Blue Sea Systems Battery Combiner / Isolator?

Discussion in 'Tips & Modifications' started by TransFueler, Oct 6, 2020.

  1. TransFueler

    TransFueler Active Member Supporting Captain

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    Captain Starbucks has a very nifty Blue Sea system on his Mackinaw. Looks like a good addition to any boat. What's the model number of it, Rob?
     
  2. Captain Starbucks

    Captain Starbucks Well-Known Member

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    Let me look it up tomorrow when I'm on a real computer.

    Spend some time on the Blue Seas website anyway. They have some really innovative stuff!
     
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  3. Mistress

    Mistress Well-Known Member Staff Member Supporting Captain

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  4. Rusty Rod

    Rusty Rod Well-Known Member

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    BEP also makes battery combiners and clusters
     
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  5. Captain Starbucks

    Captain Starbucks Well-Known Member

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    Ed,

    Here's what I have. I highly recommend. As you can see, there are plenty of others out there.

    I like the Blue Seas for not only their quality, but they are made in USA, made local (Bellingham), and if you have any questions, you can call and a not only does a real person answer the phone, but they put you right through to an electrical engineer/designer. Pretty solid company on many levels.

    https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A

    Nice to meet you last weekend and let us know if you have any more Q's.

    Rob
     
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  6. Fish Witch

    Fish Witch Well-Known Member

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    Rob - that looks like it would charge at a higher level off the alternator than with the battery isolator that came with my boat which shows about 13.2-13.5 v full charge due to the diodes in the isolator which the Blue Seas don't depend on for isolating. I haven't had a problem with this but aware my batteries aren't kept up to full charge by the alternator alone. Did yours come with the battery isolator originally and you swapped it out? It would definitely be a plus if not on shore power to charge up to full level regularly like I do.
     
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  7. Mistress

    Mistress Well-Known Member Staff Member Supporting Captain

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    That's long been the problem of diode based isolators. ~1V dop to the charging.

    Combiners use a relay with voltage sensing. Near 0V drop.

    On my RV I use a simple solenoid as an isolator. Key ON = batts are parallel. Key OFF batts are separate.
     
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  8. Captain Starbucks

    Captain Starbucks Well-Known Member

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    Hi Ken,

    I think the isolator is actually still in there on my boat. Right by the water heater, right? Not sure if it's still hooked up. I've not done anything with it. Regardless, to answer your question, I routinely see 14.7 volts on my digital (no name brand cheapo) voltmeter. Once in a while it will hit a little over 15 but briefly.

    Since we're on the electrical subject, what batteries do you have and do you recommend? My Optima Blue Tops are 6 years old and need to be replaced. I had to parallel a few times this summer after sitting for just a few weeks. I like the batteries I have, but quite expensive.

    Rob
     
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  9. Fish Witch

    Fish Witch Well-Known Member

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    Rob - my isolator (Guest) is located in the engine room on the bulkhead with the water heater on the other side. It has 3 terminals, one for the alternator and one for each of the two batteries.
    I get my batteries from Costco, Interstate Group 27 deep cycle marine and they've done me well. My boat is a 2003 and I got it in 2008. No notes from the PO on new batteries and I don't remember which ones were in it but the first set I changed out was in 2011, then again in 2016 which are still going strong. 5 years seems to be my experience so next year I'll likely be looking for a new set. I'm pretty easy on the batteries though, alternating batteries every day I'm running, only anchoring out a few nights a year and when I do, I turn off the fridge so it doesn't drain the battery. I also have them plugged into the boat's charger most of the year in the slip and when I pull it for the winter so they rarely get drawn down. And you know how our Yanmars start, on the first roll every time so start load is pretty easy on them too. If I was anchoring out regularly with the family, running the fridge at night, needing lights (ha! You know what I mean, it never gets dark up here during boating season), etc. I might be looking at more expensive batteries to keep up with the higher demand. The Costco Interstates are the most economical for my boating needs for now which is mostly day boating out to the fishing grounds and back. You might be putting more demand on them with your growing family and I know there are a lot of different opinions about which is best. It all depends on what demands you put on them IMO.
     
  10. Captain Starbucks

    Captain Starbucks Well-Known Member

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    Hi Ken,

    After looking at the Group 27 specs between the Blue Tops and the Interstate Marine, I'd say the Blue Tops might have an edge in performance, but they are $330 each. The Interstates at my Costco are $88 each. Bit of a no brainer for me! I do stay on the hook a bit in the summer, but our nights are also pretty short. By the time we actually need the cabin lights, it's about time for the sack anyway. And like you, I always turn off the fridge at night.

    I didn't go look at the isolator I have, but after I thought about it, I'm pretty sure it is a galvanic isolator, not a battery isolator.
     

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