Outback FX shutdown...

siyotanka

I have developed a small system, Outback MPPT80, 6 deep cycle marine batts = 12 VDC, 200 AH@, Outback Inverter 12VDC, Hub and FlexNet DC, plus MATE. My inverter keeps shutting down on the system. The inverter indicator lights show Low Battery and so does the Mate. Yet when I measure each battery it showes full charge (13.5 VDC) on each individual battery, and the FlexNet DC lights shows fully charged (all the idiot lights are on). I am inputting into the total system around 20+ VDC from the array, so there is current into the system.

Anyone have any ideas why the shutdown?

BB.

Re: Outback CC shutdown...

Check the voltage at the inverter's input lugs (assuming it is the inverter that is shutting down).

I don't know about Outback specifically--but most inverters shut down around 10.5 volts or so.

Your wiring may be too small in diameter and/or too far from the battery. A 1,000 watts can easily be near 120 amp draw on a 12 volt battery bank. Need lots of copper (and batteries) to sustain that current.

Also, check for loose electrical connections (bad crimp, check nuts and bolts).

-Bill

siyotanka

Re: Outback FX shutdown...

BB

I did check all the connections...ok. The Inverter and batter bank are right next to each other...maybe 8-9 inches apart, soI don't think the cable diameter is a problem. Like I said I measure each individual battery and they show fully charged. I have 6 deep cycle marine batteries in series running 12 VDC with a total AH equalling aproximately 1200 AH. What concerns me is as I said the batteries are fully charged and with my described layout, the draw should be equall accross the full string of batteries, should they not?

Cariboocoot

Re: Outback FX shutdown...

Measure the batteries' specific gravity with a hydrometer too. They can read 13.5V yet only 1125 SG. If the inverter has to supply significant power, the battery voltage will drop.

Also check the wires for voltage drop with everything running. You should have the same V at the batteries as at the inverter input, +/- about 0.1 V (for example - in other words it should be really close).

How are your batteries/inverter/charge controller wired? As in how many batteries and how do they connect to the other devices? You have six batteries in parallel - that's a lot. There is a potential problem with just "piggy-backing" connections - especially with smaller connector wires. The CC could be hooked to one set at one end of the string and the inverter to the other end and by the time the power goes from 'in' to 'out' there's too much wire resistance.

BB.

Re: Outback FX shutdown...

When you run the inverter--does it work at all (i.e., with 100 watt load runs, 1,000 watt load fails. Seems to work then shuts down when a refrigerator starts--or what)?

The "resting" or charging voltage of the batteries is certainly important--but the inverter's input voltage when under load is the only thing it cares about. 12 volt systems require the wiring to be done well (short, large diameter cables, with little voltage drop). The cabling (battery to battery, and common point to inverter) needs to be the same size as the battery cables on your car--or larger--for proper operation.

Your batteries, under load, can easily get down to 12 volts. That leaves 1.5 volts of drop between the battery terminal and the inverter input. Motor loads can easily surge 5x their running current--and that energy comes from the battery bank, the inverter does not store very much energy locally to supply surges.

It is possible that the inverter has a programmable shutdown voltage--and that was accidentally set high.

-Bill

siyotanka

Re: Outback FX shutdown...

A point waas raised I did not think about...

I have my CC connected into one end of the battery array, and the FX at the other end of the bank. Could this be causing me the problems? Should I have BOTH FX & CC connected at the same end?

BB.

Re: Outback FX shutdown...

It should not matter if the wiring is done correctly... If the issue is low voltage, during the day having the controller at the other end of the battery bank (on the same power points as the inverter) will reduce the voltage drop a little bit... Obviously, will not affect the problem when the sun is down.

In some cases (other charge controller manufacturers--the little I know, I have not heard a problem with Outback specifically)--having the CC on the same location as the inverter can confuse the CC's MPPT tracking software (inverters impose a 120Hz current wave form on the battery).

-Bill

siyotanka

Re: Outback FX shutdown...

Bill:

When I start the system the FX does run...it then stops and displays Low Battery voltage. Again, running manual VDC measurements it show all batts and bank at or above 12VDC. I measured the CC connect points, PV+/- (20VDC) from panels. Output from CC to battery bank (10.5 VDC)

Is this output to bank low? I would think it should be at or above the nominal rating for the type batt used...??

Cariboocoot

Re: Outback FX shutdown...

siyotanka wrote: »

A point waas raised I did not think about...

I have my CC connected into one end of the battery array, and the FX at the other end of the bank. Could this be causing me the problems? Should I have BOTH FX & CC connected at the same end?

The problem is the inherent resistance in wires; by the time the current from the charge controller goes through the extra wires to reach the battery 'at the far end' so to speak, there could be significant voltage drop. Thus that battery doesn't get completely charged. Likewise the inverter draw produces the opposite effect and can never make full use of the battery at the charge controller end. With a "two battery system" it is recommended that the CC & inverter have their respective (+) and (-) connections at diagonally opposite terminals in order to 'even out' the current flow to/from each battery. With more than two batteries take this gets a bit tricky.

For your system you want equal length, equal sized (large enough to handle full current) wires from each battery meeting at a common connection point for both the charge controller and inverter. This way the wire lengths, and thus resistance, is equal to/from each battery.

It may not sound like much, but it adds up. Especially on a 12V system every Ohm counts. How large are your battery wires?

I should add that the full effect of this problem does not show up right away; it takes time for the batteries to become unevenly charged - and begin to sulphate, thus loosing capacity. Have you ever done an equalization charge?

boB

Re: Outback FX shutdown...

siyotanka wrote: »

A point waas raised I did not think about...

I have my CC connected into one end of the battery array, and the FX at the other end of the bank. Could this be causing me the problems? Should I have BOTH FX & CC connected at the same end?

I was going to say, seeing 13.5 Volts, usually means that there is some kind of charger online, probably sitting in the Float stage.

It could be that this 13.5 Volts you measure is coming from that CC when there is little or now loads and the battery itself is not charged... And the CC cannot supply your loads through the inverter. i.e. a false 13.5 V source reading.

I'd use a decent DC voltmeter and check the inverter battery terminals while running a load.

boB

Cariboocoot

Re: Outback FX shutdown...

siyotanka wrote: »

Bill:

When I start the system the FX does run...it then stops and displays Low Battery voltage. Again, running manual VDC measurements it show all batts and bank at or above 12VDC. I measured the CC connect points, PV+/- (20VDC) from panels. Output from CC to battery bank (10.5 VDC)

Is this output to bank low? I would think it should be at or above the nominal rating for the type batt used...??

10.5V is the standard "shut down" voltage for 12V inverters. How much current is the CC putting out under full sun?

boB

Re: Outback FX shutdown...

boB wrote: »

I was going to say, seeing 13.5 Volts, usually means that there is some kind of charger online, probably sitting in the Float stage.

It could be that this 13.5 Volts you measure is coming from that CC when there is little or now loads and the battery itself is not charged... And the CC cannot supply your loads through the inverter. i.e. a false 13.5 V source reading.

I'd use a decent DC voltmeter and check the inverter battery terminals while running a load.

boB

Of course, as soon as you try this, your CC wll be able to supply the load and everything will look great ! (or your battery will be charged.)

Second thought... Disable your CC and THEN measure the DC Voltage.
If the battery is bad, that voltage may drop in a few minutes.

boB

BB.

Re: Outback FX shutdown...

siyotanka wrote: »

Bill:

When I start the system the FX does run...it then stops and displays Low Battery voltage. Again, running manual VDC measurements it show all batts and bank at or above 12VDC. I measured the CC connect points, PV+/- (20VDC) from panels. Output from CC to battery bank (10.5 VDC)

Is this output to bank low? I would think it should be at or above the nominal rating for the type batt used...??

Can you clarify:

1. Are you measuring 10.5 volts wiht our meter or asking me about 10.5 volts
2. Get a good hydrometer and measure the specific gravity of each cell (you should write this down--you can use it over time to identify charging/battery problems). It is possible that you have one shorted cell that takes the rest of the bank down once the charge current is removed (one reason I don't like lots of batteries in parallel--a common failure can take the rest of the bank down).
3. Unhook a solar panel lead (or wait for dark). Measure the battery bank voltage. Put a smallish load on the inverter and measure the bank voltage again (watch it over 10 minutes or so).... If the bank is good, the voltage at the battery should stay above 12.5 volts. If it goes below 12 volts (with a light load)--your batteries are undercharged (recharge them) and/or sulfated (turning to junk).
4. What are the loads on your inverter (10 watts, 100 watts, 1,000 watts)?
5. What is the size (awg, diameter of the copper, etc.) that you are using for wiring.
6. With the inverter running--What is the voltage on one of the batteries. And what is the voltage on inverter terminals (under same conditions).

Something is not correct... You may have undersized wire, old batteries, undercharged batteries (which can cause early life failure) or some other issue.

The battery is the "heart" of your system. Everything else hangs off them. If the batteries are good (around 12 volts under a good sized load)--then your problem is in the wiring or the device(s). If the batteries are under 12 volts (after a "full charge")--then as you describe your setup--then one or more of the batteries are failing and/or you have a wiring problem somewhere.

It is possible that the batteries died because of storage/age... Or they are not getting charged, or they are chronically undercharged (deficit charging).

There is the symptom (failing batteries) and then there is the cause (too little charging, too much loading, wiring or device issues, etc.).

-Bill

crewzer

Re: Outback FX shutdown...

6 deep cycle marine batts = 12 VDC, 200 AH@, Outback Inverter 12VDC,

A heavy load on a small- or marginal battery bank can cause the battery voltage to drop briefly but sharply (the "coup de fouet"). This momentary low voltage condition may be causing the inverter to shut down.

What brand and model batteries, and what are the loads on the inverter?

HTH,
Jim / crewzer

tallgirl

Re: Outback FX shutdown...

crewzer wrote: »

A heavy load on a small- or marginal battery bank can cause the battery voltage to drop briefly but sharply (the "coup de fouet"). This momentary low voltage condition may be causing the inverter to shut down.

What brand and model batteries, and what are the loads on the inverter?

HTH,
Jim / crewzer

And while we're at it, cable size from batteries to inverters. At 12VDC, the current is going to be pretty high and Vdrop on those cables ain't helping.