Batteries die but can't find the reason.

peterjaw

peterjaw

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Dear captains,
Could 3 CO monitors flat out two 80 Ah batteries in a week?
My CO monitors are CMD5-M from Fireboy.
CMD5-M.jpg

They are direct connected to the batteries, no switch, I can't turn them on or off.
 
Last edited:
peterjaw said:
Dear captains,
Could 3 CO monitors flat out two 80 Ah batteries in a week?
My CO monitors are CMD5-M from Fireboy.
View attachment 75987

They are direct connected to the batteries, no switch, I can't turn them on or off.
Click to expand...

No, according to their specs they daw less than 4mA, which equates to around 2Ah being taken from your 160Ah bank in a week by all three of them. You either have a dud battery/ies or you have something else drawing current
 
CLB said:
No, according to their specs they daw less than 4mA, which equates to around 2Ah being taken from your 160Ah bank in a week by all three of them. You either have a dud battery/ies or you have something else drawing current
Click to expand...

The nominal current draw is 4mA, but the max (presumably when the alarm is going off) is 45mA. Could that have been happening all week?

But, even if you multiply CLB's figures by a factor of 10x, still not enough to flatten a 160Ah (or is that 80Ah at 24V?) bank, assuming it was fully charged when the boat was last left. Could have put a bit of a dent in it, though, if the batteries are old and no longer holding full charge.
 
Perhaps the batteries have reached end of their life? What tests have you done to check the batteries?
 
My boat is Quicksilver 855 weekend and was just delivered brand new on last August.
During my left on last week and today, someone switch my battery selector to 1+2 and
when I went to marina today, the engine would not start.

The battery selector is located outside of my cabin, with no lock on the cover, so anyone
can accesses to it. My cabin is still locked without any sign that anyone ever broke in.
That is to say, no other equipment were turned on in the past week.

I know the CO monitors is directly connect to battery and can't be shut off. All other equipments need human being to turn them on even the battery selector is switched on.
 
Angele said:
The nominal current draw is 4mA, but the max (presumably when the alarm is going off) is 45mA. Could that have been happening all week?

But, even if you multiply CLB's figures by a factor of 10x, still not enough to flatten a 160Ah (or is that 80Ah at 24V?) bank, assuming it was fully charged when the boat was last left. Could have put a bit of a dent in it, though, if the batteries are old and no longer holding full charge.
Click to expand...
Nobody ever entered my boat in the past week. So I don't think the alarm had any chance to go off.

I have two batteries: battery 1 and battery 2. They are either isolated or parallel depends on the battery selector, 1, 2, or 1+2.
 
You have a drain somewhere else. There is no way those CO Monitors could flatten those batteries. If you had stand alone CO monitors they work off small dry cells that last months
 
Get yourself a digital clamp meter, something like this :

61OtxPFZZ4L._SL1285_.jpg

And check / trace fault for current draw from the batteries till you find the fault or whatever is drawing the power.
Check your charging mechanisms both battery charger and alternator.
Check that you dont have a dead cell in one of the batteries. if 1+2 was selected a bad battery will quickly kill a good battery if on the same circuit.
 
Batteries have a boat life of on average of about 6 years, some last longer some shorter, it depends on use etc. If you have them plugged in and on a batterie charger check that, they can blow fuses. You could disconnect them and see if they still go flat. that would tell you if it was them or not.
 
powerskipper said:
Batteries have a boat life of on average of about 6 years, some last longer some shorter, it depends on use etc. If you have them plugged in and on a batterie charger check that, they can blow fuses. You could disconnect them and see if they still go flat. that would tell you if it was them or not.
Click to expand...

IIRC he does not have either shore power or genny and relies on his outboard motor to charge his batteries so I doubt they are ever up to 100% SOC
 
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BruceK said:
Get yourself a digital clamp meter, something like this :

View attachment 75994

And check / trace fault for current draw from the batteries till you find the fault or whatever is drawing the power.
Check your charging mechanisms both battery charger and alternator.
Check that you dont have a dead cell in one of the batteries. if 1+2 was selected a bad battery will quickly kill a good battery if on the same circuit.
Click to expand...

Thank you very much. I will go get a clamp meter and check by myself.

As regarding to the charging mechanisms and (dud) batteries, I will have to totally rely on the dealer. However, my boat is still under warranty so I am a little bit of hesitating to fully trust them.....
 
Croftie said:
IIRC he does not have either shore power or genny and relies on his outboard motor to charge his batteries so I doubt they are ever up to 100% SOC
Click to expand...

Exactly.

I went for a 2 hours trip before leaving my boat last week, so I assume the batteries were fully charged.
I know a healthy fully charged battery reaches to 12.8 v ~ 13 v, but a dud battery can do this while drops quickly when working.
Other than the voltage reading, is there any meter/instrument that tell me the status of a battery?
 
One simple check is to connect a voltmeter to the battery and run the boat, if it is charging then the voltage will rise after a short period of running and then fall off slightly. Swap it over and check the second battery.

You could fit an ammeter between the alternator and batteries, this would show if the batteries are receiving charging current and at what rate, if they receive nothing then the alternator is shot.

Check the alternator wiring as it should have an excitation wire, this starts the alternator charging and without being excited it will simply spin and do nothing, if this received a full voltage with the ignition on and you get no charging current you can isolate the alternator as at fault.
 
If your boat is under warranty and you are not sure about these things I think you should inform the Dealer and see what he suggests. I assume you paid a lot for your boat and the Warranty is all part of this cost.

If the Alternator is shot this would I assume be a warranty item
 
BruceK said:
Get yourself a digital clamp meter, something like this :

View attachment 75994

And check / trace fault for current draw from the batteries till you find the fault or whatever is drawing the power.
Check your charging mechanisms both battery charger and alternator.
Check that you dont have a dead cell in one of the batteries. if 1+2 was selected a bad battery will quickly kill a good battery if on the same circuit.
Click to expand...

I am not sure you can get one of those for DC Current can you ?
 
peterjaw said:
Exactly.

I went for a 2 hours trip before leaving my boat last week, so I assume the batteries were fully charged.
I know a healthy fully charged battery reaches to 12.8 v ~ 13 v, but a dud battery can do this while drops quickly when working.
Other than the voltage reading, is there any meter/instrument that tell me the status of a battery?
Click to expand...
I use one of these, it shows the instant health of a battery
https://www.amazon.com/BA9-40-1200-...rds=Solar+ba9&qid=1550560441&s=gateway&sr=8-2
Just unhook the batteries so they can be tested separately. It’s the easiest way to test a battery and it can even test the alternator (but I’ve never done this). There are lots of YouTube videos on how to use them. But basically you take the information written on the battery and enter it in the tester and it tests it in a second to see if your battery meets the original specs.
But I would tell the dealer to send a technician, because if there is a problem you want it diagnosed, fixed and bad batteries replaced.
 
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