For solar experts

[motion30]

I recently increase the size of my solar array and I added an Outback fm80 to the existing FM 60, 2 solar panels feeding each controller going to a single battery Bank.. these controllers are not playing nice together, under bulk they seem to be putting out similar wattage but once they go into absorption setting One controller goes in float mode and the other controller is outputting all the power. I have searched the internet but I have read conflicting information. So my question is exactly what do I need to make these two controllers play nice together

[sailorboy1]

Would need to get both controllers calibrated perfectly to be together. That’s impossible.

So what’s really important is just to realize that if one controller is in absorption it is putting into the batteries all they can accept. The controller that is putting out less senses the other controller is doing this and sees it isn’t needed.

I don’t feel you have a problem at all.

[FlyingScot]

It sounds like you are running into a battery chemistry problem. I don't think you mentioned size of panels, size and type of battery bank. How many amps are going in the batteries when it is only one controller feeding it (ie the other is in float)?

But as SB1 says, it sounds like one charger is giving enough amps to exceed the CAR of your battery bank under those conditions (SOC, temp, etc).

[motion30]

Chris
I installed 4 panels of 435 watts each i have 1290 anp hr of batteries. I think the one controller was out putting about 45 amps. And the second controller was putting out almost nothing 11 or 12 amps. I understand out that makes an mate that can synchronize the charge controllers but I am unclear which one and if their hub is also required

[FlyingScot]

What type of batteries do you have? Is your house bank 12v?
If you disable one of the controllers does the other immediately start putting out more?
I see no harm in one pair doing more work than the other pair.
Per this: http://www.outbackpower.com/download.../specsheet.pdf
You are exceeding the recommended panel wattage for the 60 amp model. They recommend 750w as max.
Is it always the same controller that puts out more in absorption?
What settings do you have programmed into the controllers? Are both 100% the same?

[motion30]

6volt gc la batteries. I've already had this system up and running for two days so I not know everything yet. the first full day I generated 4.4 kilowatts. Today the 60 amp controller went into float which seemed premature to me
I previously had four 275 watt panels charging through the 60 amp charger.. in the summer time I have Peak amps from that controller exceeding 65 amps.

[FlyingScot]

You have a lot of work ahead of you. You need to figure out what settings everything is using to charge (bulk/absorb/float). This is determined by your battery mfg. They should list it, if not you'll need to make an educated guess. You'll need to setup both controllers the same. Having 6v golf cart lead acid batteries doesn't dictate your house battery bank voltage other than it having to be a multiple of 6v. You likely have a 12v or 24v system. Your charge settings will be based upon battery type and house battery voltage.

You could be ruining your batteries right now, or not, it seems neither of us know this yet.

Before you had 275w x 4 = approximately 75-80 amps (@ nominal 12v). Meaning your 60 amp charger was working it's maximum and clipping off the excess at the top. Meaning it was lost forever and not used to charge your house bank.
Now you have 435w x 2 = 60-65 amps. Likely no clipping but I prefer to not run stuff at 100%.

If the sun is shining bright, you battery bank may not be able to take 130 amps (This being the sum of all 4 panels and both controllers). This is dependent on charge voltage setting, battery State of Charge (SOC) as well as the battery temperature. Higher voltage would permit higher amps into the battery but too high risks boiling your batteries. You should be running temperature compensation to account for the change in temperature.

[motion30]

Chris
With the previous 275 watt panels in good sun. I have seen peaks of 65 amps, but sustained charging Hoveround 55 amps. That system was fine in the summer here in South Florida, but did not quite meet my needs in the winter time. The first day with this new system I saw a peak of 100 amps and sustain charging of 80amps. I am charging within the parameters of the battery manufacturer. 14.8v absorption and 13.5 V float. My goal now is to divert some of the charge to make hot water

[FlyingScot]

I use excess solar to heat water. There are threads that discuss this. I did it using the existing inverter and swapping to a 375 watt @ 110vac (1500 watt @ 220v) heating element. It takes 3-4 hours to reach 140F from 75-80F. I like warm showers...

My 1440w bank routinely makes between 4 and 6 kWh per day (make sure you use the hour).

[motion30]

Originally Posted by FlyingScot

I use excess solar to heat water. There are threads that discuss this. I did it using the existing inverter and swapping to a 375 watt @ 110vac (1500 watt @ 220v) heating element. It takes 3-4 hours to reach 140F from 75-80F. I like warm showers...

My 1440w bank routinely makes between 4 and 6 kWh per day (make sure you use the hour).

what kind of 12 volt amperage draw are you seeing through your inverter?

[FlyingScot]

Originally Posted by motion30

what kind of 12 volt amperage draw are you seeing through your inverter?

30-31 amps continuous out of my bank until it reaches temp. Then it would cycle off and on a handful of times overnight. I normally flip the switch off before it starts draining my bank late in the day. I tested it by leaving it on for 4 days straight.

My inverter is a modified sine wave unit which are more efficient at this type of load than the newer models.

[motion30]

Chris. 30 amps it's less than I expected and very doable.
Your 375 watt heating element is more or less than what was stock when your hot water heater?

[FlyingScot]

Originally Posted by motion30

Chris. 30 amps it's less than I expected and very doable.
Your 375 watt heating element is more or less than what was stock when your hot water heater?

My unit is a 110v 6 gallon hot water heater. 1500 watt.

I bought a 220v 1500 watt heating element which can also be called a 375 watt 110 volt element.

Takes 4 times longer but 1/4 the amps while doing it.

[motion30]

Chris
sounds like you have a large array. What panels do you have and what are you using for a charge controller?

[FlyingScot]

I have 4 LG Neon 360's. 1m x 1.6m in size per panel. Each wired to their own Victron 100/30 Smart Controller. Voltage dropped calculated between 2-2.5% from panels to controller and from controller to battery bus bars. My bank is 450 ah FF Oasis.