Sanity Check on Wiring Plan

[Target9000]

Since I've decided to attach all the charge sources to the house bank I suppose the echo charge would work fine for us rather than a ACR/VSR. I just need to decide which is best for us.

I'm loving all the feedback. Thanks guys!

[Maine Sail]

Originally Posted by CharlieJ

Now, I will happily admit that my scheme has replaced two, four position switches with three On/Off switches and an ACR or DuoCharge, but the functionality and safety of the overall system has been significantly enhanced.

But you've now given up the ability to isolate a bank, in the event of an internal battery failure, and to use the start for house & starting loads or the house for starting & house loads..

Your only fail safe is to "combine" two banks. If one has catastrophically failed, as happened to a customer of mine this past summer, who had a Blue Seas DCP switch, he lost both banks because he could not "isolate" the bad bank without physical re-wiring...

Another customer killed an 800Ah AGM bank when his alt failed and he never knew it. He was motoring off shore in no winds and as such has been using his water-maker and inverter which took the bank to dead after having been on the hook for four days..

His only option was to use the "parallel" switch to get emergency house loads. He left it in that position a little too long and zap went his starting battery and it did not have enough juice to fire the motor. He was dead in the water with no wind... If he could have "switched" to the start battery and taken the house off line he may have had enough juice to safely get by with minimal devices. Turned out to be a failed external regulator...


There is no one right answer just LOTS of options!

Many of my customers prefer the wiring below when the want to isolate starting and house. It leaves them with full isolation and redundancy options and two switches are simply used as ON/OFF's..


(for simplicity fusing and other details not shown)



Emergency Bank Failure Switching


START BATTERY FAILURE - If the starting battery goes bad turn the 1/2/BOTH/OFF to BOTH and flip the ON/OFF to OFF you can now start your engine and run house loads off the house bank. Your starting battery is now isolated.

HOUSE BANK FAILURE - If the House bank goes bad flip to position #2 and leave the ON/OFF turned to ON. This will allow powering house and starting loads from the starting battery and allows it to act as your reserve bank.


Normal Every Day Use
Turn the 1/2/BOTH/OFF to #1/ON (I often place an ON sticker over #1) and the ON/OFF to ON..





While a tad more "complicated" than a single ON/OFF (DCP), or the three ON/OFF's, you have two ON's to do it is still very easy compared to most boating things. I leave a laminated use card in the nav desk. I have yet to have a customer misunderstand how it is use after an explanation.

In an emergency situation, they can happen, you still retain all the flexibility and isolation you'd want or need.

No one right or wrong way to wire them.

I generally prefer to be able to completely isolate a bank if needed and use an alternative bank as "reserve/emergency" if necessary as I have had enough examples of problems when "combine" or "parallel" are the only emergency options...

When wiring the alt direct to the battery I generally prefer to add a "service switch" or use a lever arm breaker with the proper AIC. This disconnects the alt when working on the engine and is out of sight for guests and crew..

[btrayfors]

Maine...

I think you missed the option (posts #17 and #18) of wiring the third "emergency" switch to the LOAD side of the other two switches, rather than the battery side.

That allows you full flexibility to switch out either battery bank or to use either bank for starting/house/whatever.

Bill

[knottybuoyz]

Originally Posted by btrayfors

I think you DID just make that up :-)

Kinda, sorta Bill!

I have the first version of the Blue Sea ACR. It's slightly different than the current SI model. I went back to find the literature on it and it's not on the site anymore. Here's how the new ones work.

Connect the alternator to charge battery 1 (start battery), and connect the charger to charge battery 2 (house battery). When the charger is charging battery 2, the ACR will combine battery 2 and battery 1 for charging. When the alternator is charging battery 1, the ACR will connect battery 1 and battery 2, and both batteries will be charged. With the installation of the ACR, when at dock and plugged into shore power, the charger is supplying a charge to both battery banks; when the engine is running, the alternator is charging both battery banks.

Still simple as apple pie. Follow the directions and you can't go wrong. I did and I have a habit of burning stuff up with electricity. You know? That mysterios blue smoke?

[btrayfors]

Yeah, Rick...you gotta watch that blue smoke. In most electronic devices, it's the smoke which makes 'em work, and if you let it out it's damnably hard to put it back :-)

Yes, the BSS ACR is just an automatic relay...it is a two-way device which combines the batteries whenever it senses a charging voltage on either battery, thereby allowing the charge to be distributed between the connected batteries.

The battery having the lowest SOC will benefit the most from whatever charging current is available. Eventually, over time, the batteries will stabilize at the same voltage and SOC.

Depending on several factors, it might still be best to connect the alternator directly to the house batteries, since direct connection to the start battery could trick the regulator into believing the batteries to be charged are at a higher SOC than they actually are, thereby needlessly and prematurely reducing its output.

Bill

[Target9000]

Originally Posted by Maine Sail

But you've now given up the ability to isolate a bank, in the event of an internal battery failure, and to use the start for house & starting loads or the house for starting & house loads..

Your only fail safe is to "combine" two banks. If one has catastrophically failed, as happened to a customer of mine this past summer, who had a Blue Seas DCP switch, he lost both banks because he could not "isolate" the bad bank without physical re-wiring...

Another customer killed an 800Ah AGM bank when his alt failed and he never knew it. He was motoring off shore in no winds and as such has been using his water-maker and inverter which took the bank to dead after having been on the hook for four days..

His only option was to use the "parallel" switch to get emergency house loads. He left it in that position a little too long and zap went his starting battery and it did not have enough juice to fire the motor. He was dead in the water with no wind... If he could have "switched" to the start battery and taken the house off line he may have had enough juice to safely get by with minimal devices. Turned out to be a failed external regulator...


There is no one right answer just LOTS of options!

Many of my customers prefer the wiring below when the want to isolate starting and house. It leaves them with full isolation and redundancy options and two switches are simply used as ON/OFF's..


(for simplicity fusing and other details not shown)



Emergency Bank Failure Switching


START BATTERY FAILURE - If the starting battery goes bad turn the 1/2/BOTH/OFF to BOTH and flip the ON/OFF to OFF you can now start your engine and run house loads off the house bank. Your starting battery is now isolated.

HOUSE BANK FAILURE - If the House bank goes bad flip to position #2 and leave the ON/OFF turned to ON. This will allow powering house and starting loads from the starting battery and allows it to act as your reserve bank.


Normal Every Day Use
Turn the 1/2/BOTH/OFF to #1/ON (I often place an ON sticker over #1) and the ON/OFF to ON..





While a tad more "complicated" than a single ON/OFF (DCP), or the three ON/OFF's, you have two ON's to do it is still very easy compared to most boating things. I leave a laminated use card in the nav desk. I have yet to have a customer misunderstand how it is use after an explanation.

In an emergency situation, they can happen, you still retain all the flexibility and isolation you'd want or need.

No one right or wrong way to wire them.

I generally prefer to be able to completely isolate a bank if needed and use an alternative bank as "reserve/emergency" if necessary as I have had enough examples of problems when "combine" or "parallel" are the only emergency options...

When wiring the alt direct to the battery I generally prefer to add a "service switch" or use a lever arm breaker with the proper AIC. This disconnects the alt when working on the engine and is out of sight for guests and crew..

If you were going to use a 1/2/B and On/Off instead of 3 x On/Off....

Why wouldn't you do it like this to really no brain it. You could just expose the On/Off to the crew for simplicity and only have to fiddle with the "more complicated" switch in the event of a failure.

[Target9000]

Also,

As a side note for those of you interested in wiring and diagrams. I found this site which I've been using to make my wiring diagrams.

Diagramly - Draw Diagrams Online

Its free. I've finally vanquished Visio for good!

[Maine Sail]

Originally Posted by knottybuoyz

Kinda, sorta Bill!

I have the first version of the Blue Sea ACR. It's slightly different than the current SI model. I went back to find the literature on it and it's not on the site anymore. Here's how the new ones work.

Connect the alternator to charge battery 1 (start battery), and connect the charger to charge battery 2 (house battery). When the charger is charging battery 2, the ACR will combine battery 2 and battery 1 for charging. When the alternator is charging battery 1, the ACR will connect battery 1 and battery 2, and both batteries will be charged. With the installation of the ACR, when at dock and plugged into shore power, the charger is supplying a charge to both battery banks; when the engine is running, the alternator is charging both battery banks.

Still simple as apple pie. Follow the directions and you can't go wrong. I did and I have a habit of burning stuff up with electricity. You know? That mysterios blue smoke?

This will work fine IF your house and start banks are close to the same size. If they are differing sizes you can create what is called relay cycling. It can take some time for the relay to remain latched to the house bank if the alt is feeding the starter battery first.. Blue Sea advises wiring to the house bank first if it is "larger"....

This is what they say in the installation instructions:

"Alternator connected to a larger battery bank is most efficient."


They then say this, as applied to sailboats, in their technical brief:

"A simple solution for boats with a large House battery bank and a relatively small Start battery bank, including many sailboats, is to connect the charging source to the House battery bank (see wiring diagram). This solution works because the Start battery bank is typically smaller and less discharged than the larger House battery bank. When the battery banks are combined for charging, there isn't a significant drain to lower the system voltage to the disconnect level."



There is no "recharging the start battery first" with the Blue Sea ACR. If it is wired to the start battery the voltage comes above "combine" VERY quickly and it "parallels" to the house. You have not put much of anything "back", in those few short seconds, and only driven the voltage up to combine level because the SOC of the start battery is near full anyway.

If the start battery was depleted your still not "re-charging it first" before it combines with the house. It combines when it hits 13.0V for 120 seconds or 13.6V at 30 seconds.

It is impossible to recharge a depleted battery in 120 seconds at 13.0V or 30 seconds at 13.6V..

With the older 7600 series you'd be best to wire the alt to house (if it is larger) and then connect the house to the "A" sense side so that it can combine with the starter when the house voltage is sufficient. The newer 120SI does a better job at limiting relay cycling..


Bill, I and others don't make this stuff up. Blue Sea wrote a technical article on this back in 2007:

Preventing Cycling in Battery Combiners, Voltage Sensitive Relays, and Automatic Charging Relays

[donradcliffe]

You guys really have too much time on your hands! Its going to be a sunny 67 degrees here, so I don't have to spend the day cooped up inside.

I would definitely NOT wire the alternator to the start battery. If you do the ACR has to transfer the full alternator output to the house battery. If you wire the alternator to the house battery, the ACR will only have to carry the small brief load needed to recharge the start battery.

I thought about the circuit that Maine uses to eliminate one switch. It will work, but I didn't suggest it because it requires some thinking to use it properly--your house battery has failed at 0300 (that's the time they always go) and your delivery crew needs to get things going again--do you want them to have to consult a wiring diagram and detailed instructions??

As far as using a multi-stage regulator to keep the starting battery topped up--only an electrician who is padding your bill would suggest that.

[CharlieJ]

Maine Sail Post #32
You have completely missed the point of my post #2. If the starting battery fails, open the start battery isolation switch and close the emergency start switch and the house battery is now available to start the engine or engines.

I have installed this system on a number of commercial fishing boats and the fishermen love them because of the simplicity and the hands off nature of keeping all the batteries on board charged.

Hope this clarifies.
Charlie

[Maine Sail]

Originally Posted by CharlieJ

Maine Sail Post #32
You have completely missed the point of my post #2. If the starting battery fails, open the start battery isolation switch and close the emergency start switch and the house battery is now available to start the engine or engines.

I have installed this system on a number of commercial fishing boats and the fishermen love them because of the simplicity and the hands off nature of keeping all the batteries on board charged.

Hope this clarifies.
Charlie

I agree but in re-reading my post should I can see it should have been clearer and included the "when not properly wired" statement. My comments were based on the way I most often see them wired, which is the incorrect way to wire them..

All too often, probably 8 out of 10 installs (including one reputable builder) I have seen the three ON/OFF's wired with the "parallel" switch on the battery side of the ON/OFF's when it should be connected to the load side.

If connected "properly" you do have isolation IF you turn OFF the battery switch for the offending bank and turn ON the parallel switch. The Blue Sea DCP switch tries to simplify on this concept but does not allow you to fully isolate a bank.

These are not difficult to install properly but sadly many don't. For many owners they already have a 1/2/BOTH and it is often located in a DC panel so adding the ON/OFF to it becomes the least invasive and least expensive method for the customer if slightly more complicated...

[Kettlewell]

Charlie J: The three-switch method sounds relatively simple for the knowledgeable boater, but I think it is not something that is completely intuitive for the uninitiated, or the person who is not thinking clearly when the anchor is dragging at 2 AM on a black night. Using the 1,2, Both switch as a distributor of power, but not as a distributor of charging makes normal boat ops. pretty straightforward. The main reason I don't like it is that I like to have a fully charged, dedicated start battery as the normal one the engine starts on to provide maximum cranking power and to isolate the electronics (which run off the house battery) from any power drops or voltage surges. Your system of three switches does that, but without knowledge of how that third parallel switch is wired up it is very likely that the unitiated will leave all switches on, thereby unintentionally or without thinking combining both banks in an emergency, possibly resulting in the start battery losing cranking power as it floods into the totally depleted house bank. I think that is the main objection to the three-switch scheme.

On my own boat I keep trying new switching schemes to get the most intuitive possible. If my wife or one of my kids has to call me up from the boat when she is there and I am at work to ask me exactly how to switch battery power around, I am not happy. I want it to be obvious what is happening.

[Maine Sail]

Originally Posted by Kettlewell

Charlie J: The three-switch method sounds relatively simple for the knowledgeable boater, but I think MaineSail (don't want to put words in here that aren't his--these are mine) is saying that he prefers something that is completely intuitive for the uninitiated, or the person who is not thinking clearly when the anchor is dragging at 2 AM on a black night. Using the 1,2, Both switch as a distributor of power, but not as a distributor of charging makes normal boat ops. pretty straightforward. The main reason I don't like it is that I like to have a fully charged, dedicated start battery as the normal one the engine starts on to provide maximum cranking power and to isolate the electronics (which run off the house battery) from any power drops or voltage surges. Your system of three switches does that, but without knowledge of how that third parallel switch is wired up it is very likely that the unitiated will leave all switches on, thereby unintentionally or without thinking combining both banks in an emergency, possibly resulting in the start battery losing cranking power as it floods into the totally depleted house bank. I think that is the main objection to the three-switch scheme.

On my own boat I keep trying new switching schemes to get the most intuitive possible. If my wife or one of my kids has to call me up from the boat when she is there and I am at work to ask me exactly how to switch battery power around, I am not happy. I want it to be obvious what is happening.

When I wire the three ON/OFF method, which I do, I place a LARGE sticker or engraved plaque that says EMERGENCY PARALLEL directly above it or below it....

Should be no confusion.... People can still forget to turn OFF one of the bank switches though and combine a good bank with a bad one.

There is no "ultimate" set up I have found and all of them have their pro's & con's.

Heck on my own boat I use a simple 1/2/BOTH only and start of the house bank. I know blasphemy.....

I have done so for well over 20 years and don't experience drop out and have not been able to measure any "transient spikes" on the DC panel side of the system even with a very fast o-scope, batteries are great filters... Certainly what I choose to do is not for every one but it works well for me. I treat my second battery bank as my "reserve"......

There are MANY boats & owners where I would adamantly advise against doing this and some I have no problem with it..

I even install the DCP switch on some fishing boats even though I am not crazy about it on deep cycling cruising boats......

Plenty of options out there!!

[CharlieJ]

Kettlewell-
Yup...you can lead a horse to water but you really haven't accomplished much unless you teach him the backstroke!

I have been able to "train" commercial fisherman so the system is not that difficult to figure out!!

I, like MainSail, placard the emergency starting switch with, you guessed it, "EMERGENCY STARTING SWITCH". I do not use the term paralleling switch since this system does not parallel, it substitutes.

Charlie

[Kettlewell]

For a very long time I set up various boats to have just one large battery bank that was either on or off, period, and I kept an eye on the voltage. All the charging sources and loads went to one bank (super simple). I had solar panels connected direct to the batteries via switches so that I would still get charging when everything else was off. Normally I would leave all the panels feeding power to the batteries, but when I left for a long time I would shut down all except for a small 5-watt panel that kept the batteries topped up. I lived aboard that way for more than 12 years straight at one point. As long as you keep an eye on things it works fine and can eliminate a lot of other problems that you create by trying to be too clever and have your system be able to cover every contingency with some series of switches and devices. It would be easy to carry a small starting battery or jump starter somewhere as your ultimate backup for starting; however, I wonder if we overthink this and create more problems for ourselves than we solve.