Fried Battery?

[MarkJohnson12345]

Refering to my previous post about a 15 minute discharge of my 110 ah battery, I returned to the boat today to see what was what.

I measured the fried battery, and bless her heart, she told me that she had 12.3 volts.

I then re-connected the batteries, and sure enough the monitor agreed she had 12.3 volts.

But 2% charged!

So I dared put on the 15a/h 3 stage charger which is wired to shore power.

Aftern an hour or less, voltage is up to 13.4v, and capacity is up to 7%.

Does this sound good ? Or wil be a repkacement battery?

I don't dare leave the battery attached to the charger when I am not here as I am not sure of the worst that could happen, but am going to leave the 20w solar panel on unti Friday night.

I suspect the battery will unreliable in the long run, mind it is onlt two years old.

 

[Heckler]

Sounds to me as if it is taking a charge, if it was definitely discharged then it will be sucking in the juice, when it gets towards fully charged then the voltage will go up. Dont forget that a std 60amp alternator with Sterling booster can put out 60amps plus, it makes your 15 amp charger look puny. Keep putting juice in and perhaps reset your monitor
Stu

 

[James_Hortop]

If the battery is knackered, forcing 50A plus in with a booster could actually be dangerous. You are better off putting it on a decent 4 stage smart charger (I presume you have one). At 110Ah it will take around 3 hours to reach 80% charged. The final 20% can take anywhere between 1.5 and 3 hours depending on the state of the battery.

Some chargers have equalise mode which may well recover it.

You may have an issue with your battery monitor. If you are bypassing the shunt with the negative cable of the charger it won't be able to count the current going back into the battery.

James

 

[Cliveshep]

When I was working in Garage years ago they used to boost a flat battery saying that it was the only way to "lift" it and that a normal charger couldn't do it. After a while on boost, by which I mean 100 amps plus for perhaps 15-20 minutes, they would then revert to normal charging to finish the charge.

 

[Mrnotming]

your battery should have 12.7 Volts resting even after many days.You are wise not to leave the charger on, as if there is a shorted cell heat will be generated as the charger tries to force a now 10V batttery to be a 12 V battery. Somewhere in between 12.7V and 12.3 volts lies damage.
So to avoid a fire or explosion scrap the battery.If you can use a hydrometer on the battery, that is if it is wet lead acid with access, the cell will show up as a different reading.If sealed or gel, tough as only one cell might be measured by a green eye type indicator, leaving the other five cells unmeasurable.Good sailing to all.

 

[Bilgediver]

I suspect the battery will unreliable in the long run, mind it is onlt two years old.
+++++++++++++++++++++++++++++++++++++++

Leisure batteries appreciate a bit of rough treatment from time to time! All this molycoddling with 18watt solar cells and 10 A rms chargers may be ok from time to time and a holding charge but what the battery really is dying for is a few hours of BULK charge at a rate which is the result of a charging voltage of 14.4 to 15 volts.

I discovered this years ago when I found the easiest way to get a 5 cell 10 volt battery was to charge it with an elcheppo charger.

More recently my brother in law on the Thames had simlar problems to you and so I gave him a Sterling multistage charger for his birthday. He has this rigged up with a bog standard socket timer in the mains supply and it goes on about 2 hours a day....Result now he has battery power for away days....his wife is happy as the engine always starts on the button.

I suggest you need to charge with you multi stage which should give the 14/15 volt charge when needed and so get you up to 100% fully charged,

 

[William_H]

The battery will be dud if it can';t exhibit a capacity of aroujnd 50% of that advertised. You need to fully charge it then use it discharging keeping an eye on time and current. along with voltage.
I doubt your battery monitor could correctly measure the massive discharge in the fault and then the charging so fully charge the battery then reset the monitor. good luck olewill

 

[MarkJohnson12345]

Thanks all for inputs. I left the battery yesterday having charged it at 15 amp/hr for two hours.

The monitor read 13.5volts and the cpapacity was 25%.

I did not leave the charger on in case there was a problem.

But I did leave the 20 watt solar panel on for 24 hrs.

Anyway this evening the battery, before connecting to the charger, reads 12.7 volts, and the capacity was up to 90%. Just shows how good these mointors are!

Any she's back on charge and taking 8 amp/hr.

So we shall see what happens after a 12 hour charge. I am actually using the battery to power the fridge, so several amps/hour are going there.

Only once the electrics are repaired and back in use will I be certain that the battery got away with it!!

We shall see.