catastrophic battery failure !

[grafozz]

Went down to the boat last week after a spell of cloudy weather and found the batteries were at around 10/ 11 volts .
So I turned the fridge off which left nothing on at all in the whole system .

Went down today after 4 days of fine sunshine to find both battery monitors were off / blank .

Out with the multimeter and all batteries were showing less than 2 volts !!

tested for drain on both banks and nothing was showing up .

Ok ,the system is :
2 x banks of 2x 85 amp deep cycle batteries all less than 2 years old .
2x 80 watt and one 40 watt solar panels ( tested today showing `18/19 volts )

What on earth has happened ?
Can I hear some of your thoughts , please ?

 

[RichardS]

Went down to the boat last week after a spell of cloudy weather and found the batteries were at around 10/ 11 volts .
So I turned the fridge off which left nothing on at all in the whole system .

Went down today after 4 days of fine sunshine to find both battery monitors were off / blank .

Out with the multimeter and all batteries were showing less than 2 volts !!

tested for drain on both banks and nothing was showing up .

Ok ,the system is :
2 x banks of 2x 85 amp deep cycle batteries all less than 2 years old .
2x 80 watt and one 40 watt solar panels ( tested today showing `18/19 volts )

What on earth has happened ?
Can I hear some of your thoughts , please ?

In the past have your solar panels consistently produced sufficient power to run the fridge overnight and then top the batteries back up to 100% before sundown with the fridge still running?

Richard

 

[grafozz]

Yes , the fridge stays on all year , the panels produce enough power to do this .
I did motor ,2 weeks back , for 6 hours and the batteries only reached 12.6/8 volts , which seemed a bit low , and after 2 hours running the lights they showed 12.2 volts - a bit odd / low ?

 

[RichardS]

Yes , the fridge stays on all year , the panels produce enough power to do this .
I did motor ,2 weeks back , for 6 hours and the batteries only reached 12.6/8 volts , which seemed a bit low , and after 2 hours running the lights they showed 12.2 volts - a bit odd / low ?

12.6 / 12.8 volts is fine if that is the voltage after the charging has been stopped for 30 minutes and the fridge is still in circuit.

Are all your panels connected through a regulator of some sort - PWM or MPPT type. If so I suspect that something has gone wrong with the regulator and there may well be 18 or 19 volts going in but possibly there's precious little coming out?

Richard

 

[OldBawley]

While solar power is abundant in summer, in autumn with the sun low and lots of clouds solar input can be real low.
Solar input is measured in amps / h. Voltage means nothing.
The now cheap sold solar panels are delivering good current in sunny conditions, but almost nothing as soon as a bit of clouds cover the sun.
In a cloudy week, with the fridge running, even with 200 watt of solar, input will be less then the consumption of the fridge.
Voltage drops, in a real bad case plates bend.
Battery's are never fully loaded, so sulfation starts. Beginning of the end.

I charge with 170 watt solar AND make sure the panels are orientated and free of shadow all day.
We also charge with two wind generators of witch one is a real power booster.
Nevertheless, the fridge is switched of at night during autumn and winter.

 

[RichardS]

While solar power is abundant in summer, in autumn with the sun low and lots of clouds solar input can be real low.
Solar input is measured in amps / h. Voltage means nothing.
The now cheap sold solar panels are delivering good current in sunny conditions, but almost nothing as soon as a bit of clouds cover the sun.
In a cloudy week, with the fridge running, even with 200 watt of solar, input will be less then the consumption of the fridge.
Voltage drops, in a real bad case plates bend.
Battery's are never fully loaded, so sulfation starts. Beginning of the end.

I charge with 170 watt solar AND make sure the panels are orientated and free of shadow all day.
We also charge with two wind generators of witch one is a real power booster.
Nevertheless, the fridge is switched of at night during autumn and winter.

But the OP has stated that his panels have produced enough to run his fridge continuously for the last two years and keep the battery charged up. Surely this is not the first spell of cloudy weather in the last two years?

Perhaps it is ..... but if not I suspect that something has failed.

Richard

 

[halcyon]

Yes , the fridge stays on all year , the panels produce enough power to do this .
I did motor ,2 weeks back , for 6 hours and the batteries only reached 12.6/8 volts , which seemed a bit low , and after 2 hours running the lights they showed 12.2 volts - a bit odd / low ?

You should have been 14.2 volt or more, faulty / damaged battery or alternator fault, need to do some checking.


Brian

 

[OldBawley]

had a client who complained that his battery's died every two years. He was never leaving the marina and always on mains. Victron 10 ah charger.
So one day I went over to have a quick look at his boat.
It just took some minutes to find the problem. His yacht was a big HR and was during summer the cottage by the sea. Wife, kids, computers, even a hair dryer fed by an inverter.
The consumption of all appliances was almost 10 Ah so in fact his battery's ware never charged.
All and more his shore power charger could deliver was used directly.
Poor charged battery´s die.
Sold him a 25ah charger and the problem was solved.

How much Ah is your fridge using in 24h ? Any idea ?

 

[silver-fox]

I had a similar experience.
I think it was a cell failure in one battery that dragged down the voltage and ultimately the batteries that were wired in parallel.

 

[ribrage]

I had a similar experience.
I think it was a cell failure in one battery that dragged down the voltage and ultimately the batteries that were wired in parallel.

Id go with this answer - once one battery drops a cell for whatever reason if not noticed fairly early on you can pretty much guarantee it will kill the other battery as well - it's good practice to change both batteries at the same time or you will continually have one old battery "killing" the new one after a fairly short period of time.

Replace the the batteries and start checking for faults. IE A drain in the system from something fairly big also take a look at running your fridge from a 240 volt supply assuming you have mains power available ? Ours switches from 24 volts to 240 volts automatically when connected to shore power so avoids draining the battery's at all - a fridge is a big consumption and constantly "working" the battery's.

we recently replaced all of our domestic bank which was five years old for a similar reason - personally I buy the cheapest 100 ish amp batteries I can find - usually Carrefour Or feuvert, we paid around €80 per battery which were 110 AH and they will generally last 4/5 years with a bit of TLC - avoid anything with "marine" written on it.

 

[grafozz]

12.6 / 12.8 volts is fine if that is the voltage after the charging has been stopped for 30 minutes and the fridge is still in circuit.

Are all your panels connected through a regulator of some sort - PWM or MPPT type. If so I suspect that something has gone wrong with the regulator and there may well be 18 or 19 volts going in but possibly there's precious little coming out?

Richard

2x panels through an MPPT regulator and 1x through PWM type , MPPT screen was blank also .

 

[vyv_cox]

Can you check the acid level in the batteries? I find that the combination of permanently connected solar panels and a Sterling alternator regulator tends to drive off water from the cells. Once the tops of the plates are exposed the capacity of the battery reduces considerably. My previous wet-cell battery bank of three consumed several litres of deionised water per season and my present bank of 'sealed' batteries, that have screwed tops by special request, need occasional topping up. You have far more solar power than I have (200W : 125 W) but only about half the battery bank capacity (170 Ah : 330 Ah).

2x panels through an MPPT regulator and 1x through PWM type , MPPT screen was blank also .

The regulator needs power for the display so with no volts in the batteries it will shut down.

 

[25931]

Went down to the boat last week after a spell of cloudy weather and found the batteries were at around 10/ 11 volts .
So I turned the fridge off which left nothing on at all in the whole system .

Went down today after 4 days of fine sunshine to find both battery monitors were off / blank .

Out with the multimeter and all batteries were showing less than 2 volts !!

tested for drain on both banks and nothing was showing up .

Ok ,the system is :
2 x banks of 2x 85 amp deep cycle batteries all less than 2 years old .
2x 80 watt and one 40 watt solar panels ( tested today showing `18/19 volts )

What on earth has happened ?
Can I hear some of your thoughts , please ?

Is the fridge connected to both banks ?

 

[grafozz]

"You have far more solar power than I have (200W : 125 W) but only about half the battery bank capacity (170 Ah : 330 Ah"

I have 2x 85 amp on each side so total battery capacity is 340 amp ,
well thats what the labels say ,
I suspect a fair bit less now !

 

[grafozz]

Good question ,
I dont know ,
I will go and find out today .
I believe both banks are independent from each other which suggests the fridge would be on one bank , but I,ll check .

 

[vyv_cox]

"You have far more solar power than I have (200W : 125 W) but only about half the battery bank capacity (170 Ah : 330 Ah"

I have 2x 85 amp on each side so total battery capacity is 340 amp ,
well thats what the labels say ,
I suspect a fair bit less now !

Sorry, missed the two banks part! Worth checking that there is some acid in them.

 

[RichardS]

Sorry, missed the two banks part! Worth checking that there is some acid in them.

Definitely worth checking the acid levels and also getting to the bottom of which battery bank is connected to which regulator and where the fridge connects into this lot.

It doesn't sound likely that both regulators have failed, assuming that both are powering the fridge, but you can check the output with a meter or even take the regulators out of circuit and connect the batteries directly to a solar panel with the fridge off to see if that keeps the battery charged but you need to monitor this unless you just use one panel as with 340Ah you don't want to connect more than the 40W panel unattended for more than a day or two if the sun's out.

I would start by trying to get all the topped-up batteries charged on a mains charger if you have one which will operate from such a low voltage. If they won't charge on a mains charger then they are shot.

Richard

 

[Chris_Robb]

Definitely worth checking the acid levels and also getting to the bottom of which battery bank is connected to which regulator and where the fridge connects into this lot.

It doesn't sound likely that both regulators have failed, assuming that both are powering the fridge, but you can check the output with a meter or even take the regulators out of circuit and connect the batteries directly to a solar panel with the fridge off to see if that keeps the battery charged but you need to monitor this unless you just use one panel as with 340Ah you don't want to connect more than the 40W panel unattended for more than a day or two if the sun's out.

I would start by trying to get all the topped-up batteries charged on a mains charger if you have one which will operate from such a low voltage. If they won't charge on a mains charger then they are shot.

Richard

This summer I had a problem with my fridge. This is run off a bank of 4 x 100ah. The fridge Freezer takes a steady load of 8 amps when running. Sitting anchored off Bodrum in July, the fridge suddenly failed to start. The battery monitor showed 12.6V which I thought was a little low. As the solar panels had always taken care of everything, I assumed there was something wrong with the fridge motor. In panic as the grandchildren were due on board - I got a local expert to come out to the boat to check it out. First thing he did was go to the batteries and check them - he just said - batteries ****ed....Get some more.

He then took a look at the compressor, and took of a small PCB that he said controlled the speed of the motor (ie fast for more raw cooling power) and then said - it will now run ok, but replace the batteries. Yes the motor started at once and drew only 3 amps which is fine as I am only using the freezer as a fridge.

On testing the batteries ashore, one had a dead cell. They said that this one dead cell had caused the other 3 to sulphate and thus to fail prematurely - at 4 years old.

The fridge engineer would not charge me any money for the time he had taken to come out to the boat - probably a good hour or more - as there was no fault with the fridge. Who said the Turks were money grabbing? I insisted on paying him.

 

[grafozz]

ok today the batteries were checked after standing disconnected for 24 hours the results were :
port , 1275 and 1160
stbd 1195 and 6.73 !
so looks like a dud battery may have brought the others down as suggested ?
I reconnected the 3 others to solar power and they seem to be taking cahrge ok .

However ,one strange thing occurred when connecting the 2 x good port batteries as soon as the lead touched the post
the port engine starter tried to engage !

nothing was switched on at all,

thanks all for the good input .

 

[ribrage]

ok today the batteries were checked after standing disconnected for 24 hours the results were :
port , 1275 and 1160
stbd 1195 and 6.73 !
so looks like a dud battery may have brought the others down as suggested ?
I reconnected the 3 others to solar power and they seem to be taking cahrge ok .

However ,one strange thing occurred when connecting the 2 x good port batteries as soon as the lead touched the post
the port engine starter tried to engage !

nothing was switched on at all,

thanks all for the good input .

Glad you sorted the battery problem out - I'd get a sparky to look at that wiring as the starter shouldn't get a supply to the solenoid and engage unless your hand is on the key.