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Mike, Master Electrician
Category: Electrical
Satisfied Customers: 1425
Experience:  Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
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Need complex technical help. I have a small solar panel

Customer Question

Need complex technical help.
I have a small solar panel system on a cabin with 1475 watts of panels, 850 Ah of Rolls flooded lead batteries for a 24 volt system and a 3500W inverter. I have very few loads in the cabin: a refrigerator and freezer (each using 1 KW/day) and a few lights and fans. My panels keep the batteries charged but I occasionally need to charge them with my generator.
I am using a small portage Generac LP3250 generator. I thought with my small system that my need for battery charging would not be frequent or high wattage.
The inverter's controls (a MATE3 system for a FlexPower1 VFX 3524 Outback unit) register the input from the Generac as varying greatly in voltage and Hz. The computer shuts down the generator over and over because of the fluctuations.
In addition, the generator revs up and down while trying to charge the system.
1. Does the LP 3250 not send a consistent voltage and should not really be used for more sensitive electronic systems like mine?
2. If "no" to #1, is there a problem with my LP 3250 that needs servicing?
3. Is the power of the LP 3250 too low for my system to begin with?
4. An Outback tech suggested that perhaps when I wired the generator into the Outback and my AC panel, I put too many neutrals to ground, and this may be causing the problem. Possible, or not?
5. If "yes" to #1 and #3...what Generac generator would you suggest I get to give a consistent and powerful enough voltage and amperage to my system.
My battery specific gravities are getting lower and lower and are in peril.
Trevor at***@******.***
Submitted: 1 year ago.
Category: Electrical
Expert:  Phil replied 1 year ago.

Hello, this is not an answer, I will leave this link for you and then opt out, but it is the absolute root of your problem, a problem you could opt to spin your wheels on for a long time and get absolutely nowhere with.

Customer: replied 1 year ago.
Thanks. PhilI am not pissed at you (it that is what the http://generac.pissed link implies)... (there was a glitch in my trying to pay: the system demanded a password ***** I did not have. I tried to create one. I was never sent the promised temporary password. So I thought I was toast.
I am still willing to pay for the advise if your computer will let me. I would love you or another tech to help me with this problem.Trevor at***@******.***
Expert:  AssuredElectrical replied 1 year ago.

Welcome. My name is ***** ***** would be glad to assist.

Trevor, I have read all the information and had a few questions.

1. How is the generator connected to charge the batteries?

2. Do you have a good voltage tester to monitor the voltage?

3. How is the interlink to the solar treated when you run the generator to charge the batteries?

The generator is plenty big for your information posted, so it should have no problem

Let me know and we can continue,


Customer: replied 1 year ago.
1. How is the generator connected to charge the batteries?3-prong plug to AC input of Outback VFX FlexPowerI 3524 inverter/charge regulator. The connection should be OK. Recent. Doubt short.2. Do you have a good voltage tester to monitor the voltage?I could test the voltage across the AC input breaker into the Outback unit. I think this would be crucial. If the voltage is varying widely here (at the point where the generator power comes into the unit) then the generator is the cause. If not, the problem could be in the unit. My schedule and location is such that I will not be able to test the unit with a voltage tester until Thursday.3. How is the interlink to the solar treated when you run the generator to charge the batteries?Don't quite understand the question. The Outback unit accepts the AC input from the generator and permits the inverter to turn into a battery charger which charges the battery (if the input amperage and voltage are within the battery parameters (it is)). The system starts working, but the alerts say that the incoming voltage is too high or too low and it won't permit the batteries to receive the charge. The voltage range I allow is, like 80 - 130 volts. These parameters are not exceeded...but the Hz input also fluctuates widely. The Outback computer does not seem to like these fluctuations and it stops the charging.
Expert:  AssuredElectrical replied 1 year ago.

Ok, thanks for all the details.

You answered the question on the interlink, the outback unit has its own port for the generator connection and then it is in full control at that point.

When you can perform the test, that will tell quite a bit.

The generator should run with no ill effects even at idle speed if that is all that is needed.

It sounds like there is something happening at the Outback unit that is triggering the generator and making it cycle.

This can happen if if it tries to put the generator online and then takes it back off due to some type of switching in the unit.

The hertz will also change as this is happening.

I would first, test the generator connections to see what the voltage is actually doing, monitor and record the up and down cycle as much as possible.

Then, I would disconnect the generator from the Outback unit.

Fire up the generator as a stand alone unit and try to plug as much as possible into it and monitor it that way.

Cycle the load and see how the generator acts when that happens as well.

That will be the tell tell on the situation and lead you to which is ailing, generator or Outback.

How is the generator wired? Just plug in the receptacle on the generator and 3 wires on the other end to the outback?

If the generator is being used as a permanent installation for backup power, Is the generator frame grounded outside with a grounding rod?

It should ground to the same rod as the Outback unit

Also, if you have a distribution panel for your power in the cabin, it cannot have a neutral/ground bond. The generator will have one and the Outback unit will have one, NO OTHER should be present.

This is from the manual:

If a bond is made between neutral and ground, make sure only one bond is present in the AC system at any time. The FLEXpower ONE comes with a neutral-ground bond installed. If a neutral-ground bond exists elsewhere in the system, the neutral-ground bond in the FLEXpower ONE will need to be removed. See Figure 18.

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