I got 99 problems and the Batts are one

[DanMax&Belle]

Hi,

Helping a friend with a leisure battery problem. New batteries around 4 months ago, boat empty, on a leisure mooring, starter battery (sitting nicely at 13.2 v on smart charger). The new leisure batteries (not connected to a smart charger) arent dying, or on the way out they are gone i mean GONE!! im flabergasted that they seem to be registering 0v not even 0.1v, nothing! i even tried a different voltimeter and the same result. having never seen a battery register 0v i can only assume there was a short connection which hasnt blown a fuse and the little electrons have been happily jogging around the circuit for the last 4 months until they ran out of puff. Anyone have any other theory? incase you ask/say:

• i isolated the LBs before testing them
• i've not searched for a short circuit yet
• none of the fuses have blown
• all the 12v applications (leds, pumps etc) don't work.
• i have advised the owner to connect the smart charger to the LBs and isolate the starter batts once we've got to the bottom of this and replaced the LBs

Thanks in advance.

Dan

[mrsmelly]

Hi Dan

Have you put the meter directly onto batt terminals?

[DanMax&Belle]

Just now, mrsmelly said:

Hi Dan

Have you put the meter directly onto batt terminals?

i did indeed mrsmelly - i removed the terminal connectors and tried 2 seperate voltimeters on the =/- with the same suprising result.

I must say i was expecting 6v or something equally condemning but no it read 0! 

cheers

[WotEver]

A small current drain over a period of 4 months, coupled with self-discharge can indeed completely flatten a battery. 

4 months is approx 3000 hours. If you had 220Ah to start with then a draw of 70mA will flatten them over that time - no need for a ‘short’. 

[DanMax&Belle]

1 minute ago, WotEver said:

A small current drain over a period of 4 months, coupled with self-discharge can indeed completely flatten a battery. 

4 months is approx 3000 hours. If you had 220Ah to start with then a draw of 70mA will flatten them over that time - no need for a ‘short’. 

ok interesting - so a small LED left on for example will do the same if left for long enough? i know there's no solar or other means of trickle charging so this is a feasible explaination. the short would take considerably less time though right?

thanks

[nicknorman]

A short circuit would likely burn or melt something and of course should blow a fuse. Much more likely is that some service was left on. How about the bilge pump, does the boat have an automatic one powered by the leisure batteries? Maybe the float switch stuck and it ran continuously until the batteries were totally flat? Or something like that.

[DanMax&Belle]

2 minutes ago, nicknorman said:

A short circuit would likely burn or melt something and of course should blow a fuse. Much more likely is that some service was left on. How about the bilge pump, does the boat have an automatic one powered by the leisure batteries? Maybe the float switch stuck and it ran continuously until the batteries were totally flat? Or something like that.

its a possibility, i'll check it out.

thanks 

[WotEver]

52 minutes ago, DanMax&Belle said:

so a small LED left on for example will do the same if left for long enough?

Absolutely. As I said above, 70mA over 3000 hours is over 200Ah. If Batteries are going to be left for a period of months you need to ensure that absolutely nothing is connected. 

Obviously a larger load such as a bilge pump as suggested by Nick would flatten them much more quickly. 

[MtB]

3 hours ago, DanMax&Belle said:

i even tried a different voltimeter and the same result.

 

Did you disconnect the batteries then use the multimeter to measure the resistance across the battery cables?

It ought to have been open circuit (infinite resistance) but you will probably find a hundred Ohms, or even a few dozen. If so this will explain the rapid death of the batteries. Why were new batteries fitted in the first place? A similar problem I bet!

Probably the battery isolator was left turned ON in error. If OFF but still some circuit present, time to start following the wires connected before the battery isolator switch to find out what is presenting a power-consuming load.

[BEngo]

Car radio memory feed perhaps?  4 months is a long time and there will be significant self-discharge even if there is no load.  Most makers expect their stored, filled, batteries to be charged monthly.

There will also be lots of sulphation once the battery gets partly flat though whether this would affect the remaining capacity I know not.

Fit a new battery.  Set the meter to the 10 A range and connect the +  lead only. Test between the - terminal and the - lead.  There should be no current flow registered. Reset the meter for progressively lower current ranges and repeat the test on each range until you find a measurable current flow.  Then find out what is causing it and isolate that before leaving the boat.

 

N

[Nightwatch]

What I would do, possibly not the correct thing to do,is, start the engine and leave running above idle for three plus hours. The batteries will charge, hopefully. It is then that you find out if they are done or not. Good luck to your friend.

[bizzard]

If you can't get the batteries to begin charging it might be worth taking them to a garage or car sales place, they would both have powerful boost- start chargers, you know the ones on wheels.  10 minutes or so each at 100amp wiould probably kick them back into life. I've done it many times at my garage.

[Nightwatch]

Good advice. 

[Robbo]

Another way to charge would be to charge with a healthy battery.   

[WotEver]

31 minutes ago, Robbo said:

Another way to charge would be to charge with a healthy battery.   

I’d be worried about damaging the healthy battery with the potentially very high current flow. 

[dccruiser]

I have pulled totally flat batteries back with an oxford oximiser ... takes a couple of days but they charge the battery at a very low rate when they are too far gone to pick up from a normal charger

Rick

[DanMax&Belle]

i think i finally, after weeks of dropping in every few days and testing things progressively, worked it out!

 

i found the sump box under the kitchen sink was "whining".

 

Symptoms:

- it seemed to wait until it was nearly full of water before triggering the pump (when working properly it would be triggered by the float switch at around 60% full).  

- between 60% full and 90% (the seeming trigger point before cleaning) it 'whined', very quietly, had to hold my ear to it, made a sound which sounded like the pump was turning very slowly

- i had the voltimeter on the + and - whilst this was happening and it was displaying a rapidly changing voltage of between 9 and 12.5 volts 

- whilst the voltimeter was clipped onto the + and - of the sump i used a different voltimeter to the voltage at the battery, it was fluctuating here but much less pronounced.

 

I wonder if the sump had been unwittingly filled and left somewhere between 60% and 90%. The pump was turning at a snails pace but was doing so which was causing the battery to short and given it was left for days in this state it ran down the battery to 0 without blowing a fuse? Incidentally the float switch and pump were gunked up and after a thorough clean with an old tooth brush it went back to working fine.

What do you recon canalworld?

[Alan de Enfield]

Are you saying that your kitchen sink drains into a bilge, and that it is then pumped overboard ?

 

[DanMax&Belle]

Just now, Alan de Enfield said:

Are you saying that your kitchen sink drains into a bilge, and that it is then pumped overboard ?

 

god no where did you get that from? its a sump box which sit directly below the sink and is plumber into the U bend/trap. Same as some people use for showers (and kitchens)

[Stilllearning]

11 minutes ago, DanMax&Belle said:

god no where did you get that from? its a sump box which sit directly below the sink and is plumber into the U bend/trap. Same as some people use for showers (and kitchens)

So rather than a gravity drain from sink out into the cut, there is a pump assisted drain from the sink?

[Alan de Enfield]

16 minutes ago, DanMax&Belle said:

god no where did you get that from? its a sump box which sit directly below the sink and is plumber into the U bend/trap. Same as some people use for showers (and kitchens)

So what does this 'whirring sump box' do ?

 

Why do you not just have the traditional (normal) method of a sloping pipe going directly from the sink waste to a hole thru the hull.

I have never seen a NB with a 'pump-out' sink - a pump-out shower - yes - as that is below the water line.

[DanMax&Belle]

2 minutes ago, Alan de Enfield said:

So what does this 'whirring sump box' do ?

 

Why do you not just have the traditional (normal) method of a sloping pipe going directly from the sink waste to a hole thru the hull.

I have never seen a NB with a 'pump-out' sink - a pump-out shower - yes - as that is below the water line.

thanks for your thoughts Alan.

The box does as all sump boxes do. It's whining not whirring. Its a deep, belfast style, sink which sits close to the waterline. It's not mine.

Any thoughts on the battery problem? 

[DanMax&Belle]

20 minutes ago, Stilllearning said:

So rather than a gravity drain from sink out into the cut, there is a pump assisted drain from the sink?

sounds totally loopy doesn't it Stilllearning - why would anyone do such a thing!

[Alan de Enfield]

8 minutes ago, DanMax&Belle said:

Any thoughts on the battery problem? 

 

On ‎05‎/‎04‎/‎2018 at 20:42, DanMax&Belle said:

Hi,

Helping a friend with a leisure battery problem. New batteries around 4 months ago, boat empty, on a leisure mooring, starter battery (sitting nicely at 13.2 v on smart charger). The new leisure batteries (not connected to a smart charger) arent dying, or on the way out they are gone i mean GONE!! im flabergasted that they seem to be registering 0v not even 0.1v, nothing! i even tried a different voltimeter and the same result. having never seen a battery register 0v i can only assume there was a short connection which hasnt blown a fuse and the little electrons have been happily jogging around the circuit for the last 4 months until they ran out of puff. Anyone have any other theory? incase you ask/say:

• i isolated the LBs before testing them
• i've not searched for a short circuit yet
• none of the fuses have blown
• all the 12v applications (leds, pumps etc) don't work.
• i have advised the owner to connect the smart charger to the LBs and isolate the starter batts once we've got to the bottom of this and replaced the LBs

Thanks in advance.

Dan

I'm not sure what 'battery problem' you are referring to.

 

Once a battery goes beyond a certain point it is dead, deceased, defunct and has departed this life.

I would suggest that having a 'whining' sump box (I am still not sure what that is) for a few weeks will take the batteries to the point of no return.

 

Now the problem has been resolved a new set of batteries should sort out 'the battery problem'.

[BruceinSanity]

5 minutes ago, DanMax&Belle said:

sounds totally loopy doesn't it Stilllearning - why would anyone do such a thing!

I've seen a number of boats which have this, usually because they have a deep, Belfast type sink whose base is too close to the waterline for a simple drain. So you have one of these sump box arrangements to empty it. But as with the shower, I don't see why you can't have a manually switched Whale gulper pump to empty it, much simpler and therefore less to go wrong.