battery monitor - follow-up

Bill Roosa · Nov 19, 2008

RESET the monitor FIRST

It is easy and cost nothing!!!!!!!!
OR
Go out an buy an new charger ........and then reset the monitor.

What you have been describing is a system where the batteries are charged and the charger is not coming on except occasionally when you are on the boat using the water pump or lights. You can't MAKE the charger come on if the batteries are charged!!!! The monitor is indicating a "Charge" of minus something when the batteries are clearly charged. Depending on what you want the monitor to read (keel offset is a good analogy) you can have the monitor read either zero AH when the batteries are dead or zero AH when the batteries are 50% discharged (or any other % for that matter). In fact you have a situation where the monitor reads negative when the batteries are charged up fully.
Break out the instruction manual and reset the sucker to your battery bank AH capacity (or 50% of it if you are doing the "keel offset" stuff).

If you are going to "embrace the horror" of DC electricity then embrace the horror and be done with it!

If all the above is confusing then you need to consider the following:
If you take a mercury thermometer and take the scale off the back then it will still respond to a change in temperature but you will have no valid reference to compare it to. If you put the scale back on in some place not identical to where it came off you will have a way to calculate temperature change but folks are going to think you are strange when you say it is 32 degrees out and the water is not freezing. You can accurately say the temp changed xx degrees but cannot tell the actual temperature. That is why you need to RESET it to a KNOWN state. Stick the sucker in water that is 32 degrees and then RESET the scale to read correctly.

Bill Roosa · Nov 19, 2008

Oh yea, I almost forgot

Achems razor

All other things being the same, the "solution" is usually the simply one!!!!!

Stu Jackson · Nov 19, 2008

Welcome back, John

I've been having problems, as posted to Phil, to find your earlier Link 1000 posts. I do recall our suggestions back then.

You're mixing apples and oranges in your questions.

What we suggested is that, as Bill just said, you need to reset your Link with fully charged batteries (yup, just like the manual says), but you also need to, as we suggested, make sure your charger is working by checking voltages, and making sure your A.C. switch is working.

If you haven't done those things, yet, all the questions in the world simply aren't gonna help.

John (again) · Nov 19, 2008

yes, but...

Stu Jackson said:
I've been having problems, as posted to Phil, to find your earlier Link 1000 posts. I do recall our suggestions back then.

You're mixing apples and oranges in your questions.

What we suggested is that, as Bill just said, you need to reset your Link with fully charged batteries (yup, just like the manual says), but you also need to, as we suggested, make sure your charger is working by checking voltages, and making sure your A.C. switch is working.

If you haven't done those things, yet, all the questions in the world simply aren't gonna help.

Yes, I remember Stu's advice (for which I thank him, as always) about resetting the battery monitor. I already set it to read what the batteries hold when fully charged. I know there is another setting I can make for the amp hours discharged, but the reason I'm wondering about that is this:

First, A week and a half ago, the monitor read -22.8 (or something like that); yesterday it was reading -36.8. If it's simply a matter of having to reset the monitor, why should it show having been discharged over these ten days, despite the fact that the shore power was plugged in and the AC main switch on?

Second, something seems to be screwy as far as showing the hours left. When the batteries are being charged, it should read "ccc", yet under certain conditions it shows the hours left even when the shore power is connected, the AC main is on and the charger is connected and its lights are on.

Third, as I said, when I reset the monitor to "flooded" batteries, after a half hour it showed a decrease in the amount discharged (by .1 amps).

I bow to Stu's far greater knowledge, but what I don't understand is if the problem is simply that the monitor needs resetting, how does this explain these things, the main one being why over ten days it would show that the batteries discharged almost 15 amps?

Stu Jackson · Nov 19, 2008

Phil fixed the search link, so, John,

here's the link to the last Link 1000 post you made:

http://forums.catalina.sailboatowners.com/showthread.php?p=578679

Reply #5 in that discusses how the Link "learns" your system. Reread that thread, please.

One of the comments was parasitic load, which is covered in the manual.

As previously noted, we are not sure that your charger is actually working, so, once again, why not do the diagnostics that are required, and find out if it really is working? Check the voltages. When you turn off the power to the charger, and then turn it back on, it should start up (at 14.4 or so) volts, because it's restarting its cycle. It'll most likely drop soon (to 13.2 (or so) for float). Or, see below, the bank is full and the charger doesn't have to work at all.

I already set it to read what the batteries hold when fully charged. I know there is another setting I can make for the amp hours discharged...

These are two different things. One is what you "declare" as the battery bank capacity. The other is a choice of how you read what the state of the battery amp hours remaining are.

why should it show having been discharged over these ten days,

See parasitic load above and the earlier discussion.

When the batteries are being charged, it should read "ccc", yet under certain conditions it shows the hours left even when the shore power is connected, the AC main is on and the charger is connected and its lights are on.

Yes it should show ccc when charging. That's why I keep saying I think you have an issue with your charging. Not necessarily your charger, per se, but your charging wiring, which i recall goes through your A.C. panel and requires you to leave it on. The lights may be on, but maybe nobody's home. You NEED to confirm that the amps ARE ACTUALLY GETTING from the charger to the battery bank, as recommended before you left. Or, see below, the bank is full and the charger doesn't have to work at all.

Third, as I said, when I reset the monitor to "flooded" batteries, after a half hour it showed a decrease in the amount discharged (by .1 amps).

Bill commented on this - all you're doing is changing from different charging voltages - it's meaningless.

but what I don't understand is if the problem is simply that the monitor needs resetting, how does this explain these things, the main one being why over ten days it would show that the batteries discharged almost 15 amps?

The good ole parasitic load of the Link 1000, which WILL occur because this is AMP HOURS and not AMPS. The reset to zero, which we've been suggesting to you, is the amp hours of your bank, and you seem still to be confusing this with amps being drawn or put in by your charger.

Bill may have nailed it, and you're dealing with full batteries with an out of whack Link 1000.

Either reset the Link with your full bank, OR deliberately discharge the house bank (leave some lights or the fridge on overnight). Take readings of everything before and after. Then charge up the bank after confirming that your charger output is actually getting to your bank, and reset the Link.

Again, as Bill said, if your battery banks are FULL, NO charging current will be shown, because the banks are full and the charger, while still ON, is no longer putting any amps into the batteries.

As noted in the previous linked thread, if you have the TrueCharge set to the position where there is no float, then the charger is turning itself off, and the parasitic load is showing negative amp hours.

Don12364 · Nov 19, 2008

Voltage is Important too.

John,
Don't get obsessed with the Ampere Hours of discharge without considering the battery voltage. If the voltage is 12.6 or below and you turn the charger on then you should see plenty of charging current.
For a voltage of between 12.6 and 13.5 there should be some charge rate but nothing like the full output from the charger.
Above 13.5 the charge rate will be minimal.
All the above voltages will vary a little due to differing types of battery technology (AGM, flooded etc.) They will also vary a little with temperature.
Again the above voltages are from a standing start without the charger switched on.
If the charger is functioning properly the voltage with the charger on will rise to 14.7.
If you are not seeing much charging current then suspect:-
1) The Link's shunt might not be in the correct position in the circuit. It MUST be either the first and only thing connected to the positive battery post or to the negative battery post to ensure that all current in or out goes through the shunt. (Only relevant if a new installation or someone has been tinkering with the wiring. If it once worked okay disregard this point).
2) The charger is not working correctly.
3) The batteries are duff.

To verify whether the charger or the Link is defective disconnect either pos or neg battery lead and temporarily insert an ammeter in circuit and see if and how much current is flowing. A cheap digital meter with a 10A or 20A range should suffice, even if it reads off scale you will still get your answer.

If the charger is US (unserviceable - sorry) then try it on another battery. To do this it might be necessary to take it home.
I have a Link 2000 on my Freedom (Xantrex) and it invariably tells the truth.

John (again) · Nov 20, 2008

This helps

Okay, this helps. The voltage reads above 14 (I forget exactly how much).

My main concern is not that it shows negative amp hours, but that this seems to be steadily increasing -- going from -22.6 to -36.9 over a ten day period, while the shore power was plugged in and the AC main switch was on. Maybe I'm missing something, but I can't understand how this could be merely due to the monitor needing to be reset - why the ah discharge should increase over time when it's supposed to be charging.

I'm going back down to the boat this afternoon to see what has happened in the last 24 hours.

Donalex said:
John,
Don't get obsessed with the Ampere Hours of discharge without considering the battery voltage. If the voltage is 12.6 or below and you turn the charger on then you should see plenty of charging current.
For a voltage of between 12.6 and 13.5 there should be some charge rate but nothing like the full output from the charger.
Above 13.5 the charge rate will be minimal.
All the above voltages will vary a little due to differing types of battery technology (AGM, flooded etc.) They will also vary a little with temperature.
Again the above voltages are from a standing start without the charger switched on.
If the charger is functioning properly the voltage with the charger on will rise to 14.7.
If you are not seeing much charging current then suspect:-
1) The Link's shunt might not be in the correct position in the circuit. It MUST be either the first and only thing connected to the positive battery post or to the negative battery post to ensure that all current in or out goes through the shunt. (Only relevant if a new installation or someone has been tinkering with the wiring. If it once worked okay disregard this point).
2) The charger is not working correctly.
3) The batteries are duff.

To verify whether the charger or the Link is defective disconnect either pos or neg battery lead and temporarily insert an ammeter in circuit and see if and how much current is flowing. A cheap digital meter with a 10A or 20A range should suffice, even if it reads off scale you will still get your answer.

If the charger is US (unserviceable - sorry) then try it on another battery. To do this it might be necessary to take it home.
I have a Link 2000 on my Freedom (Xantrex) and it invariably tells the truth.

Benny · Nov 20, 2008

Go back to basics, test the batteries themselves with a volt meter. If they are fully charged chances are your charger is working and just running on "maintenance". If dicharged look for a load or closed/short circuit and test the charger. Then worry about the battery monitor.

Bill Roosa · Nov 20, 2008

Boat batteries 101

Batteries are typically measured in their capacity to store electrons. Course saying my battery has 1X10^32 electrons is not very informative. Amps hours is a much more useful measure of utility as we don't really use electrons we use electron flow. The electrons flow right back to the battery so you really never "use" electrons. But amps is the flow of current so we need to introduce a time factor to get back to numbers of electrons because a batteries charge can't be measured in current flow.
or
number of electrons = amps (electrons/sec) X time (in hours). But seconds and hours will not cancel out you say and shouldn't there be a 3600 floating around here somewhere? Yes and no. Yes to get an answer that is scientifically meaningful but we are not doing science we are just trying to get the batteries charged. No because we ALWAYS use AH so the 3600 is floating into and out of all our work and we can ignore it. Just like you ignore the fact that the electrons really flow from negative to positive and not the other way round.

So a 100 AH battery is fully charged and your Link 1000 is set to some odd starting point like 23 AH. If you discharge the battery for 1 hour at 1 amp the battery will actually have 99 AH in it (100-1) and your link 1000 will show 22 AH (23-1) remaining. Now if you discharge the battery for 1 hour again at 25 amps the charge left will be 74 AH (99-25=74) and your link 1000 will show -2 AH (23-25=-2)! If you again discharge it for 1 hour at 10 amps the charge remaining will be 64 AH (74-10=64) and the link 1000 will show -12 AH.(-2-10=-12)
If you charge the battery for 1 hour at 5 amps it will have 69 AH (64+5=74) in it and the link 1000 will show -7 (-12+5=-7). You charged the battery and the absolute value of the link 1000 AH decreased!!!!!!!

The link 1000 values are not wrong just off by a constant factor (in this case) of 100-23=77 to low. Now if you reset the link to read that actual AH stored in the battery it might be a little less confusing as the AH leaving the battery would actually show as a smaller number (instead of a bigger negative number) on the link too.
You can do this in a variety of ways. the easiest being as the manual recommends charge the batteries completely and press the "reset AH to battery fully charged state" button sequence.

I think there is some confusion in the difference between AH used and AH in the battery. The two are related but completely different. AH used is change in battery charge while AH stored is the actual charge left in the battery. Just like your bank account adding $5 to your account does not mean you have $5 in it.

The easiest way to confirm the charger is working is to note voltage changes when it comes on.

For completeness:
Volts; the "pressure" that causes those electrons to flow through a resistive circuit.
Amps; a measure of the amount of electrons (measured in moles BTW) flowing past a given spot in 1 second. 1 mole of electrons flowing past you in 1 second is 1 amp.
Resistance; anything that causes the flow of electrons to be reduced for a given circuit voltage. Similar to friction but with some interesting types of "friction" being displayed by AC currents. Lowering the circuit voltage will also cause a reduction in the flow of electrons but we cover that in 102.

Volts (V) = amps (A) X resistance (R) V-IR
Watts (W) = Volts X amps P=VA Watts is a measure of power
Amp-hours (AH) = amps X time (t) (in hours not minutes etc)

I've clearly got too much time on my hands.

sailingdog · Nov 20, 2008

Bill-

You have a tiny error. V=IR, not V-IR...

You might also want to explain that Watts = Power = Volts x Amps

Volts (V) = amps (A) X resistance (R) V-IR
Watts (W) = Volts X amps P=VA Watts is a measure of power
Amp-hours (AH) = amps X time (t) (in hours not minutes etc)

Stu Jackson · Nov 20, 2008

Once again

John (again) said:
My main concern is not that it shows negative amp hours, but that this seems to be steadily increasing -- going from -22.6 to -36.9 over a ten day period, while the shore power was plugged in and the AC main switch was on. Maybe I'm missing something, but I can't understand how this could be merely due to the monitor needing to be reset - why the ah discharge should increase over time when it's supposed to be charging.

John, thought we'd covered this before. IF, I say again IF, your charger is not working, for whatever reason, this will happen because of the parasitic discharge of the Link itself. It's what i called DO THE MATH in the linked post from two weeks ago.

Why is your charger not working? One, it could be your A.C. side power to the charger. Two, it could be you left the Truecharge 20 on the setting where it does NOT switch to float, essentially turning itself OFF (i.e., position 2 that you described bulk/absorption).

This is from your earlier thread:

One of the switches on the Truecharge inverter/charger has three settings:
(1)bulk/absorption/flood; (2)bulk/absorption; and (3) (I forget exactly what it says, but it shows also 13.5, which I assume is the voltage.) I originally had it set on #2. When I switched it to #1 it the monitor showed that it was charging and within five minutes the ah went from -20.3 to -20.2.

We'd be interested in what you learn this afternoon.

Steve Dion · Nov 20, 2008

Maybe I am missing something here, but can't he just charge the battery and check the voltage with a multi-meter? This should show the actual voltage.

Stu Jackson · Nov 20, 2008

No problemo

John, your batteries are FULL.

As a few of us have been urging you to do: simply recalibrate the danged Link 1000.

It'd be a LOT easier for us to talk, rather than my fingers taking a beating in going through the details. Give me a call.

sailingdog · Nov 21, 2008

No, if you're trying to get the actual real voltage, you have to remove the surface charge that exists after charging the batteries. This "surface-charge" gives an artificially high voltage for the batteries. To get rid of the surface charge, you have to place the batteries under a load for a short period of time.

Steve Dion said:
Maybe I am missing something here, but can't he just charge the battery and check the voltage with a multi-meter? This should show the actual voltage.

John (aain) · Nov 21, 2008

conversation with Stu

Stu was kind enough to spend some time on the phone with me this morning. He agreed that if the monitor is showing a continually increasing negative amp hours (going from -22.4 to -39 or so over several weeks), and if this has happened while the shore power is plugged in and the AC switch is on, then there is some other problem. His suggestion was to check all connections, etc. Also, one point that I hadn't mentioned before on this forum is that the charger is plugged into a gfi receptacle. From time to time, this gfi pops. Stu's thought is that maybe this outlet is faulty. Over the weekend, I will trace this from the shore power source itself forward (or backward). I will let you know what I find.

None of this means that I should not recalibrate the monitor, but at this point I don't know what to recalibrate it to; I don't know when the batteries are fully charged up (vs. almost fully charged). Once I settle the other problems, then I will recalibrate the monitor.

John R. · Nov 22, 2008

I had a screw loose

My wife claims I still do and that she's been trying to tighten it down and recalibrate me for some time, without any success, but that's a different matter. As for the battery on the boat:

I had the idea of plugging the charger into an extension cord plugged into a different gfi to see if the gfi was bad. When I did that, bells and whistles went off, a siren sounded and there were flashing strobe lights and a beautiful woman descended from above with some prize money -- well, not really, but the monitor did show the charger was charging. I turned on the battery and all the different accessories, and turned off the AC. The monitor showed about a 10 amp draw. After drawing down the batteries a little, I turned the AC main back on and the monitor showed the battery being charged by about 8 amps and then descended as the battery charged up. Then I plugged the charger into the other gfi and everything was still working.

That seemed strange... What had changed? The only thing that had changed was that I'd been moving the plug around, so I thought maybe something was loose inside the plug. Sure enough, one of the wires inside it was loose. I reconnected that, and everything worked fine.

I did recalibrate the monitor as suggested, and it seems to be reading the battery status accurately.

My electrician friend had told me weeks ago to check all connections first... She was right!

Thanks to everybody who made suggestions and gave information.

Stu Jackson · Nov 23, 2008

Congratulations

Gee, these forums really DO work!

battery monitor - follow-up

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John (aain)

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