![ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]](https://cdn.shopify.com/s/files/1/0469/0945/6544/files/106601XL.jpg?v=1763589079)
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Description
ARCO Marine BI-1203-3A Battery Isolator - 120A - 1 Alternator, 3 Battery [BI-1203-3A]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
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)
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.2 ★★★★★
Based on 24 reviews
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Product Reviews
★★★★★ 5
Great scale, an excellent buy
Color: Black&Silver
Is it possible to fall in love with a scale? I unboxed this one and, without reading any directions, put an empty 1/4 cup on it, turned the scale on, filled the 1/4 cup with coffee beans till I had the desired 17 or so grams, and turned the scale off. Easy-peasy! It’s small but sensitive, able to tell when a single bean has been added or removed. I almost didn’t get it because of the charging issue, but at least it tells you what the current charge is, and the way I use it I believe it will last several months without recharging. I’m so glad I bought this scale!
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Reviewed in the United States on April 14, 2026
★★★★★ 5
Simple yet easy must have for discerning coffee drinkers
Color: Black&Silver
I seem to never get the same results from my coffee machine and it varied even more with the new brand that we just bought. I now have to make more adjustments with the water temperature, based on age, type of beans, etc. That affects the amount of ground dispensed and consistency in the shot until I get a new batch dialed in.
So the only way to regulate these changes is to weigh both the beans and water. Using this little scale has made things easier, less frustrating and more predictable.
What’s awesome is that it will automatically begin the timer with the first drop and stop when the pressure remains constant.
Simple yet easy and super convenient. If you are looking for a great little digital scale this should do the trick. Highly recommended.
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Reviewed in the United States on February 4, 2026
★★★★★ 5
Great Digital Scale!!
Color: Black&Silver
The Maestri House S2 scale has been clutch for dialing in my espresso shots. Memphis heat or not, this thing stays accurate and steady. The timer starts up quick, the readings are fast, and the compact size fits perfectly under my Breville without feeling cramped. It’s built solid, charges by USB‑C, and the precision really shows when you’re trying to get that perfect pull.
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Reviewed in the United States on June 7, 2026
★★★★★ 4
Has fit perfectly into my morning espresso
Color: Black&Silver
This seems to me to be an excellent small kitchen scale. I am new to the complexities of espresso making and have begun using this scale every morning to measure my dose and output. It is working just fine. Easy to operate, keep clean and store. I did not give it 5 stars because I have limited comparisons but I don’t expect and will not bother looking for anything better.
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Reviewed in the United States on May 30, 2026
★★★★★ 5
Perfectly fits what I needed for my espresso habit!
Color: Black&Silver
This Maestri House mini coffee scale is a great little tool for espresso and pour-over. The size is compact enough to fit under a portafilter or cup, and the 0.1g accuracy makes dialing in coffee much easier. I like the built-in timer, rechargeable USB-C battery, and clean black-and-silver look. It feels precise, practical, and easy to keep near the espresso machine. Great value for anyone who wants more consistent coffee.
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Reviewed in the United States on June 2, 2026
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