Multiple Battery set up question

So we took my boat out yesterday and it didn't want to start? It acted like the batteries were really dead, it started but only ran for about 30 seconds. After it died it acted like the batteries were really low and it would barely crank over at all and then it just died.

First off I have 3 Kinetic batteries all wired together (not sure if you call that series or what not) and the batteries are less then a year old and I've never had this problem before. Everytime I come in from the lake I plug them into a Kinetic battery charger so they get recharged.

First we thought it was the alternator but it was tested today and it was operating fine. So my next idea is the batteries? My buddy put a volt meter on them and it showed 13 with motor off and at the alternator it showed 11 volts while running.

So my question is do I need to disconnect each battery and take them in and have them all load tested individually? I'm thinking it might be one bad battery in the bunch.

Also my starter relay was smoking a little while we were trying to start the motor, this has happened a couple of times before. Why would the relay do this?
Thanks

The batteries need to be connected in parallel. If the batteries are connected series the voltages would add so you would be putting 3 * 12 = 36V into your system - not good.

One bad battery will discharge the other batteries. I would get a load test done on the batteries independently. I had this problem with my Excursion.

11 volts while running is too low. Should be around 14V.

Yes they are hooked up in Parallel. If I have 2 good batteries and one is bad wouldn't I still have no problem starting the motor? Especially since they should have been fully charged as they are always pluged in? And with the alternator putting out 14 plus volts wouldn't that make up for a bad battery for a very short period. Because it honestly immediatly showed 11 volts once the motor started.

Sounds like your alternator is dead?

Having three big batteries wired together will surely kill most alternators in short order. If you are running a normal alternator with a normal voltage controller you should break the system in to a start-priority and stereo-secondary setup with a combiner used to control the charging duties of the secondary setup. This will help to keep your new alternator alive.

alt is dead. ( or maybe just the voltage regulator?)

I had a similar problem. I replaced the batt cables to starter and ground, fixed the problem. I am running to optima batteries.

Having one big bank is a bad idea. If you sit and drain down the batteries a bunch every time you start you are putting unneeded stress on your critical electrical systems. You need to either leave your stereo bank as a stand alone bank and charge it like you do every night or you need to find someway to separate/combine a starting bank and stereo bank. This can be done with a Perko selector switch, a Sure Power Combiner/separator(I recommend because it does everything for you automatically) or you can do an isolator but they cause a voltage drop unless you know how to wire one so it doesn't cause a voltage drop. Whatever you do get a starting battery that during starting is separate from the other batteries.

They could be right on the alternator as well. If you drain your batteries way down listening to music and then try and drive around to charge them up you are making your alternator work to it's absolute limits for long periods of time. Remember an alternator is designed to maintain the batteries, not charge them from a discharged state.

Also like Jack said. Check all your connections and clean them up and tighten down. Grounds are just as important as positive cables.

My alt. was checked by the electrical shop and it tested ok. the alternator is a custom built 200 amp bad boy which is fairly new. The one thing the stereo shop and the guy who built my alternator stressed to me is the concern of running the system with the motor off or at high volumes at low RPM. So with that in my head I don't run my system with the motor off and if I do its very low volume and short periods of time. Every time I come in at night I plug my batteries into my Kinetic battery charger and leave them on till the next use. Also the charger only charges the batteries to what they need so they don't get over charged. Any other ideas? I'm taking my boat in today to the stereo shop that did the install and they are going to pull all the batteries and do a load test on each one to see if it could be a bad cell.

Well, if your batteries are at 12.5v or higher that is not enough to hurt the starting really. If you want to check the cables get a mulimeter and check the voltage at the alternator then at the batteries. There should be more than a .2 volt difference. IF it is more check all your connections. Pull them off and use a wire brush on all connections.

When you say the relay was smoking are you talking about the starting solenoid or an actual relay? Those relays are very inexpensive if you want to replace.

What exactly did the guy building your alternator do? If he just took the stock one and messed with that it's life is going to be terrible. Those small frame units do not have the mass to dissipate heat that well. That and maybe they put a smaller pulley on it to try and drive up the RPM at the alternator which would make it run hotter as well. Also, do you have a single v pulley or a serpentine pulley on the alternator? A single V pulley won't be able to handle 200 amps.

So I had the stereo shop pull each battery and they tested perfect. And I took the alt to the guy who built it and he tore into it while I was there. Everything looked and tested perfect. So this leads me to believe its either a connection issue with a possible ground or its the starter or the selonoid?? If you remember the selonoid would smoke if I kept trying to crank it over. Another idea the alt guy told me is in the plug he thinks he installed a diode for both the ignition and the always hot wire. He thinks its a possibility the diode for the ignition could be fried which would not allow the voltage reg. to work on the alt. Any other ideas?

To check your alternator yourself. you need to unhook the main power cable to it. and crank up the boat. check the voltage that is coming from it then. it should put out 14. volts. not 11
11 volts wont charge your batteries, and will cause your batteries to discharge. especially if you are running the sterio loud while tghe motor is runing

So I installed the alternator back up today and fired up the boat. Tested at the alt and it read 13.7 volts so it was fine. Weird thing was though when I fired it up it ran at idle but when I went to give it throttle it wouldn't rev higher RPM. So I noticed my perfect pass wasn't on. I looked at my volt gage and it was running a little low. not even 10 seconds later the perfect pass came on and I noticed the Volt gage went up as well. I stopped and started the boat several times and it didn't happen again but I know Perfect Passes are very sensitive to low volt and I heard they will not work or shut down if the voltage gets low. So not sure if we narrowed down the problem or not but its working now so possibly their was a loose connection or something....

Wow so after realizing the batteries and the alternator tested good and the boat started up fine in my driveway I decided to take it out. Sure enough as soon as I put it in the water the boat acted like the batteries were low and would not start. My theory was that it started at home so I decided to pull it out of the water and sure enough it started. So I'm confused to why the heck it would start out of the water but not in!!! Something to do with the pump????? I have know idea.