Basic Solar Wiring - 1 2 Both Switch

[ramblinrod]

Originally Posted by skipmac

My opinion (for what that's worth) but also that of several boating experts whose opinions I highly respect like Maine Sail aka Compass Marine, the simplest, best, safest and most bulletproof option is to connect ALL charging sources directly to the house batteries. Several reasons.

1. The house batteries are by far the ones that need charging. Starting uses a tiny fraction of the amp hour capacity from the start batteries.


[COLOR="Red"]If one has a dedicated, isolated start battery, and no automatic combining device, then the best failsafe solution is to connect the alternator to the start battery.

Per your suggestion, if the alternator is connected to the house bank, and the switch is not put to both when the engine is run, eventually, the start battery will die (unbeknownst to the operator if not monitoring batteries). If the house bank is also drained (due to lack of monitoring), there is no way to start the vessel (if not equipped with hand crank, booster pack, etc.).

Conversely, if the alternator is connected to the start bank as I suggest, under the same conditions, and the house bank dies, they can still start the engine with the start battery, and recharge the house bank.

The only "no start" fault mode in the method I described, is if one leaves the switch in the both position to run loads and all batteries are killed. This will happen in either scenario.

Therefore the way I have described IS the most failsafe solution.

But everyone is free to do as they wish.

I agree that when using an ACR, it makes more sense to connect the alternator to the house bank, BUT not when a 1/2/Both/Off switch is used instead. COLOR]

2. The alternator will always be connected to a battery so will avoid any risk of accidentally disconnecting and damaging the alternator with or without an ACR.

Correct, from this aspect, it makes no difference if the alternator is connected to either the house bank or start.

3. Install one of the several, very reliable and simple auto battery connectors which can be ACR, VCR, Echo Charge, Combiner, etc. This gives automatic, no user intervention, fail safe charge to the start battery so it will always be charged with zero risk of someone (like a tired captain, "helpful" guest, curious child) putting the 1/2/Both switch in the wrong position leaving the start battery dead.

This is an alternate solution to a 1/2/both/off switch, and as I said in my post above, with an automatic combining device, then it is wise to connect to the house bank, as the starter battery is automatically charged without intervention, as in the method I described when a 1/2/Both/Off switch is used instead of an ACR.

4. The various types of automatic combiners are not expensive, $90-$125 if I recall, are reliable and easy to install.

And then there are the cables, connectors, and the risk of connecting it incorrectly if the boater is not well versed in battery handling and marine electrical wiring, or the cost of the marine electrical technician to do it properly.

My battery monitor and batteries are wired so all current in or out is counted by the monitor so net amps in or out are constantly and correctly shown. The monitor only counts amps IN/OUT for the house batteries but shows voltage for the start battery which is all that's needed.

Not possible if the start battery is being switched in and out by an automatic device. Is the coulomb counter considering the capacity of the house bank, or the house bank and starter? This will screw up the results of any coulomb counter. (Especially when people are making mistakes like connecting loads like windlasses or APs to the starter battery.) It has no way of knowing when the starter battery is or isn't combined with the house bank. This is true regardless of whether an ACR or 1/2/Both/Off switch is used.

You may think that you are just monitoring the house bank, but really you are receiving false information from what you think is the state of the house bank (because the coloumb counter can't alter the total capacity of the system based on when the start battery is switched in and out. This is also true of the new Balmar monitor; really screws them up.

This can only be solved if there is no switching in and out of batteries, ie. all house loads, windlass, thruster(s), and engine starter supplied by house bank. Which is a valid option (and the one I use), but not the most "failsafe". One has to monitor their batteries religiously to ensure they don't drain them so low the engine can't be started.

[ramblinrod]

Originally Posted by Maine Sail

Coulomb counters have many issues but this is not one of them. That is unless of course you wire the start battery to the shunt incorrectly, which I see regularly...

With a shunt based Ah counter the start battery is always wired to the load side of the shunt so that any energy taken by the start battery or fed by it to house is accounted for.. ACR's don't change the shunt wiring..

There is no way to make the coloumb counter display correctly when batteries are combined in and out.

Here is the wiring diagram provided by Xantrex.

http://www.xantrex.com/documents/Acc...-01_rev-C).pdf

When the house bank and start battery positive terminals are combined (by any means), current flowing from the start battery through loads, and current flowing from the charge source through the start battery is not counted. All display information relates to the house bank, not what the charging system(s) are actually supplying to the boat, nor what the loads are actually drawing from the combined battery sources. In this case, the house bank SOC will be as accurate as it can be.

If one moves the start battery neg. to the other side of the shunt, the opposite is true, now all of the current consumed by loads is accounted for, and all charge current to the batteries is accounted for, but the house bank SOC is off, as the calc is based on the capacity of the house bank, not the combined house bank and start battery.

So one must decide whether they want accurate house bank SOC or accurate vessel AH consumed and charged when wiring a coloumb counter type battery monitor.

Only way to solve this is run everything off the house bank.

[skipmac]

Originally Posted by oivivio

Good call skipmac. If I end up increasing my house bank capacity, I should probably consider increasing the alternator.

Thank you for all the advice! I'm ready to get this thing wired up correctly and keeping those batteries topped up.

Cheers!

Brad


Sent from my iPhone using Cruisers Sailing Forum

Good luck with the project. Run into any glitches help is just a keystroke away.

[skipmac]

Originally Posted by ramblinrod

Not possible if the start battery is being switched in and out by an automatic device. Is the coulomb counter considering the capacity of the house bank, or the house bank and starter? This will screw up the results of any coulomb counter. (Especially when people are making mistakes like connecting loads like windlasses or APs to the starter battery.) It has no way of knowing when the starter battery is or isn't combined with the house bank. This is true regardless of whether an ACR or 1/2/Both/Off switch is used.

You may think that you are just monitoring the house bank, but really you are receiving false information from what you think is the state of the house bank (because the coloumb counter can't alter the total capacity of the system based on when the start battery is switched in and out. This is also true of the new Balmar monitor; really screws them up.

This can only be solved if there is no switching in and out of batteries, ie. all house loads, windlass, thruster(s), and engine starter supplied by house bank. Which is a valid option (and the one I use), but not the most "failsafe". One has to monitor their batteries religiously to ensure they don't drain them so low the engine can't be started.

All correct but there really is no need to monitor amps in/out for the starting battery so I see no issues or confusion using a standard battery monitor.

The preferred way (at least my preferred way) to use a battery monitor is to "count coulombs" for the house bank only. That's the bank with the biggest loads, draws and charging so the one that one should monitor.

My monitor has a second connection to monitor voltage only on a second battery which is perfect for a start battery. Since it's used occasionally and often allowed to rest you can get a pretty good idea of SOC by checking the resting voltage.

No confusion, no problems and information you need for each system.

[Maine Sail]

Originally Posted by ramblinrod

There is no way to make the coloumb counter display correctly when batteries are combined in and out.

Here is the wiring diagram provided by Xantrex.

http://www.xantrex.com/documents/Acc...-01_rev-C).pdf

When the house bank and start battery positive terminals are combined (by any means), current flowing from the start battery through loads, and current flowing from the charge source through the start battery is not counted. All display information relates to the house bank, not what the charging system(s) are actually supplying to the boat, nor what the loads are actually drawing from the combined battery sources. In this case, the house bank SOC will be as accurate as it can be.

If one moves the start battery neg. to the other side of the shunt, the opposite is true, now all of the current consumed by loads is accounted for, and all charge current to the batteries is accounted for, but the house bank SOC is off, as the calc is based on the capacity of the house bank, not the combined house bank and start battery.

So one must decide whether they want accurate house bank SOC or accurate vessel AH consumed and charged when wiring a coloumb counter type battery monitor.

Only way to solve this is run everything off the house bank.

Rod,

You are not fully understanding how the Ah counter works. Paralleling batteries in or out of the system, or bringing on line an alternator, or charger or solar, (the bank also has no idea how big they are) has no effect on the house banks reading of current going into or out of the HOUSE bank.

The shunt reads the neg side current flowing into or out of the bank, it could also read the positive, but it does not for general safety purposes. It only needs to measure current in one side as it is the same on either.

To measure correctly the START battery, and all other loads, (as shown in the diagram) must be correctly wired on the LOAD side of the shunt. The start battery is just another load to the shunt and can either send current into the HOUSE or pull current from the HOUSE. Either way the shunt counts it.

The HOUSE bank Ah capacity does not change, nor does it need to, if the system is wired correctly. The shunt keeps track of what goes into the HOUSE bank, or out of it, hence the name Ah/Coulomb counter.

If you incorrectly wire the start battery to the house bank side of the shunt then you will really mess up the Coulomb counting. No loads can be on the HOUSE battery side of the shunt and this includes a start battery.

Coulomb counters are fraught with issues but paralleling is not one of them, if they are wired correctly, which many are not.


Also the Smart Gauge remains extremely accurate once the batteries are discharging again. This despite bringing parallel banks on-line or charge sources. Once the Smart Gauge "learns" the house banks discharging behavior it can hone in quite quickly once the banks once they isolate again, or charging ceases.

Merlin, the makers of the Smart Gauge, even offer a VSR/Combiner themselves called the Smart Bank. I would urge you to conduct some controlled testing so you have a better idea of how these things actually work.

Heck before I actually began many months of putting the Smart Gauge through the paces, I was convinced it could not work.. I proved myself wrong on that one.

[ramblinrod]

Originally Posted by Maine Sail

Rod,

You are not fully understanding how the Ah counter works. Paralleling batteries in or out of the system, or bringing on line an alternator, or charger or solar, (the bank also has no idea how big they are) has no effect on the house banks reading of current going into or out of the HOUSE bank.

The shunt reads the neg side current flowing into or out of the bank, it could also read the positive, but it does not for general safety purposes. It only needs to measure current in one side as it is the same on either.

To measure correctly the START battery, and all other loads, (as shown in the diagram) must be correctly wired on the LOAD side of the shunt. The start battery is just another load to the shunt and can either send current into the HOUSE or pull current from the HOUSE. Either way the shunt counts it.

The HOUSE bank Ah capacity does not change, nor does it need to, if the system is wired correctly. The shunt keeps track of what goes into the HOUSE bank, or out of it, hence the name Ah/Coulomb counter.

If you incorrectly wire the start battery to the house bank side of the shunt then you will really mess up the Coulomb counting. No loads can be on the HOUSE battery side of the shunt and this includes a start battery.

Coulomb counters are fraught with issues but paralleling is not one of them, if they are wired correctly, which many are not.


Also the Smart Gauge remains extremely accurate once the batteries are discharging again. This despite bringing parallel banks on-line or charge sources. Once the Smart Gauge "learns" the house banks discharging behavior it can hone in quite quickly once the banks once they isolate again, or charging ceases.

Merlin, the makers of the Smart Gauge, even offer a VSR/Combiner themselves called the Smart Bank. I would urge you to conduct some controlled testing so you have a better idea of how these things actually work.

Heck before I actually began many months of putting the Smart Gauge through the paces, I was convinced it could not work.. I proved myself wrong on that one.

Please refer to the Xantrex Link Lite Battery Monitor wiring diagram I supplied the website link to above.

Note that the house bank negative is connected to the shunt "+" and the start battery negative connected to the shunt "-".

Is this the wiring scheme you are referring to?

[Maine Sail]

Originally Posted by ramblinrod

Please refer to the Xantrex Link Lite Battery Monitor wiring diagram I supplied the website link to above.

Note that the house bank negative is connected to the shunt "+" and the start battery negative connected to the shunt "-".

Is this the wiring scheme you are referring to?

If you zoom in on that image you will see that Xantrex has labeled the shunt "Battery -" & "System -". In other words the house battery side and load side of the shunt. The start battery is always wired to the "system -" or "load side" of the shunt. By doing this any start battery contribution or draw on the house bank gets seen & measured by the shunt.. The only thing that should be on the the house battery side of an Ah counter shunt is the house banks neg battery terminal.

The I+ and I- terminals are the volt sense wire connections for converting the mV drop across the shunt to a current reading inside the Link display.

[ramblinrod]

Originally Posted by Maine Sail

If you zoom in on that image you will see that Xantrex has labeled the shunt "Battery -" & "System -". In other words the house battery side and load side of the shunt. The start battery is always wired to the "system -" or "load side" of the shunt. By doing this any start battery contribution or draw on the house bank gets seen & measured by the shunt.. The only thing that should be on the the house battery side of an Ah counter shunt is the house banks neg battery terminal.

The I+ and I- terminals are the volt sense wire connections for converting the mV drop across the shunt to a current reading inside the Link display.

Sorry, I was using my own terminology (+ and -) to describe shunt connections.

To avoid all confusion lets refer to the diagram terminology.

Referring to the diagram, (especially the 3 polarity symbols in circles on the left side):

1. If a load is applied between "Battery Positive Main" and "Battery Negative (System Ground)", that current flows through the shunt.

2. If a load is applied between "Battery Positive Aux" (starter battery) and "Battery Negative (System Ground)", that current does not flow through the shunt.

3. If we connect "Battery Positive Main" to connection "1" and "Battery Positive Aux" to connection "2" of a 1/2/Both/Off switch and the switch "feed" to the load panel, then

i) In position "1", the load is supplied by the "Main Battery", and the resulting current flows through the shunt and is counted.

ii) In position "2", the load is supplied by the "Aux Battery", and the resulting current does not flow through the shunt and is not counted.

iii) In position "Both", the load is supplied by both batteries, some current coming from the "Main Battery" which is counted, and some current coming from the "Aux Battery" which is not counted.

[Maine Sail]

Originally Posted by ramblinrod

Sorry, I was using my own terminology (+ and -) to describe shunt connections.

To avoid all confusion lets refer to the diagram terminology.

Referring to the diagram, (especially the 3 polarity symbols in circles on the left side):

1. If a load is applied between "Battery Positive Main" and "Battery Negative (System Ground)", that current flows through the shunt.

2. If a load is applied between "Battery Positive Aux" (starter battery) and "Battery Negative (System Ground)", that current does not flow through the shunt.

3. If we connect "Battery Positive Main" to connection "1" and "Battery Positive Aux" to connection "2" of a 1/2/Both/Off switch and the switch "feed" to the load panel, then

i) In position "1", the load is supplied by the "Main Battery", and the resulting current flows through the shunt and is counted.

ii) In position "2", the load is supplied by the "Aux Battery", and the resulting current does not flow through the shunt and is not counted.

iii) In position "Both", the load is supplied by both batteries, some current coming from the "Main Battery" which is counted, and some current coming from the "Aux Battery" which is not counted.

Bingo! And now you've just explained why paralling the banks does not change the Ah capacity of the house bank and why paralling the banks does not throw off Ah counting of the house bank...

[ramblinrod]

Originally Posted by Maine Sail

Bingo! And now you've just explained why paralling the banks does not change the Ah capacity of the house bank and why paralling the banks does not throw off Ah counting of the house bank...

Yes, but this represents the problem, as I indicated, when start and house banks are combined it screws up the coulomb counter, it only addresses what is happening with the house bank, instead of the entire system. Ahrs charged on the Prolink, may be a fraction of what the charging system actually put out. Hrs consumed from the house bank, may be a fraction of the total energy consumed. Depends on how loads are connected and used.

To have the coulomb counter represent what is actually happening with all load and charging systems, all loads and charging systems must be connected to the house bank, which is not a fail safe system, as there may be insufficient energy left to start the engine.

[Maine Sail]

Originally Posted by ramblinrod

Yes, but this represents the problem, as I indicated, when start and house banks are combined it screws up the coulomb counter, it only addresses what is happening with the house bank, instead of the entire system. Ahrs charged on the Prolink, may be a fraction of what the charging system actually put out. Hrs consumed from the house bank, may be a fraction of the total energy consumed. Depends on how loads are connected and used.

To have the coulomb counter represent what is actually happening with all load and charging systems, all loads and charging systems must be connected to the house bank, which is not a fail safe system, as there may be insufficient energy left to start the engine.

Nope all loads only need to be connected to the load side of the shunt for the shunt to count what needs to be counted for the house bank. The start battery does not at all effect the Ah counting for the house bank it is just a load/source like any other...

[ramblinrod]

Originally Posted by Maine Sail

Nope all loads only need to be connected to the load side of the shunt for the shunt to count what needs to be counted for the house bank. The start battery does not at all effect the Ah counting for the house bank it is just a load/source like any other...

We are saying the same thing from different perspectives.

A) The battery monitor can accurately
Indicate what is going on with the house bank.

B) The battery monitor does not accurately
Indicate what is going on with the "system" when the start battery is combined with the house bank. (It still only monitors the house bank.)

[Maine Sail]

Originally Posted by ramblinrod

We are saying the same thing from different perspectives.

A) The battery monitor can accurately
Indicate what is going on with the house bank.

Absolutely!! I was addressing your statements below that were awfully confusing and could be very confusing to a newbie or less electrically inclined individual.

Originally Posted by ramblinrod

Beware that ACRs wreak havoc with coulomb counter type battery monitors, that aren't aware that various batteries are being switched in and out, especially with small house banks and light loads.

Originally Posted by ramblinrod

Not possible if the start battery is being switched in and out by an automatic device. Is the coulomb counter considering the capacity of the house bank, or the house bank and starter? This will screw up the results of any coulomb counter. (Especially when people are making mistakes like connecting loads like windlasses or APs to the starter battery.) It has no way of knowing when the starter battery is or isn't combined with the house bank. This is true regardless of whether an ACR or 1/2/Both/Off switch is used.

You may think that you are just monitoring the house bank, but really you are receiving false information from what you think is the state of the house bank (because the coloumb counter can't alter the total capacity of the system based on when the start battery is switched in and out. This is also true of the new Balmar monitor; really screws them up.

This can only be solved if there is no switching in and out of batteries, ie. all house loads, windlass, thruster(s), and engine starter supplied by house bank. Which is a valid option (and the one I use), but not the most "failsafe". One has to monitor their batteries religiously to ensure they don't drain them so low the engine can't be started.

Originally Posted by ramblinrod

There is no way to make the coloumb counter display correctly when batteries are combined in and out.

Originally Posted by ramblinrod

B) The battery monitor does not accurately
Indicate what is going on with the "system" when the start battery is combined with the house bank. (It still only monitors the house bank.)

The battery monitor is there to monitor the house bank, that is all it does, other than perhaps providing voltage of the start battery. If you want to know what is going on with a start battery, not really necessary other than voltage, then you would need an Ah counter for the start bank too.

I fully agree that using BOTH is almost never a good idea because you can forget and then discharge the start battery to 50% SOC along side the house bank. This of course has nothing to do with Ah counting the house bank it is just a forgetful move on the owners part. If you are using an actual thin plate el-cheapo "starting battery" then it won't put up with this for very long doing so. An Ah counter that monitors voltage of a start battery will alert you to the start battery being at other than 12.7V/full.

Using an ACR/VSR/Combiner is a much better choice than BOTH as it will automatically isolate the banks at a voltage level where we are not using actual stored capacity other than perhaps some surface charge. Unlike a human it does not forget to isolate the banks upon discharge. But again none of this messes with the Ah counting of the house bank for Ah's in or out...

Ah counters have many, many issues but paralleling banks for charging is not one of those issues. It is a device designed to monitor the house bank, not the other banks on-board. For those banks you would more battery monitors.

[ramblinrod]

Originally Posted by Maine Sail

Ah counters have many, many issues but paralleling banks for charging is not one of those issues. It is a device designed to monitor the house bank, not the other banks on-board. For those banks you would more battery monitors.

I have been drawing attention to the fact that it doesn't monitor what is happening with the start battery.

When start batteries and house banks are combined via switch or auto method, the data displayed is not related to the combined capacity, only the house bank.

This is especially relevant if one has a small house bank for light loads and uses the start battery a lot. This could be due to a hard starting engine, or if one has heavy loads connected to the start battery, like windlass, AP, or bilge pump (that I don't recommend but some people insist on doing anyway).

If a depleted start battery is combined to a fully charged house battery, with a solar charging system putting out 20 Ahrs over a period of time, the battery monitor will not report any of that if it all goes to the start battery.

In fact, some Ahrs may be drawn off the house battery by the start battery (none are really consumed, just transferred from one battery to the other).

For those who insist on splitting up the house bank, it's even worse.

And I completely agree, if one wants accurate data for all isolated banks, one needs a monitor for each bank OR just use one big bank for everything and one monitor, so that Ahrs in, Ahrs, out, SOC, and reserve capacity are accurately reported for the VESSEL, as I suggested in the first place.

[Stu Jackson]

Originally Posted by Maine Sail

Using an ACR/VSR/Combiner is a much better choice than BOTH as it will automatically isolate the banks at a voltage level where we are not using actual stored capacity other than perhaps some surface charge. Unlike a human it does not forget to isolate the banks upon discharge. But again none of this messes with the Ah counting of the house bank for Ah's in or out...

I just spent the past six weeks sailing our boat from San Francisco to British Columbia. Maine Sail and I have been proponents of his design for many, many years. I have a Link 2000 that does both batteries, but we kept our switch on the house bank all six weeks, we have a combiner, with the alternator output to the house bank. I did a LOT of motoring: 161.34 hours of it.

The system is flawless.

It's nonsense to deal with saying that coulomb counters don't work with this system.

No one should use BOTH on their 1-2-B switches, unless charging sources are present and ON. AND their ACR/combiner is broken.

This is so simple it boggles my mind every time this discussion arises.