Need help - lost 12v

[Cadence]

Originally Posted by George_SD

I'm afraid that may be the case. However what is really strange is that i get 0 needle movement on the panel. Not even a twitch. I'm going back there tomorrow with the multimeter.


Additionally - shouldn't I have 12v still working from shore power or is it always form batteries only?

Not to sound crass. Buy a book on
AC an DC fundamentals it will pay for itself.

[garychurch]

Sometimes chargers quit working.

[Tom_F]

My Jeanneau has a circuit breaker right where the shore power connection enters the boat. It is high up in the lazarette under the port side helm seat and hard to see. I had a similar problem once and found I had somehow tripped that breaker. Once the breaker was reset everything worked fine.

[pmclachlan]

Originally Posted by George_SD

I'm afraid that may be the case. However what is really strange is that i get 0 needle movement on the panel. Not even a twitch. I'm going back there tomorrow with the multimeter.


Additionally - shouldn't I have 12v still working from shore power or is it always form batteries only?

I had a similar situation after installing new batteries. Turned out the Xantrax 20 was set to flooded instead of AGM and the temperature was set to cold instead of warm. So it’s important to know what kind of batteries you have.

[George_SD]

UPDATE:



Well, I went to the boat yesterday and found that the negative switch was in the OFF position. Probably someone moved it with their foot accidentally when getting in and out of the aft berth. (It's right at the entry to the berth 2 inches off the floor. Batteries are good and are charging well.

While researching the issue from home - i've read the entire Xantrex manual, read and watched about AC/DC boat systems, etc. I'm still a newbie, but at least now have some basic understanding of the principles and two power systems.

Thank you all for your suggestions and guidance.

[JimsCAL]

Glad the solution was easy. Sounds like you have an unusual setup with separate positive and negative switches. One thing to watch is never disconnect the battery from the alternator when the engine is running. It can wipe out the diodes in the alternator.

[hlev00]

Doh! We have a negative switch and didn't think of it. Glad that was it. Our switches in the aft berth and I am always worried about guests staying there might kick one.

Here is a somewhat related story.

We always shut off the negative and both battery banks when we get off the boat. We usually just start from the house bank, though once a month we start with the start battery. Due to some miscommunication when we boarded the boat for the weekend, I tried to start the engine with the house battery switch was on but the negative switch off. I turned the key to on, and the blower and alarm started fine. I turned the key to start and everything went quite. Next time I tried turning just to on, nothing happened. I pretty quickly noticed that the negative was off. I turned the negative on, along with the house, and the boat started normally. We tested a start with the start battery and that was fine too. Though it felt like we blew a fuse nothing seemed to be amiss, so we continued on.

Later that day we noticed that the bilge pump LED on the DC panel was not glowing as brightly as the others. Eventually we found that a fuse on the negative lead for the always on bilge pump wiring, that bypasses the battery switches, had blown. The starter had tried to start through that wire. Obviously a damn good thing that both the pos and neg were fused.

I'm not certain what is wrong but the fuse blown, the bilge pump must have been getting a ground back through something else. Without the negative switched on, the key should not have responded at all. I still have some more investigating to do, then decide what to do about it.

Regarding the problem of shutting off the positive switch with the engine running. Blue Sea has a battery switch with a built in field disconnect. https://www.bluesea.com/products/900...witch_with_AFD In the event that the battery switch goes to off, the field disconnect stops the alternator from generating electricity and protects the diode. I thought that I saw Blue Sea offering an AFD device to locate near the alternator without having to change the switch to get the same result, but I'm not seeing it on their webpage, which is too bad. I had hoped to install one as part of a winter project.


Harry
s/v Juno
juno423.blogspot.com