Electrical Oddities - Help!

[Bella Sera]

Problem: Turned the battery switch to off, the cabin lights stayed on. Tried other AC breakers and their systems worked with the battery switch off as well. Thought "This can't be good". As an electrical idiot, thought I would see if anyone has a good starting place or simple solution.

My system is a Marinetics AC/DC CB panel, standard off/1/2/both battery switch mounted on the panel, house bank and starter battery, and a Link 2000 Inverter/charger.
In troubleshooting, here is what I have discovered so far: (1) With shore power disconnected, everything works as advertised....ie none of the boats systems can be powered on until both the battery switch is turned on and their CB is flipped on. (2) When shore power is connected, the Link 2000 comes on immediately (doesn't matter which position the AC "Shore power" CB is in)....but even though it shows"Charge", it doesn't reflect any amps passing until the battery switch is turned to 1, 2, or both....then appears to work fine. (3) With shore power connected and the battery switch in the off position, I can turn systems on just by flipping their DC breaker switch.....but they seem to be undervoltage (ie cabin lights are dimmer than normal) and I hear a faint hum (assuming this is coming from the charger in the cockpit locker). If I flip the battery switch on, the hum goes away, as does the apparent undervoltage.

So is this a miswired Link? Bad battery switch? Gremlins? Am I running a risk operating the system as it is? I've had the boat just over a year and didn't notice this issue throughout last sailing season......but was rarely onboard while plugged in. Think the Link was installed about 5 years ago.

Suggestions welcome. Thanks,

[ChuckSK]

It could be that the inverter/charger battery connection is made to the load side of the battery switch. When shore-power is connected the charger is supplying DC power to the load panel but is not charging the battery. When shore-power is disconnected the battery is required to supply the DC panel. The Link 2000 is powered from the load side of the battery switch and would be powered by the inverter/charger when shore-power is connected.

Hope this helps.

Chuck

[senormechanico]

I came up with the same conclusion before reading ChuckSK's response.
It's gotta be the output(s) of the charger hooked up to the common output side of the battery switch.

Steve B.

[CorrinaCorrina]

After installing several electrical systems on boats this is what I conclude
1) Your inverter is wired before the main AC Breaker. You want this wired afterwards (boat side not shore side) so that if something were to go wrong you can quickly flip the Main AC CB and this will shut off all AC power to the boat.
2) Your 1/2/Both switch is properly connected. When you apply AC power to the boat with your Main AC breaker off, your inverter/charger is recieving AC power that is bypassing the Main AC Breaker and this is then being converted to DC power. This DC power then travels from your inverter/charger to your 1/2/Both switch. With the 1/2/Both in the OFF position, your inverter is tied directly to your DC panel main feed. There is a way to prevent this from happening. You will need to insert a CB into your DC panel feed. This will allow you to quickly shut off all power to your DC panel in case of an emergency and will prevent the backfeed from your inverter.

[CorrinaCorrina]

Oh yeah, by the way I live in Annapolis on a Mason 44.

[Rick]

The preferred way to connect the inverter/charger is to wire the dc cables directly to a house bank (via an appropriate fuse) with a minimum of cable length. Make sure that the ON/Off switch on the inverter/charger is always in the OFF position so that the Link 2000 remote is in control. The charger will always "see" a battery with this installation (unless there is a fault). You can always use your battery switch to parallel other batteries, if desired. Keep in mind that with the Link 2000 there is no reason to have two separate house banks.

Use the INVERT and Chg buttons on the Link 2000 remote to enable automatic operation of the charger and/or inverter functions. Normally the "auto invert" function is left disabled in case your shore power is disconnected when you are away from the boat thereby preventing unnecessary discharging of your battery. Normall the auto chg function is enabled so that whenever ac is present you charge the batteries.

Note that you can set up the Link 2000 so that if shore power is intermittent that the charge function always goes directly to float, if desired.

[hellosailor]

Sounds like someone INTENTIONALLY wired up the charger to the output side of the A/B switch, so they could use the existing switch as a way of shunting the charger to A/B/Both and selectively charging.

Which produces the "unsafe" condition of having live DC circuits when the battery switch is supposedly OFF.

I suppose that's a valid kludge, but if you really want that kind of selectivity...a second switch and some cables might be a better way to do it. Break out another hundred, I suppose.

[Bella Sera]

Steve, Corrina, Rick, HS - Bingo. I found a hand written note dated when the system was installed in 1999 that reminded the then owner that the battery switch had to be on (1/2/B) to charge the desired battery, and that it would power DC systems directly from the charger when plugged into shore power and the battery switch off....."a condition to be avoided". So the installer obviously put it together this way intentionally, and I suspect wired it this way to avoid needing a second switch to get battery power back to the inverter? At any rate, has apparently worked for 10 years, so won't rewire right away.....other than to add a 30A CB inline just downstream from the shore power receptacle so I can shut off the whole thing while onboard. That and remembering to turn all DC breakers off before turning battery switch off should keep me OK. I think/hope.....

Thanks for the thoughtful answers.