false propane alarm

[wfleenor]

Every time my batteries run an absorb charging cycle, my propane alarm in the galley goes off. Anyone else ever experience that issue? In my power catamaran the batteries are on the same level as the galley. I suspect in most installations the batteries are lower than the galley.

 

[Comodave]

I have heard of that before. Can you get some ventilation going on to get rid of the fumes?

 

[High Wire]

Double check your charger settings against the battery manufacturers recommendations. What type of battery?
The gas that comes out of batteries is hydrogen, lighter than air.

 

[SteveK]

propane is heavier and hydrogen lighter than air.
Can you lower the sensor for the propane alarm?

 

[psneeld]

Every time my batteries run an absorb charging cycle, my propane alarm in the galley goes off. Anyone else ever experience that issue? In my power catamaran the batteries are on the same level as the galley. I suspect in most installations the batteries are lower than the galley.

Yes. The boat I just sold started having that issue on my delivery trip.

The propane sensor was well below and distant from the batteries.

I didn't have much of a chance to troubleshoot but I suspect the age of the battery or some resistance in the charging lines was convincing the Promariner inverter/charger to up the voltage or hold the absorb too long. My next step was to see if I could adjust the Promariner and replace the batteries.

For the rest of the delivery, the new owner disconnected the inverter/charger and used the Promariner battery charger backup charger plus a simpler inverter. Haven't heard further but that seemed to fix the issue.

So either the inverter/charger was running out of spec (not sure could be adjusted) or in combo with those batteries had met its match for proper ops.

 

[Bmarler]

I had the same issue a while back. My genset starting battery had a couple bad cells. Essentially acting like a load and keeping the charger working too hard. I turned off the charger and isolated my three battery banks so I could test them. After 24 hours it was obvious what was going on.

 

[rwidman]

Can you lower the sensor for the propane alarm?

Or just remove it altogether?

Seriously, the propane alarm is doing what it's supposed to do, telling you that there is a problem. Don't mess with the alarm, fix the problem.

One possibility is that the charger is set incorrectly and causing the batteries to release gas. Hydrogen gas floating around in your boat is not a good thing. Remember the Hindenburg?

A simple (but not inexpensive) solution would be to replace the batteries with sealed batteries (AGM comes to mind).

 

[Sealife]

Had the same problem when batteries were going bad. New batteries, problem gone. 2 had shorted cells.

 

[SteveK]

Or just remove it altogether?

Seriously, the propane alarm is doing what it's supposed to do, telling you that there is a problem. Don't mess with the alarm, fix the problem.

One possibility is that the charger is set incorrectly and causing the batteries to release gas. Hydrogen gas floating around in your boat is not a good thing. Remember the Hindenburg?

A simple (but not inexpensive) solution would be to replace the batteries with sealed batteries (AGM comes to mind).

I find your reply rude.
The propane sensor is not doing what it is supposed to do, sense propane, if it is sounding off and there is no propane issue. Placing it lower may avoid false readings from other gases that rise and which are not intended to be monitored.

 

[Nick F]

On a point of information:

The "propane" sensor is not specific to propane. It is actually a "flammability" detector.

In the sensor, a small bead of catalyst material causes any flammable gas to react with the oxygen in the air even when the concentration is well below that required to sustain a flame (the "lower flammability limit", LFL*). This minor reaction causes increased temperature of the bead which is sensed and, at a certain level, used to initiate an alarm. The alarm level is usually adjusted to correspond to 10% of the propane concentration of the propane LFL. The LFL for propane is 2.1% in air, so 10% LFL means a a propane concentration of about 0.2%.

Any flammable gas will make the sensor react, however the initiation of alarm may not correspond to 10% LEL for different gasses.

Of interest, the LFL for hydrogen in air is 4%.

* the terms LFL "lower flammability limit" and LEL "lower explosive limit" are interchangeable.

 

[psneeld]

Add to the list .... read up on AGM, and maintenance free batteries....a LOT of different websites discuss they do vent off gassing if bad enough through a relief valve.

I can't say for sure...but it is worth researching/considering before the problem is resolved or if you are just curious about this "safety" issue or thinking of changing batt types.

 

[C lectric]

Actually AGMs can be damaged by improper charging. Once they off gas, VENT, there is no getting it back and some capacity has been lost. There is a seal that, once it opens it is no longer sealed.

The propane alarm sounding from battery off gassing is not an unheard of phenomenon.
It is actually a common warning something is amiss with the batteries and/or the charger.

 

[jgwinks]

I had a propane alarm trip when a paint can leaked. Pretty much any hydrocarbon can set them off. Also the sensors don't last forever, that same sensor that tripped on the paint can eventually failed, sounding continuously. Could be the OP's alarm sensor is on its way out. Better to have nuisance trips instead of not going off when it should.

 

[wfleenor]

I want to thank all for the replies. For what it's worth, the sensor is on the same floor level as the batteries. The batteries are nearly 8-years old, so my plan is to replace them with lithium this summer and add solar panels before heading to the Sea of Cortez in the near future. The nuisance of the alarm will give me further motivation. Thanks again.

 

[Nick F]

William - I would not call the alarm a nuisance! It was a BONUS! It gave you a heads up on a problem you may not have been aware of.

Regards,
Nick

 

[Sofa King Fishy]

Yep- out gassing batteries will trip CO and LPG sensors.

 

[RT Firefly]

Greetings,
From time to time I check my propane sensor which is in the propane locker. A quick flic of a Bic without igniting soon triggers an alarm.

 

[rgano]

I mounted one of the twin sensors of my new Cintex system hard by the three-battery starter bank and a foot away from the port Lehman drip pan, and it never went off unless I shot some gas from a lighter at it. Had it begun to do so after some years of installation without any other indication of a leak, I would probably have looked at replacing the sensor before I ever figured out off-gassing batteries were a likely issue. With two 120 Lehmans and an Onan down there in the same space, there was always a lot of hydrocarbon about.