The 10 Best Boat Battery Switches
This wiki has been updated 6 times since it was first published in October of 2019. Not only do battery switches increase the overall safety and reliability of any boat's electrical system, but they can also help protect against common problems, like self-draining circuits and accidental discharges. Our list ranges from simple on-off switches to more complex 4-switch models, but regardless of which you choose, always take proper precautions when dealing with high voltages. When users buy our independently chosen editorial selections, we may earn commissions to help fund the Wiki.
April 09, 2020:
Adding a battery switch to your boat's electrical system is an inexpensive way to improve it significantly. The two main benefits of adding a switch are that it can help prevent self-discharge, if you leave your boat unattended for a few months for example, and also grants enhanced control over which battery your boat is using during different stages of operation.
Most of the items on our list are 4-position, meaning that they provide options for disconnection, running on either of 2 battery banks, or using both power-sources simultaneously. A typical usage of this kind of switch would be to select a cranking battery that's good at delivering a quick surge of power while starting your engine, but utilizing a separate deep-cycle battery when using electronic equipment like stereos or televisions with the engine off. While the option to sum both batteries' power is passed while switching, this mode is typically only used in an emergency situation wherein each separate battery doesn't have enough juice to start your engine. The best all-around 4-position switches on our list are the Blue Sea Systems E-Series, Blue Sea Systems m-Series, and Perko 8511. It's hard to go wrong with any of these options, since they all provide a switch made from quality materials and amperage and voltage ratings that will be perfectly adequate for most people's needs. If one has a system that requires a particularly large amount of power however, such as a large yacht or a huge twin-engine setup, they should take a look at the slightly more expensive Blue Sea Systems HD-Series, which offers a super robust maximum amperage rating in a similar form factor as the aforementioned models.
Though they are slightly less popular, there are several manufacturers that make more affordable 4-position switches that will still be great solutions for many people. Models such as the Guest Battery Switch, Lotfancy Master Cutoff, and Attwood Marine Selector are very functional despite their low prices, but it is true that they generally have lower maximum amperage ratings and slightly lesser build quality than higher end models.
People who have a simpler electrical system on their boat might be using a single hybrid battery, but just because they don't have a need to switch between 2 battery banks doesn't mean a switch won't benefit them. Choices like the Perko 9601 are great because they bring all the quality of robust 4-position models to a disconnect switch, but more generic options like the inexpensive Zoostliss Kill Switch will work equally well for preventing long-term battery drain on small motorboats.
The more unique options on our list are the Blue Sea Systems m-Series and the Perko 8502. The former is an interesting variant that allows the simultaneous activation of 2 totally isolated battery systems, allowing your engine to run on only your cranking battery and your appliances to run on the house battery at all times. It's similar to using a separate switch on each circuit, however its emergency "combine batteries" mode allows for both batteries to be used for all loads simultaneously, similar to the "1+2" position on a 4-way switch. It is thought that all switches can help secure your boat if they are well hidden, but the aforementioned Perko actually features a keyed lock to further deter thieves. It's one of the few locking options that features a typical lock rather than a plastic key with just one notch, and even though it wouldn't be the hardest thing in the world for a determined thief to bypass it still makes your boat a more troublesome target, which might make all the difference in a real-life situation. Both of these are great choices, but it should be noted that several variations of each are available, such as a 4-position m-Series or a non-locking Perko 8502.
Battery switches enhance the safety, reliability, and utility of your boat's electrical system, but always be careful when installing them and dealing with high current and voltage. For more information on the best components available for your boat, check out our articles on items like batteries, chargers, and trolling motors.