An electrical questions for the pros,

I have an '01 SAN and over the winter I disconnected the batteries to swap out an amp, put a running light on the tower, upgrade my PP, and add some LEDS. I have dual batteries with a Perko switch (1,2,both,off positions). I have everything hooked to the 2nd battery and use the 1st battery just for emergency starting only. There is 1 ~10 gauge positive wire (w/ 30 amp fuse) that goes from the 2nd battery to the breaker box in the front of the boat and then is distributed thru the box to everyting else. Last weekend at the lake, I noticed that when I switched to the 2nd battery with this positive wire, the volt meter in the dash would drop to 12 volts. If I was on position 1 or all I would read 14 volts. I switched the wire to the battery#1 and the same thing, it would drop to 12 volts, but 14 volts in the #2 or all position. Could it be that I am bybassing the voltmeter and showing no charging with this positive wire connected or maybe a short somewhere? The fuse is good. Any idea's. Sorry for the long post.

Get a volt meter and test the voltage across the battery terminals. You should be getting 12 when the boat is off, (Battery voltage) and something like 14 when the boat is running (alternator voltage). If you are not getting 14 when the boat is on, then you are not charging the battery, nor are you running whatever you are powering from the alternator.

Your SAN is probably wired like my 211. It has either 8 or 10 from the rear up to the front to run everything, maybe 15', connected with so-so crimped connectors. Several guys on PN, including Wakejunky, have solved thier low voltage issues. I am not quite sure I follow your verbal description of the wiring layout. If you pencil it out, scan it, and post it, I might be able to help you identify a weak link. I hate to say it but wiring systems and plumbing systems are not the Nautique's strongpoints.

Giddy:

Are you saying that the main fuse panel (and thus the stereo, lights, ignition, etc.) are wired to Battery 2, and the starter is wired through the battery switch?

I suspect that the problem (or maybe its a feature) is that the alternator connects to the starter/relay terminal. When the engine is running the alternator is doing a great job of charging the starting battery, but unless you have the battery switch on BOTH the second battery isn't getting any of it.

While this isn't the recommended way to wire the batteries up it can work, but you will need to provide a way to keep battery 2 charged up. Either always run on battery 2, keeping battery 1 as a reserve, or install a battery combiner.

Thanks for the replies guys. Rod-that is exactly whats going on. The alternator goes to the starter and then to the Perko switch. If I run around all day on "both position" everythings good. I guess my main concern was that whichever bank I attach the the main breaker box wire (ECM box-I think West Coast CC called it) to it shows no chargeing while that battery is selected on the perko switch. I'm going to buy a voltmeter after work today to measure the voltage across the bateries while the boat is running to amke sure they are both being charged by the alternator. On a second note Rod, is there a better/more effient was to set this up without a combiner. I use to have one and WCCC said it fried my breaker box ($900) by a spkie in voltage. So I'm trying to keep is simple. Thanks again for the help. Mike

Mike:

The basic problem is that you can't have the batteries totally isolated and have them both charge without some additional stuff.

It is more common to have the alternator connect to the "common" terminal of the battery switch instead of directly to the starter and/or battery. Likewise, it is also more common to have all the electrical (starter and main panel) connect directly to the "common" terminal of the switch instead of directly to a battery.

If you want to keep your arrangement, where one battery is used only for starting and the other battery is used for everything else then you need to provide a way for one alternator to charge two systems.

This can be done "manually" by switching the battery switch to BOTH while the enigne is running then switching to just one of the batteries while the engine is off. This requires you to remember to operate the switch and is prone to failure.

A battery combiner is like an automatic operation of the battery switch. When the alternator is charging, the batteries connect together. It is fool proof and has viturally no downside.

Another approach is to use a "battery isolator" on the alternator. In this setup the output of the altenator connects to the isolator, which in turn connects to the batteries (a separate connection for each battery). This has the advantage of being automatic and foolproof but the isolator creates a voltage drop which can dramatically reduce the output of the alternator.

By the way, there is no way that the battery combiner could have fried your system. There are other ways that an inproper battery/switch/altnerator wiring combined with improper operation could fry it though, so I suspect that it was a result of some previous wiring connection. For example, in the "textbook" connection of a battery switch the alternator connects to the "common" terminal along with everything else. If the engine is running, and the alternator is cranking out a lot of amps to recharge the battery and you turn the switch to "OFF", very bad things can happen including destroying antyhing electronic.

Hey Rod-Thanks a million (I owe you a beer or two), those were the answers I was looking for. I think I'll run on the "both" position this summer and redo it next winter. Thanks Again! Mike

Rod, Does it hurt to leave it on both for 10-15min while listenign to the stero with engine off?

Won't hurt it at all! Just don't forget about it and listen all day only to end up needing a jump when both batteries are day.

10-15 minutes would be no problem.

When your 10-15 minutes turns into all afternoon it will be a problem.

mikeski

hows your yandina c100 working? mine's working like a champ.

Works great, I didn't expect it to keep up with those little leads but it does.