Overton sayes,
“Avoid The Senseless Death Of Your Boat Battery With PriorityStart® When you've accidentally left on accessories or had a power draining short circuit, PriorityStart® saves the day. This automatic computerized on/off switching system monitors your battery level and disconnects the battery when voltage drains below 11.9 volts. When you're ready to start the boat, PriorityStart® automatically reconnects the battery when the ignition key, running lights, or other electrical device is turned on. Handles 1000 starting amps. Installs in minutes with three easy steps”
The description of the Battery Protector in Overton’s, does not jive with accepted battery science. A battery voltage of 11.9 volts indicates that the battery is discharged. A tutorial of batteries characteristics can be viewed at:
http://www.batterystuff.com/tutorial_battery.html and at
http://www.marine-electronics.net/te..._faq/b_faq.htm
As a reference the following table provides state of charge vs. voltage.
100% 12.7
75% 12.4
50% 12.2
25% 12.0
0% 11.9
An alternative scheme is;
A dual battery connected via a selectable battery switch,
http://www.perko.com/Perko%20Catalog/105-120/lfbbs.pdf or similar, and a means of charging the second battery using a battery combiner
http://www.yandina.com/acrobats/C70Manual.pdf would be a way that provides engine starting.
If the primary battery is dead due to electrical load that is left on, then switch the dual battery switch to battery # 2,
which is fully charged, and start the motor. While on you way to your destination, the battery combiner will charge the primary battery. The two battery scheme give you a fully charge battery all the time and especially in time of crisis.