Russell wrote:The problem with what Maine Sail describes above is that generally most people will switch to "Both", exactly the same as "Emergency Combine" if the engine fails to start, which would provide the exact same results he described. The battery switch I recommend, which he apparently does not, keeps the user experience simple and in 99% of cases it works flawlessly. That 1% case, its likely user error will still cause the same problem.
That said, still, sticking with a 1/both/2/off switch and using combiners, and basically leaving your switch on 1 pretty much at all times except the rare time the engine does not start (when you switch to 2 FIRST and try, before BOTH) is still better then the old style way of wiring.
Oh, and my boat with a Blue Sea Duel Circuit Plus is far far more complicated then a small fishing boat and is about as complicated as a cruising boat can possibly get. I still strongly recommend it and see countless cruising boats with knowledgeable owners using the same setup (oddly less knowledgeable cruisers use more complex systems). Not trying to pick on Maine Sail here, he is knowledgeable and offers a lot of great insight to this board, but in this case I disagree strongly. Not going to post more on this topic as this can easily disrail to the point that it does not help Robert.
Russel,
You can always disagree strongly, it creates good conversation. When you're on the receiving end of the "issues" I see, and have seen, with the DCP it gets tiring. I DO install them just not usually on cruising boats where one bank is deeply cycled unless the owner is fully educated as to the pros & cons of the multitude of configuration options avaiable.
The reality still remains that you lose features, redundancy, complete bank isolation and the ability to use your second bank as a "reserve house or everything bank", if needed, without physically digging into the wires and re-wiring your boat in an emergency.
So what do you get for your money? Some simplicity with only an ON/OFF/COMBINE and dedicated house and starting banks. Unfortunately the banks become locked into this service, and this service only, unless using the "combine" feature.
A 1/2/BOTH used as a ON/OFF saves money and is very simple but offers LOTS more safety and flexibility. I have yet to have one customer admit they've ever used the ALL feature after I have re-wired their system and sat with them and explained in detail how the system now works..
You also pay more for a DCP and throw away what is very often a perfectly good switch. If I re-wire a 1/2/BOTH I simply place an ON or House label over bank #1 and the owners then use it as a simple ON / OFF. They can however use the second bank that they already have on-board as an emergency house bank, if necessary, all without having to "combine".
Once I re-wire a 1/2/BOTH for a customer and educate them as to why not to use BOTH/ALL they don't use BOTH again but the "feature" is still there..
Just a few weeks ago I had another customer make great use of his 1/2/BOTH in an emergency at 2:00 am out in the middle of Casco Bay. He simply flipped his 1/2/BOTH to bank #2/Reserve and was back in business. The issue with the house bank wiring was addressed the next morning. If he had a DCP he would have been dead in the water as he would not have wanted to combine banks with a yet unknown issue on the house bank. He simply took that bank 100% off line, because he could, and used his second bank for house loads until morning..
I wish I could say these issues are 1% with the DCP.. As I mentioned a solid 8 out of 10 that I see are installed incorrectly.. Can you say relay cycling from improper installation..?
DCP simple? Sure.. Better? Not as far as redundancy, flexibility and safety is concerned....
Russell wrote:I still strongly recommend it and see countless cruising boats with knowledgeable owners using the same setup (oddly less knowledgeable cruisers use more complex systems).
Yes I guess this unknowledgeable, ABYC certified marine electrical systems specialist and cruiser, uses something "more complicated"......
1/2/BOTH
Bank #1 can be used as house or starting or starting & house
Bank #2 can be used as house or starting or starting & house
Can easily be used as a simple ON/OFF
Can be used to combine
Bank #1 can be 100% isolated/offline while still using bank #2
Bank #2 can be 100% isolated/offline while still using bank #1
Can be used to "direct" charge current (if wired as such)
No need to combine good bank with bad/dead bank in "emergency"
Slightly less simple OFF/1/ALL/2
Does no isolate starting circuit from house loads
DCP Switch
House Bank can only be used as House Bank
Start Bank can only be used as Start Bank
Can be used to combine
Is used as an ON/OFF
House Bank is isolated from Start bank but locked into this service
Start bank is isolated from House bank but locked into this service
Must combine good bank with bad/dead bank in "emergency"
Simple OFF/ON/COMBINE