That was interesting… Battery catastrophically died

[gregcope]

So daughter and I go aboard to motor to a local anchorage for the evening.

The house bank is just over seven years old and mostly dead. It could not start the engine. I know it has virtually no capacity (15Ah from a 240Ah bank) and needs replacing. However replacement did not seem urgent.

Whilst motoring i was surprised that the alternator was putting 35A into the batteries, yet the voltage was still only 12.5V and looked like it was falling. “Hum” i was thinking. Did i leave something on last time as the batteries were flat? We have solar panels that should have kept them charged. At the time it seemed they were flat and needed a charge.

When we anchored and stopped going down below there was a foul smell. Within a few seconds I twigged. I checked the batteries and one of the house bank was very hot and burbling.

I hurriedly disconnected them and removed the suspect one to the deck and reconnected the okay one whilst opening all the hatches and then sitting in the cockpit… as the smell was most probably hydrogen sulphide

Moral of story…

1. Replace batteries when you think they have died …
2. Have an easier way to disconnect in a hurry. Anderson SB175s come to mind. Fiddling around with multiple battery connections whilst avoiding a short could be avoided.
3. I have a few things directly connected (vhf, bilge pump, chargers) to first house battery. These should probably be on a busbar with a way to switch them.
4. When you have abnormal voltage/amperage that does not make sense check the batteries. This could have got serious if we motored longer.

After all the excitement the anchorage was lovely. We did not use the batteries.

 

[PaulRainbow]

I hurriedly disconnected them and removed the suspect one to the deck and reconnected the okay one whilst opening all the hatches and then sitting in the cockpit… as the smell was most probably hydrogen sulphide

This was totally insane and could easily have led to very serious injury or loss of sight.

The correct procedure it to isolate the batteries, vent the gas/allow to cool and only then to disconnect them.

You almost certainly had a shorted cell in the faulty battery, which effectively makes it a 10V battery, charging at about 14V, so the cells boil and vent hydrogen, the smallest of spark will likely cause an explosion. People often disagree with me on that point (on here) but the picture below is from a friends Bavaria, where pieces of battery casing were buried in the wooden battery box top. Luckily no one was injured.

 

[Refueler]

Paul and I have our moments .... but here we totally agree.

You are extremely lucky .....

 

[chrishscorp]

This was totally insane and could easily have led to very serious injury or loss of sight.

The correct procedure it to isolate the batteries, vent the gas/allow to cool and only then to disconnect them.

You almost certainly had a shorted cell in the faulty battery, which effectively makes it a 10V battery, charging at about 14V, so the cells boil and vent hydrogen, the smallest of spark will likely cause an explosion. People often disagree with me on that point (on here) but the picture below is from a friends Bavaria, where pieces of battery casing were buried in the wooden battery box top. Luckily no one was injured.

View attachment 121568

Happy to be told im wrong, but i dont think lockdown has done our boats much good they clearly dont like not being used, batteries do seem to be high on that list.

Apart from monitoring battery voltages i presume battery tempratures are next on the list for an early warning ? This is something I have been mulling over what are the options for doing that ?

 

[PaulRainbow]

Happy to be told im wrong, but i dont think lockdown has done our boats much good they clearly dont like not being used, batteries do seem to be high on that list.

Apart from monitoring battery voltages i presume battery tempratures are next on the list for an early warning ? This is something I have been mulling over what are the options for doing that ?

Some things did suffer during lockdown, batteries past their best were possibly affected, i had one customer who'd brand new batteries were left off charge for 18 months, after which they were still 80% charged, no harm done.

There are battery temperature monitoring solutions out there now, we don't tend to fit them much though, perhaps because these problems aren't every day issues ?

 

[chrishscorp]

There are battery temperature monitoring solutions out there now, we don't tend to fit them much though, perhaps because these problems aren't every day issues ?

I had an interesting set up in my new to me van as it was formerly a mobile workshop so has excellent LED lighting in the back, eberspercher CH, a 3.1KW inverter and a 1/2 ton loading ramp so it needed a second 110Ah battery. That went wrong and like above it got very hot and the sides bulged outwards, battery cabinet door shut very quickly and i disconected off the main battery in the cab and left it too cool. I was lucky and realised what was happening and didnt try to mess with it. Maybe not an everyday issue but once bit twice shy

 

[pvb]

Apart from monitoring battery voltages i presume battery tempratures are next on the list for an early warning ? This is something I have been mulling over what are the options for doing that ?

Some battery monitors include battery temperature sensing and alarms. Simarine and Victron spring to mind.

 

[LadyInBed]

After all the excitement the anchorage was lovely.

You were very lucky not to have had a fire ?

 

[gregcope]

@PaulRainbow @Refueler agree with everything you say. We were very lucky.

To clarify the battery comparment is vented (outside) and opening hatches is the 2nd thing we did after switching all the things off. There was a good breeze and we also aggressively pumped the bilge (although both hydrogen and hydrogen sulphide are lighter than air). There was a hiatus of a good 20mins before I very, very carefully disconnected. I was confused as to why my solar regulators were still powered when not connected to the batteries and double/tripple checked.

 

[gregcope]

Some battery monitors include battery temperature sensing and alarms. Simarine and Victron spring to mind.

My Victron 702 battery monitor can do temp or another battery voltage. I had it set on the engine battery voltage. Might reconsider that or think about another Victron solution like the Victron battery sense

 

[gregcope]

Some things did suffer during lockdown, batteries past their best were possibly affected, i had one customer who'd brand new batteries were left off charge for 18 months, after which they were still 80% charged, no harm done.

There are battery temperature monitoring solutions out there now, we don't tend to fit them much though, perhaps because these problems aren't every day issues ?

My batteries had been on chargers throughout lockdowns/last season. They are however just over seven years old.

Another thing that has suffered is that nearly every single zip onboard has corroded. Some have just disintergrated when trying to unstick them.

 

[pvb]

My Victron 702 battery monitor can do temp or another battery voltage. I had it set on the engine battery voltage. Might reconsider that or think about another Victron solution like the Victron battery sense

If your engine battery is suitably independent, there's no real need to monitor its voltage, so you could use the 702's facility to monitor the house battery temperature and set its high temperature alarm at a suitable level.

 

[Boater Sam]

My batteries had been on chargers throughout lockdowns/last season. They are however just over seven years old.

Another thing that has suffered is that nearly every single zip onboard has corroded. Some have just disintergrated when trying to unstick them.

That is likely to be the H2SO4 formed from the gas, think what it does to your lungs.

 

[LittleSister]

That is likely to be the H2SO4 formed from the gas, think what it does to your lungs.

Which reminds me: can one still buy stink bombs?

 

[Big-Bang1]

Funny enough we had a very similar situation yesterday. Motored back from a day out in the bay and when we got back to the mooring my boy said he could smell something nasty down below. On investigation it was clearly the house battery , so I hurridly isolated all the batteries and we sat above deck with all the hatches open for a good while before setting off in the dinghy.
I've been back to the boat today to remove the failed battery and discovered that I have to disconnect all of the wires to the master switch before I can remove the battery - not Ideal. Battery voltage on the failed battery today when tested at home was 5.022 volts.

 

[oldgit]

 

[gregcope]

Ouch. Mine did not appear to be deformed or bulged in anyway. Just hot.

Interestingly the other house battery (same type, purchased at the same time) seems to be okay and working okay. Ie the capacity issues could be mostly down to that one battery misbehaving…

 

[sailinglegend420]

Why Are My Water Pipes Vibrating Randomly? | ESTES SERVICES

... i had one customer who'd brand new batteries were left off charge for 18 months, after which they were still 80% charged, no harm done.....

Some harm will have been done because with batteries disconnected their voltage will have slowly fallen from about 12.8v to 12.5v or less because of self-discharge in the electrolyte, which then causes lead sulfate crystals on the plates. Over time these crystals will have permanently hardened and reduced the useable area of the plates and hence the Ah capacity of the batteries.

So a 100Ah battery will no longer deliver 100Ah!

 

[PaulRainbow]

Why Are My Water Pipes Vibrating Randomly? | ESTES SERVICES

Some harm will have been done because with batteries disconnected their voltage will have slowly fallen from about 12.8v to 12.5v or less because of self-discharge in the electrolyte, which then causes lead sulfate crystals on the plates. Over time these crystals will have permanently hardened and reduced the useable area of the plates and hence the Ah capacity of the batteries.

So a 100Ah battery will no longer deliver 100Ah!

"Some harm", as in less harm than cycling them for 18 months.

Pedants, pah!!

 

[PaulRainbow]

@PaulRainbow @Refueler agree with everything you say. We were very lucky.

To clarify the battery comparment is vented (outside) and opening hatches is the 2nd thing we did after switching all the things off. There was a good breeze and we also aggressively pumped the bilge (although both hydrogen and hydrogen sulphide are lighter than air). There was a hiatus of a good 20mins before I very, very carefully disconnected. I was confused as to why my solar regulators were still powered when not connected to the batteries and double/tripple checked.

You should disconnect the panels from the controller before disconnecting the batteries.