Charging option?

ampie

I've got a DC coupled XW 6048 with a MPPT 60 150 charge controller. Do I enable charging on both the Inverter and charge controller or just on one?
Thanks for the help :-)

vtmaps

Tell us more about your system... Do you have grid power?  --vtMaps

Dave Angelini

Just on the mppt-60 if you use solar only. If you have a generator/grid you can enable charging on the inverter/charger. It really does not matter if they are both enabled but the solar needs the mppt enabled.

BB.

It also depends on the battery bank size/type too... More or less, for a standard flooded cell battery, you have concerns if the rate of charge is >~13% (based on the battery's 20 Hour Rating)... For a deeply cycled battery that is charged with higher current, the battery can get hot/over heat. Also, hot batteries have lower charging voltage requirements--Very hot batteries can look "under charged" to a charge controller (and get even more charging current/time and hit thermal runaway).

Higher end solar charge controllers (and inverter-chargers) have remote battery temperature sensors (optional for most). For systems with >13% rate of charge (and systems in non-climate controlled conditions), remote temperature sensors will help prevent thermal runaway and help ensure proper charging voltage.

For systems with RBTS--20 to 25% rate of charge is not uncommon.

Also--Note that if you are equalizing your flooded cell lead acid battery bank(s)--5% rate of charge maximum is typical recommendation (and can still easily overheat a battery bank--monitor temperatures during equalization to make sure all is OK). It is even possible to overheat a lead acid battery with >2% continuous rate of charge (AC charger plugged into wall, 24x7 genset, etc.).

Also, keep an eye on water usage--If you are replacing water every 2-3 months, probably you are charging "OK". if you have to replace water every month or less, perhaps too high of charging voltage. Never add water, probably not enough charging voltage (note, there are lead acid battery types that do use less water).

Other battery types (AGM, VRLA) and chemistries (various Li Ion), have their own requirements/cautions.

The details do matter.

-Bill

new2PV

You can do  both but its best to use one.  If your trying to charge with xW charger enabled with the sun up, it will use more power from the grid /generatopr over the power from the sun defeating the purpose of the charge controller.

Dave Angelini

If the voltage setpoint of the solar is a few tenths of a volt higher that the xw charger, the battery will take all the power from the solar and supplement with the generator or grid to get to the set-point of the solar.
 If it gets to the setpoint it will reduce the load from the gen/grid. Almost all makes do this by the way.  Some other grid parameters may interfere but generator settings will always back-off if set correctly.

new2PV

Not sure if I had the xw charger set points higher than the mppt set points, but, I did not have good results.

Dave Angelini

That is not what I am saying BTW. It is the opposite if you read my post. I love the internet.....

new2PV

If i had the xw charger voltage higher then the solar, then it would be the cause of the grid being favoured? I have only tried this once so please bear with me.

BB.

Yes--That is correct. The charging system/method "with the highest voltage, wins". You want the solar charger to have a bit higher voltage than generator/grid charging so that is what supplies most of the power.

With complex systems (like the XW)--They have different modes of operation--So you have to really study the manual (and ask questions here and of the Mfg.) to program them "correctly".

-Bill "not an expert" B.

new2PV

Thanks for the explanation.