Installing a dedicated starter battery

[u079721]

Mine is essentially identical to Glenn's. The only difference is that I have a switch between the starting battery and starter (1/2 of the BlueSea 5511), and I also have a solar charger connected to the house bank.

I'd be interested to know what items people have connected to the house bank BEFORE the switch? Bilge pump? Devices like stereos that need constant juice to retain memory? Battery monitors?

-mark

I never thought about stereos and such, but yes, I had my system wired so the bilge pump (fused!) attached directly to the house bank and by-passed the main battery switches. That way I could readily turn everything in the boat off without disabling the bilge pump. And it is amazing how few boats are wired that way!

 

[MarkA]

A thought about combining the two banks....

I don't know much about AGM batteries, so perhaps this is moot. But when I was considering a 4-battery bank, I read in several places that it's very important to ensure that all batteries connected in parallel are in nearly identical condition: same age, same capacity, same history of usage, etc.--and it was recommended to start with brand new batteries. I'm assuming your four batteries were purchased at the same time, but I'm wondering if one bank was used more heavily than the other, and may be at a later stage of it's lifespan?

I wonder what others have to say about this. Is it that important? Maine Sail?

 

[Loren Beach]

Mine is essentially identical to Glenn's. The only difference is that I have a switch between the starting battery and starter (1/2 of the BlueSea 5511), and I also have a solar charger connected to the house bank.

I'd be interested to know what items people have connected to the house bank BEFORE the switch? Bilge pump? Devices like stereos that need constant juice to retain memory? Battery monitors?

-mark

We have kept the stock factory panel with one breaker on the DC distribution panel for "bilge pump." We have no device-wiring taking off prior to the main switch except the sense wires for the panel volt meter, and those are both (nowadays) fused at the battery.

Therefore the house bank is powered up all the time. This also keeps the refer running.

Luckily we have reliable shore power at our moorage. I realize that anyone keeping a boat on a mooring or docking where the shore power wiring is suspect would do this very differently.

LB

 

[mherrcat]

Since I have been thinking about the "dedicated starting battery" for a while I just want to make sure I understand the circuit switching and the switches everyone is describing.

The panel that Loren posted, the Blue Sea 8080, has two switches. When the top switch is in the "ON" position the house bank is connected ONLY to the DC panel loads AND the starting bank is connected ONLY to the starter simultaneously. In the "OFF" position BOTH banks are disconnected from their respective loads simultaneously. When the bottom switch is in the "ON" position BOTH the house bank AND the starter bank are COMBINED; the top switch then connects or disconnects the COMBINED banks to BOTH the house and starter loads simultaneously. Is this correct?

If I use the last drawing that MaineSail posted and my existing 1-2-BOTH-OFF switch I would need one of the following in the position between the starting battery and the starter. Is this correct?



I take it I could then connect my alternator to the house bank directly and add an ACR to charge the starting battery?

 

[Stu Jackson]

Since this topic comes up so frequently, I've summarized it here for you: http://c34.org/bbs/index.php/topic,6604.msg43331.html#msg43331


Mark, I don 't think so, those are both only ON/OFF, switches, you still need a 1-2-B switch, so if you follow the wiring diagrams as discussed above you should be able to select a correct Blue Sea switch, like the 3002: http://bluesea.com/products/3002.

All the best,

Stu

 

[mherrcat]

I understand the diagrams. I was more trying to understand the function of the dual-circuit switches. I have a 4-way switch now; I do not have a dedicated starter battery or the 2-way switch between it and the starter as illustrated in MaineSail's diagram.

 

[Stu Jackson]

Hi, Mark,

The dual circuit concept works like this: http://bluesea.com/files/resources/sales_sheets/6833.pdf and this: http://bluesea.com/files/resources/sales_sheets/6833.pdf

You can search for more information on the Blue Sea website.

Maine Sail provided a VERY good discussion about this concept, and its serious shortcomings, in his excellent discussion called "Darn AGMs" --- http://forums.catalina.sailboatowners.com/showthread.php?p=848465&highlight=dual circuit

I've since added a link to it in the new "Battery Wiring Diagram" topic. Thanks for helping me to find it again.

If you have any more questions about this system, which we do not recommend and The WHY NOT is included in that link, please feel free to ask.

All the best,

Stu

 

[Flight Risk]

Wow, good discussion from all! Just one request from us marine engine techs: Whatever switch method is put in place, make sure it is clearly labeled for each position so anybody can quickly and easily isolate the battery....... For repair work or an emergency.

Same goes for aux switches such as fuel primimg pumps and oil evacuation pumps. One of my techs accidentally discharged a portion of the holding tank contents of a customer's boat because the "hide out o/b discharge" switch was next to the engine oil evac pump switch in the engine room........ No labels no problem right?!?!? Yuk.......

Chris
Flight Risk

 

[MarkA]

Wow, good discussion from all! Just one request from us marine engine techs: Whatever switch method is put in place, make sure it is clearly labeled for each position so anybody can quickly and easily isolate the battery....... For repair work or an emergency.

Chris
Flight Risk

Yeah, that's my main concern about the 1/2/B/Off + on/off solution proposed by Maine Sail and Stu. As a defender of manufacturers in product liability lawsuits, I can tell you such a counterintuitive and confusing setup would never survive in the consumer product world--even with detailed labels and directions. The potential to confuse owners is bad enough, but when you introduce guests, service techs, etc., problems will occur.

If people like me want to keep our house and starter circuits separate, yet retain the flexibility to switch the banks that feed those circuits, dual 1/2/B/Off switches are the way to go--one for each circuit. AND, everything needs to be clearly labeled. This adds what?--$10 to the cost? Big whoop.

As for the vehement hatred for the BlueSeas 5511 dual circuit switch being expressed in the links, it is totally misplaced. Personally, I found the switch because I was searching for a device that would do exactly what it does, which is to keep the circuits separate. I was not swayed by any of the advertising that is being maligned. The irony is that it's biggest "danger" is the combine battery setting--WHICH IS ALSO PRESENT IN THE 1/2/B/OFF SWITCHES! And, I think both Stu and Maine Sail admitted that a huge percentage of boats they encounter have their precious 1/2/B/OFF switches improperly set to BOTH! Why vilify the BlueSeas switch, when it sounds like the potential for trouble exists in ALL switches that allow combining of banks?

The BlueSeas Dual Circuit switch lacks one ability that might be nice to have, but I can't imagine myself using it: The ability to switch banks. In the cited examples, the house bank died, and people killed the starter battery by combining. I can't imagine myself ever doing that. If my house bank dies, there is NO WAY IN HELL I'm going to expose my starter battery to whatever problems discharged the house! Why would I? The first thing I would do is inspect the house bank, check for anything drawing current and turn it off or disconnect it, and then start the motor or whatever other charging devices I have, and replenish the house! If that doesn't work, I'll motor or sail wherever I need to go to replace the house batteries! Meanwhile, the alternator will supply enough juice to run whatever I need. If not, I keep handheld backups, and alkaline batteries, for all essential communications and navigation. But why on Earth would I risk discharging the precious starter battery???

I respect the expertise of Maine Sail and Stu, and I value their opinions and appreciate their input. But on this one issue they've taken to the soapbox, I suspect I'm just not smart enough to agree with them.

 

[Sven]

Yes--or fuses. They must be within 7 inches of the power source (battery).

Do they have to be between batteries too when wired in parallel (in case a battery shorts out) or is it implied that it is within 7" of a battery bank ?

I solved that with these terminal fuse blocks: http://bluesea.com/category/5/21/productline/specs/378

Is the fuse actually in that device or do you attach the fuse to it ? I've looked at it for quite a while and think I must have gotten locked into looking at it the wrong way because I can't quite figure out what I'm looking at

Thanks,



-Sven

 

[Sven]

Sven,

If you want simple:

1- Wire the alt directly to the house bank and fuse as close to the battery as possible (preferably within 7")

2- Use Echo Charger to charge your "reserve" bank.

3- Use position #1 as your HOUSE/PRIMARY bank and #2 as "RESERVE/START" or SECONDARY bank.

4- Use only switch position #1 for everything, starting, house loads etc.. Turn to #1 when you get to the boat and OFF when you leave. Very, very simple..

5- If you should accidentally kill your house bank switch to #2 and start the engine. One would hope that with expensive AGM's however you are not routinely dipping below 50% state of charge..




The 1/2/BOTH/OFF switch is a GREAT tool and one that offers the most redundancy for emergencies..

This is actually what I'd originally been thinking but I wasn't sure it made sense, it seemed too logical but nobody seemed to do it that way. Maybe the cost of the echo charger is what keeps it from being a standard solution. One would probably want to start from the #2 position every once in a while to make sure that the starting battery hasn't failed for some reason.




-Sven

 

[mherrcat]

Is the fuse actually in that device or do you attach the fuse to it ?

I believe the fuse is the plastic part below the hex nut. I couldn't figure it out the first time I saw a picture either, until I looked at it in a West Marine store.

 

[Sven]

I believe the fuse is the plastic part below the hex nut. I couldn't figure it out the first time I saw a picture either, until I looked at it in a West Marine store.

I think I finally figured it out after reading the description on the Jamestown site http://www.jamestowndistributors.co...milyName=Blue+Sea+Systems+MRBF+Terminal+Fuses .

Required fuse for the Blue Sea Systems Terminal Fuse Blocks PN 5191 or PN 2151. Do not mount the fuse directly to the battery terminal. MRBF (Marine Rated Battery Fuse)

Thanks,



-Sven

 

[mherrcat]

I still think this starting battery looks promising:



http://madmariner.com/blogs/boat_shows/100997

Especially for my space-challenged 30+ since it is only 4.5" x 3" x 2.8" and weighs only 1.7 lbs. (the battery, not the boat...)

 

[windjunkee]

Sven,

In a quite-recent event, the boat I had sailed Transpac on suffered some electrical problems. On the return voyage, the starter got stuck and remain engaged. When the engine was turning, the starter converted into a generator pumping out over 17 volts. It blew the fuses on the batteries and fused some wires before they discovered the problem. The starter battery was isolated from that loop and avoided damage so they were able to 'jump' some of the more critical electrical needs (navigation and communication) to the starter battery. So there is wisdom in keeping the starter battery out of the loop.

Just to finish the story, we were able to talk to the boat once a day via sat phone to give them weather updates and routing advise and to stay up on their progress. We directed them to isolate the house batteries one at a time to run the water maker. However, somehow, someway (the answer is still unclear), they figured out a way to start the engine again. It continued to pump out 17 volts, but they would manually hook the batteries into the system and let them charge for a few minutes at a time. They made it back safely, though they ended up trying to motor through the pacific high and astonishingly, got over 96 hours of engine time on a 40 gallon tank.

Jim McCone
Voice of Reason E-32
Redondo Beach, CA

 

[Maine Sail]

Sven,

In a quite-recent event, the boat I had sailed Transpac on suffered some electrical problems. On the return voyage, the starter got stuck and remain engaged. When the engine was turning, the starter converted into a generator pumping out over 17 volts. It blew the fuses on the batteries and fused some wires before they discovered the problem. The starter battery was isolated from that loop and avoided damage so they were able to 'jump' some of the more critical electrical needs (navigation and communication) to the starter battery. So there is wisdom in keeping the starter battery out of the loop.

Just to finish the story, we were able to talk to the boat once a day via sat phone to give them weather updates and routing advise and to stay up on their progress. We directed them to isolate the house batteries one at a time to run the water maker. However, somehow, someway (the answer is still unclear), they figured out a way to start the engine again. It continued to pump out 17 volts, but they would manually hook the batteries into the system and let them charge for a few minutes at a time. They made it back safely, though they ended up trying to motor through the pacific high and astonishingly, got over 96 hours of engine time on a 40 gallon tank.

Jim McCone
Voice of Reason E-32
Redondo Beach, CA

A prime reason why battery fusing is so important and complete isolation of banks is so important. With wires still fusing/melting it sounds as if they did not have their OCP sized correctly, but it still tripped before the wires caught fire, which is the most important part.

That is why I feel so strongly that each bank on the boat can act as either house or starting or both and still be 100% isolated from the other bank with the quick flip of a switch.

If that was a "dedicated" hard wired start battery, as I see all to often on boats that don't require it, and it was conforming to current ABYC standards it would not require a fuse. SCARY!!!!!!!!!

The situation could have been made much worse without a fuse, as in, FIRE. Start battery fusing on sailboat aux engines is one area where I strongly disagree with the ABYC on over current protection.. If that had been a system where the only way to get reserve power from an alternative bank was to "combine" the banks the situation could have been made even worse.

 

[mherrcat]

On the return voyage, the starter got stuck and remain engaged.

Sounds like a 1967 MGB-GT I used to have. The starter mounting bolts would work loose and when you tried to start the car the pinion gear would engage the flywheel, the starter would get jacked to one side and the pinion and flywheel would jam. The car wouldn't start, however, so the starter was never engaged while the engine was running. Had to bang on the starter with a tire iron to disengage it.

I'm surprised the starter didn't burn up completely quite rapidly as I don't believe they are designed for any kind of continuous operation.

 

[Rocinante33]

Sven,

Maybe you should consider one of these to provide a battery bank fuse. Easy to install.
http://bluesea.com/products/2151

 

[Maine Sail]

I think I finally figured it out after reading the description on the Jamestown site http://www.jamestowndistributors.co...milyName=Blue+Sea+Systems+MRBF+Terminal+Fuses .



Thanks,



-Sven

Yes there are two parts.

The fuse

and fuse holder (available in both a double and single)

They can also be used off a buss bar which makes them very handy

 

[Tom Metzger]

Maine Sail - Two questions on your bus layout, assuming it is an actual boat in the photo.

1) How is the battery switch lead connected? I don't see a lug.

2) What does the fuse on the house bank lead protect?