine or alternator bracket with cable clamps or similar so there are at least a couple of inches of cable between the electrical connection to the alternator and the cables physical connection to the engine. This will ensure there is no physical load or vibration on the electrical fragile electrical connection. 2) Dead end the heavy wire on a terminal block or similar close to the engine and then use a much lighter and flexible wire for the last 12 inches or so to the alternator. Gauge depends on your alternator size and length of the final connection. 3) If you can't manage either of the above, then at least make sure the heavy cable is run in such a way that it is free to move with the engine vibrations and cannot put any physical load on the alternator positive terminal.
Good luck with your installation.

[sanibel sailor]

Great info. I am going to check mine. Been ok so far, but...

[olaf hart]

Originally Posted by Charlie

I bought some time with Maine Sail. Worth every penny I spent. After speaking with him I came up with a less expensive cleaner and more robust rewire.

Remove the two 1-2-Both switches. Replace with On/Off switches

Add a third on/off switch to be used as an emergency switch to use the house bank to start the engine.

Run all charging systems to the house bank on the battery side of any switches (protects the alternator)

Install a VSR to charge the reserve bank.

Simplicity. You want to turn the engine on? Turn on the engine switch.

You want to turn on the house bank turn on the house bank switch.

Emergency switch allows for combining both banks to start the engine or to use either bank individually.

Thanks for the schematic, what is the size of the fuse(e) on the house bank?

[sailah]

Originally Posted by Charlie

I bought some time with Maine Sail. Worth every penny I spent. After speaking with him I came up with a less expensive cleaner and more robust rewire.

Remove the two 1-2-Both switches. Replace with On/Off switches

Add a third on/off switch to be used as an emergency switch to use the house bank to start the engine.

Run all charging systems to the house bank on the battery side of any switches (protects the alternator)

Install a VSR to charge the reserve bank.

Simplicity. You want to turn the engine on? Turn on the engine switch.

You want to turn on the house bank turn on the house bank switch.

Emergency switch allows for combining both banks to start the engine or to use either bank individually.

Awesome. I never spoke with Rod but I used enough of his articles that I made a donation to his site through PayPal as thanks for the work he put in.

It sounds like you are going closer to his schematic. I only made 1 change in that I didn't really have space for the 3 switches, although I will agree it does give more absolute flexibility to truly isolate the banks. In my case I used the Blue Seas parallel switch which does almost the same thing. The only thing it does not do it take the start bank completely out of the loop in a paralled bank situation. If I ever face the scenario of a dead start bank I can always manually disconnect the cable at the fuse to take it offline during a emergency start.

100% agree with all your charging going to house bank and then ACR to start. Since I've made these changes, my start bank is always 100% no matter how much I abuse my house bank. There's an ignition interrupt circuit on the ACR I suggest you wire that will prevent the banks from being paralleled during a start if either bank has a charge voltage on it like a solar panel. In my case, even voltage from my small solar panel is enough to keep banks paralleled so I'm glad I wired this. It's all covered in his ACR article.

[Cheechako]

I had a boat with the alternator output connected at the starter + also. It seems to be a thing. Saves cable sometimes I guess.

[Captn_Black]

Worked out at 3 feet, and 55 amps for your alternator, the #8 wire is fine btw.

[mitiempo]

Originally Posted by Cheechako

I had a boat with the alternator output connected at the starter + also. It seems to be a thing. Saves cable sometimes I guess.

Typically how engines are delivered.

[transmitterdan]

It also saves alternators. If the factory did not connect alternator to starter then alternator might not get connected to battery. Alternators can be destroyed if run disconnected from the battery. So this wire saves the factory some nuisance warranty claims for blown up alternators. It’s hard to run the starter without first connecting battery.

The post on rewiring per Compass Marine has the best alternative method of wiring alternator to battery.

[capn ken]

Save yourself some grief,Download ABYC wiring specs ,gauge and color .And no the charging system should not be wired direct to the starter !

[jimbunyard]

Originally Posted by capn ken

...And no the charging system should not be wired direct to the starter !

Suggest you contact all the marine engine manufacturers with this information...