I have two ReadyNAS NV+ in two different locations (home and summerhouse) and they are both supported by two "APC Back-UPS CS 500 (BK500EI)".
Instead of just replacing the old batteries I've been recommended by APC to "trade in" both my BK500EI to the "APC Smart-UPS SC 420VA 230V (SC420I)". It's a cost difference of about €160, for 2 units, from just replacing the batteries (2 x €40 vs 2 x €120).
Anybody know if the SC420I UPS is supported by the ReadyNAS NV+ or not? Anybody know if the SC420I UPS is supported at all by any ReadyNAS unit?
An alternative to the SC420I is the "APC Power-Saving Back-UPS Pro 550 (BR550GI)" which it seems is working, according to other posts on this list, but is slightly more expensive (an extra €10 per unit).
Have you considered seeing if you can find suitable batteries from other sources. There happens to be a battery supply store near me that stocks suitable batteries for my older APC units. When I bought two of my current units some four years ago, it was cheaper buying new units that getting new batteries from APC. (I bought the units at a discount store).
As to the specific units mentioned, I have no personal experience as mine are two 750 watt units (1250VA) and an 865 watt unit (1500VA) unit.
