![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](http://boatpartsdepot.com/cdn/shop/files/op_blade_hero_icast2024_1.png?v=1758553857&width=3840)
![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](http://boatpartsdepot.com/cdn/shop/files/lumitec.png?v=1758638733&width=3840)
![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](http://boatpartsdepot.com/cdn/shop/files/garmin.webp?v=1758640530&width=3840)
![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](http://boatpartsdepot.com/cdn/shop/files/Untitled_design_-_2024-08-27T113233.566.png?v=1724740371&width=3840)
![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](http://boatpartsdepot.com/cdn/shop/files/kraken.jpg?v=1758232543&width=3840)
![13 Fishing AL13 Spinning Reel - 5.2:1 - 3.0 [AL13-5.2-3.0]](http://boatpartsdepot.com/cdn/shop/files/105635XL.jpg?v=1726202266&width=3840)
![13 Fishing AL13 Spinning Reel - 5.2:1 - 3.0 [AL13-5.2-3.0]](http://boatpartsdepot.com/cdn/shop/files/105635BXL.jpg?v=1726202268&width=3840)
![13 Fishing AL13 Spinning Reel - 5.2:1 - 6.0 [AL13-5.2-6.0]](http://boatpartsdepot.com/cdn/shop/files/105637XL.jpg?v=1726202347&width=3840)
![13 Fishing AL13 Spinning Reel - 5.2:1 - 6.0 [AL13-5.2-6.0]](http://boatpartsdepot.com/cdn/shop/files/105637BXL.jpg?v=1726202349&width=3840)
![13 Fishing AL13 Spinning Reel - 6.2:1 - 6.0 [AL13-6.2-6.0]](http://boatpartsdepot.com/cdn/shop/files/105639XL.jpg?v=1726202411&width=3840)
![13 Fishing AL13 Spinning Reel - 6.2:1 - 6.0 [AL13-6.2-6.0]](http://boatpartsdepot.com/cdn/shop/files/105639BXL.jpg?v=1726202413&width=3840)
![13 Fishing Concept A Baitcast Reel - 5.6:1 - RH [A2-5.6-RH]](http://boatpartsdepot.com/cdn/shop/files/105556XL.jpg?v=1726201865&width=3840)
![13 Fishing Concept A Baitcast Reel - 5.6:1 - RH [A2-5.6-RH]](http://boatpartsdepot.com/cdn/shop/files/105556BXL.jpg?v=1726201867&width=3840)
![13 Fishing Concept A Baitcast Reel - 6.8:1 - RH [A2-6.8-RH]](http://boatpartsdepot.com/cdn/shop/files/105558XL.jpg?v=1726201884&width=3840)
![13 Fishing Concept A Baitcast Reel - 6.8:1 - RH [A2-6.8-RH]](http://boatpartsdepot.com/cdn/shop/files/105558BXL.jpg?v=1726201886&width=3840)
![13 Fishing Concept A Baitcast Reel - 8.3:1 - RH [A2-8.3-RH]](http://boatpartsdepot.com/cdn/shop/files/105562XL.jpg?v=1726201928&width=3840)
![13 Fishing Concept A Baitcast Reel - 8.3:1 - RH [A2-8.3-RH]](http://boatpartsdepot.com/cdn/shop/files/105562BXL.jpg?v=1726201930&width=3840)
![13 Fishing Concept A3 Baitcast Reel - 6.3:1 - RH [CA3-6.3-RH]](http://boatpartsdepot.com/cdn/shop/files/105571XL.jpg?v=1726202049&width=3840)
![13 Fishing Concept A3 Baitcast Reel - 6.3:1 - RH [CA3-6.3-RH]](http://boatpartsdepot.com/cdn/shop/files/105571BXL.jpg?v=1726202051&width=3840)
![13 Fishing Concept A3 Baitcast Reel - 8.1:1 - RH [CA3-8.1-RH]](http://boatpartsdepot.com/cdn/shop/files/105573XL.jpg?v=1726202072&width=3840)
![13 Fishing Concept A3 Baitcast Reel - 8.1:1 - RH [CA3-8.1-RH]](http://boatpartsdepot.com/cdn/shop/files/105573BXL.jpg?v=1726202074&width=3840)
![13 Fishing Inception G2 Baitcast Reel - 6.6:1 - RH [ING2-6.6-RH]](http://boatpartsdepot.com/cdn/shop/files/105581XL.jpg?v=1726202089&width=3840)
![13 Fishing Inception G2 Baitcast Reel - 6.6:1 - RH [ING2-6.6-RH]](http://boatpartsdepot.com/cdn/shop/files/105581BXL.jpg?v=1726202091&width=3840)
![13 Fishing Inception G2 Baitcast Reel - 7.3:1 - RH [ING2-7.3-RH]](http://boatpartsdepot.com/cdn/shop/files/105583XL.jpg?v=1726202107&width=3840)
![13 Fishing Inception G2 Baitcast Reel - 7.3:1 - RH [ING2-7.3-RH]](http://boatpartsdepot.com/cdn/shop/files/105583BXL.jpg?v=1726202109&width=3840)
Built for the Water
Lighting the Way Below – Enhancing Every Dive
Underwater Glow, Unmatched Visibility
![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](http://boatpartsdepot.com/cdn/shop/files/106601XL_180x.jpg?v=1731012018)
BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 BatteryThe Arco Marine BI-1203-3A is an inboard/outboard battery isolator that can handle 1 alternator, 3 batteries, and 120A max. Rated for use with 10 to 350-amp...
Available:
In stock
Guaranteed safe checkout:
Same-Day shipping
This item is available for 2 day shipping
BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery
The Arco Marine BI-1203-3A is an inboard/outboard battery isolator that can handle 1 alternator, 3 batteries, and 120A max. Rated for use with 10 to 350-amp alternators on 12, 24, or 32-volt negative ground systems.
*Includes exciter terminal
Features:
- 1 alternator, 3 batteries, 120A max
- Inboard and outboard battery isolators are solid-state devices that allow electrical current to flow in one direction ONLY, thus permitting the alternator to be connected directly to two batteries without fear of one higher-charged battery discharging into the lower-charged battery.
- Both batteries are always being charged automatically, in proportion, to their needs whenever the engine is running.
- When battery isolators are used in conjunction with selector switches, it is not necessary to change the switch position to provide for charging of both batteries.
- Isolators provide proportioning of the output or charging current on the alternator to the batteries as required, regardless of switch position.
NOTE: Battery Isolators cannot be used on 12 volt charging systems with 24 volt trolling motors or newer outboard engines with rectifier-regulator charging systems.
This product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns.Quick Guide (pdf)
Related product
ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]
RECENTLY VIEWED PRODUCTS
![Garmin Navionics+ NSSA004L - Mexico, the Caribbean to Brazil - Inland Coastal Marine Chart [010-C1285-20]](http://boatpartsdepot.com/cdn/shop/files/96095XL.jpg?v=1723585545&width=3840)
![Humminbird CoastMaster Premium Northeast Coastal V1 [602024-1]](http://boatpartsdepot.com/cdn/shop/files/105912XL.jpg?v=1744930449&width=3840)
![Navionics Platinum+ NPSA010R - Central America Caribbean [010-C1459-40]](http://boatpartsdepot.com/cdn/shop/files/101644XL.jpg?v=1723618809&width=3840)
![Garmin BlueChart g3 HD - HXUS031R - Southwest Caribbean - microSD/SD [010-C0732-20]](http://boatpartsdepot.com/cdn/shop/files/35565XL.jpg?v=1723093835&width=3840)
![Garmin BlueChart g3 Vision HD - VUS011R - Southwest Florida - microSD/SD [010-C0712-00]](http://boatpartsdepot.com/cdn/shop/files/30367XL.jpg?v=1723085338&width=3840)
![C-MAP REVEAL X - Gulf of Mexico Bahamas [M-NA-T-204-R-MS]](http://boatpartsdepot.com/cdn/shop/files/93619XL.jpg?v=1723570953&width=3840)
![Garmin Navionics Vision+ NVUS008R U.S. West [010-C1292-00]](http://boatpartsdepot.com/cdn/shop/files/92679XL.jpg?v=1723565285&width=3840)
![Garmin BlueChart g3 Vision HD - VUS009R - Jacksonville - Key West - microSD/SD [010-C0710-00]](http://boatpartsdepot.com/cdn/shop/files/30364XL.jpg?v=1723085312&width=3840)
![Humminbird LakeMaster VX - Great Plains [601003-1]](http://boatpartsdepot.com/cdn/shop/files/96671XL.jpg?v=1723588900&width=3840)
![Humminbird LakeMaster VX Premium - Quebec [602021-1]](http://boatpartsdepot.com/cdn/shop/files/96694XL.jpg?v=1723589100&width=3840)
![Garmin BlueChart g3 Vision HD - VUS037R - Vancouver - San Diego - microSD/SD [010-C1003-00]](http://boatpartsdepot.com/cdn/shop/files/35805XL.jpg?v=1723094258&width=3840)
![Garmin Navionics Vision+ NVSA010R Central America Caribbean [010-C1451-00]](http://boatpartsdepot.com/cdn/shop/files/102667XL.jpg?v=1723625872&width=3840)
![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](http://boatpartsdepot.com/cdn/shop/files/Untitled_design_-_2024-08-28T110403.265.png?v=1724825283&width=3840)
