The battery monitor is a very useful tool for a boat-owner who has to survive on battery power. When properly installed, calibrated and monitored they can extend the life of a battery bank especially when used smartly.
With new battery technologies costing three to ten times what wet cell technology does and many boaters moving to newer technologies such as Gel, AGM, TPPL and LiIon accurate monitoring of an expensive bank is almost a prerequisite.
People often ask me questions about how to install a battery monitor so I took some time and tried to make it simple. They are actually easy to install but there are a couple of "gotcha" traps that you may find your self falling victim to.
There are a fair number of monitors on the market. Blue Seas, Xantrex, BEP, Victron, NASA and a few others make them. Currently the Victron units are the easiest to install and also the least expensive making them a good value. A Victron BMV-600S single bank monitor can be purchased right here for $184.25. Buy A Battery Monitor (LINK)I chose to do this article with the Victron BMV-602S.
I currently use a Xantrex Link-Pro on my own boat but they all do basically the same thing. The Victron however is a significantly better deal than the Xantrex..