Electrical Diagram

[davevancat]

hey all you 12volt gurus i have a quick question. my boat 12 volt system goes as follows.
from the alternator there is a big battery wire that runs from the back of the alternator to the back of my batt switch center pole. from my batt switch my house battery and start batteries are connected. my question is this my buddy's boats alternator goes directly to his house battery and he has some kind of solenoid on a switch that connects the 2 batteries together for charging. now is this a better method of charging batteries than mine is my setup incorrect or ????? thanks all

[Sailmonkey]

his is automatic, your's in manual. yours has a downside, the person can forget to seperate or combine the batteries. your friends is automatic, but the solenoid can fail.
I wired ours with the alt to the house, with a solenoid controlled by the alt regulator to parallel when the house is charged.

[davevancat]

thanks for the reply sailmonkey now is there any performance difference between the 2 setups. does 1 mtheod charge faster or better than the other , aside from user error with the battery switch is the charging still the same.

[AnchorageGuy]

Our alternator connects to the house bank with an echo charger to the start battery. Has worked great for a long time. The house and start batteries are right next to each other, so we have a pair of jumper cables for emergencies. We have never had to use the jumpers.

[Sailmonkey]

Originally Posted by davevancat

thanks for the reply sailmonkey now is there any performance difference between the 2 setups. does 1 mtheod charge faster or better than the other , aside from user error with the battery switch is the charging still the same.

Yes and no. If you have no smart regulator neither method will charge any better or worse than the other. Generally when you go straight to the house bank you've already upgraded the alternator and regulator and house bank. When this is done you usually have a batt temp sensor that should be on the bank that is fed directly by the alt. So if done in this manner.........yes the direct to the battery will charge better, but there's a lot more information that'd be needed from you to make any further judgement on either system!!

[osirissail]

The alternator feed should be routed directly to a battery bank - or through a diode to several battery banks. Wiring the alternator output to the common terminal on the main battery switch is rather dangerous to the life of your alternator - especially if you are running the engine and forgot to put the battery switch in "both" BEFORE starting the engine. Switching the battery switch with the alternator running can "disconnect" the alternator from its battery "load" resulting in voltage "run-a-way" and failure of the alternator. There are special main battery switches that have a "field" interruptor provision to protect the alternator, but if your main battery switch does not have this feature be sure to move the alternator output cable off the "common" terminal and to one or the other battery cable terminals on the switch.

[CharlieJ]

Switching the battery switch with the alternator running can "disconnect" the alternator from its battery "load" resulting in voltage "run-a-way" and failure of the alternator.

Only if you rotate the switch through the OFF position and that is why some switches have the optional field disconnect feature. Otherwise, modern battery switches have make before break contacts when going from either 1 or 2 to BOTH.

Charlie