Xantrex MPPT Charge controllers

[maple flats]

AS mentioned in a couple of other threads, I have an XW6048 inverter (6000 watts continuous/120/240V), grid tied, with battery backup. I currently have an Outback FX80 CC and I just tried looking up a Xantrex CC so the CC and inverter can communicate with each other. Since the battery backup portion of my 6.32 KW array is only 1480 watts worth (The rest is grid tied only using a Fronius 5000 watt inverter), I don't need as large a CC as I originally planned. I seem to only find 60 and 80 AMP MPPT charge controllers by Xantrex. Does Xantrex make any smaller charge controllers that are MPPT? If yes, please give a model number and/or source. It seems I'd only need a 30A CC. My system is on a 48V battery bank.
Thanks,
Dave

[Sunking]

Sorry Flats but most CC made for 48 volts are going to be 45, 60, and 80 amps. At least any worth having.

[Mike90250]

... I seem to only find 60 and 80 AMP MPPT charge controllers by Xantrex. Does Xantrex make any smaller charge controllers that are MPPT? .....

Nope, that's it. Midnight Solar makes the Classic, which is quite nice.

[maple flats]

Nope, that's it. Midnight Solar makes the Classic, which is quite nice.

It's my understanding that I need a Xantrex if it is to communicate with the Xantrex inverter. Otherwise I'll have the same issue I'm trying to get away from. I guess I'll be ordering a Xantrex 60A MPPT CC.

[Mike90250]

I'm not sure why you need the controller to communicate with the inverter. And to do that with Xantrex, you will need a SCP (SystemControlPanel) if you don't have one already.

What is the purpose to have the charge controller talk to the inverter ? About all they can share is the BTS, and maybe turn off the AC1 charger in the inverter, if the PV charger is working.

[maple flats]

They need to talk to each other for maximum battery life. As it stands now, My batteries are charged only to float charge and then they start selling to he grid. I do have a system control panel, but with the Outback CC it can not communicate with the SCP nor the inverter to hold 100% battery charge before going to sell mode. Today, I ordered a Xantrex 60A MPPT CC for system maximizing potential. The only other way would have been to dis able the sell function when the batteries got to 100% so the batteries could be at 100% when needed. I do not want to shut off the sell function on the XW6048 inverter.

[Sunking]

Flats wait a minute here partner. The batteries are never used in a hybrid system unless there is a power outage. They are also never charged via solar unless the commercial power is out, the batteries are charged with the inverter built in charger to charge the battery from the grid or optional generator. You might want to rethink things. If you have a generator, then you do not need a charge controller.

Flats have I ever lied to you in the past 4 years?

[Mike90250]

They need to talk to each other for maximum battery life.

Whoa, I think someone is pulling a fast one on you.

As it stands now, My batteries are charged only to float charge and then they start selling to he grid......

Sounds about right. Doing anything else will either overcharge the batteries, or needlessly cycle them. Who is your vendor/installer. This all should have been covered with your initial install.

How much solar PV is in your battery system ?

[maple flats]

Schneider electric is the one who said I needed a Xantrex CC. They told my installer how to make it function with the equipment I have (at my request), but the Schneider Tech. said that the batteries will be not ever fully charged if I continue to use the Outback FX80. My original system now runs thru the FX80 CC, to the batteries and then to the XW6048 inverter. The inverter then has a grid connection which goes to the main entrance panel. I no longer have a generator in the system and will not tie that back in unless I experience a long power outage.
Are you telling me that the Schneider Tech. gave me bad info? Since the only connections from that 1480 watt array to the inverter and then the grid must pass thru the battery bank, how can it not charge the batteries? Where is the error? How can the array not charge the batteries with this configuration? Initially, after the rest of my system was installed I was never getting anything from this 1480 watt array feeding to the grid, that array was just charging the batteries and then tapering way down.. The Schneider tech walked my installer thru the process (My installer has several years experience but had never used an Xantrex inverter but said the batteries would not get fully charged without a communication cable from a Xantrex CC to the inverter. He said without that the inverter had to be programmed to sell at a lower voltage, but when I got an Xantrex CC I could keep the batteries fully charged and still sell to the grid. Who is right? I listened on speaker phone while he was talking to my installer.

[Naptown]

I was having a conversation with a potential customer who knows the folks who started Outback.
they started producing their controllers out in back of the xantrex factory. Hence the name Outback
The FX prefix on their charge controllers actually stands for F*** Xantrex.
Not a lot of info for the thread but I thought funny.

[inetdog]

He said without that the inverter had to be programmed to sell at a lower voltage, but when I got an Xantrex CC I could keep the batteries fully charged and still sell to the grid. Who is right? I listened on speaker phone while he was talking to my installer.

Everybody is wrong. That simplifies things.

1. Since neither the Xantrex nor the Outback read the battery current from a shunt, each one will only know about the current that it is producing/consuming and about the common voltage.
2. For a pure off-grid inverter, this is not a problem, since the CC will just set whatever voltages it needs to charge the batteries and the inverter will take whatever it needs to service the loads.
3. But when the inverter has a sell option, it will try to sell whenever the battery voltage goes above a configured value, while the CC will be trying to set a variety of voltages during different stages of charge, and also cutting back on the current it provides to make that happen.
4. If you set the sell voltage low, the CC will never be allowed to get the voltage high enough for its purposes.
If you set the sell voltage too high (above the Float value), the inverter will never get a chance to sell anything because the CC will stop supplying power before the inverter is ready to sell.

PS: Since the Absorb voltage is higher than the Float voltage, you would potentially have to set sell above Absorb too to get proper charging.

5. If they talk to each other, they can coordinate that. For example the CC can tell the inverter not to sell yet because it is still charging. And the Inverter can tell the CC to put out all the current it can because the Inverter will sell any extra and not let the batteries overcharge.

You can get the Xantrex and the Outback to play tolerably well together, but they will never be best of friends and you will have to choose between manually turning off sell from time to time (or always) to allow the batteries to charge fully, or else accept less than fully charged batteries.

[maple flats]

Thanks, I needed that!!
Dave

[Sunking]

Are you telling me that the Schneider Tech. gave me bad info?

No Sir I am telling you no one has a clear picture of what you want to do. Everyone is guessing based on what little info they have. The challenge is there are a dozen different ways to configure a Hybrid System. The Schneider Tech i sjust picking one of a dozen flavor and hopes it fits.

Since the only connections from that 1480 watt array to the inverter and then the grid must pass thru the battery bank, how can it not charge the batteries? .[/QUOTE]

Very simple, water flows down hill just like power from the higher source to the lower source. Everything has to balance and equal ZERO.

For example let's start with the conditions that will present 99.9% of the time. Batteries are fully charged and will not require any power except a float charge each day which consumes a few watt hours each day, say 10 to 20 watt hours to overcome self discharge. It is insignificant and can be ignored. Basically the batteries are just sitting there doing absolutely nothing except cost you money replacing them every few years. The batteries are only used when and if commercial power fails. Otherwise they sit there and collect dust and use no power.

OK that leaves you with two power sources;

• Grid.
• Solar.

1. When your farm demands more power than the panels can produce, you are buying from the grid.
2. When your panels generate more power than the farm is using, you are selling power to the grid.
3. Batteries are not doing squat 99.9% of the time under normal operating conditions. The do not supply or use any power. They just cost you money and collect dust 99.9% of the time.

Now when and if commercial power fails, the batteries come on line and do something. What that something is depends on your remaining 11 of 12 options which no one knows about and are guessing.

My option when commercial power fails if I was in your shoes would be just like a hybrid electric car with solar. Use the panels to provide as much power as they can, and have a good generator to make up the rest until commercial power is restored. In other words when power fails, size the batteries just long enough to carry the load for a few hours. If the panels cannot keep up, the generator comes on and supplies the load and recharges the batteries back up. When the batteries are charged up, the generator turns off and the cycle repeats itself until commercial power is restored.

Have I mislead you in 4 years?

[inetdog]

Thanks, I needed that!!
Dave

I am including myself in that too, of course.

[Mike90250]

1) your installer needs to verify your XW inverter has the latest firmware. He will need the special Xantrex Iplanter to download the firmware. Xantrex has these for loan to dealers.
Repeat for the MPPT controller. Both boxes need the LATEST firmware to work best together.
May as well get the updates for the SCP too, while the Implant tool is there

2) read the XW manuals, there are many sections and options. The Sell settings are very complex and interdependent, as Sunking says, there are many ways to skin this cat.

3) Get the manual for your batteries, you need to come up with a setpoint to be able to keep the batteries in float, and use surplus power to sell to grid. Set too low, you sulfate your batteries, too high, and they boil the electrolyte away. you will need a well calibrated meter to set this to a hundredth of a volt. It's that critical, don't rely on the skanky $9 meter in the bed of the truck to be accurate enough to risk your $5,000 battery bank.

4) understand how to hook up your 240VAC generator to AC2, as you will eventually need it in case of
a grid failure. Do you have the XW autostart module, or will you manually start ?

Having the XW MPPT charger only simplifies this configuration process a tiny bit, by the time you understand all the nuances to get it to work with XW & XW, you can get it to work with XW and any charger. AND you need the Battery Temperature Sensor too (BTS) !

It's not rocket science, I've updated my SCP and inverter myself, but you have to know what you are doing. Few dealers understand this stuff enough for me to think this will go smoothly.