XW6048 Charger Settings

Re: XW6048 Charger Settings

Whatever "Enhanced grid support" software is, it must significantly change the functionality. Setting grid support at 64 vdc would seem to effectively turn off grid support so they must have done something in software to interact with another setting. This is the thing I hate about XW, software run amuck so you have a hard time figuring out what it is actually doing.

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from other thread

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Enhanced interactive mode This mode is suitable for Xantrex XW Systems with
only Xantrex XW Solar Charge Controller(s) networked to Xantrex XW Series
Inverter/Charger(s) through Xanbus. In this mode, Grid Supp Volts is set as
the charge controller’s Bulk and Absorb voltages (for example, 32 volts on a
24 volt system and 64 volts on a 48 volt system).
In enhanced interactive mode the Xantrex XW Series Inverter/Charger
automatically tracks the Xantrex XW Solar Charge Controller voltage as it
transitions through all charge states (from bulk to absorption to float). This allows
the Xantrex XW System to execute a full battery charge cycle while still
converting excess DC power to AC power to support the loads or export to the
utility grid. In doing so, the Xantrex XW Series Inverter/Charger only uses what is
not accepted by the battery to support local loads and sell to the grid, thereby
maximizing the use of the array. Since this mode allows the battery bank voltage
to reach absorption levels (when PV harvest is adequate), the state of health of
the battery is improved. The sell entry and regulation voltage level is 1 V below
absorption and float of Xantrex XW Solar Charge Controller set points. The sell
exit from sell is 1.5 V below absorption and float of Xantrex XW Solar Charge
Controller set point

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So it appears to be taking Grid Enable voltage setting from the XW charge controller setting. This effectively means if Grid support sell is enabled and charge controller is pushing out power, and batteries are at float (or absorb if CC in that mode) then XW inverter will take off excess power. It will shut down grid support regardless of grid support voltage setting if CC is not producing excess power (beyond battery charging needs). It seems the main change is it allows battery to go to absorb level where prior software did not.

The way it used to seem to work was:

1) Grid Support Enabled, Sell disable, Load Shave disabled. - Inverter will push power to ACout node if battery voltage goes above Grid Support voltage setting. There are other interactive conditions to this. Obviously if battery is going through its first and second phase of charging it won't be pushing power out. Being that Sell is not enabled, any pushed power to ACout node must be consumed by ACout load. No power will be allowed to go back up AC1in port. If ACout load cannot consume the pushed power then the battery voltage will be allowed to rise. Presumably the PV controller will take over the regulation and prevent battery voltage from continue rising.

2) Grid Support Enabled, Sell disabled, Load Shave enabled. - Exactly like above with the difference being inverter will be allowed to push power at lower battery voltage, down to 2 volts above LBCO setting. It will push power to ACout as needed to suppliment need based on limit placed on ACin current (through breaker amps setting @ 80% setting level) to provide load shaving limiting current on ACin.

3) Grid Support Enabled, Sell Enabled, Load Shave Disabled. - Just like like 1) with allowance of any excess pushed power (beyond consumed by ACout load) to exit out AC1in port to grid. Range of battery voltage is active at Grid Support voltage, deactivate at Grid Support voltage - 0.5 vdc.

There are voltage and current senses on AC1in, AC2in, Inverter out, and ACout to manage the power flow directions.

Re: XW6048 Charger Settings

Upgrading the firmware entails risk and should only be done to get a new needed feature or fix an old problem. I would not just do it because I could.

That being said, The enhanced interactive mode is the best way to run a grid tied system. I operate mine in Enhanced mode, sell disabled, load shave enabled while the sun is shining. This mode will always keep the batteries near 100% which is a good thing. At night it will go into AC passthrough and use the grid if available

During the day, when the SCC enters float mode, the XW inverter will suck only the excess power off to run the AC loads and throttle back the PV to maintain that load. Here is where a dump load comes in, By adding a dump load, the SCC will load the panels and put the excess into heat (for DHW). Without the dump load, you will be wasting PV watts in enhanced mode.

But if you choose to not use the enhance mode, then the grid support will be draining your batteries at night and recharging them during PV production. The cycling will use your batteries life up faster than keeping them at 100% so you have to make a decision on how you want to run your system.

Re: XW6048 Charger Settings

You should probably upgrade the software since you are using an XW charger controller with Xbus link to XW inverter. If you where using a non-Xantrex charger controller then the upgrade would do nothing for you. I think without it the XW inverter will not let the PV charge controller take the battery above grid support voltage setting.

If you set grid support voltage to float level then batteries will never be allowed to go above float (unless grid goes down and XW inverter does full charge cycle when grid is restored).

If you set grid support voltage between float and absorb voltage then you will not havest PV power until PV charger gets the battery to the higher voltage level.

With the new software the XW inverter will takes its que to from charge controller. If charge controller is in bulk charge mode then XW inverter will not be allow to harvest until battery reaches 1v below absorb level. When PV charge controller drops to float voltage then XW inverter will harvest at 1 v below float level.

Question I have on this new software is will PV charge controller ever get out of bulk phase since XW inverter will cap battery voltage rise to absorb voltage -1 volt. You may have to set a timeout limit for PV charge controller to drop to float level. You don't want it to get hung up indefinately at bulk - 1v voltage on batteries.

Bulk phase used to mean constant current phase. There are chargers that allow a separate higher voltage limit trigger point during constant current bulk phase before the voltage is reduced to contant voltage absorb phase. This causes the constant bulk current to continue to run up to, say, an equilize voltage level before dropping back and entering the absorb constant voltage phase. It will shorten time spent in absorb phase.

AGM's absorbs charge pretty well so there is probably no reason to jack the final bulk phase voltage higher then 57.2 vdc normal absorb voltage. You also have to avoid too much gas creation at the higher voltage that can cause venting from the sealed battery.

Battery SOC will lag behind the cell voltage and this lag is greater the greater charging current. If your bulk current is 25% AH rating and absorb is set to terminate charge at 2% AH rating current then absorb phase contant voltage, tapering current , will last longer then if the battery was bulk current charged at 10% AH rating, which would spend more time in bulk phase.

The boosted Bulk voltage capability is good if you are charging from generator where you want to get the most SOC for the least amount of fuel and run time on generator. It is a little harder on the battery and probably should not be used for any sealed lead acid batteries which would include AGM's.

Re: XW6048 Charger Settings

Joe_B wrote: »

It handles it nicely, the XW will not enter grid support mode until the batteries reach float. Then it begins to invert and holds the battery at float-1 volt by drawing energy from the batteries to support loads.

This does not jive with the description:
"The sell entry and regulation voltage level is 1 V below
absorption and float of Xantrex XW Solar Charge Controller set points. The sell
exit from sell is 1.5 V below absorption and float of Xantrex XW Solar Charge
Controller set point ."

I guess what you say is true if the the XW inverter does not initiate the pull until the charge controller reports that it is done with its cycle first. You need CC to execute its timeout on absorb cycle if PV power never can get the battery to absorb voltage level or XW inverter would never initiate sell even with battery voltage holding at 56 volts. Of course for this condition you may not have much power to sell anyway.

Joe_B wrote: »

Yeah this is a big problem with the XW, no current shunt means that it is estimating S.O.C. from the voltage and the loads. I found that there is a slight stairstepping error that results in the system thinking that the battery is at 100% when in fact it is dangerously low. You need to really keep an eye on the S.G. and initiate a full charge cycle when it gets low. This essentially resysncs the battery monitoring software. I have to do this about once a month.

It would be nice to have an actual DC current shunt input but "calculated" is a better description then "estimate". It does the calculation based on knowing the AC power coming and going through inverter, with inverter efficiency factored in. Every AH current tracking monitor accumulates errors over time if the batteries are not allowed to be taken through full absorb cycle to reset the 100% capacity reference point.

Additional error comes into play because the current contribution by the charge controller is out of the inverter power in/out loop. An external current shunt directly inline with battery could capture the combined XW and Charge controller currents coming and going from battery.