UPS12-540MR and Xantrex XW MPPT-60-150 setup

Hi j s,

OK, from the title of this thread, it appears that you are planning on using a battery bank that is composed of six strings of two of these batteries, which appear to be about 150 - 160 AH SLA batteries. So you would have about 930 AH nominal battery Capacity.

These appear to be a common UPS battery, from the search results ...

However, you should try to find exact charge specifications from the manufacturer of the battery.

It seems most likely that these SLAs are probably Gel type batteries, So, there might well be a limitation on the Maximum charge current into any/all strings of batteries.

The programming of your MPPT Charge Controller (CC) will depend upon the exact information that you receive from the battery manufacturer.

As an aside, I did search for your previous posts, but of the six that you are noted as having made, only this one was visible -- it is often helpful to try to find out more about what you are trying to do, either from a Signature line, and/or from previous posts, BUT, due to the sporty Upgrade to the Forum software, we are quite limited in what we can see in historic posts, images, and many other things ... OH, think that we are don ragging on Vbulletin software ... sorry ...

So, guess that this is a backup power system, that runs and charges from the grid, when it is available, OR Solar, but runs a UPS when needed ... or ... just what is it that you are doing?

Thanks, VIc

Hi just starting,

Thanks for the added information on your system.

These batteries may well be an Industry Standard design, and therefore, charge info may be fairly consistent from one battery to the next ...
BUT, please try contacting the manufacturer of your exact batteries to get information on:

Maximum charge current per battery string
Absorption voltage for daily cyclical charge
Suggested method to end daily Absorption stage (Ending Current ? Max time, etc)
Float voltage for daily charging
Temperature coefficient of battery voltage

Did not see a reference to the Charge Controller (CC) that you are using with the PV modules.
Please tell us what CC you are using.

With Sealed batteries, it is very, very important to use a Remote Temperature Sensor (RTS or BTS) on all charge sources, and also find out the correct battery voltage temperature coefficient to set into the CC and perhaps Inverter/charger to compensate the charge/Float voltages for changes in battery temperature. These Sealed batteries are VERY sensitive to Maximum charge voltage, as well as correct charge/Float voltages for proper charging.

One other important thing, is that with the many parallel battery strings that you are using, monitoring how well each string is sharing charge and discharge currents is very important. A DC Clamp Ammeter will help you monitor this current sharing, and help you know when to try to rebalance the strings to get sharing current where it needs to be.

More Later, Thanks, Vic