Hi jtwrace,
Good question!
There are two separate items - the SLA battery charger (external to our products), and the Red Wine Audio SMART board (internal to our products):
-- The battery charger is an SLA, 2-stage charger (Bulk charge, and float charge). It can be left plugged into the product indefinitely, as the float charge (or "trickle charge"). This is something you can buy off the shelf (not designed or built by Red Wine Audio).
-- The Red Wine Audio SMART board is a circuit board that we install in our components. Our new SMART board can be configured for our 12V and 24 products (and we also have a larger one that can do 3 or 4 batteries for 36V or 48V). The SMART board continuously monitors the battery voltage, and if it falls to low, it automatically switches off the unit and beings the charge process (so you will never accidentally deep-cycle your SLA battery or batteries, and don't have to monitor their voltage). You can keep the charger plugged in at all times, but when the unit turns ON, the SMART board internally disconnects both the positive and negative leads of the charger from the battery (so the unit completely runs on battery and is isolated), and when the unit turns OFF, the SMART board removes battery power from the (the circuitry of the audio component) and automatically connects the battery to the charger. Besides that, our new SMART board has in-rush current limiting, high-current latching relays, and when ON or OFF, it consumes negligible power from the battery. It's "brain" is a PIC micro-controller with our own firmware that we flash program into here at the factory.
However - we do not sell this SMART board for the DIY community....
All the best,
Vinnie