Sully's battery problem

[Alan Wheeler]

Cut and pasted from a thread Sully started in Sailing Forum.

1) House bank is charging off solar and wind only and not getting any of the 14VDC twin Yanmar alternator output. Doesn't matter which direction I put the Guest Isolators in, I read only a dying battery voltage in the house bank even with engines in gear at 2200RPM. Engine starting batteries are getting proper juice. Problem seems to be on the ground side, which scares the hell out of me since when we hauled for survey, the props were eaten away and needed to be replaced. I hope that's not where my extra juice is going!!

[Alan Wheeler]

OK Sean, like I said, your electrical system should have a common ground and that should be bonded at one point which is the engine Block. So a couple of questions which may help everyone.
1: Has each engine got it's own start bank?
2: Do both engines have an alternator each?
3: Anychance just one alternator supplies the house bank and its start battery and the other alt just supplies it's respective start battery? More detail would help
4: It won't matter what speed you have the engines at or if they are in or out of gear. The charge *should* kick in at about 1000-1200RPM if not sooner.
5: If engine start are getting "proper juice" then you ahve to assume the alts are producing current and thus it will not matter what RPM you are running the engines at anyway.
6: Am I correct in seeing another post somewhere saying you have 150W of solar? That is a sizeable chunck of current and should be making the batteries do something toward maintaining a voltage.
So to me at first glance, you may have a simple issue of a breaker or Isolator somewhere you don't know or haven't identified yet.

The props being eatin, what are the props? Alloy or bronze? I suspect Alloy, am I right?? You may have a very simple and logical reason why they are eatin if they are Alloy. Let me know.

[scotte]

Things could also be bonded at a shunt, as used in a battery monitor. That electrically (sort of) doesn't change anything in terms of being commonly grounded, but could be another spot to look at when chasing down cables.

Also, as asked on the other thread - knowing if the solar+wind is charging, just not the engine alternators, was not clear to me but is an important part in troubleshooting where to look.

[Islandmike]

Wheels,

Actually I think he stated twin 150watts solar panels, 300watts, I would love that much input, however, I dont have a 12v refer either.

[ssullivan]

Ok, thanks for all the guesses so far. I know you all had very little to go on, since I wasn't able to put in the full detail last night. Here goes:

The Setup:

*Twin Yanmar Diesel engines, each with its own Gel starting battery (Deka brand).
*Twin banks of Deka group 27 house batteries, with qty (3) 12V batteries in each bank, for a total of 6 group 27 house batts in both banks.
*House banks have the ability to be put in parallel by a Guest switch that puts them in parallel. I have kept them in parallel during this exploratory.
*Each starting battery (qty 2 total, one for each engine) has the ability to be isolated from the main bank by a Guest switch (qty 2 Guest switches, one for each engine).



The Evidence:

*Xantrex charge controller is blinking a single green flash, which means that
the batteries are "well below bulk voltage" according to the Xantrex manual.

*Xantrex Freedom Inverter/Charger is showing between 12.5V on in direct semi-equatorial sunshine, and 11.5V when I'm desperately trying to type on the Cruisers Forum at night. The only load in this case was my computer and the Inverter on for it.

*I'm showing a .6VDC difference in potential between the Yanmar engine block and the ground for the house bank. The ground for the starting battery is actually tied to the engine block through a single cable, so there is no potential difference there.

*When measuring the voltage of the house bank, I am getting 12VDC no load (all this is no load). When measuring the starting battery's voltage, I am getting 12.6VDC. See the .6VDC creeping in here?

*When engines are running, I'm seeing 14VDC on both starting batteries from the alternators. No matter what position I put the Guest battery isolation switches in, I still only see ~12VDC on the house bank when the engines are clearly charging the starting batteries.


Questions:

1) I've never had solar and wind. Shouldn't I be seeing a charging voltage on the house bank (say 13-14VDC) if I have a bright sunny day and the solar panels are charging the batts? I am getting some charge back, but not seeing any normal voltages.

2) If I see a difference of potential between the ground for the house bank and the ground for the starting battery, relative to the engine block is this what ate away the props?? Props are aluminum or some alloy like that. Like an outboard. These are Yamar SD-20 saildrives.

3) If my house batteries won't go above 12VDC or so, could the bank be shot even though everything else is working? They get hot, but don't show a full charging voltage under solar *or* under alternators. (There has been zero wind to test that)

4) I used the hygrometer (hydrometer? sorry), to test the batts. Cells varied a little but, but were mostly in "poor" to "fair" range.

5) Essay question: Please write in your own words, what the h*ll is going on here... ha ha

[ssullivan]

Originally Posted by scotte

Things could also be bonded at a shunt, as used in a battery monitor. That electrically (sort of) doesn't change anything in terms of being commonly grounded, but could be another spot to look at when chasing down cables.

Also, as asked on the other thread - knowing if the solar+wind is charging, just not the engine alternators, was not clear to me but is an important part in troubleshooting where to look.

Yes, there is a shunt. The boat is wired for a Link 10, but the Link 10 exploded! Maybe another clue??

The shunt is located in the proper spot, on the negative to the battery. Directly on the other side of the shunt, the negative runs into the Xantrex Freedom Inv/Charger. From there... it must come out some negative terminal output and on to the breaker panel. Real tough spot to see what's going on between the inv/charger and the breaker panel, but both are in the opposite direction of the house bank and engines.

[ssullivan]

Up to 12.5VDC on the house bank right now. I have initiated the Xantrex charge controller's "equalization mode", which to me, seems like it should be in the 14V range, not the 12V range. ????

What am I missing?

Sure miss the simplicity of just pouring some diesel in a tank and pressing "start" to charge my batteries! Maybe solar and wind will work and not cost me a fortune to buy new devices that are broken?

I'm lost because I don't understand how all these "black boxes" or "gizmos" work. I know the basics, but shouldn't charging take place at higher voltages when in the bulk phase? I'm seeing 12.5VDC. That's not normal for AC powered battery chargers.

[sluissa]

I know it probably doesn't apply, much anyway. But even though I can hook up a voltmeter to my small 6 watt solar panel and read something like 20 volts coming from it, once it's hooked up to the battery, all I read is the battery voltage. around 12.3-12.7 depending upon it's charge.

[ssullivan]

Originally Posted by sluissa

I know it probably doesn't apply, much anyway. But even though I can hook up a voltmeter to my small 6 watt solar panel and read something like 20 volts coming from it, once it's hooked up to the battery, all I read is the battery voltage. around 12.3-12.7 depending upon it's charge.

Actually, I think that does apply. I only know normal "plug in, AC battery chargers." I don't have a clue on this solar stuff. So when you are charging from a solar panel, the charging voltage is much lower? Is that because it doesn't have the energy that a 30A shore power cable and battery charger has?

Interestingly, I'm seeing the exact numbers you are describing.

On a plug-in charger, I would see 13.65VDC as my float and somewhat higher for my bulk charging current. On this solar charge controller, I'm seeing the voltage range you are describing.

Also, here is a BIG clue with the alternator stuff, I think:

[with the engines running...]:

When I use the engine block as my ground, I am seeing full Yanmar alternator voltage of 14.1VDC when I touch the positive end of the meter to the battery post on the starting battery on both engines.

I am also seeing the full 14.1VDC when I use the engine block as a ground and touch the positive end of my meter to the house bank. This is good, right?! BUT!!.....

When I use the main house negative cable as my ground (which is also attached to the Freedom Inv/Chg) , I get 1.4VDC less than if I use the engine block for my ground, touching the same positive terminals! Oddly, the voltage I see in that case is *exactly* the same voltage I would see if the solar charger was on by itself without the engine running! Does this make sense to anyone??

It's like something is eating up the alternator output from the point of view of the house batteries, which are of course connected to that main negative bus cable that gets me low charging readings.

What's going on here? Why do I have 2 different grounds??

Is it something to do with the Freedom Inv/Chg?

[sluissa]

I don't know anything about solar chargers. I thought it wouldn't apply because I thought the solar charger should be regulating the voltage to charge the batteries better. I don't use a charger simply because my panel is so small and I was told, that as long as you don't go over a certain amount of input (something like 5% of your total amp hours in amps I think) then you don't need a charger.

Also, I'm not sure, but are these batteries the same that you are used to? I've heard that gel/AGM batteries have slightly different charging needs than flooded batteries. Namely, if you used to use gel/agm and these are flooded, I think gel/agm requires(or can take? I dunno) a bit more voltage than the flooded ones are designed to take.


Your alternator problem, it does sound like a problem, but nothing I have any idea of unless you've got something stuck in between the alternator and the house batteries?


I'm just poking around in the dark here, honestly, sorry I can't be of more help. I'm just spitting out thoughts hoping maybe I might inspire someone with more knowledge to figure it out.

Edit, not that they would need it, just sometimes the answer is right in front of your face and you need someone to point it out to you. I've had it happen to me many times, and I've helped other people with that a few times as well. (As a stupid side anecdote. The time my friend's car was overheating. He didn't know much about cars, so I went out, I looked, checked the radiator to see if it had airflow, checked the oil, checked various other things. Finally he said, "Maybe we should check the coolant." Duh... the coolant resivoir was bone dry.)

[hellosailor]

Sully, I'm afraid my brain feels like your Link10, about to explode trying to build and hold a mental picture of that complexity.

May I suggest "DIVIDE AND CONQUER" ? Disconnect the solar and wind power. The wind generator will need to be secured not simply unplugged, of course. Get the totally out of the picture and out of the loop.

Now, confirm that the regulators and anything else in the system are set for GEL BATTERIES, which usually require a change from the defaults.

Then go over the charging system, with paper and pencil in hand, and diagram the whole thing. I'd really like to see that diagram, too.

If you are showing a voltage loss os 1.4VDC at some point in the system, you should also be able to take a voltmeter and start working "down that leg" of the system until you can isolate exactly which fitting or device has the loss. Could there be an old-fashioned diode isolator or other gizmo lurking in there? Or simply a corroded or loose cable?

Last time I did a "total gut rewire" we left only one cable, the engine block ground cable, in place. We figured "It's all the way back there and has so many coats of paint over it, it can't be bad." Surprise surprise, one day we saw it SPARKING from that cable, somehow quite loose actually and screwing up everything. Whopping huge sparks, too.

Once you figure out the charge problem...the solar and wind are still going to need attention. The solar wants an MPPT controller, the wind needs a "dump" source, neither of them can just integrate with your conventional regulators without confusing the hell out of them, so unless you attach different gizmos to different banks--there's more fun to come, but that's only AFTER you solve the problem.

If the wind gen is dumping power and that's somehow getting down the prop shafts...sure, that could eat props in no time. Sounds like there is just Too Much Stuff right now, and too little documentation about how it was glommed together.

[Alan Wheeler]

What do you mean the controller exploded How are you controlling anything??? You can not place the charger into equalise without the controller. Please do not "over emphasis" to be dramaticle. It can become missleading when we are trying to diagnose. So if it really exploded, you have a major problem at hand here.

You will NOT see any high voltages than you are most likely measuring now, because the "load" of the battery will pull everything down to where it (the bank) is at in it's charge. So the panels for instance may give a reading of 20V, but the charge side of their regulator will be down to the bank voltage wich could be your 12.7 or 14V or what ever you measured. I would expect to see a good charging voltage to be around the 13.8V in a perfect world measured across the bank terminals.

Something may not be connected quite right with the shunt. The shunt is the very last thing connected in that neg. cable between it and the neg. post of the bank. BOTH house bank AND start bank should have their Negs. tied together at the engine block. So that is No1 place to trace back from.
Is the shunt a Single or dual shunt?? I mean by dual, it will have a "main" connection block and two minor connection blocks. One is for each bank. If it is a sinlge block, you will have a single Bolt on each end of it and two smaller screws for connecting the sensor leads. The neg. ban post will be connected to one side and the charger to the otherside. The charger will be piggybacking one other cable to the DC supply panel. Make sure those connections are clean and tight.

I suggest you go to the xantrex webstie. They have some good info and some simple diagrames that will help you understand how it all gets connected.

As for the props, I doubt an electrical problem has caused them to be eatin. House elctrical that it. The anodes will be the first thing to suffer and the legs would also be damaged. I suspect some dipstick has painted copper based anit-foul on the alloy props. Take a look in the photo gallery and you will see a photo of a prop I posted in there a few years back. It show's what happens when copper is painted on Aluminium props.

[Fishspearit]

Originally Posted by Alan Wheeler

BOTH house bank AND start bank should have their Negs. tied together at the engine block. So that is No1 place to trace back from.

I agree that this should be a good starting point. From what I read it sounds like your house bank ground isn't connected to the engines?(It only needs to go to one engine, but the two engines need to be grounded together with a battery cable) The house bank doesn't need to be grounded to the engine to run the house loads or to be charged by the wind/solar, but it will need to be for the alternator to charge properly.

[Tropic Cat]

Wheels, I love your explanation of the missing props... Heck, I'm still laughing, although I'm fairly certain that the fella who painted them did not find this so amusing. When Sean told me the boat did not have a shore electical connection, I was thinking about a marina that is so 'hot' electrically that the fish jump in your boat already cooked!!

Your explanation makes a lot more sense.

As to the missing 1.4 volts. Clean every ground connection/junction you can find. The glorious Florida weather we have here makes this the number 1 candidate as battery connections corrode spectacularly in this part of the world.

[ssullivan]

I've been working through this today, as well as a few other items.

As you guys said, the fact that I have two negatives at at least 1VDC apart is unsettling.

Right now, I have the Xantrex Freedom Inv/Charger running and it has achieved 13.6VDC charging voltage on the house battery bank (as measured from terminal to terminal on the house battery or from shunt to terminal on the house battery, or from Freedom charger to terminal on house battery. All 13.7VDC. Nice!

HOWEVER, when measuring between the ground that is connected to the enging (starting battery ground), I have 12.6VDC to the house bank terminal.

So... the negatives are still 1VDC apart, even with the charger doing its job correctly and bringing the batteries up to a full 13.6VDC charge voltage.


I had though as the other posters said earlier that I need to tie the negatives together to get rid of that pesky 1VDC difference in my grounds. Well, I jumpered between the battery side of the shunt to the cable that grounds the starting battery, effectively tying both of my grounds that are at 1VDC potential to each other.

Well, a VERY large current ran though that jumper. It didn't spark much, but when I attached it, it hummed and I could feel the AWG 1/0 cable vibrate in my hands. Scared of what the hell was putting that much current through there, I backed off for fear of blowing my charger or something.

I might be hosed... I can't seem to get this one right.

Hellosailor: You're right. I think the space shuttle has less wiring.