Boat Battery Isolators & Charging Relays

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Promariner Marine Battery Isolators, 1-2 Alternator, 2-3 Batteries, 70/130 Amp
Promariner Marine Battery Isolators, 1-2 Alternator, 2-3 Batteries, 70/130 Amp
Isolators allow one or more devices to charge multiple battery banks, allowing current to flow in only one direction, preventing batteries from …
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List price: $91.53
In stock

API Battery Isolators
API Battery Isolators
These automatic solid state devices allow you to connect your engine alternator directly to both batteries or multiples of batteries without fear of …
Starting at: $63.45
List price: $70.00
In stock

50/60A Fail Safe Galvanic Isolator - Guest (Marinco)
50/60A Fail Safe Galvanic Isolator - Guest (Marinco)
Product Features: Voltage Rating: 115/230VAC Passes necessary AC ground current for shore power safety Frequency Rating: 50/60Hz Current Rating: 50/ …
Your price: $331.05
In stock

ProMariner ProIsoCharge Battery Isolator 120Amp 1-Alt 3-Bat - 12V
ProIsoCharge Battery Isolator 120Amp, 1 Alt, 3 Bat, 12V - ProMariner
ProIsoCharge Series Model ProIsoCharge120 1•3™ Part No. 23124 System Volts DC 12 Max DC Amps 120 Amp Alternator Input 1 Battery Outputs …
Your price: $170.65
List price: $210.39
In stock

ProMariner ProIsoCharge Battery Isolator 120Amp 1-Alt 2-Bat - 12V
ProMariner ProIsoCharge Battery Isolator 120Amp 1-Alt 2-Bat - 12V
ProIsoCharge Series Model ProIsoCharge120 Amp, 1 Alt, 2 Battery Part No. 23121 System Volts DC 12 Max DC Amps 120 Amp Alternator Input 1 Battery …
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List price: $196.30
In stock

ProMariner ProIsoCharge Battery Isolator 130Amp 2-Alt 4-Bat - 12V
ProMariner ProIsoCharge Battery Isolator 130Amp 2-Alt 4-Bat - 12V
ProIsoCharge Series Model ProIsoCharge130 2•4 Part No. 23127 System Volts DC 12 Max DC Amps 130 Amp Alternator Input 2 Battery Outputs 4™ …
List price: $387.83
In stock

ProMariner ProIsoCharge Battery Isolator 250Amp 1-Alt 3-Bat - 12V
ProMariner ProIsoCharge Battery Isolator 250Amp 1-Alt 3-Bat - 12V
ProIsoCharge Series Model ProIsoCharge250 1•3 Part No. 23126 System Volts DC 12 Max DC Amps 250 Amp Alternator Input 1 Battery Outputs 3 Size 8. …
Your price: $250.45
List price: $308.86
In stock

ProMariner ProIsoCharge Battery Isolator 180Amp 1-Alt 2-Bat - 12V
ProIsoCharge Battery Isolator 180Amp, 1 Alt, 2 Bat, 12V - ProMariner
ProIsoCharge™ Series Model ProIsoCharge180 1•2 Part No. 23122 System Volts DC 12 Max DC Amps 180 Amp Alternator Input 1 Battery Outputs …
Your price: $181.85
List price: $224.29
In stock

ProMariner ProIsoCharge Battery Isolator 250Amp 1-Alt 2-Bat - 12V
ProIsoCharge Battery Isolator 250Amp, 1 Alt, 2 Bat, 12V - ProMariner
ProIsoCharge Series Model ProIsoCharge250 1•3 Part No. 23123 System Volts DC 12 Max DC Amps 250 Amp Alternator Input 1 Battery Outputs 2 Size …
List price: $254.34
In stock

160 Amp 1 Alternator 3 Bank Battery Isolator - Charles
160 Amp 1 Alternator 3 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $168.39
List price: $287.93
In stock

70 Amp 1 Alternator 2 Bank Battery Isolator - Charles
70 Amp 1 Alternator 2 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $99.89
List price: $162.71
In stock

70 Amp 2 Alternator 3 Bank Battery Isolator - Charles
70 Amp 2 Alternator 3 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $144.30
List price: $239.52
Out of stock

130 Amp 1 Alternator 2 Bank Battery Isolator - Charles
130 Amp 1 Alternator 2 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $216.53
List price: $265.78
In stock

190 Amp 1 Alternator 3 Bank Battery Isolator - Charles
190 Amp 1 Alternator 3 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $173.89
List price: $296.63
In stock

160 Amp 1 Alternator 2 Bank Battery Isolator - Charles
160 Amp 1 Alternator 2 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $258.39
List price: $317.16
In stock

70 Amp 1 Alternator 3 Bank Battery Isolator - Charles
70 Amp 1 Alternator 3 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $171.27
List price: $210.22
In stock

90 Amp 1 Alternator 2 Bank Battery Isolator - Charles
90 Amp 1 Alternator 2 Bank Battery Isolator - Charles
All Charles Battery Isolators are ignition protected and prevent over-charging. They feature a heat chamber design, protective boots on heavy-duty 5/ …
Your price: $102.99
List price: $177.31
In stock

60 AMP FAIL SAFE GALVANIC ISO - ProMariner
60 AMP FAIL SAFE GALVANIC ISO - ProMariner
Failsafe galvanic isolators interrupt galvanic current with other boats in your marina when installed on a boat which is connected to shore power. It …
Your price: $399.99
List price: $442.89
In stock

30 AMP FAIL SAFE GALVANIC ISO - ProMariner
30 AMP FAIL SAFE GALVANIC ISO - ProMariner
Failsafe galvanic isolators interrupt galvanic current with other boats in your marina when installed on a boat which is connected to shore power. It …
Your price: $299.99
List price: $332.69
In stock

Remote Battery Switches - ML-Remote Battery Switches -Blue Sea Systems
Remote Battery Switches - ML-Remote Battery Switches -Blue Sea Systems
500 Amp magnetic latching (bi-stable) switch provides high-amp switching under load, manually or from remote locations Manual override knob provides …
Starting at: $189.98
List price: $223.51
In stock

Blue Sea Systems Si-Series Automatic Charging Relay
Blue Sea Systems Si-Series Automatic Charging Relay
Automatically manages the charging of two battery banks and isolates batteries during starting to protect sensitive electronics. 120 Ampere …
Your price: $85.33
List price: $109.99
In stock

L-Series Solenoid Switch
L-Series Solenoid Switch
Hermetically sealed contacts, vaporproof. Ignition protected. Pulse circuit requires very low current draw when contact is closed. Input voltage: 9 …
Your price: $133.93
List price: $216.99
In stock

Mini Battery Switch & Auto Charging Relay 65 Amp - Blue Sea Systems
Mini Battery Switch & Auto Charging Relay 65 Amp - Blue Sea Systems
Simplifies switching and automates charging for a complete two battery bank solution for outboard powered boats. The Mini Add-A-Battery offers a …
Your price: $80.14
List price: $124.23
In stock

Battery Isolator (Pro Mariner)
Battery Isolator (Pro Mariner)
Rated for 70 amps maximum alternator. Operates on 6, 12, 24 & 32 volt negative ground systems. Electrical current able to flow from DC source …
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List price: $91.53
In stock

Heavy Duty Battery Isolator (Cole Hersee)
Heavy Duty Battery Isolator (Cole Hersee)
For 12-36 volt, DC negative ground electrical systems. Isolate each battery to prevent the battery with the higher charge from draining into the …
Your price: $73.69
List price: $99.49
In stock

Fail-Safe Galvanic Isolator (Marinco/Guest/Afi/Nicro/Bep)
Fail-Safe Galvanic Isolator - Mastervolt
Prevent galvanic corrosion between boats due to dissimilar metals. Gold plated terminals provide superior corrosion resistance for harsh environment …
Your price: $249.04
List price: $382.29
In stock

Iso-Guard Isolation Transformers (Charles Marine Products)
Iso-Guard Isolation Transformers (Charles Marine Products)
Designed to be a viable alternative to using a galvanic isolator with status monitor, as is now required by ABYC. Offers all of the benefits and …
Your price: $607.14
List price: $705.99
In stock

Automatic Charging Relay, 65A 12V - Blue Sea Systems
Automatic Charging Relay, 65A 12V - Blue Sea Systems
Automatically combines batteries during charging, isolates batteries when discharging or at rest. 65 Amp continuous rating manages the charging …
Your price: $62.25
List price: $73.24
In stock

Blue Sea 7620 ML-Series Automatic Charging Relay (Magnetic Latch) 12v DC - Blue Sea Systems
Blue Sea 7620 ML-Series Automatic Charging Relay (Magnetic Latch) 12v DC - Blue Sea Systems
7620 Manual Control: No Coil Voltage: 12V DC Combines battery banks during charging and isolates under discharge 300 Ampere continuous rating …
Your price: $219.35
List price: $257.95
In stock

Maretron DCR100-01 Direct Current Relay Module
Maretron DCR100-01 Direct Current Relay Module
Maretron's DCR100 contains 6 Direct Current (DC) relays, each capable of switching up to 10amps. The DCR100 connects directly to an NMEA 2000 network, …
Your price: $335.75
List price: $395.00
In stock

Automatic Charging Relay, 500A, 12V
Automatic Charging Relay, 500A, 12V
500 Amp magnetic latching (bi-stable) relay automatically combines batteries during charging and isolates batteries when discharging and when …
Your price: $232.37
List price: $274.71
In stock

Digital Duo Charg 12/24V - Balmar
Digital Duo Charg 12/24V - Balmar
The DDC-12/24 offers the smartest system yet for current and voltage controlled charging between the house and starting batteries eliminating the …
Your price: $253.57
List price: $324.00
In stock

37 results 1 of 2 pages
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Isolators How-To's

ACR

Selecting the Correct Automatic Charging Relay

When selecting a particular Automatic Charging Relay (ACR), there are many things to consider in order to get the correct system for your application. You will need to ... read more take into account the continuous rating and the intermittent rating. The continuous rating will need to reach levels above the highest alternator output rating, and the intermittent rating will need to be above the biggest load for the battery. You will then need to carefully consider which preset ACR settings to choose, followed by the product features.

Preset ACR Settings



Combine Voltage:
  • Batteries will share the present charge.
  • Voltage:13.0 at 2 minutes.
  • Closed relay and combined batteries.
Open Voltage:
  • No present charge; charge input loads will not exceed set limit.
  • Voltage: 12.75 at 30 seconds.
  • Batteries do not share the charge.
Under Voltage Lockout:
  • Charge may or may not be present.
  • Voltage: 9.5.
  • Batteries do not share the charge.

Product Features


Auxiliary Battery Priority (Optional):
  • Combines batteries and closed relays for extended length of time.
  • Open voltage ranging between 12.25 and 12.75 volts.
  • Engine must be running.
Start Isolation (Optional):
  • Batteries are isolated, and the relay is open.
  • Vulnerable products will be shielded by isolated batteries.
  • Engine must be starting.
Start Assist:
  • Closed relay, combined batteries.
  • Batteries share power.
  • Engine must be starting.
Engine Isolation:
  • One relay will be open, while the other will be closed.
  • Two engines must be running.

We do recommend consulting with a mechanic or technician in the process of choosing an ACR and its features.
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INfographic

Blue Sea Systems Tech Tip: Automatic Charging Relays Explained

Here you can learn about Automatic Charging Relays, Battery Isolators, and Zero Drop Isolators.
... read more Infographic: Automatic charging Relays Explained

Automatic Charging Relays allow two banks on a vessel's alternator to be charged simultaneously from one unit. Doing so, keeps the batteries isolated when not charging. This benefit is useful in the case of one battery failing and having another battery as an emergency back-up. There are a few main styles to choose between:

  • Automatic Charging Relays: Combined voltage and relays that reach over 13V DC will charge two batteries at the same time. When the charge is inactive or overloaded, the voltage will drop to around 12.75V DC. The relay will open, and the two batteries will be isolated. An Automatic Charging Relay allows the current to pass easily from one battery to the next.

  • Battery Isolators: Currents will flow more swiftly to the battery. However, because of the presence of diodes, the voltage is more likely to decrease, which consumes more energy and does not charge batteries quite as quickly. Also, the heat levels will most likely rise, and the currents will split.

  • Zero Drop Isolators: These isolators are useful in addressing the problem of voltage- dropping. These will cost more than the other options due to limited market acceptance.

Applying one of these three concepts to your alternator will bring about different advantages and will inevitably improve the lifespan and quality of your batteries. We recommend, for the sake of safety and accuracy, consulting with a technician or a mechanic in choosing the appropriate method before making any purchases.
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