I recently had a power windlass professionally installed on my Ben 352. It was fairly simple installation - the circuit is connected to the house batteries (two D4's) with a circuit breaker. No other connections I am aware of. After two weeks of normal operation I discovered the starter battery (SB) was dead. It had been boiled dry! I always keep the SB isolated and never have it on the charger with the house batteries. I only use it for back up (and check it regularly), in the unlikely event the house batteries can't start the engine after a day or two on anchor. So with my voltmeter I checked and found that even with the SB switch in the off position, with the battery charger on, there was 13 volts coming to the SB's. That didn't happen before. The battery switch seems to be operating normally. Without the battery charger off, there is still 0.5 volts coming to the SB - from the house batteries? There must be some electrical leak back to the SB. What gives? Murray
Starter Battery Switch & Charger Issue
- Thread starter Murray16764
- Start date
We're going to need a lot more info on this one. Do keep in mind that with many Beneteau's you have two ON/OFF battery switches (Start & House) but when both switches are ON both banks are in parallel and they are NOT isolated from one another.. It is a poor switch design that can catch many owners by surprise when they wind up with two dead banks, not just one......
*Switch Configuration & wiring diagram or photo of back side of switches
*Installed charger brand, model etc.
*Charge management devices eg: isolator, ACR/VSR/Combiner or Echo or Duo charger
Yes, there are four battery switches, behind and on top of the engine compartment. One is negative, the next is the SB and two for the HB's. I normally have the SB in the off position. I have learned from experience that you should not use or charge the HB and SB at the same time. This was never a problem before. The charger is the original equipment and is a Sentry G120 2NXJS. It is charging the HB, as usual. I have a call into my marine electrician who did the windlass work, but I expect he is pretty busy. For the time being I have a replacement SB, but will only connect it in an emergency until I sort this out. The HB's seem fine, connects are clean, water levels are normal and power is good.
Update: my contractor is of the belief that the SB would be receiving a charge from the battery charger whenever it is on, regardless of whether the SB switch is in the on or off position. My owner's manual is on the boat so I can't check what it says if anything, but my belief based on years of practice is that if the switch is in the off position, it will not be at all connected and will not receive a charge from the charger. The contractor suggested that i might have a dead cell in my house battery causing the charger to work overtime, killing the SB in the process. I'll check that over the weekend.
If the charger charges both banks, and the other one is fine, then the only reasonable cause would be a start battery.......
The charger should be wired to the battery for maximum efficiency , but like in my B323, it is wired to the panel where the battery switches (3, in my case) are, and before the switch. This means that in the off position, the battery gets charged. If more than one battery switch is on, this means the charger feeds are bridged together via the 12-volt buss.
Sure it did, that is the way your system is wired. See that little jumper between your House and Starter disconnects? Don't blame your technician. Doubt you really do have 4 battery switches.
Gunni's right because Beneteau wires their boats as he shows. Here's another. It takes some exploration and understanding.
When we got out boat 10 years ago I spent a lot of time trying to figure out optimal configuration of house and start switches, then I saw same as Gunni picture where it made no difference since they were wired together anyways with a jumper. I just decided to rewire to something I knew how worked using various sources I trusted, I recommend if you really want to dig into this look for a solution and rewire it yourself, make sure you don't make it worse though 
)
A couple of things I did were: replace jumper between house to starter with a Yandina combiner, I then rewired the alternator to go directly to house ONLY battery, not using the yanmar harness for charging, starter still wired to start battery.
One note about switching to charge house over start batteries: Stu's schema is good as it shows what I think is the "lamp" from alternator that goes into harness and to start battery, if I remember right that is connected internally in alternator and would provide a connection between house and starter batteries, outside the combiner, so I rewired that as well.
So... was it worth it? I doubt it, honestly I'd just go sailing and keep eye on batteries charge state, fluid levels and so on, which I do anyways. I still have the Beneteau jumper cable and backup battery for emergency but knowing more about this does give some peace of mind...
) A couple of things I did were: replace jumper between house to starter with a Yandina combiner, I then rewired the alternator to go directly to house ONLY battery, not using the yanmar harness for charging, starter still wired to start battery.
One note about switching to charge house over start batteries: Stu's schema is good as it shows what I think is the "lamp" from alternator that goes into harness and to start battery, if I remember right that is connected internally in alternator and would provide a connection between house and starter batteries, outside the combiner, so I rewired that as well.
So... was it worth it? I doubt it, honestly I'd just go sailing and keep eye on batteries charge state, fluid levels and so on, which I do anyways. I still have the Beneteau jumper cable and backup battery for emergency but knowing more about this does give some peace of mind...
Crimey, Gunni... in post 3 he spells out what each switch is, yet you want to say he's lying? Come on. 352 are not necessarily wired like a 411.
In a thread a few weeks ago, a fellow had a problem, and said that strap across the house/engine strap was NOT there on his boat. IIRC rather than put that strap in, he was going to do a bigger rewire ala MS.
Murry needs to trace his wires to what they are NOW, then change it if he wants some other arrangement.
He says he has 4 switches. I have 4 switches on my Bene 352. One black (negative) , One Red (Starter) , One Red (HB) , One Red (Invertor). All factory installed. If he has the AC transfer switch on the AC Panel, he probably has the invertor. Not sure if a possible combination would have the invertor connected to the starter battery without him knowing it?? I'd have to look at my schematic back on the boat.
He says he has two house battery disconnects, no mention of an inverter disconnect or an inverter. A Sentry G120 battery charger?? In any case, Beneteau DC systems are very straighforward, handle orientation clearly indicate load disconnect. That should include the windlass.
Okay thanks for your help. I think I sorted it out. The cause was a weak starter battery that got over charged and fried. I didn't know that the battery charger is wired around the battery switches, so they are always on charge when the charger is on. At lease I was half right. Having the SB in the off position saves it in the event that your HB gets discharged somehow. Joker is right, I have four switches, the one on the far starboard side does not seem to do anything. I have an inverter, factory installed, but I could never get it to work. The two HB's are controlled by one switch as they are wire in parallel. Over the weekend I will check the cells in the HB's to make sure they are okay. I will install a new SB and I think everything will be back to normal. I'll let you know how it all works out. Thanks again. Murray
Murray, the extra red disconnect simply powers up a panel switch that turns your inverter on. I believe mine was a button switch very near the inverter. It lit up when on. Because you don't need to have the disconnects in the on position to charge your batteries suggest you keep the disconnects off to prevent any load demand that would cause your charger to run excessively.
Your charger has a single voltage regulation point and can not over charge one battery without over charging the others. You most likely just had a bad battery.
That's what I thought since Beneteau doesn't supply separate switches for the house bank.
On a side note, you probably have the 2512 invertor. (2500 watts).
What problem are you having with it?
Good news, with the new starter battery installed everything is back to normal. The battery charger is cycling on and off, like usual. I checked the condition of the cells in the house battery and they are all in "good" condition according to the hydrometer. The starter batter tested 12.6 volts and the house batter 13.5 volts using the on-board volt meter. I think the lesson learned is that if you have a weak battery in the system, that can't get up to charge, the charger will go nuts and destroy your battery and maybe all batteries. Like I said, I didn't know the charger was wired about the main battery switches. Thanks for all your help. Murray