Battery bank and monitor question

Chief RA · Dec 27, 2014

centerline: I am with you on to much backup! Pretty soon they need to paint a new waterline! You just can't be too careful in case you lose shore power! Happy New Year, Chief

Bob 04 H260 · Dec 27, 2014

Chris, I went with the Echo charger on our boat because I thought it was a better solution than an ACR, but everyone has their own ideas of what is best.

I start my diesel once in a while on my emergency battery to test it but usually just leave all the switches in one place and then there is no chance I'll forget to switch it back.

I have 3 outputs on my 50 A charger. I ganged them all together with a piece of copper bar, then ran the wire to the selector switch. I think it is easier on the charger that way. Even though they can run 50 Amps through one output stage I think the charger will last much longer if they are all running at a lower current. As an expert in electronics I know you get this.

Fair winds, Bob

Benny17441 · Dec 27, 2014

Maine Sail said:
He already has a back up bank, it's called the starting bank.. He was wired for a third back up bank... How many spare tires do you carry....

I'd seen no mention of a starting battery in the original post and I'd missed that in a latter post he mentioned that by the way he had a starter battery. In such case he would be best served by combining the house batteries into a larger bank as indeed a starting bank would provide a redundant source of power. For those that do not have a starting battery and just use a standard two battery systems my recommendation still goes. Consider your needs and only trade away a backup source of power if you have to. As far as spare tires I do not have a trailer for our boat. :naughty:

mitiempo · Dec 27, 2014

The positive wires from each battery should be fused close to the post. The negative should not be fused.

centerline · Dec 27, 2014

holdech said:
I'm learning a lot from this thread.

For charging "on the hook" the alternator/solar/wind/etc sources will be connected directly to the "house bank" (which will be a pair of parallel wired group 27's). I'll use an ACR (or echo charger) to keep the starting/backup battery charged (single group 24).

On shorepower, I currently have a Xantrex Truecharge 40+ wired to each individual battery (the house bank is currently not wired in parallel but to a 1/2/both switch). If I run from only one of the house batteries then the charger manages each batteries charging individually (which is good).

In my new configuration, I can use one of the Xantrex outputs to charge the "house bank" (both batteries in parallel). Since I will be discharging both batteries "as one", this should be fine for charging.

Note- the Xantrex charger I have will provide a max of 40 amps to batteries, divided across the batteries connected to it. So my house bank could receive all 40 amps even if connected to only one output on the charger.

So now my question - what about the starting/backup battery? An ACR will essentially "parallel" connect it to the house bank. The starter/backup battery will see extremely little use/discharge. Will this be any problem when paralleled to larger capacity batteries that will be deeper discharged?
Alternatively, the "echo charger" claims to control charging of the slave battery and shut of when it's charged - although it costs twice what an ACR does.

I feel like I'm over-thinking this... A problem with us northern sailors over the winter months - when we can't work on our boats

Oh - a comment about starting on the house bank. Why? I start from the starting battery so I always know it's condition.
If I only use it for emergency/backup then I take a chance if it's not "tested" on a periodic basis (by using it to start the engine). To me it's like a computer backup i.e. an untested backup is like no backup.

Chris

when you get the ACR "combiner" hooked up. you will connect the the charger/solar to only the house bank... the start battery will be down stream and will not be damaged by overcharging, but will have all the charge voltage spilling over into it that it needs... no worries at all.

as for the claims of the echo charger controlling the charge of the slave battery, without a few more wires being needed, it isnt possible. and is unnecessary for the distances we are using. if the banks were a boat length apart, it would make a difference.

so, as the juice flows from the charger into the batteries that the charger is connected to, the battery that is connected remotely to them will be able to benefit and uptake some of that power...
when its full of charge and cant take anymore, the current flow will essentially "backup", and if the other batteries are also full, the charger will sense it and shut off....

if during several starts, you lower the charge in your start battery enough, some of charge from the house bank, assuming its still full, can spill over thru the ACR to replenish the loss from the start batt... this is a very slow transfer process, so the house bank cant be used to "start" the engine. (you will have to use the "1-2-both" switch for that)
if this drops the charge enough in the house bank, the charger will kick on and bring them all equally up to snuff again.

if you deeply discharge the house bank and the charger is running full tilt trying to get them back up to where they need to be, the high current/voltage is NOT running thru the downstream battery to get to the house bank. so there is no problem.
the ACR works in mysterious ways to keep the separate banks charged and protected

it really is a good secure setup...

with the proper set up, there is no reason or need to test the two different systems by starting the engine with them.... with proper care and maintenance (which means we have the right tools for the job) you will always know the condition of the banks and the condition of the individual batteries....

Bob 04 H260 · Dec 27, 2014

I used an echo charger on my emergency battery. This keeps the emergency battery fully charged and separated from the house bank. I thought an ACR could connect a large battery bank (400 Ahr's in my case) that was down maybe 40% on to a fully charged emergency battery of only 100 AHrs in size.

I don't know when an ACR combines the house and emergency banks but if it as soon as the alternator turns on I think there maybe a lot of current flowing between the small fully charged emergency start battery and the half charged house bank. I did not think this was a good idea.
If the ACR is smart enough to wait until both banks are equal then it would not be an issue.

I have never owned an ACR so it may not be a problem, it might be something to check into.

Bob

mitiempo · Dec 27, 2014

centerline said:
as for the claims of the echo charger controlling the charge of the slave battery, without a few more wires being needed, it isnt possible. and is unnecessary for the distances we are using. if the banks were a boat length apart, it would make a difference.

if during several starts, you lower the charge in your start battery enough, some of charge from the house bank, assuming its still full, can spill over thru the ACR to replenish the loss from the start batt... this is a very slow transfer process, so the house bank cant be used to "start" the engine. (you will have to use the "1-2-both" switch for that)

Neither an ACR nor an Echo Charger will pass on current to the start battery unless the house bank is being charged. The Echo Charge needs 13 volts to be activated to pass current. An ACR needs 13 volts (for a period of 90 seconds) to combine. The house bank will be below this voltage unless it is being charged.

Not sure what you mean by "...claims of the Echo Charge controlling the charge of the start battery..." That is exactly what it is designed to do and it is very effective at doing.

mitiempo · Dec 27, 2014

Bob 04 H260 said:
I thought an ACR could connect a large battery bank (400 Ahr's in my case) that was down maybe 40% on to a fully charged emergency battery of only 100 AHrs in size.

I don't know when an ACR combines the house and emergency banks but if it as soon as the alternator turns on I think there maybe a lot of current flowing between the small fully charged emergency start battery and the half charged house bank. I did not think this was a good idea.
If the ACR is smart enough to wait until both banks are equal then it would not be an issue.
Bob

A Blue Seas ACR will combine at 13 volts after a period of 90 seconds or at 13.6 volts after 30 seconds. When the batteries are combined they will each accept what they need. I have not ever seen a problem with an ACR regardless of the voltages of each bank. One of the most reliable items on a boat.

woodster · Dec 27, 2014

the echo charger is a good product and it will keep the start bat up when the alt is running
and it will not combine the two banks it just uses what is extra from the house bank charge..but then if you never use the start bat it does not have to work to hard

Bob 04 H260 · Dec 27, 2014

holdech said:
Hey Bob - we sailed the North Channel together back when you had your Mac 26S! Nice to hear from you.

Chris

Hi Chris, good to "see" you again. I remember you well. Enjoyed the cruise in the North Channel very much.
Let me know when you are going to do your alternator up grade. I did it on our Yanmar a couple of years back. There are some pics of it in my profile album if you are interested. I also added the flat serpentine belt conversion and external regulator as well.

We are heading south Jan 1st and intend do a cruise to the Bahamas on our Hunter 356.

Take care and stay in touch, Bob

mitiempo · Dec 28, 2014

Chris

Fuses should be in the positive cable within 7" of the battery post. ABYC calls for fusing in the positive cable. Do not fuse the negative. Fuse each bank, not each battery. If you are using 2/0 for each bank both should be fused at 250 amps as both can be used for starting. If the wire to the panel is smaller - likely it is - fuse it appropriately.

Maine Sail · Dec 28, 2014

centerline said:
as for the claims of the echo charger controlling the charge of the slave battery, without a few more wires being needed, it isnt possible. and is unnecessary for the distances we are using. if the banks were a boat length apart, it would make a difference.

The Echo Charger works perfectly fine and is specifically intended for keeping small AUX or starting batteries topped up. There is no need for any additional wires.

In many instances an Echo Charger wind's up being less costly than installing an ACR due to the larger wiring and over current protection needed for the ACR.. Remember a 3% voltage drop at 14.4V results in just 14V at the battery... With the Echo's limit of 15A this means AUX or Start battery charging can be done with significantly smaller wiring no matter how big the alternator, charger, inverter charger etc...

centerline said:
when its full of charge and cant take anymore, the current flow will essentially "backup", and if the other batteries are also full, the charger will sense it and shut off....

Charger's don't shut off. They simply pulse the power supply on and off to maintain a voltage. Some do a MUCH better job than others at low mA level current delivery. Some good ones are stable down to 0.1A or lower while some others can't do much below 2A without pulsing the power supply......

ACR's and Echo or Duo Chargers only shut off/un-combine when the system voltage drops below a pre-set point. Most are in or around 13.0V for automatic turn on... Echo's & Duo's are voltage followers. They follow the voltage of the house bank minus a tad bit of voltage drop. neither will go into float on its own they only float when the house bank floats. ACR's are nothing more than an automatic BOTH device which turns on or off based on voltage. They are technically called VSR's or voltage sensitive relays.. With VSR's batteries charge in parallel at the same voltage for both banks.

centerline said:
if during several starts, you lower the charge in your start battery enough, some of charge from the house bank, assuming its still full, can spill over thru the ACR to replenish the loss from the start batt... this is a very slow transfer process, so the house bank cant be used to "start" the engine. (you will have to use the "1-2-both" switch for that)
if this drops the charge enough in the house bank, the charger will kick on and bring them all equally up to snuff again.

Again teh ACR combines based on voltage. If the house bank comes up to 13.0V then the banks are paralleled. Only a drop in voltage can make the ACR un-combine. The "transfer process" with a VSR/ACR is as fast as the batteries can accept the current at XX% SOC and XX.XX volts or as much as the system can deliver.. The only limit to an ACR is what the relay itself can handle. If you have a 120A rated model then you don't want a 160A alternator....

centerline said:
if you deeply discharge the house bank and the charger is running full tilt trying to get them back up to where they need to be, the high current/voltage is NOT running thru the downstream battery to get to the house bank. so there is no problem.

This is true! IF the ACR is PROPERLY wired for a deep cycled house bank. The proper wiring for any ACR, on a cycling bank, is to run ALL charge sources direct to the larger house bank. This prevents relay cycling.

centerline said:
the ACR works in mysterious ways to keep the separate banks charged and protected

There is absolutely nothing mysterious about the ACR. It is nothing more than an automated BOTH feature....

Voltage Above Turn On = Batteries Paralleled/Combined
Voltage Below Turn On = Batteries Isolated/Not Combined

VSR/ACR's, Echo Chargers & Duo Chargers are all excellent products and what you are doing or trying to accomplish with them dictates which product you choose for the job...

Bob 04 H260 said:
I thought an ACR could connect a large battery bank (400 Ahr's in my case) that was down maybe 40% on to a fully charged emergency battery of only 100 AHrs in size.

An ACR can connect banks of any size you need to. It is no different than you flipping the BOTH switch to BOTH only it does so automatically based on system voltages.[/quote]

Bob 04 H260 said:
I don't know when an ACR combines the house and emergency banks but if it as soon as the alternator turns on I think there maybe a lot of current flowing between the small fully charged emergency start battery and the half charged house bank. I did not think this was a good idea.

There is sooo much misinformation out there about ACR's that it is really sad.. If the house bank has come up to 13.0V then it will combine. At that point the batteries will take what ever current they need or can accept, off the system bus, at XX.XX volts and XX% SOC. Very simple devices...

Bob 04 H260 said:
If the ACR is smart enough to wait until both banks are equal then it would not be an issue.

Again there is no need to wait until the banks are equal because they will take what they need.... The start battery will need next to nothing so it will take next to nothing off the system. The house bank has the greatest need so it will take almost all the current... Once battery voltage reaches parity (parallel), which happens quickly, the batteries simply take what they need in current..

Bob 04 H260 said:
I have never owned an ACR so it may not be a problem, it might be something to check into.

Bob

Between all the manufactures of VSR's there are literally millions of them in service world wide.. No issues other than installer error.... If you already have an Echo charger and it works for what you do then keep it.... If you are starting from scratch then weigh the options and true installed cost......

holdech said:
Alternatively, the "echo charger" claims to control charging of the slave battery and shut of when it's charged - although it costs twice what an ACR does.

The Echo Charger manual is not only grossly misleading it is blatantly incorrect in many cases. I have been after Xantrex to make changes to that manual now for almost 10 years. They could really care less about the inaccuracies or misleading information and even today the manual remains unchanged..

FACT: The Echo Charger DOES NOT TURN OFF WHEN THE BATTERIES ARE FULL. It only turns off when house bank voltage drops below 13.0V. Pulling the fuse or dropping below 13.0V are the only things that turn off the Echo Charger.

More:

1) The manual is rather unclear that this device MUST be fed from the HOUSE bank and that ALL charge sources, solar, wind or alternator MUST be attached to the house bank. Competent installers know this but DIY's RARELY pick up on this. I have had approx 20 or more service calls for improperly wired Echo Chargers due to the piss poor manual. Because of this a $120.00 device quickly turns into a $300.00 device....

The Echo should not be used with a factory wired 1/2/BOTH/OFF switch where the alternator feeds back through the starter cable. The Alternator needs to be re-routed to the house bank for the Echo Charger to work properly.

2) The Echo Charger does not work BACKWARDS and WILL NOT work in reverse like an ACR can/will. If your starting bank is wired to position #2 on the battery switch and the charge sources are feeding it first, because of the battery switch position, eg: factory wiring scenario, the Echo Charger will do NOTHING other than sit there and look pretty. This is not made clear in the manual..

3) I will quote the manual here:

Xantrex said:

When the input voltage is 13.0/25.5 volts DC or higher, echo-charge automatically switches ON. The LED glows a steady green.

Click to expand

So far so good but the input voltage for the Echo is always measured at the HOUSE bank therefore ALL charge sources need to be fed to the HOUSE bank first.This is not made clear in the manual and many of them get installed incorrectly then don't work.

Xantrex said:

When the input voltage is lower than 13.0/25.5 volts, the echo-charge automatically switches OFF, and the LED blinks green.

Click to expand

Again this is correct information. When the house bank voltage drops below 13.0 Volts the unit turns off.

Additionally the unit NEVER turns off otherwise! This too is not made clear and should be.. The Echo DOES NOT turn off when the start battery is full as many owners AND professional installers think it does. 13+ volts is ON, less than 13 volts is OFF. The state of charge of the start or reserve battery DOES NOT turn the device on or off UNLESS it is greater than a 10V difference and then the Echo shuts off or won't turn on at all. They NEED to make this clear that the Echo does NOT turn off when the start battery is "full"..

Back to the manual:

Xantrex said:

If the input voltage is above 14.4 volts (or 28.8), output will be limited to a maximum of 14.4/28.8 volts.

Click to expand

This is accurate and good because who wants to feed a fully charged battery at 14.5-14.8 volts despite the "low current".. The limit of 14.4 volts is a good one, unless of course you have a flooded battery that wants 14.6V to 14.8V to remain healthy such as Trojan.....

Xantrex said:

When it reaches 14.4/28.8 volts, the charge current will decrease, maintaining a float condition. The starter battery will be fully charged without overcharging.

Click to expand

Again this is grossly misleading and is pure BS. 14.4V is NOT a float voltage. All they are saying here is that the battery will accept less current when it is full than it does when less full. This is simple battery charging/acceptance 101.. The Echo does not, and will not, enter float mode independently from the house bank. As long as the house bank is in absorption or bulk the Echo is simply "following" its voltage up to a max of 14.4V.Nowhere on this planet is 14.4V a "float condition"...

So in summary:

1) The Echo DOES NOT shut off when the start battery is full.

2) Charge sources like wind, solar, alternator and charger need to be fed directly to the house bank. A wiring diagram and description including all charge sources is needed.

3) The Echo Charger is a one way device. It senses voltage from the house bank TO the starter bank. It will not work backwards like an ACR can.

4) It does not float the start battery independently of the house bank..

walt · Dec 28, 2014

I looked at the Echo manual.. it shows the charging source connected to the house battery..

Also, the manual does say the Echo will limit the charging current to the aux battery when the aux battery voltage reaches 14.4.

The Echo charger has the ability to limit current (other wise you would be blowing that 20 amp fuse) and measures voltage for both the house and aux batteries. It would be very simple for it to measure the voltage at the aux battery and cut back (or stop completely) current from the house bank when the Echo sensed that the aux battery reached 14.4 volts... Very easy..

If I read the last email correctly, you are saying that the Echo charger does not limit current flow from the house battery to the aux battery if it senses the aux battery at 14.4 volts.

How do you know this?

Here is the manual I found http://www.xantrex.com/documents/Ac...er/Echo-charge-OwnerGuide(445-0204-01-01).pdf

Maine Sail · Dec 28, 2014

walt said:
I looked at the Echo manual.. it shows the charging source connected to the house battery..

Also, the manual does say the Echo will limit the charging current to the aux battery when the aux battery voltage reaches 14.4.

The Echo charger has the ability to limit current (other wise you would be blowing that 20 amp fuse) and measures voltage for both the house and aux batteries. It would be very simple for it to measure the voltage at the aux battery and cut back (or stop completely) current from the house bank when the Echo sensed that the aux battery reached 14.4 volts... Very easy..

If I read the last email correctly, you are saying that the Echo charger does not limit current flow from the house battery to the aux battery if it senses the aux battery at 14.4 volts.

How do you know this?

Here is the manual I found http://www.xantrex.com/documents/Ac...er/Echo-charge-OwnerGuide(445-0204-01-01).pdf

Walt,

It is the start battery that limits how much current it will accept at 14.4V and X% SOC not the Echo.. The Echo has an overall current limit of 15A.. Once the battery comes up to 14.4V the only way for the current to go is DOWN. The Echo does not cause this, the SOC and declining acceptance at 14.4V cause this to happen as the SOC gets higher and higher.

My point is Xantrex is trying to get folks to think the Echo will "Float" batteries and the only way it will do that is if the house bank is also floating... Stopping when the bank hits 14.4V does not mean the battery is full just that it reached absorption voltage. You don't want it to stop at 14.4V or it never gets a healthy gassing voltage.

I have yet to talk to a single Xantrex Echo Charger owner who fully comprehends how it works. This is pretty sad and is a direct result of the very poorly worded and written manual? The product is great, the manual is absolutely horrible.

Remember this is a device meant and intended to be used with all charge sources feeding from the house bank to the AUX bank..

Xantrex said:
The Xantrex Digital echo-charge is specially developed for charging an
auxiliary battery with FreedomTM or Fleet Power® Inverter/Chargers or with any charging source.

This means wind, solar, hydro gens, battery charger and alternator can all be used with the Echo Charger. Sadly there is not one mention in the manual about making sure all charge sources go to the house bank. The diagram only includes a photo of an inverter/charger. Many owners have made the mistake of wiring it incorrectly due to the piss poor manual. I always feel badly charging folks to correct these issues, but it is what it is, because of the manual..

Again, I know of not one battery manufacturer of 12V batteries who considers 14.4V a float voltage? Calling a reduction in current that has to happen due to declining battery acceptance a "float condition" is entirely & grossly misleading.

walt · Dec 28, 2014

Batteries them selves don’t limit current. Acceptance is a from a combination of the charger - battery working as a system. For example, a battery might be limiting acceptance current at 14.4 volts. But if the charger were changed to try and operate the battery at 20 volts, there might be a huge current into the battery - even though its voltage is at 14.4.

If I read the manual correct (and have no reason to think they are lying), it says that the Echo charger will shut down current into the aux battery when the aux battery reaches 14.4. Sure.. most batteries on a charger at 14.4 would have their current limited because that is all they would accept. But in this case, the manual says that the Echo charger will limit current to the aux battery.. The charger itself can shut down current to the aux battery at 14.4. Somehow I thought you said this was not true, maybe I just read things off (which has happened before..). Also, the Echo charger can shut down current if the difference between the batteries is greater than 10 volts. It likely does this to limit internal heat.

Now does this matter much.. nope. But here is an example. Say you had a charging source on the house bank that was for some reason trying to charge the batteries to 15 volts. With the ACR, both batteries get connected at 13 volts and always stay connected even at 15 volts.

But according the Echo manual, in the example above, even though the house bank was being charged at 15 volts (just what I picked for the example, you would "mostly" not want this), the Echo charger would connect both batteries at 13 volts but when the aux battery reached 14.4V, the Echo charger would limit or reduce to zero the current to the aux battery so that the aux battery does not go above 14.4.

I understand the issue of the manual calling 14.4 float..

And.. good point abouit equilizing.. with the Echo charger, you coulld equilize the house bank but you could not get the aux battery over 14.4

centerline · Dec 28, 2014

Quote:
Originally Posted by centerline View Post
if during several starts, you lower the charge in your start battery enough, some of charge from the house bank, assuming its still full, can spill over thru the ACR to replenish the loss from the start batt... this is a very slow transfer process, so the house bank cant be used to "start" the engine. (you will have to use the "1-2-both" switch for that)
if this drops the charge enough in the house bank, the charger will kick on and bring them all equally up to snuff again.

clarified by MaineSail

Again teh ACR combines based on voltage. If the house bank comes up to 13.0V then the banks are paralleled. Only a drop in voltage can make the ACR un-combine. The "transfer process" with a VSR/ACR is as fast as the batteries can accept the current at XX% SOC and XX.XX volts or as much as the system can deliver.. The only limit to an ACR is what the relay itself can handle. If you have a 120A rated model then you don't want a 160A alternator....
------------------------------------------------------------------------------------------------------
MaineSail, Thanks for all the great explanation of it in your earlier post, but i still need a bit of help understanding the above paragraph that you wrote.

does the ACR in fact, actually act as a combiner to supply high amperage from the "house" when/if the starter needs more amps than the "start" battery has in it to give?...(such as a damaged battery, or too small of battery)

the whole point of my post was to simplify a rather indepth explaination of how it all works together, and that if the ACR gets connected correctly, its basically fool proof....
the above paragraph is meant to explain in a short simple way that it does NOT automatically combine the banks for starting when you hit the starter switch, because any rate of transfer between the banks would be too slow for that purpose.
but maybe im wrong...

Battery bank and monitor question

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