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CO alarm in the night - Unsure of cause


DShK

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3 hours ago, blackrose said:

 

Have you worked out why it keeps happening? 

 

Yes.

Having an old battery bank of 6 x 230Ah batteries, 2 installed one year, 2 a year later and 2 another year later (previous owner dated each battery) so they are failing in date order)

 

The one that failed last year was 7 years old, the two that failed 2 weeks ago were 7 years old, and the two left will be 7 years old next Summer.

No idea why the  'odd' original one appears to be still going strong.

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On 26/05/2022 at 10:53, rusty69 said:

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

 

Or could someone moored nearby have been running a generator or had the stove lit and their CO drifted into the OP's boat?

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19 hours ago, AndrewIC said:

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.

Good call, will do this, thanks.

 

23 hours ago, David Mack said:

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

From the rest of the electrics. There are isolation switches but as far as I can see they don't isolate the batteries. I did have a BSS cert done as part of the sale, so either I'm missing something or the surveyor was a bit shit.

 

16 hours ago, Drayke said:

Is it me or does the second battery up on the left hand side have both positive and negative terminals connected to positive terminals on other batteries or is this a 24v setup?

12v but constructed from 6v cells. I don't know what the advantage of this is.

 

50 minutes ago, cuthound said:

 

Or could someone moored nearby have been running a generator or had the stove lit and their CO drifted into the OP's boat?

I'm in a marina, so no generators. I think the boats around me were empty, and it wasn't that cold a night.

 

23 hours ago, Alan de Enfield said:

 

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 ?

I spoke to a guy at a chandlery, he said batteries do gas, it's only if (as you said) they get hot or bulge, or it happens often that I should be worried. I'll continue to monitor, if the alarm goes off again I'll check if they are hot etc. On this note, how often should I be checking my electrolyte levels generally? (obviously more at the moment)

 

I just want to get another year out of these batteries, I will be replacing them with lithium in due time. 

 

Thanks for the help and advice everyone!

 

Edited by DShK
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I see your batterys appear to have removable screw vents that will allow you to visuslly  check the state of the plates, as  well as topping up with distilled water.  A shorted cell will generally have muddy brown electrolyte rather than clear acid.  I have seen this in a faulty battery that provided the lighting for my old camper van.  A fully-charged  healthy cell will have a deep chocolate brown positive plate (lead peroxide) and a metallic slate grey spongy lead negative plate. In a discharged cell, both plates are grey lead sulphate. 

 

Gassing happens in the normal charging operation, which is why open vented cells need to be checked periodically for the need to top up with distilled water. Such cells, being normally  unpressurised, will not swell or  explode due to gassing as they will incorporate gas vents. Some leisure batteries intended for use inside caravans or motor homes,  include a spigot for connecting a tube for venting  the highly explosive oxygen/hydrogen gas mixture safely to the outside. 

 

Sealed cells incorporate a catalyst that re-forms the hydrogen and oxygen gasses that are always  generated in the course of normal charging, back to water, and such sealed cells neither require, nor have provision for,  topping up. They can however swell and bulge alarmingly if overcharged. 

 

I had this happen to the three  12V 12Ah SLA batteries that my electric bike uses when the charger, an automatic electronic one which should have been able to be left connected permanently,  developed a fault. Instead of the approx max 42V  output, the charger  was producing  something over 50V, and had been left connected in this state for several days. Being professional quality cells, the cases swelled alarmingly but did not leak, but the distortion meant they had to be levered out of their battery box housing and had lost most of their capacity. They were also very hot. 

Edited by Ronaldo47
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On 26/05/2022 at 10:58, DShK said:

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

 

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

 

Ask yourself one question. Would you prefer an alarm that gave a few false positives, or one that gave a single false negative? 

 

 

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Update - Alarm went off again in the night. Same procedure as before, opened hatches, turned off gas and disconnected shore power and it stopped. I felt the batteries and none felt hot. I also can't smell egg. Interestingly the back cabin doors were closed (batteries being in the mid engine room). I'll check the electrolytes in the morning though. I'm a bit stumped and spooked.

 

Could the batteries be sitting at a voltage too high for them and gassing excessively without shorting and getting hot?

Edited by DShK
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I was hoping in a year or so I would upgrade to lithium, I don't particularly want to shell out for a new set of lead acid batteries now. I am now wondering if replacing the batteries now with lead carbon types might be the way to go - cheaper than lithium, a bunch of the advantages and it will hopefully deal with this likely gassing issue.

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9 hours ago, DShK said:

Update - Alarm went off again in the night. Same procedure as before, opened hatches, turned off gas and disconnected shore power and it stopped. I felt the batteries and none felt hot. I also can't smell egg. Interestingly the back cabin doors were closed (batteries being in the mid engine room). I'll check the electrolytes in the morning though. I'm a bit stumped and spooked.

 

Could the batteries be sitting at a voltage too high for them and gassing excessively without shorting and getting hot?

Yes.

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8 hours ago, Mike Hurley said:

Have you checked the starter battery?

It didn't feel hot, I couldn't see any inspection ports like the others, just the little viewing glass thing. Maybe it's sealed - I'll have another look. I do have a smartbank so it's entirely possible it's involved.

 

7 hours ago, Alan de Enfield said:

 

Why ?

How ?

 

Incorrectly set charger could cause problems no? If it's set to charge at a voltage higher than the batteries want?

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33 minutes ago, Tony Brooks said:

Don't some CO and smoke alarms start sounding when they think their batteries are flat? Maybe worth putting new ones in in case  the ambient temperature is allowing the battery voltage to alter. 

Can they actually properly go off? Obviously I've heard smoke alarm "chirping" before but this is different. The temp thing would make sense - we've had some chillier nights recently and at 2am in the back cabin it would be nippy. I'll try changing them and in the meantime I'm going to only charge during the day, so at least I won't get panic filled awakenings!

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If this keeps happening, with the same alarm, and for no apparent cause after reasonable investigations, then I’d start to doubt the alarm itself, and for the sake of a tenner or so get a new one. Worst case, both go off and confirm that you really do have a problem elsewhere. Best case, the old one proves to be duff.

 

(Not directly relevant, but one of our optical smoke alarms went off in the middle of the night last year. Full alarm, no failing battery chirping, but turned out to be the battery.)

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28 minutes ago, AndrewIC said:

If this keeps happening, with the same alarm, and for no apparent cause after reasonable investigations, then I’d start to doubt the alarm itself, and for the sake of a tenner or so get a new one. Worst case, both go off and confirm that you really do have a problem elsewhere. Best case, the old one proves to be duff.

 

(Not directly relevant, but one of our optical smoke alarms went off in the middle of the night last year. Full alarm, no failing battery chirping, but turned out to be the battery.)

Might be worth doing. This boat didn't come with a smoke alarm so I need to buy one of those too anyway. My concern is that it does look like there is evidence of gassing on the batteries - corrosion, wet areas (I assume this is acid, a result of gassing?) But how much of that is over a long time? When it happened recently, the back cabin doors were closed - I assume that quite a lot would need to build up to penerate them, and yet no smell. So it could go either way at this point. I think either replacing the batteries or the alarm is sensible.

 

On the plus side, it has got me considering if lead carbon batteries are a better idea than lithium, which could save me a few pennies.

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1 hour ago, DShK said:

On the plus side, it has got me considering if lead carbon batteries are a better idea than lithium, which could save me a few pennies.

 

Lead carbon batteries have been around for at least 20 years, admittedly with chopped up carbon fibre rather than carbon nanoparticles. (Elecsol anyone?). At first, they seem to at least partially meet the advertised claims but as time went on thee seemed to be more and more problems. Eventually the company disappeared, so any warrantee was of no use. I note that when failures were reported the advice to the customer amounted to do an equalization charge and to me that suggest they did find they sulphated, just like ordinary lead antinomy and lead calcium batteries.  They also used a weaker acid than typical for lead batteries so that would help to reduce plate erosion.

 

If they only cost a small price uplift over ordinary batteries then by all means give them a try. At least you will keep the relatively simple charging system, but if it is a hefty premium I would let others get some years of life and experience of them first.

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24 minutes ago, Tony Brooks said:

 

Lead carbon batteries have been around for at least 20 years, admittedly with chopped up carbon fibre rather than carbon nanoparticles. (Elecsol anyone?). At first, they seem to at least partially meet the advertised claims but as time went on thee seemed to be more and more problems. Eventually the company disappeared, so any warrantee was of no use. I note that when failures were reported the advice to the customer amounted to do an equalization charge and to me that suggest they did find they sulphated, just like ordinary lead antinomy and lead calcium batteries.  They also used a weaker acid than typical for lead batteries so that would help to reduce plate erosion.

 

If they only cost a small price uplift over ordinary batteries then by all means give them a try. At least you will keep the relatively simple charging system, but if it is a hefty premium I would let others get some years of life and experience of them first.

 

Ah, that is dissapointing. They did seem a little too good to be true. Well, the dilemna for me is that the original plan was to get lithium batteries. I will potentially be quite abusive to batteries, my desktop PC using maybe ~100 amps, 5 days a week (I am looking into ways to convert this to 12v for some extra efficiency, but not cheap). Having this amount of power will be "mission critical" to me (I will likely moor in a marina in the winter). Having a gardner, running the engine when moored isn't a great solution to get power. In comes an LPG generator - and I worry that when I need to run a generator to get the battery fully charged, it's going to be a massive waste of a limited resource that allows me to work. Lithium solves this issue, but I need to upgrade my solar (and get a generator) first - so I can't afford to refit that much of my electrical system to accomodate lithium yet. I don't want to pay ~£1000 for new lead-acids if I will replace them with lithium in the next year. So lead carbon seems to solve the issue of potentially needing to replace the batteries now, and putting up with the abuse I will put them through. Unfortunate that doesn't seem to be the case. I will just have to hope that the alarm is dodgy, not the batteries! Otherwise I might just have to get the lithium batteries now, although I believe Ed Shiers at four counties marine likely has a long wait list.

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7 minutes ago, DShK said:

my desktop PC using maybe ~100 amps, 5 days a week

 

I am afraid that is a nonsensical statement. An Amp is an instantaneous measurement of current flow so has no time associated with it. If you want to add time it needs to be Amp hours (Ah). I suspect you mean 100 Ah but is that per day for five days  or in total over the week. Unless you are into some very processor heavy applications like video editing or digital special effects I would have thought a high spec laptop running from a 12V adaptor would do the job as well as a desktop.

 

I assume the generator is powering a mains charger. If not most generator 12V outlets only provide a few amps and are often unregulated so there is a potential to overcharge the batteries but with the cost of gas or petrol that is unlikely.

 

Be aware that I only suggested caution with the claims made. Someone told me lead carbon only cost £20 more than lead acids and at that it would be worth a punt. Almost certainly per battery.

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10 minutes ago, Tony Brooks said:

 

I am afraid that is a nonsensical statement. An Amp is an instantaneous measurement of current flow so has no time associated with it. If you want to add time it needs to be Amp hours (Ah). I suspect you mean 100 Ah but is that per day for five days  or in total over the week. Unless you are into some very processor heavy applications like video editing or digital special effects I would have thought a high spec laptop running from a 12V adaptor would do the job as well as a desktop.

 

I assume the generator is powering a mains charger. If not most generator 12V outlets only provide a few amps and are often unregulated so there is a potential to overcharge the batteries but with the cost of gas or petrol that is unlikely.

 

Be aware that I only suggested caution with the claims made. Someone told me lead carbon only cost £20 more than lead acids and at that it would be worth a punt. Almost certainly per battery.

I mean Ah yes, got lax with with units. 100 amp hours, per day, 5 days a week. I make video game art for a living so I do need a powerful rig. It's less the CPU that is the power hungry part but the graphics card. I've taken steps to minimize this - I've capped it's power draw to 50%, I limit when the game can render and I've capped the framerate. Reduced my power draw per day by hundreds of watt hours!  A laptop powerful enough would probably be ~£2500+ and I'm not about to tell my work that the PC they bought me isn't good enough because I've moved onto a boat :) That kind of "gaming" laptop runs super hot and generally die after a few years as a result - very poor economy there. Plus I need two monitors/an ultrawide, so I start to see diminishing returns using a laptop there. I have found a 12volt power supply but it's ~£400 itself. I'd need to find an ultrawide monitor with an external power brick to conver that to 12v - need to source one that meets colour accuracy requirements. Plus I'd need to sell my current fancy monitor, trying not to lose too much on it. lots to do! Part of the reason I bought the boat was to solve puzzles like these though, I enjoy it.

 

Generator would be plugged into a mastervolt combi, I believe this should be up to the job!

 

Sure, but if LC are then also only marginally better than regular lead-acids, I've dumped a lot of money that could be put towards a solution that actually works.

 

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6 minutes ago, DShK said:

I mean Ah yes, got lax with with units. 100 amp hours, per day, 5 days a week. I make video game art for a living so I do need a powerful rig. It's less the CPU that is the power hungry part but the graphics card. I've taken steps to minimize this - I've capped it's power draw to 50%, I limit when the game can render and I've capped the framerate. Reduced my power draw per day by hundreds of watt hours!  A laptop powerful enough would probably be ~£2500+ and I'm not about to tell my work that the PC they bought me isn't good enough because I've moved onto a boat :) That kind of "gaming" laptop runs super hot and generally die after a few years as a result - very poor economy there. Plus I need two monitors/an ultrawide, so I start to see diminishing returns using a laptop there. I have found a 12volt power supply but it's ~£400 itself. I'd need to find an ultrawide monitor with an external power brick to conver that to 12v - need to source one that meets colour accuracy requirements. Plus I'd need to sell my current fancy monitor, trying not to lose too much on it. lots to do! Part of the reason I bought the boat was to solve puzzles like these though, I enjoy it.

 

Generator would be plugged into a mastervolt combi, I believe this should be up to the job!

 

Sure, but if LC are then also only marginally better than regular lead-acids, I've dumped a lot of money that could be put towards a solution that actually works.

 

 

Now we know what you do I fully understand why you can't do much about it. I would suggest limp on with what you have while you save for the lithiums and their control system.

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Roger that, I'll give the lead carbons a miss. I guess I should go right for the lithiums over the solar/generator. Honestly I would quite like to get an electrician to rework my electrics cupboard anyway, it's a bit of a rats nest. I think I'll give Ed a call soon and see what it's likely to cost/when he's available.

 

Thanks for the advice!

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  • 1 month later...

Update to this - batteries continue to gas when charging from a moderate discharge state. I just fitted 1500W of new solar panels and these are now causing the alarm to go off.

 

I began to wonder if the previous owner had set the voltage wrong - so reached out to the battery supplier for info.  They are monbat GC2B 6v cells. I can't quite make heads or tails of the datasheet they gave me though - the graph given for voltages doesn't match my understanding for a IUI charge profile. It looks like 12v raising to 14.4V for bulk/absorption. But then it raises even further to 15.9? I don't understand why this graph doesn't drop to a float voltage. 15.9 Seems extremely high. The charger is currently set to 14.8V which is higher than that 14.4V value - perhaps this is causing the gasing? Or do my batteries just need replacing?

 

As a perhaps point of note - it seems to me that the alarm is always getting set off when the smartguage has hit 100% - not sure if just latency, but I did turn on the charger when the batteries were already at 100 (I think I accidentally turned the charger off, unless the switch on it is also somehow a breaker?) and the batteries began to gurgle quite loudly.

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Edited by DShK
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