CO alarm in the night - Unsure of cause

[DShK]

Hi, I've been on my first boat for about a month now (I live aboard in a marina). Last night my CO alarm went off. I got myself and my dog off the boat, and opened all my hatches and doors. Turned off the shore power and isolated the gas. The alarm stopped.

 

I could see no reason for this to happen. I was not burning anything, no heaters, no cooking. The boats around me are usual empty and it's not cold enough to need heating etc.

 

I have since read that the alarms can pick up hydrogen gassing from charging batteries. I was plugged into shore power at the time so I suspect this might be the cause? I hadn't done anything different to usual though. I suspect these batteries are getting on a bit, it's a bank of 6x 6v batteries, wired up to produce about 700ah at 12v. The starter is 12v and connected to the main bank via a smart bank. Extrapolating between my shunt readings and the smartguage, I get about 160amps of useable capacity. (This is assuming that the smartguage isn't set to show 50% as 0% or something weird). There are some copper oxide furries forming on some terminals. I measured the voltage across each battery and they all matched.

 

Any idea if the batteries are the cause? Anything I should check? It's a bit spooky to have that alarm go off and not know why. 

 

Thanks for any help!

[rusty69]

I

5 minutes ago, DShK said:

 

 

Anything I should check? I

 

Electrolyte levels

Signs of batteries bulging, or any other distortion.

 

@Alan de Enfield will be along in a mo. I recall he had a similar problem

Edited May 26, 2022 by rusty69

[Alan de Enfield]

I had this a couple of years ago, and again 2 weeks ago.

 

I'd say it is almost definitely you have a battery (or batteries) with internal shorts - if you don't isolate it and remove it (them) from the bank it will get hotter and hotter until it explodes - you don't want to be trying to clean that up.

 

Feel each battery, is one warmer than the others ?

Look at the batteries, is one low on water ?

Look at the batteries, is one a bit distended at the ends ? (I had one that was almost rugby ball shape and I reckon was within minutes of exploding. It was so hot I could not touch it)

 

[DShK]

12 minutes ago, Alan de Enfield said:

I had this a couple of years ago, and again 2 weeks ago.

 

I'd say it is almost definitely you have a battery (or batteries) with internal shorts - if you don't isolate it and remove it (them) from the bank it will get hotter and hotter until it explodes - you don't want to be trying to clean that up.

 

Feel each battery, is one warmer than the others ?

Look at the batteries, is one low on water ?

Look at the batteries, is one a bit distended at the ends ? (I had one that was almost rugby ball shape and I reckon was within minutes of exploding. It was so hot I could not touch it)

 

Okay that's fairly spooky. It's hard to tell if they are bulged at the ends, they are packed into this box pretty tightly. None feel warm from what I can touch. None look like they have their plates exposed. Maybe one is a bit lower but it's hard to tell. I wonder if the lid stains shown below might be clues? Is there anything else that might be a giveaway? I might need to break this wood box to see if they are bulged.

 

It's also unfortunate because as far as I can tell, this installation (I think the previous owner must have done it) has no way to isolate the batteries. There are 3 isolation switches, I know what 1 does, the other two I have no idea!

 

Thanks so much for the replies!

[Alan de Enfield]

I'd start by looking at the one(s) with snotty-stuff on the terminals. The battery(s) will have been gassing and the gas attacks the lead and copper

 

 

Switch you battery charger back on and monitor the battery temperatures - you'll feel the difference by touch.

 

You've got an easy job getting yours out - mine are 230Ah and weigh 55kgs each and you have to lift them out whilst lying down under the floor.

 

2 weeks ago one 'went' so disconnected it, the following night another one 'went'.

Disconnect by removing the battery interconnects, but obviously using 6v batteries you'll need to diconnect the pair.

[rusty69]

Could the CO alarm itself be faulty, or past its expiry date?

[DShK]

Okay thanks, that helps a lot. I'll give that a go. And report back.

 

1 minute ago, rusty69 said:

Could the CO alarm itself be faulty, or past its expiry date?

Good point, just checked - it was installed 2019 and says replace after 10 years. So should be fine I imagine.

[Alan de Enfield]

Does the ratchet strap go over the lid or over the batteries ?

Not a good idea to have anything metal loose near battery terminals.

 

Zooming in & looking at the pitting on the ratchet it does look like acid-gas attack corrosion

 

Purely on a visual basis I'd suspect the 2nd battery down on the left hand side.

[mrsmelly]

18 minutes ago, rusty69 said:

Could the CO alarm itself be faulty, or past its expiry date?

Rusty.........yaaaay......................Rusty..........Rusty, Rusty, Rusty................

[ditchcrawler]

1 hour ago, DShK said:

 

It's also unfortunate because as far as I can tell, this installation (I think the previous owner must have done it) has no way to isolate the batteries. There are 3 isolation switches, I know what 1 does, the other two I have no idea!

 

Thanks so much for the replies!

 

 

To isolate the batteries you have to disconnect the terminals, you may then find different voltages on them

[Tracy D'arth]

Take off all the connections and measure the voltage of every battery. Any seriously low readings will be the duff ones.

[DShK]

Thanks for the replies (will reply properly in a bit) I texted the previous owner and asked what the batteries were so I could swap like for like. He said the alarm went off for them a couple times and it will gas when bulk charging (they would have been on absorption at the time). He said they just increased ventilation. Seems a bit dodgy to me? He said they were 4 years old.

 

I have them on charge right now, will see if any get warm.

Sounds like I need to disconnect the batteries and check voltage one by one afterwards

Edited May 26, 2022 by DShK

[Peugeot 106]

I have a calcium starter battery (Halfords). It had a bullseye indicator the same as yours on the larger right hand battery. Yours in indicating green. Mine is a red dot in the centre with a green background? Does anyone have any idea what this means I can’t find any info on the Halfords website? Incidentally after 24 hours not running or charging it’s showing 12.8 volts on the Smartmeter.

It seems to be working ok. 

Thanks

[Alan de Enfield]

11 minutes ago, Peugeot 106 said:

Does anyone have any idea what this means I can’t find any info on the Halfords website?

 

 

It means another sucker thinks they have bought something that shows the state of charge of the battery.

 

It is a simple plastic ball that floats in just one of the six cells in the battery - it supposedly shows green when the battery is charged and black or red when discharged.

 

It is a big con and reliance on them destroys many, many, batteries.

 

At best it can only indicate the state of one cell, and as we all know, any of the other 5 could have an internal short leading (potentialy) to a battery explosion.

Stick a bit of insulation tape over it and forget it is there, and concentrate on charging and 'managing' the batteries properly.

[DShK]

Been for a little while now, not noticing any warmth. Will continue to monitor.

[LadyG]

3 hours ago, rusty69 said:

Could the CO alarm itself be faulty, or past its expiry date?

I hadn't two, both in date, but one kept chirping when nothing was on, I put it outside and it stopped. It got rained on, and now is faulty, so that was not clever.

I did have a chirp started when a boat behind ran engine for an hour.

[Alan de Enfield]

20 minutes ago, DShK said:

Been for a little while now, not noticing any warmth. Will continue to monitor.

 

Ours started screeching about 8 hours after switching on the battery charger.

 

All 3 times (1x 2 years ago and 2x in the last couple of weeks) have happened in the middle of the night, maybe it is calmer, less air moving about not opening doors etc.

 

Maybe it is not a faulty battery ?

[David Mack]

4 hours ago, DShK said:

 

It's also unfortunate because as far as I can tell, this installation (I think the previous owner must have done it) has no way to isolate the batteries.

From each other or from the rest of the boat electrics?  The latter is a BSS requirement.

[Tracy D'arth]

Does methane set CO alarms off? H2S  does.

[Alan de Enfield]

Just now, Tracy D'arth said:

 H2S  does.

 

I blame the trains !!!

 

 

1 minute ago, Tracy D'arth said:

Does methane set CO alarms off? 

 

If it did our dog would be setting them off continuously !

[Tracy D'arth]

Just now, Alan de Enfield said:

 

I blame the trains !!!

 

 

 

 

Dyslexia?

[Alan de Enfield]

3 minutes ago, Tracy D'arth said:

Dyslexia?

 

Dunno, cannot remember that far back but I think that what I call out when I want the TV channel 'turning over'.

[Peugeot 106]

1 hour ago, Alan de Enfield said:

 

 

It means another sucker thinks they have bought something that shows the state of charge of the battery.

 

It is a simple plastic ball that floats in just one of the six cells in the battery - it supposedly shows green when the battery is charged and black or red when discharged.

 

It is a big con and reliance on them destroys many, many, batteries.

 

At best it can only indicate the state of one cell, and as we all know, any of the other 5 could have an internal short leading (potentialy) to a battery explosion.

Stick a bit of insulation tape over it and forget it is there, and concentrate on charging and 'managing' the batteries properly.

Thanks I guess it’s ok then! I only have one starter and one domestic battery but have an Adverc and Smartmeter to help look after the batteries . I don’t think the domestic has ever been below 90% and the engine starts first time so I didn’t anticipate any problems but l was curious about the bulls eye indicator. You  have explained it well. Thank you

[AndrewIC]

6 hours ago, ditchcrawler said:

To isolate the batteries you have to disconnect the terminals, you may then find different voltages on them

And while you’re at it, suggest you adjust the position of the two positive cables that appear to be resting on negative terminals, in case of chafing of the insulation.

[blackrose]

8 hours ago, Alan de Enfield said:

I had this a couple of years ago, and again 2 weeks ago.

 

I'd say it is almost definitely you have a battery (or batteries) with internal shorts - if you don't isolate it and remove it (them) from the bank it will get hotter and hotter until it explodes - you don't want to be trying to clean that up.

 

Feel each battery, is one warmer than the others ?

Look at the batteries, is one low on water ?

Look at the batteries, is one a bit distended at the ends ? (I had one that was almost rugby ball shape and I reckon was within minutes of exploding. It was so hot I could not touch it)

 

 

Have you worked out why it keeps happening?