Blue Sea Starting Isolation (SI) Dual Sensing Automatic Charging Relay

Priced: $99.99 Rated:   - 3 stars out of 5 by 6 reviews.
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Blue Sea Starting Isolation (SI) Dual Sensing Automatic Charging Relay -

This device allows temporary isolation of house loads from the engine circuit during engine cranking to protect sensitive electronics. It automatically combines battery banks during the charging cycle and isolates them while discharging. 12/24 Volt auto ranging voltage input. Hermetically sealed contacts/vaporproof/ignition protected for use aboard gasoline powered boats. Remote LED output indicates relay state away from ACR; LED light indicates when batteries are combined. Supports high-output alternators up to 120A.

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Blue Sea Starting Isolation (SI) Dual Sensing Automatic Charging Relay Reviews:

Positive Reviews:

Works great but there is a trick

I don't know what Robert is talking about. The installation is simple and straight forward. The unit is well built. There are tabs on the sides and bottom which are removable to accommodate the battery leads.

One advantage is that it will close the relay with a small charger on either battery and charge both batteries.
The only difficulty ( the trick )in installation, comes from the start isolation feature which requires you to locate a momentary circuit coming from the key or the starter solenoid. It is an option to install but if you have an engine that will draw down your power enough to kick off your chart plotter then it's a good option.
Marvin the Martian at on 12/12/2010

Great product but must stay within specs

I have had this product for about 2 years. Been flawless up til now. Its just such an ideal product in a small size. It does it all and you have nothing to worry about.

Though now I have to look at replacing or upgrading because now for some reason after running for while I find second battery is dead and I look at box and light flashing. It stops charging second battery and then goes into lockdown once second battery voltage drops to low. No clue why but could be I'm drawing to much from battery.not sure yet.
Just-speed at on 05/05/2013

High Quality item, works as designed

I replaced my old West Marine 70/2 battery combiner with this item and it worked perfectly after running through all system tests. I have a mobile command post SUV with a fire engine dual battery charging system (Kussmall) and this item was a perfect upgrade/replacement for my failing 70/2. I would highly recommend this item if it fits your application. It does take a 3/8" lug, which would have been nice to know upfront, it's not listed in spec sheet. I did not install the remote LED, the imbedded one is adequate, although small.
Flagship CP at on 07/07/2011

Negative Reviews:

This unit failed 3 times.

I saw this unit at the Miami boat show when it came out and won best of show. It is a great idea but does not live up to the billing. The guys at product support are real helpful but I needed them a lot. I had to change the main component three times and the unit left me with out a charge many times. Usually on a week or two long trip to the keys. I am back to a simple battery switch and I am in charge of charging.
Dan at on 03/03/2011

Not an Isolator but an Equalizer

I used this product as it an isolator. I installed it between two 4D start batteries and a genset start battery attempting to "isolate" the genset battery. The onboard 110vac charger went to fault allowing the batteries to discharge. As the two 4D batteries went the "isolator" opened and took the genset battery with them. The client couldn't start the genset to recharge the two 4D's. Unhappy client.
MM at on 05/05/2012

Yellow-colored cover tabs ...

Yellow-colored cover tabs are fragile, and break easily. No instructions come with the devce. There is lttle flexibility in be able to angle cales to attach to the device.
Robert at on 06/06/2008