Blue Sea Systems Battery Switches, Fuses & Relays
Blue Sea Systems makes the battery switches, fuse blocks and charging relays that marine electricians, van builders and RV owners use when a 12V or 24V system has to be dependable. Everything here is listed with its Blue Sea part number.
Which Blue Sea battery switch?
An on/off switch isolates one battery bank. A four-position switch (1, 2, both, off) lets you choose between two banks by hand. A Dual Circuit Plus switch keeps the engine and house circuits separate with one turn and can combine them in an emergency; paired with an automatic charging relay, as in the Add-A-Battery kits, both banks charge whenever a charging source is running. Size the switch for the continuous current of the circuit it carries. Related: battery isolators and combiners, fuses and circuit protection and Victron Energy.
What does an automatic charging relay do?
It connects two battery banks when it senses charging voltage, so both charge, and separates them when charging stops, so loads on one bank cannot drain the other.
Is Blue Sea only for boats?
No. The same switches, fuse blocks and relays are widely used in camper vans, RVs and off-road vehicles.
Which fuse block do I need?
Count your circuits and add spares, then decide whether you want a negative bus on the block. The ST blade fuse block here has 12 circuits and a negative bus.
What is the difference between the Blue Sea m-ACR, SI-ACR and ML-ACR?
Mostly the current they carry. The m-ACR (7601) is rated 65A, the SI-ACR (7610) 120A and the ML-ACR (7622) 500A. The 7622 is a 12V model with a manual control switch.
What comes in a Blue Sea Add-A-Battery kit?
A Dual Circuit Plus battery switch and an automatic charging relay. The 65A kit (7649) pairs the m-Series switch with the m-ACR, for charging systems up to 65 amps; the 120A kit (7650) pairs the e-Series switch with the SI-ACR, for charging systems up to 120 amps.
Does Blue Sea make a Class T fuse block?
Yes. The Class T fuse block with insulating cover (5502) takes 225 to 400A Class T fuses. The fuse is sold separately.
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