Are my house batteries dead?

As the batteries continue to charge, the voltage should drop slightly. Keep going and see what happens but if the batteries are actually taking a charge, you'll see it gradually reduce but as already mentioned, this could take a LONG time!

Something someone sent me a while ago when discussing this https://www.optimabatteries.com/en-...nators-are-not-designed-charge-dead-batteries

webcraft said:
After another hour or so's charging the voltage at the terminals is 15V. Is it normal/good for the voltage to rise as the batteries charge?

- W
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All understood and tx for all your advice. Voltage while charging now 14.3 - am going to stop soon and will check battery voltage in a few hours - should be 12.6 - 12.7 if fully charged, yes?

- W
 
not sure what you mean by battery voltage in the 'green'
12V would def not be good imo, not unless your engine starter or bow thruster (!) was running.

long term you need to monitor your battery voltage much more closely using a proper display, to avoid this kind of interest, unless you like fixing things whilst away of course :)
 
webcraft said:
After another hour or so's charging the voltage at the terminals is 15V. Is it normal/good for the voltage to rise as the batteries charge?

- W
Click to expand...

The volts will rise slowly as the batteries charge but only up to the volts at which the alternator regulator controls it They should not rise as high as 15 volts. Normally no more that 14.4. Lower for older alternators, and higher, up to 14.8, for modern alternators designed for use with modern batteries. ( assuming of course it's not your wind turbine pushing out over 15 volts)

I'd not expect the batteries to charge so quickly either !

I suspect you have a dodgy voltage regulator ( alternator or wind turbine ??) and batteries that are no longer charging properly.
 
webcraft said:
All understood and tx for all your advice. Voltage while charging now 14.3 - am going to stop soon and will check battery voltage in a few hours - should be 12.6 - 12.7 if fully charged, yes?

- W
Click to expand...

12.7 ish after resting with no load or further charging for at least 12 hours. and measured with a high impedance ( eg digital) meter
 
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simonfraser said:
not sure what you mean by battery voltage in the 'green'
12V would def not be good imo, not unless your engine starter or bow thruster (!) was running.

long term you need to monitor your battery voltage much more closely using a proper display, to avoid this kind of interest, unless you like fixing things whilst away of course :)
Click to expand...

I suspect he is using one of those analog battery condition meters ???
 
webcraft said:
Not really. The house batteries weren't flat, they became flat after several days use and - obviously - not enough charging. They are always topped up when setting off, tx to the wind genny.

And - I only change fuel filters if there is a reason. I put all my fuel in through a filter funnel, but a very rough passage has shown me it is time to siphon the sludge from the tank sump again.

And anyway. It is much easier to fix stuff while away on a pontoon in a place with services than it is on a swinging mooring in the middle of nowhere, and I carry all the necessary spares and tools. Also, it's a sailing boat, and all that side of things is working.

I don't regard this as 'trouble', if I did then I might consider swallowing the anchor. One of the best definitions I have seen of cruising is 'fixing boats in strange places'

- W
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Diesel bug, five year old filters and flat batteries not a problem then. Not my idea of a relaxing cruise but each to their own.
 
I don't have any reason to suspect 'the bug', it mostly looked like emulsified diesel due to water. The engine is running fine, ran it for three hours this afternoon. And the batteries were fully charged when we left.

If you aren't prepared to deal with problems then maybe you should stay in port.

- W
 
I think your being over dramatic. No sign of bug, batteries weren't flat when op set out and most filters will last five seasons unless excessive motoring. Rough passage can often disturb some sediment but that's why op carries spare filters.
PS hope his 'green sector' isn't something like this. https://goo.gl/images/VrL3XP I had one and it was wildly inaccurate.
Glenlivet said:
Diesel bug, five year old filters and flat batteries not a problem then. Not my idea of a relaxing cruise but each to their own.
Click to expand...
 
webcraft said:
I don't have any reason to suspect 'the bug', it mostly looked like emulsified diesel due to water. The engine is running fine, ran it for three hours this afternoon. And the batteries were fully charged when we left.

If you aren't prepared to deal with problems then maybe you should stay in port.

- W
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Perfectly prepared to deal with problems, and I spend far more time at sea than most of my boating neighbours. I just prefer my boat to be prepared before I put to sea. Your thread title was “are my house batteries dead?”. I’d like to think I would know before starting out.

Ho finito.
 
webcraft said:
All understood and tx for all your advice. Voltage while charging now 14.3 - am going to stop soon and will check battery voltage in a few hours - should be 12.6 - 12.7 if fully charged, yes?

- W
Click to expand...

I'd suggest using a smart charger that pushes them up to 14.8V. Check the water levels first and top up as appropriate, but I find that with the Sterling shorepower charger and AtoB charger I've got checking and topping up the water every six to nine months is sufficient.

You don't have to make a permanent installation if cost is an issue but I'd suggest the plates could do with a good blast at 14.8V (I'm also assuming bog-standard lead acid).

I've got an original fit battery monitor that monitors the charge in and out of the domestics, but I've also found it useful to fit little digital voltmeters next to the batteries. A switch and fuse each and it is just a handy way of measuring volage without having to disrupt things getting to the battery compartment to use a multimeter. Didn't cost much and probably more accurate than your analogue meter. They agree with the multimeter anyway.

And a vacuum gauge is brilliant for planning when to change the filters. That didn't cost much to fit either.
 
I think you said that the voltage drop is sudden when you switch on some load. Its worth checking your Battery Isolation switches. When old they give intermittant contact that could give the symptoms you describe. To test measure across the the two connectors on each switch when the switch is turned on and with some load turned on. If you read any voltage across the switch then there is resistance in the switch and it needs replacing. I had this probelm some time ago and the systoms were similar to what you describe,
Check for any other possible poor contact from the Battery up to the distrubution panel also.
Kinsale 373
 
lpdsn said:
I'd suggest using a smart charger that pushes them up to 14.8V. Check the water levels first and top up as appropriate, but I find that with the Sterling shorepower charger and AtoB charger I've got checking and topping up the water every six to nine months is sufficient.

You don't have to make a permanent installation if cost is an issue but I'd suggest the plates could do with a good blast at 14.8V (I'm also assuming bog-standard lead acid).

I've got an original fit battery monitor that monitors the charge in and out of the domestics, but I've also found it useful to fit little digital voltmeters next to the batteries. A switch and fuse each and it is just a handy way of measuring volage without having to disrupt things getting to the battery compartment to use a multimeter. Didn't cost much and probably more accurate than your analogue meter. They agree with the multimeter anyway.

And a vacuum gauge is brilliant for planning when to change the filters. That didn't cost much to fit either.
Click to expand...

Planning to fit a smart charger and proper shore power system for next season.

How/where do you fit a vacuum gauge and what does it show?

- W
 
Kinsale373 said:
I think you said that the voltage drop is sudden when you switch on some load. Its worth checking your Battery Isolation switches. When old they give intermittant contact that could give the symptoms you describe. To test measure across the the two connectors on each switch when the switch is turned on and with some load turned on. If you read any voltage across the switch then there is resistance in the switch and it needs replacing. I had this probelm some time ago and the systoms were similar to what you describe,
Check for any other possible poor contact from the Battery up to the distrubution panel also.
Kinsale 373
Click to expand...

I've got a 1-2-both switch, will check the contacts on that when I get a chance, tx for the tip.

- W
 
webcraft said:
How/where do you fit a vacuum gauge and what does it show?

- W
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Between the primary filter and the lift pump/secondary filter. Shows the vacuum needed to draw fuel from the tank and through the primary filter. As the filter clogs the vacuum increases. Once you know what level affects the performance of your rengine you can change the filter before the vacuum gets that high.
 
Update:

Stopped charging 14 hours ago, batteries at 12.95V

I am taking this as a good sign... Now for the filters, and perhaps trying to suck the water/gunge from the tank sump.

- W
 
webcraft said:
Update:

Stopped charging 14 hours ago, batteries at 12.95V

I am taking this as a good sign... Now for the filters, and perhaps trying to suck the water/gunge from the tank sump.

- W
Click to expand...

If you are filtering fuel into the tank, where is all of this gunge and water coming from ?
 
webcraft said:
Update:

Stopped charging 14 hours ago, batteries at 12.95V

I am taking this as a good sign... Now for the filters, and perhaps trying to suck the water/gunge from the tank sump.

- W
Click to expand...

its what your batteries settle at that matters
what is the resting voltage with nothing on after an hour ?
and then how much does the voltage go down with a few amps / heater running ?
 
webcraft said:
After another hour or so's charging the voltage at the terminals is 15V. Is it normal/good for the voltage to rise as the batteries charge?

- W
Click to expand...

15V is too high. 14.4 should be the max for a marine alternator (there are exceptions). I suggest you measure the voltage directly from the battery posts and compare that with the alternator output. If the alternator output is higher you have a high resistance connection somewhere.
If you switch your meter to a low voltage range you can identify the offending joint/connection. eg. Measure the voltage drop between the alternator output and your battery switch and from battery switch to the battery’s lead post.
In 12v charging systems a tiny increase in resistance has a huge effect on the charging regime.

Saying all that, it does appear you simply aren’t putting enough amps back in the battery with an hour’s running.
 
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