I have a reverse polarity light that comes on when I switch the battery switch to battery #2. Installed are the following Freedom 2012 2000w inverter/charger. Guest 2430 battery isolator. An off-1-2-both battery switch. Two 30amp AC power lines. The reverse polarity light only comes on AC panel "A" and only when the inverter draw/charger is on battery 2. I swapped the two AC power lines and it stayed on panel "A" so it is not my power from the dock. Inverter is only 6 months old. Battery 1 is 8d about ten months old. Battery 2 is 8d about 51/2 years old. Charge on battery 2 was 13.4 volts. Attached battery tester and after throwing switch to induce heavy draw the battery still showed 12.5 volts. Anyone have suggestions as to what might be causing the reverse polarity light to come on?
Electrical problem
- Thread starter Scosta
- Start date
My first thought is that you have the leads to incorrect terminals on that battery. 
If the inverter is giving the alert, it could be a low voltage/capacity indication. Given the age of the battery it could be a capacity/current breakdown. A faulty connection could also be the culprit. Electrical issues can be difficult. I feel your pain.
If the inverter is giving the alert, it could be a low voltage/capacity indication. Given the age of the battery it could be a capacity/current breakdown. A faulty connection could also be the culprit. Electrical issues can be difficult. I feel your pain.
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rather than hooking things up in a different fashion then looking to see if the light is still on, try unhooking things, one at a time until the light goes out... then when you find the circuit than made the light go out, leave it disconnected while you connect everything else back up... one at a time, while checking the light
once you find the circuit that is causing the problem, it should be an easy fix.
once you find the circuit that is causing the problem, it should be an easy fix.
What causes a "reverse polarity" light on an AC panel? On my boat it is when there is an excessive voltage difference between ground and neutral, one cause being neutral and live have been swapped, therefore called reverse polarity.
What could cause a voltage difference between ground and neutral? A poor connection that causes the neutral bus to become elevated in voltage compared to the neutral at the source. That could be in the power cord (but you have swapped power cords) or the connections between the power cord and the panel neutral bus.
After making darn sure you have made it safe (disconnected all power cords and disabled/disconnected all invertors) go through the AC connections and ensure they are all clean and tight.
If it ever worked it can't be wired wrong.
What could cause a voltage difference between ground and neutral? A poor connection that causes the neutral bus to become elevated in voltage compared to the neutral at the source. That could be in the power cord (but you have swapped power cords) or the connections between the power cord and the panel neutral bus.
After making darn sure you have made it safe (disconnected all power cords and disabled/disconnected all invertors) go through the AC connections and ensure they are all clean and tight.
If it ever worked it can't be wired wrong.
Thanks for the suggestions. Everything has worked correctly since the new inverter was installed 6 months ago. The only time that the reverse polarity light comes on is when battery switch is set on battery #2 to supply inverter/receive charge and this problem just started to occur. I checked battery connections and they are tight. I will check other connections when I return to the boat. I suspect at this point it might be the battery itself due to it's age even thought the battery tester did not indicate any faults. Still interested in more suggestions if anyone has some.
swap the batteries before doing anything else. If the rev polarity light follows the battery to its new location you can be pretty sure that it is the battery.
IceBreaker- good suggestion I will swap battery connections. I suspect the problem will move to battery one position after the swap but we will find out.
BillRoosa- the reverse polarity light also comes on when in the "Both" position. Good clarification. I neglected to state in my original post.
Thanks again
BillRoosa- the reverse polarity light also comes on when in the "Both" position. Good clarification. I neglected to state in my original post.
Thanks again
Woodster- I have two 30amp A/C lines coming in to the boat. Line "A" is wired to the inverter/charger then it goes to the panel. This allows all the circuits on panel "A" to be supplied by the inverter when away from shore power. Panel "A" is the panel showing reverse polarity when inverter/charger draw is set to battery #2 or "both" position. Panel "B" is wired direct to panel and has no issues. I did swap the two 30amp lines coming into the boat and the issue remained with panel "A". Also this is the way the boat came wired from the manufacturer and has been no issue until now. Thanks
All the reverse polarity light does is indicate there is current flow between the AC neutral and the green ground leg. It is unlikely that this suddenly happened so it probably is really telling you that there is a voltage difference between the 2 legs from a cable/connection problem that may have occurred over time. When the light comes on are you now using a battery bank that may have a longer cable run?
see below link
http://www.jamestowndistributors.com/userportal/document.do?docId=96
see below link
http://www.jamestowndistributors.com/userportal/document.do?docId=96
Don - battery #1 and battery #2 are side by side so virtually the same cable runs. This problem just started. Quite possibly the cables on battery #2 loosened on either the battery end or the battery switch. I will check the connections. Thanks for your info.
I'm having a real hard time thinking of anything that would made a reverse polarity light come on related to just switching between battery banks. Either bank is just supplying the inverter that is supplying the AC bank. Far as the reverse polarity light goes all it cares about is the AC power from the inverter and that didn't change (including the negative and ground bus and connections).
When you switch between battery banks and are powering the AC bus via the inverter does it make a difference whether or not you have any AC loads running? If it isn't on until you run an AC load, what happens to the DC voltage when it happens?
When you switch between battery banks and are powering the AC bus via the inverter does it make a difference whether or not you have any AC loads running? If it isn't on until you run an AC load, what happens to the DC voltage when it happens?
So here is an update. Last week when I left the boat I switched the inverter draw/battery charger to battery #1 and the DC panel to draw from battery #1. This way I eliminated battery#2 and there was no "reverse polarity" light on. Yesterday when I returned to the boat I switched everything to battery#2 and there was no "reverse polarity" light on. So far today still no "reverse polarity " light. Still don't know what caused the problem but for now it appears to be gone. Thanks for all the suggestions and questions.
Please let me explain
On your shore power you have 3 connections;
hot, neutral, and ground .
As the neutral is bonded to ground on shore, there should be zero voltage potential between the neutral and ground as it comes into the boat.
One of the problems in marinas is that the 120.H&N wires can get transposed.
So, on boat builders put a bulb between the N & g conductors.
There should be normally zero voltage potential between them.
But, if the shore service has interchanged wiring, the bulb now has voltage across it.
On board batteries have nothing to do with a reverse polarity switch. Like zero.
Here is where I suspect your problem lies.
In your inverter there is a transfer switch. Which is supposed to ground the neutral when turned on. The inverter is defined as a new generation source, and under code must bond the output neutral to ground.
I would look at the inverter wiring, make sure it's properly phased.
The reverse polarity light is a very simple device.
On your shore power you have 3 connections;
hot, neutral, and ground .
As the neutral is bonded to ground on shore, there should be zero voltage potential between the neutral and ground as it comes into the boat.
One of the problems in marinas is that the 120.H&N wires can get transposed.
So, on boat builders put a bulb between the N & g conductors.
There should be normally zero voltage potential between them.
But, if the shore service has interchanged wiring, the bulb now has voltage across it.
On board batteries have nothing to do with a reverse polarity switch. Like zero.
Here is where I suspect your problem lies.
In your inverter there is a transfer switch. Which is supposed to ground the neutral when turned on. The inverter is defined as a new generation source, and under code must bond the output neutral to ground.
I would look at the inverter wiring, make sure it's properly phased.
Sorry I missed this one.
The likely culprit here is possibly a bad connection in the inverters 120V path and is possibly not representative of actual reverse polarity or the light would never go out. You may also have a leak somewhere in the system onto the green grounding wire.
When the charger is placing a high demand on the 120V feed, such as when bank 2 is selected and has been deeply discharged, there can be "leakage" current back onto the green grounding wire, if we have a high resistance point in the 120V circuit. Green should always be at 0V but sometimes its not. Voltage drop in a long run can cause this too.
These things can cause a flickering or even a constant illuminated light until charger current drops low enough for the bad connections or the leak to not bleed some current onto the ground wire...
A reverse polarity light should have a 25K Ω resistor between AC NEUTRAL (WHITE) & AC GROUNDING (GREEN). This means that under 4.8 mA (0.0048A) of leakage onto the green wire can illuminate the reverse polarity light, which is right below where a GFCI trips.. With bad connections/high resistance this can and does easily happen. The bad connection could be in the inverters internal terminal strips or in the shore power cords/inlets or anywhere in that circuit..
The more current the charger pulls the more leakage you may have being carried onto the green wire. AC current ALWAYS finds a path home to the source. If the AC white wire can't sustain the what is being asked of it during charging use some small amount of current can bleeds off to the green wire and return to the "source". Your inverter may also be bleeding some off to the chassis. At low charger current it may not illuminate at all, at high current illumination may even be constant & at medium current you may see flickering.....
The likely culprit here is possibly a bad connection in the inverters 120V path and is possibly not representative of actual reverse polarity or the light would never go out. You may also have a leak somewhere in the system onto the green grounding wire.
When the charger is placing a high demand on the 120V feed, such as when bank 2 is selected and has been deeply discharged, there can be "leakage" current back onto the green grounding wire, if we have a high resistance point in the 120V circuit. Green should always be at 0V but sometimes its not. Voltage drop in a long run can cause this too.
These things can cause a flickering or even a constant illuminated light until charger current drops low enough for the bad connections or the leak to not bleed some current onto the ground wire...
A reverse polarity light should have a 25K Ω resistor between AC NEUTRAL (WHITE) & AC GROUNDING (GREEN). This means that under 4.8 mA (0.0048A) of leakage onto the green wire can illuminate the reverse polarity light, which is right below where a GFCI trips.. With bad connections/high resistance this can and does easily happen. The bad connection could be in the inverters internal terminal strips or in the shore power cords/inlets or anywhere in that circuit..
The more current the charger pulls the more leakage you may have being carried onto the green wire. AC current ALWAYS finds a path home to the source. If the AC white wire can't sustain the what is being asked of it during charging use some small amount of current can bleeds off to the green wire and return to the "source". Your inverter may also be bleeding some off to the chassis. At low charger current it may not illuminate at all, at high current illumination may even be constant & at medium current you may see flickering.....
Just read your analysis
You are correct that there is a series resistor with the led, but the reason the current, at full voltage, is calculated to be approx 4.5 is so that it won't trip dock GFI units which are set at 5ma,
A gfi measures both the hot & neutral for imbalance, and the resistor bleeds some off through the led.
For the led to be lit brightly, the neutral conductor must be at 120v with respect to ground. I therefore have trouble with wire corrosion in the neutral circuit limiting current under load.
I'm not 100% sure what the answer is (yet).
I'm still mulling over the high resistance theory in neutral wire. I don't think this works for a few reasons.
You are correct that there is a series resistor with the led, but the reason the current, at full voltage, is calculated to be approx 4.5 is so that it won't trip dock GFI units which are set at 5ma,
A gfi measures both the hot & neutral for imbalance, and the resistor bleeds some off through the led.
For the led to be lit brightly, the neutral conductor must be at 120v with respect to ground. I therefore have trouble with wire corrosion in the neutral circuit limiting current under load.
I'm not 100% sure what the answer is (yet).
I don't know what the minimum voltage to light the LED is, but that would have to be met on the Neutral wire in order to have a light or flicker. I'm assuming the potential is on the Neutral else a fuse would blow or a breaker trip if all were doing their job and the potential were on the Ground. I would still be looking at the inverter wiring and the inverter it's self for the problem. I suppose if there were a problem with the Neutral the current might try to pass through the LED to Ground to return but that would be short lived as the LED would not assume any real current load before leaving this world.
A real puzzler
As mentioned, the reverse polarity led is wired between the neutral & ground.
Everyone, myself included have been focused on perhaps bad AC neutral wiring.
What I'm wondering is perhaps you have something going on with the AC ground picking up voltage. And this potential across the led is lighting it.
I would do a serious check of the AC ground wiring. It should be zero ohms , or very close, from the AC input receptacle all the way to the panel.
This is worth checking into.
I've been thinking about this a lot, and there might be another answer worth exploring.
As mentioned, the reverse polarity led is wired between the neutral & ground.
Everyone, myself included have been focused on perhaps bad AC neutral wiring.
What I'm wondering is perhaps you have something going on with the AC ground picking up voltage. And this potential across the led is lighting it.
I would do a serious check of the AC ground wiring. It should be zero ohms , or very close, from the AC input receptacle all the way to the panel.
This is worth checking into.