Zantrex Inverter Overload

[BuzzDoc]

Had gennie running while driving and left inverter on. 15 minutes later we smelled electrical burning smell. Stopped and inverter giving E5 OL error which I interpret to be overload due to short circuit. Checked inverter and see that negative DC cable from battery is melted.

Before I start tearing into this I thought I would ask for advice on steps to go through. Batteries are showing full charge. With inverter off and gennie running everything works. Same on shore power. On shore power inverter gives same error when turned on.

Thinking I will first repair DC cable to inverter and remove all power to inverter for awhile then restore and see if it’s ok.

Everything worked fine this morning on inverter alone. Can’t say I remember running gennie and inverter at the same time but it’s probable that I did since I like it to the switch over to the inverter when I turn off gennie. Seems like this should not have happened as inverter should have passed power through from generator without overloading DC cable. I have two 135 amp hour AGM batteries that still look fine.


Let me know if you need more info. This is a 2016 Windsport 34f.

Am traveling headed to Yellowstone KOA where I will start diagnostics and repair.

[16ACE27]

What model inverter? If OEM it is not an inverter/charger and the converter charges the batteries on SP or generator.

The inverter should also have an integrated ATS so that on generator or SP the circuit the inverter supplies is powered directly by SP or generator power. The inverter only supplies the 120 VAC to that circuit when not on SP or generator.

i only the negative inverter cable is damaged then it wasn't due to current draw by the inverter; otherwise the positive cable would have been damaged as well.

Sounds like you have had a major failure either in the inverter or other wiring that used the negative cable of the inverter as a bypass path. Your inverter is probably toast either as a result of the failure or the cause of the failure.

I'd be leary of running anything in the AC system until you've got the cause and all damage figured out.

[Bob Nodine]

Originally Posted by BuzzDoc

Had gennie running while driving and left inverter on. 15 minutes later we smelled electrical burning smell. Stopped and inverter giving E5 OL error which I interpret to be overload due to short circuit. Checked inverter and see that negative DC cable from battery is melted.

Before I start tearing into this I thought I would ask for advice on steps to go through. Batteries are showing full charge. With inverter off and gennie running everything works. Same on shore power. On shore power inverter gives same error when turned on.

Thinking I will first repair DC cable to inverter and remove all power to inverter for awhile then restore and see if it’s ok.

Everything worked fine this morning on inverter alone. Can’t say I remember running gennie and inverter at the same time but it’s probable that I did since I like it to the switch over to the inverter when I turn off gennie. Seems like this should not have happened as inverter should have passed power through from generator without overloading DC cable. I have two 135 amp hour AGM batteries that still look fine.


Let me know if you need more info. This is a 2016 Windsport 34f.

Am traveling headed to Yellowstone KOA where I will start diagnostics and repair.

My suspicion would be a poor connection on the negative battery cable. A bad connection is a resistor and as current flows thru it, the connection heats up. Replace the negative cable on the battery and make sure the connections are clean and tight. Then run the inverter and keep an eye on the cable. You may also want to invest in a good shunt that can be monitored with your phone. We use the Victron 500 amp Bluetooth shunt at the negative battery cable.

https://tinyurl.com/2bvoybf7

[BuzzDoc]

I suspect either a bad connection or the ATS died on the inverter. Hoping for cooler weather tomorrow to investigate. It’s a Zanker’s 1800 watt inverter. No charger or converter. That’s separate and under the bed with the ATS and distribution panel.

Suggestions for a new pure sine inverter? I don’t want to go the route of a total rewire for an inverter/converter. Just replace the inverter.

[ducksface]

Harbor freight.
Buy extended warranty if you're a worrier.

Others will say differently.
They might not be experienced.

Good warranty
Good price
Stores everywhere for warranty exchange.
Upgrade to better and maybe get 100% trade-in value.

[Beau388]

A Xantrex Freedom X 2000 is a drop-in replacement for your Xanterx Pro 1800. The data cable to the remote is the same. You will need a different remote control box also as the Freedom X is a pure sine-wave inverter and has many more functions plus a 30 amp ATS.


Hodges Marine has them for $655. The remote is $67. I love mine. It replaced my Xantrex Pro 1000. It has worked flawlessly for 4 years.


I would change out all the split-ring lock washers to the tooth type on the high amperage studs to prevent the nuts from working loose due to vibration. Many times the floor workers at Thor MC leave out the split-ring lock washers to speed-up production. If you hate electrical fires as I do, invest in a in-lb 1/4" drive torque wrench and follow the manufactures instructions.

[BuzzDoc]

Removed the inverter and found that the battery cables were fine. The ground wire was not grounding to chassis and it appears the burning was the bare ground wire melting the flex casing around the positive terminal. Fixed the ground issue and connected it back to a battery and it still gives the Overload fault.

Would a poor ground cause this? I think the inverter is toast. Just trying to figure out the cause. Haven’t opened the inverter to see what’s inside.

[Bob Nodine]

Originally Posted by BuzzDoc

Removed the inverter and found that the battery cables were fine. The ground wire was not grounding to chassis and it appears the burning was the bare ground wire melting the flex casing around the positive terminal. Fixed the ground issue and connected it back to a battery and it still gives the Overload fault.

Would a poor ground cause this? I think the inverter is toast. Just trying to figure out the cause. Haven’t opened the inverter to see what’s inside.

My guess is the inverter has failed, maybe one of the IGBT's has shorted. I would be looking for another inverter.

[BuzzDoc]

Camping in Yellowstone and went to order Xantrex Freedom 3000 with new remote control panel and it said “will ship in 1-2 months”. Not mission critical this trip but I like to be 100% as much as possible.

Found the same unit and controller from Hodges Marine in Florida and with taxes and 2 Day Flat Rate shipping the cost was $1,046.64 which was 40 bucks cheaper than Amazon. Feels good to see the retail store win. This is my usual practice. Find it on Amazon then search for same item at a small retailer. If the price is is better or even a little bit worse I’ll go with the retailer. No reason for Amazon to get a cut just for the convenience when the retailer offers the same return policy.

Arrives on Monday (here til Thursday) will give you an update after installed.

I suspect I’ve been asking too much of the inverter. Residential frig is 96 watts, microwave is 950 watts, coffee maker is 1500 watts, TV/soundbar resting state probably 15 watts. So too much to run the microwave and coffee maker together which I know I have. Shouldn’t the reset button on the inverter pop if I draw too much? Anyway, now with 3000 watts I should be good. With 270 amp hours of battery that should give me enough for at least an hour of breakfast cooking (right) without depleting the batteries.

[Chateau_Nomad]

Now just make sure your cables supplying DC to the inverter are robust enough (AWG) to handle the current... and don't forget to check fuse rating for the cables.

[BuzzDoc]

Great catch on the cable and fuse size. I have 2/0 cable and t type fuse is only 65 amps. Ordered 320 fuse and 4/0 cable from inverter to fuse then to battery.

Question. Do I need to upgrade all my battery bridging cable to 4/0 as well? Have two 12volt 135ah batteries bridged with 2/0 cable.

Or is it sufficient to just have 4/0 from inverter to fuse and then to battery.

[Chateau_Nomad]

I would recommend having all cables in the same circuit the same AWG. 4/0 may be overkill... BUT do the calculations as you've done above. Then use an ampacity chart based on those calculations. Fuses are generally 125% greater than the ampacity of the cable they're protecting.

Using a lower gauge cable in a circuit with 4/0 will cause the lower gauge to act as a (unreliable) fuse in a high current situation. Best to use correct cables for the situation and fuse properly.

[Beau388]

Originally Posted by BuzzDoc

Great catch on the cable and fuse size. I have 2/0 cable and t type fuse is only 65 amps. Ordered 320 fuse and 4/0 cable from inverter to fuse then to battery.

Question. Do I need to upgrade all my battery bridging cable to 4/0 as well? Have two 12volt 135ah batteries bridged with 2/0 cable.

Or is it sufficient to just have 4/0 from inverter to fuse and then to battery.

Since the max continuous amperage draw for the inverter is 250 amps @12.2 volts or 125 amps per battery; assuming the batteries have the same resistance and the cable is about 1 ft long, 2/0 awg copper is gracious plenty (2/0 is rated at 190 amps @ 30 C).

For the techies in the group: DC and AC recommended current values appear to be different because the current flow in DC is continuous and in AC it is zero twice in a cycle. The answer is the DC voltage is constant while the AC voltage is the root mean square of the instantaneous voltages. As far as the wire is concerned, the current flow in a single phase AC when compared to a similar DC circuit is the same. Voltages do not matter unless the voltage is above the insulation's capacity. Power in watts can be written as: current squared times resistance.

Note: I hope my 60 year old thermal power plant knowledge hasn't been superseded by the quantum electron theory

[16ACE27]

Originally Posted by Beau388

Since the max continuous amperage draw for the inverter is 250 amps @12.2 volts or 125 amps per battery; assuming the batteries have the same resistance and the cable is about 1 ft long, 2/0 awg copper is gracious plenty (2/0 is rated at 190 amps @ 30 C).

For the techies in the group: DC and AC recommended current values appear to be different because the current flow in DC is continuous and in AC it is zero twice in a cycle. The answer is the DC voltage is constant while the AC voltage is the root mean square of the instantaneous voltages. As far as the wire is concerned, the current flow in a single phase AC when compared to a similar DC circuit is the same. Voltages do not matter unless the voltage is above the insulation's capacity. Power in watts can be written as: current squared times resistance.

Note: I hope my 60 year old thermal power plant knowledge hasn't been superseded by the quantum electron theory

Which is it? AC amps (and voltage) is always measured/expressed in RMS which does the same work as DC voltage/current of the same measurement.

In any case, when installing an inverter, it's the DC side that you need to be concerned about sizing the cables (and fuse/breaker).

[Bob Nodine]

As noted 2/0 cable is adequate for short runs and short periods at 250 amps. But in the case of a 3000 watt inverter I would make the runs directly from the battery bank to the inverter with 4/0 cable and place a 300 amp fuse at the battery positive. This assumes the inverter is not located next to the batteries. The reason is that inverters are sensitive to input voltage so we want a minimum voltage drop across the cable connecting the batteries to the inverter. If you are using flooded batteries or AGM's then the voltage will drop significantly at high current levels. If the cable connecting the inverter drops a lot of voltage with AGM or flooded batteries it may cut off when you are running the microwave. That is one of the big advantages of lithium batteries. The voltage remains constant almost down to zero SOC. So when you pop that item in the microwave and hit the start button the battery voltage does not plummet.

[Chateau_Nomad]

To reasonably future proof...

Bridge between batteries with 4/0 using equal length of negative and positive cables.

300A catastrophic terminal fuse on positive battery terminal.

Equal length 4/0 negative and positive cables to inverter.

I used 10/2 (orange) from inverter AC to RV power center (breaker box)... 30 amp service.