That's an interesting solution, Harry. I am also running an old Xantrex 20 inverter/charger. Would that change your alternate setup at all?
1/BOTH/2/OFF Switches Thoughts & Musings
- Thread starter Maine Sail
- Start date
That's an interesting solution, Harry. I also installed an old Xantrex Freedom 20 inverter/charger. Would that change your recommendation at all?
Just wanted to thank everyone on this thread, it helped solve a wiring issue on my boat. The boat is a 2006, sometime in 2008 a Generator and a 4D House battery were added. I could not figure out what position on the switch was house no matter which battery I disconnected 12 volt side had power. After digging into the issue I figured out that the yard wired the start battery to the common post on the 1/2/B switch, still not sure of everything they did. They also wired the battery charger is such a way that all 3 banks on the charger were charging the batteries, boiled the starting battery, a flooded group 27. Replaced the starting/reserve with AGM 31, the 4D is testing good so far. Wired the shore charger to just charge the 4D, no charger on the reserve, I have an echo charger and battery monitor arriving tomorrow to take care of the starter/reserve and monitor the house. I will not run the AO to the house battery but let it flow via the cable from the engine starter, I am the only one who touches the switch and have enough sense to not go to OFF when the engine is running plus I can charge the starter/reserve if needed. I may run the AO to the house in the future; I have to see how this setup works. Great learning experience.
The Echo and the Mon. was just handed to me, arrived a day early.
The Echo and the Mon. was just handed to me, arrived a day early.
First, Thanks Maine Sail for your time and expertise on these forums. Yours' is always the voice of reason and sound consideration of your experience.
With the alt + wired directly to the house +........
'#5 With a bank failure, such as an internal short, it forces the user to use the "BOTH/COMBINE" feature and combine a good bank with a failed bank. This can leave a boater dead in the water as it did for one of my customers as recently as last summer. That customer has since switched back to a 1/2/BOTH/OFF with a second ON/OFF for engine start isolation. It is more complicated, as he has two switches to turn ON & OFF, but he has more comfort in knowing he has redundancy and full isolation without the need for using the "BOTH/COMBINE" feature, the same feature that left him dead in the water.. While these failures are rare they can & do happen. Short of re-wiring the system, when a battery dies, you have no way to isolate a bad bank."
This is the only thing that concerns me about wiring the alt directly to the positive post of the house bank. In the event of a shorted cell in the house bank it appears we have lost the ability to charge the other bank. I don't see anyway to keep the start battery up enough to keep the refer cold and nav systems on line for several days to get back to civilization. I would hate to lose the meat in the freezer ($) or the ice cream (not a lot of investment but a scoop of ice cream on a hot afternoon makes me feel like one of the rich guys). What would you suggest as the simplest or least expensive way to deal with this? Possibly a 3 way switch on the alt + lead?
With the alt + wired directly to the house +........
'#5 With a bank failure, such as an internal short, it forces the user to use the "BOTH/COMBINE" feature and combine a good bank with a failed bank. This can leave a boater dead in the water as it did for one of my customers as recently as last summer. That customer has since switched back to a 1/2/BOTH/OFF with a second ON/OFF for engine start isolation. It is more complicated, as he has two switches to turn ON & OFF, but he has more comfort in knowing he has redundancy and full isolation without the need for using the "BOTH/COMBINE" feature, the same feature that left him dead in the water.. While these failures are rare they can & do happen. Short of re-wiring the system, when a battery dies, you have no way to isolate a bad bank."
This is the only thing that concerns me about wiring the alt directly to the positive post of the house bank. In the event of a shorted cell in the house bank it appears we have lost the ability to charge the other bank. I don't see anyway to keep the start battery up enough to keep the refer cold and nav systems on line for several days to get back to civilization. I would hate to lose the meat in the freezer ($) or the ice cream (not a lot of investment but a scoop of ice cream on a hot afternoon makes me feel like one of the rich guys). What would you suggest as the simplest or least expensive way to deal with this? Possibly a 3 way switch on the alt + lead?
I also installed an EC and it was my understanding from previous posts from Maine Sail as well as the EC manual that unless all charging sources-including the Alt are led to the House Bank, the EC will not charge properly. I don't want to misrepresent what MS has said on this topic, so perhaps he can clarify...
Here's what he said:
Echo Charger Use Warning from Maine Sail: http://www.sailnet.com/forums/electrical-systems/72295-xantrex-echo-charger-rant.html
The paragraph #5 that you quoted simply was explaining the deficiencies of the Dual Circuit switch, and not those of the simple 1-2-B or the 1-2-B plus separate reserve bank switches, both of which allow either/or switching of the two banks. You might want to consider going back and rereading the whole concept.
In most cases, folks wire their AO to the house bank through a bus bar or a Power Post (AO to bus bar with a separate short wire to the house bank). If the house bank dies because of a really dead or blown battery, one either removes the bad single battery (from a bank of more than one) or disconnects the entire house bank by physically removing the wiring for or within the house bank.
The EC or ACR still works, since it's wired between the house bank bus bar and the reserve bank.
As far as your ice cream and meat, the reserve bank is not going to last long running a fridge/freezer, so you’d have to continue with charging, with whatever charging sources you have available.
That’s what I’d do. I wouldn’t put anything more than a simple I/O switch on the AO output as Maine Sail suggests for isolation of the alternator when working on the engine. You’re just complicating the situation.
Ideally the alternator & other sources would be wired to a positive charge bus bar and there would be a battery compartment ON/OFF switch to isolate the battery from the charge bus. You can then pull the house bank fuse and use combine to direct alt current to the start but an additional ON/OFF and charge bus is the best course of action.
There are many was to handle that situation and the situation is rare enough that removing the house bank fuse is one that can also work provided the alt always remains connected to a bank. I prefer an ON/OFF switch and charge bus but a charge bus and fuse pull can also work..
I have a question about the cable going from the alternator directly to the house bank. If that cable is fused and the fuse blows while the alternator is charging, wouldn't that blow the diodes in the alternator, just like if a selector switch gets turned Off? Is anyone aware if that has occurred?
Thanks
Thanks
Sized properly the fuse would only blow if there was a dead short. Much better than the alternative.
If that fuse blows, YOU NEEDED IT TO !!!!!
If the alt output shorted to ground, without the fuse, you would also damage the alt and likely start a fire because the batteries are now feeding the short......
A properly sized fuse for an alternator will be at least 150% of its output rating...
The fuse for an alt wire ALWAYS goes at the battery end of the wire, preferably within 7" of the positive battery post....
FWIW, Balmar sells a "transient spike protector" that may save your alternator diodes if the fuse blows. It's basically a sacrificial diode that runs between the positive and negative terminals of your alternator and costs about $20.
And when they work, they sometimes only work once. No one ever knows it is blown so if they do it a second time pop goes the alt... I have seen alts with Zap Stops with blown diodes...
Marinco Dual Bank Control Switch
I noticed that Marinco has a new battery switch that would work much like the Blue Sea Systems dual battery plus system when combined with an ACR but adds the ability to isolate the house bank in emergencies. You could disconnect the house bank also by pulling its fuse and setting the switch to combine if needed to start the engine.
http://www.marinco.com/en/772-dbc
I was wondering about the quality of these switches and if comparable to Blue Sea switch quality.
Isolating the house and start circuits are recommended by many chartplotter and instrument manufacturers to prevent any loss of displays due to surge spikes caused when starting engines -- but Maine Sail has stated previously that this should never be an issue with a properly set up system and most small diesels don't create the issues and I agree with this.
Your thoughts? Thanks
http://www.defender.com/product.jsp?path=-1|328|2290051|2290060&id=2541071
I noticed that Marinco has a new battery switch that would work much like the Blue Sea Systems dual battery plus system when combined with an ACR but adds the ability to isolate the house bank in emergencies. You could disconnect the house bank also by pulling its fuse and setting the switch to combine if needed to start the engine.
http://www.marinco.com/en/772-dbc
I was wondering about the quality of these switches and if comparable to Blue Sea switch quality.
Isolating the house and start circuits are recommended by many chartplotter and instrument manufacturers to prevent any loss of displays due to surge spikes caused when starting engines -- but Maine Sail has stated previously that this should never be an issue with a properly set up system and most small diesels don't create the issues and I agree with this.
Your thoughts? Thanks
http://www.defender.com/product.jsp?path=-1|328|2290051|2290060&id=2541071
I'm slow to get back here but thanks. Running it to the positive "battery direct buss" will be easy and cheap.
Great thread.If that fuse blows, YOU NEEDED IT TO !!!!!
If the alt output shorted to ground, without the fuse, you would also damage the alt and likely start a fire because the batteries are now feeding the short......
A properly sized fuse for an alternator will be at least 150% of its output rating...
The fuse for an alt wire ALWAYS goes at the battery end of the wire, preferably within 7" of the positive battery post....
Question: shouldn't the properly size fuse for an alternator be the right size to protect the wire? I know this may be nit picking; maybe sized for the wire, or 150% alternator rating, whichever is lower?
Thanks,
jv
Any properly installed direct wired high output alternator should already have wire that can easily handle a fuse at 150% of the alts output rating.. Key words there are "properly installed"... If not properly installed then you would use max ampacity tables and may need to use the 150% rule if necessary...
Hi There,
Sorry to the break the thread, but I am desperately looking for some help to completely rewire a newly purchased L34 (Lavranos 34). After purchasing, two weeks later, we had a cable melt! Smoke bellowing out of the port settee bunk.., not very exciting.
After I had a really good look at the existing wiring I really started pulling my hair out. The boat is close on thirty years old and I suspect that some of the wiring is still from the original installation. Hence the reason to rewire. I will supply an existing diagram that I am working on if there are any takers out there to help a total novice...
Thanks,
Wireman
South Africa
Sorry to the break the thread, but I am desperately looking for some help to completely rewire a newly purchased L34 (Lavranos 34). After purchasing, two weeks later, we had a cable melt! Smoke bellowing out of the port settee bunk.., not very exciting.
After I had a really good look at the existing wiring I really started pulling my hair out. The boat is close on thirty years old and I suspect that some of the wiring is still from the original installation. Hence the reason to rewire. I will supply an existing diagram that I am working on if there are any takers out there to help a total novice...
Thanks,
Wireman
South Africa
"Breaking a thread" is called "hijacking" it - to change the subject. That's a no-no. Novice, post your own question and start your own new thread. That's a yes-yes.