CO and LP detector battery drain. Solution?

[Guysakar]

Hi guys,

I just found out that the detectors in an RV use about 35-40 amps a day. On a "typical" 120 Ah system, charged to the normal 90%, and discharged to the normal 50%, the detectors will drain 75% of your usable portion of battery, every day.

WOW!

Figuring it will take a genset, say 2-3 hours (I could be wrong on this) to recharge the batteries, and figure 1/2 gallon per hour to run genset, and $4.00 a gallon for gas/fuel. (Just averages)

In theory, if you were dry camping, and used no electricity for anything else, you would spend about $112.85 a month in fuel, just to power the detectors.

HUH!?

So my question is, I wonder if there is a way to disconnect the detectors (and other drains?) when I am outside of the MH, but still want power.

Like say I am fishing during day light, sitting by campfire at night, etc... but still want to use radio, TV, lights, etc... that I have outside. Not to mention the fridge/freezer.

Then, when I go inside at night to sleep, I just flip the detectors back on.

Also, what else can I turn off that drains battery just sitting idle?

I know people are going to say, what if you forget. Well, it's just me, I don't usually forget things like that, and I am willing to run the risk.

Me wrote:
Here is my break down if anyone wants to check my math. I know every case is different, but these seem to be the averages.

40 amps per day: 35-40 amps a day to power detectors (I have read that this is the average several places)

2.5 hours genset run time: 2-3 hour charge time is what I am seeing to be the norm for a 120 Ah system.

$4.00 per gallon of gas

1/2 gallon per hour genset fuel economy

120 AH battery bank: 120*90%*.5 = 54 usable amps.



So assuming it takes 2.5 hours to put 54 amps back in the battery(s), and genset gets 1/2 gallon per hour: 2.5*.5*4 = $5.00 to recharge batteries from 50% to 90% (or to put 54 amps back in 120 Ah battery bank).

So, detectors use 40 amps per day: 40/54 = .74 (54 is the amount of usable Ah in 120 Ah battery bank)

So, to charge batteries to 90% would cost $5.00. Detectors are only using 74% of this, so $5.00*.74 = $3.70 a day in fuel to keep detectors running.

$3.70*30.5 days = $112.85 a month just to power detectors.

No %$#@^!& way am I going to pay that.

[mbopp]

I put a master on-off switch on the radio so it has no parasitic drain, and the CO detector runs on a 9V battery.
The propane detector draws 70ma (.07A) or less than 2A-H a day.

[wa8yxm]

My CO detector runs six months (or more) on a set of 3 AA batteries... Not sure how much power the Propane (Explosive gas) detector pulls, but since it is not one of those with a remote controled valve (Some will shut off propane if explosive gas is detected) I'm sure it's not much more than the CO detector.
Smoke detector uses a 9 volt retangular battery, also 2 per year.

I think you missed a decimal point on your detector current use.

[korbe]

Our draw with no obvious 12volt things on is 0.10 AH. Our frig will use an additional 0.30 AH of battery draw. Not much.

[RoyB]

If I was that concerned I would install a BATTERY DISCONNECT SWITCH...

I normally do that procedure anyway when I park my trailer and it is not connected to some sort of shore power.

When camping off the power grid this has become part of the planning on how many batteries you need and how you replenish all the power you consume each day in order to make the next day/night run of the batteries.

It does take some planning to be successful.

Roy Ken

[powderman426]

There is no reason to use any of your battery power for those devices. Kidde has a co and smoke detector that have a ten year lithium ion battery.

Oops the LP detector will still consume battery.

[pianotuna]

Hi,

Add a small solar system. The main culprit is the gas valve for the fridge.

[Tvov]

"HUH?!" is right... on my TT, the standard 12v RV battery easily lasts a week if nothing is being actively used, usually two or more weeks. Not sure that people are using the right numbers about the detectors, and/or there is probably other stuff using power that they are not aware of - I wouldn't be surprised if they are turning on the camper lights and using the camper vent fans, they all can draw more power than you might think.

We routinely dry camp on battery only for a long weekend, and sometimes a week, just being very careful of using TT power. We use battery camping lanterns in the TT when dry camping, and try to avoid using any other power (usually except for water pump).

[tvman44]

35 - 40 amps seems awful high for 2 detectors, best to measure for yourself. 🙂

[JiminDenver]

I have heard that number thrown around before, luckily for me the parasitic draws are not that high on our trailer. Then again most of the time it is just the detector and fridge control board, we have no built in stereo and leave the hot water heater off unless in use.

The only year we used a generator to keep the battery up, we were using more than just the detector, etc. We had to replace the rest of the power we used too. We would use as much as 5 gal in two weeks with the daily 2 hr run, it could have been less with a small inverter generator.

Since we didn't enjoy using the trailer like a hard sided tent and hearing a generator run everyday sucked, we got solar and no longer worry about the little loads...or the big loads anymore. Some use lots of solar like we do, so get a small system to cover the basics like you are talking. They have folding 100w kits for around $200 or less and you'd never have to worry as long as the sun shined.

[Snowman9000]

Here is my post about my previous one, which uses way less than my current one. I do think this model has been superceded by a new version. It was LP only, and we had a battery powered CO/smoke unit separately.

Low Draw LP detector

[Snowman9000]

I dunno. I suspect it's something the industry has improved in recent years.

[Guysakar]

Snowman9000 wrote:
There are detectors which use next to nothing. I've checked mine in my current and previous RVs with a multi-meter, and the usage was trivial. My current one draws 0.050a running, with a bit more at startup. So that is 1.2 amps in 24 hours.

If you want to disable it, just find the fuse that it's on, and pull it. Or put a switch in the circuit.

Thanks for the reply. So why are so many people claiming that these things use 35-40 amps a day?

Is there seriously that big of a variation in power consumption? 1.2-40 is a very large gap.

[Snowman9000]

There are detectors which use next to nothing. I've checked mine in my current and previous RVs with a multi-meter, and the usage was trivial. Once you find the fuse, you can jump your multi-meter leads across the fuse socket terminals and read the amps being drawn. The circuit might serve more than just the detector, so you'll have to watch for that. My current one draws 0.050a running, with a bit more at startup. So that is 1.2 amps in 24 hours.

If you want to disable it, just find the fuse that it's on, and pull it. Or put a switch in the circuit.