MEP 802 Short Circuit

[Coley]

I install off grid power systems for people. I have twice now paired up a 802 with a Magnum 4048 inverter and gotten the same issue.

The magnum is a 48v inverter that puts out 120 or 240 and is rated up to 4k. It also has a charge controller that can take 120 or 240 to charge the batteries. It has an autostart module that can be triggered in several ways. I usually set is for battery SOC for 60% kick on, and run to 95%. This autostart talks to the autostart that Peter at Inova Makes, and works well. My problem is that on both of these setups once it starts charging it trips the short circuit light. The charger on the inverter can be configured for the gen amps, and then again for percentage of incoming power that goes to the batteries. I have tried everything from input of 15 amps and 40% to 30 amps and 100%. It makes no difference. Peter told me that if the load is unbalanced it can also trip the SC light. I tried changing the output on the gen to 1phase 120 only thinking if there was an unbalance that would resolve the issue. Same problem. Anyone have any ideas?


CF

 

[Suprman]

I am a bit confused. Are you trying to run the same load off both the gen and the inverter with the gen autostarting with a certain load draw?

 

[Coley]

Loads are run by the inverter. When the battery bank reaches a set point (60% state of charge) the inverter starts the generator. At this point, the generator takes the loads and charges the batteries both. That is the set percentage in the charge menu of what percentage of gen power goes to the batteries. 10-100%

CF

 

[Suprman]

Are you using the generators internal charging circuit to recharge the inverter batteries? Or a power supply off the 120 volt gen output? If the gen is running with the inverter outputs directly across the gen outputs this might cause an issue. I would think you would want to toggle back and forth with a relay. If the inverter is enough to run your load, it would be simpler to run a 28 volt generator that recharges the inverters battery bank when voltage drops below a certain point.

 

[Coley]

The inverter has a built in multi stage charger for these type batteries. This is the inverter... http://www.wholesalesolar.com/2954842/magnum-energy/inverters/magnum-energy-ms4448pae-inverter

Spec sheet here.... http://pdf.wholesalesolar.com/inver...heet.pdf?_ga=1.77810708.1081946899.1474493233

CF

 

[Suprman]

How is the generator outputs connected to the load? Or does the generator just charge the batteries thru a dc power supply? Across the same terminals the solar panels are connected? Isolate dc sources with big diodes.

 

[kloppk]

Can you post up a schematic of how you have the generator, the inverter/charger and the load panel are wired?

 

[jimbo913]

The inverter requires 17.5A AC per leg for the charger. How much load are you drawing with other devices while charging? Have you attempted to disconnect other loads and only charge the battery bank to rule out pulling too much current?

 

[jamawieb]

The short circuit is tripping due to an intense surge in amperage. It only takes a millisecond for the generator to sense the surge and it trips the short circuit fault. I've had this happen on large industrial motors connected to 803a's and I had to bypass the short circuit fault sensors to keep the generator running.

 

[jimbo913]

Will the battle switch overide the sensors?

 

[Suprman]

It should but I have never tried on an 802/803 gen. But he is remote starting it and you can't start in battle short.

 

[jimbo913]

Ok, I thought you could wire it closed. I didn't realize it will disable starting. Doesn't sound like battle short is a SHTF switch by any stretch.

 

[jamawieb]

Unfortunately, battle short will not bypass the short circuit fault. It is the only safety feature that battle short will not bypass.

 

[Coley]

The short circuit is tripping due to an intense surge in amperage. It only takes a millisecond for the generator to sense the surge and it trips the short circuit fault. I've had this happen on large industrial motors connected to 803a's and I had to bypass the short circuit fault sensors to keep the generator running.

How do I accomplish that? It is what I have been thinking I need to do. I have had no problems with Short Circuit on any of the 802 or 803s I have installed with the exception of the two I have connected to these model inverters. Its driving me nuts. I have seen another post that says disconnect the wires from the 4 connections on the right rear of the sensor box.
All loads from the house are minimal. LED lights, LED TV and a toyo stove. Maybe 2 amps total with exception of the well pump when it kicks on.

CF

 

[Coley]

Can you post up a schematic of how you have the generator, the inverter/charger and the load panel are wired?

Similar to this with the exceptions of no shore power, and gen goes right into the inverter with ground, N and 2 hots. No "Main Panel" the main panel is after the inverter.

https://www.bluepacificsolar.com/picture_library/inverters/magnum-me-series-diagram.png

CF

 

[Coley]

Anyone who can advise me on how to bypass the Short Circuit fault sensors, it would be greatly appreciated.

CF

 

[robertsears1]

I having a similar problem on my MEP-804a generator while trying to start three FDECU-5 heat pumps. When I got the first FDECU, I was able to make cold and hot air even though it says the heat pump needs 60 amps of 208V and the 804a only does around 52 amps. I was having some problems with the reversing valve but in the maintenance mode, you could freeze your hand off. I bought two more figuring I could have some spare parts and possibly get two to work. I initially got the other two to work but then the problem of the gen tripping with a short circuit light on started. I even tied into a proper ground with the same result. It is almost like the generator trips easier now than in the beginning. I thought that possibly some of the capacitors in the heat pumps are bad or going bad. I bought a tester and have not found a bad one yet. With the FDECU, you can enter a maintenance mode and turn on the two fans one at a time but when I try the compressor, it trips every time lately. I can also turn on the fans and then both heat banks and it works fine. It is just when I try to get the compressor going that it trips, on all three units now every time. In the beginning, it would trip the short light once in a while and other times the compressor worked just fine. I may buy a new set of capacitors and see if that works. My 804A only had around 46 hours when I got it and now it just went over 100 hours. I even tried to use my MEP-003 generator since one member had said he was able to start a FDECU with one. All three trip the breaker as soon as the compressor is started. It could handle both fans and both heat banks.
Robert