Water Tank Heat Pads

[Sweeney]

Has anyone used heat pads on their water tanks yet? There are too many days, as late as December and early as March where daytime temperatures are in the 45-50 range, its only the overnight where there is freezing. I want to be able to keep the water tank and under-sink area warm enough to prevent freezing in overnight.

I know we could always carry a bladder or blueboy tank, but space is so precious in my tow vehicle...if I add the bleuboy then I have to leave other items behind that I may need even more, like a portable potty or generator.

I'm thinking of just keeping the tanks from freezing overnight ... when temps are in the 20's but 40's during the day....

Most of the RV pads are sized for 25+ gallons, not 8. The smallest pads I find are 80 watts, close to 7 amps each. These are of course 12 volt -- I try to keep everything within the 12 volt and within the limits of the battery charger. We're bumping right up to the capacity of the lithium and upgraded onboard.

To keep the plumbing, I was thinking maybe a small 8 watt "elbow" heater on/near the water pump to keep the space below the sink warmer.

I'm not even sure that would be enough without insulating the bottom of the sink....

Am I looking at a solution that is just a stretch too far? My Desire is obviously that this would be feasible....bu my gut is telling me I'm asking too much.

 

[TheSongDogHouse]

Has anyone used heat pads on their water tanks yet? There are too many days, as late as December and early as March where daytime temperatures are in the 45-50 range, its only the overnight where there is freezing. I want to be able to keep the water tank and under-sink area warm enough to prevent freezing in overnight.

I know we could always carry a bladder or blueboy tank, but space is so precious in my tow vehicle...if I add the bleuboy then I have to leave other items behind that I may need even more, like a portable potty or generator.

I'm thinking of just keeping the tanks from freezing overnight ... when temps are in the 20's but 40's during the day....

Most of the RV pads are sized for 25+ gallons, not 8. The smallest pads I find are 80 watts, close to 7 amps each. These are of course 12 volt -- I try to keep everything within the 12 volt and within the limits of the battery charger. We're bumping right up to the capacity of the lithium and upgraded onboard.

To keep the plumbing, I was thinking maybe a small 8 watt "elbow" heater on/near the water pump to keep the space below the sink warmer.

I'm not even sure that would be enough without insulating the bottom of the sink....

Am I looking at a solution that is just a stretch too far? My Desire is obviously that this would be feasible....bu my gut is telling me I'm asking too much.

Interesting. I've wondered myself...there are high places that get cold at night even in summer, enough to worry about leaks.

Where are the-most vulnerable points?
And how to access them?

A recent thread about gettting warm air under the mattress to help heat and dehumidify under and around the Hypervent or Froli mattress springs got me thinking about "how to direct that heated air outflow past water tanks, plumbing..."

 

[DerekD]

These should fit. 12" x 18". And less than $70 a pair with thermostat.

Sorry! Something went wrong!

I was thinking of doing the same thing, as being in Northern California, I could find myself very easily at 0 feet elevation and at 11,000 feet elevation in the same weekend.

(not sure why it says sorry up there ... link still works, however)

 

[Sweeney]

These should fit. 12" x 18". And less than $70 a pair with thermostat.

Sorry! Something went wrong!

I was thinking of doing the same thing, as being in Northern California, I could find myself very easily at 0 feet elevation and at 11,000 feet elevation in the same weekend.

(not sure why it says sorry up there ... link still works, however)

Thinking about the size of the battery, and the charger capacity --- I'm thinking 120 volt is the only truly viable option for this. Still not a bad idea....but just find myself talking myself out of 12 volt...

Do these even work 00 or is it just a bit of snake oil when it comes to real use....

 

[dirty6]

L

Has anyone used heat pads on their water tanks yet? There are too many days, as late as December and early as March where daytime temperatures are in the 45-50 range, its only the overnight where there is freezing. I want to be able to keep the water tank and under-sink area warm enough to prevent freezing in overnight.

I know we could always carry a bladder or blueboy tank, but space is so precious in my tow vehicle...if I add the bleuboy then I have to leave other items behind that I may need even more, like a portable potty or generator.

I'm thinking of just keeping the tanks from freezing overnight ... when temps are in the 20's but 40's during the day....

Most of the RV pads are sized for 25+ gallons, not 8. The smallest pads I find are 80 watts, close to 7 amps each. These are of course 12 volt -- I try to keep everything within the 12 volt and within the limits of the battery charger. We're bumping right up to the capacity of the lithium and upgraded onboard.

To keep the plumbing, I was thinking maybe a small 8 watt "elbow" heater on/near the water pump to keep the space below the sink warmer.

I'm not even sure that would be enough without insulating the bottom of the sink....

Am I looking at a solution that is just a stretch too far? My Desire is obviously that this would be feasible....bu my gut is telling me I'm asking too much.

I could be wrong (it’s happened before) but to my knowledge the mass of water in the tanks is the last thing that’s going to freeze. It’s the dribbles of water hanging out in the pump and the pipes and the faucet that are going to freeze and burst because small amounts of water will freeze well before a mass of water.

If the above is true, this seems to me like changing the oil when the truck is out of gas.

I suppose warming the water in the tanks maybe might “bloom” through the rest of the system and help protect the vulnerable parts, but doesn’t that assume there is some continuous circulation?

 

[Sweeney]

L


I could be wrong (it’s happened before) but to my knowledge the mass of water in the tanks is the last thing that’s going to freeze. It’s the dribbles of water hanging out in the pump and the pipes and the faucet that are going to freeze and burst because small amounts of water will freeze well before a mass of water.

If the above is true, this seems to me like changing the oil when the truck is out of gas.

I suppose warming the water in the tanks maybe might “bloom” through the rest of the system and help protect the vulnerable parts, but doesn’t that assume there is some continuous circulation?

This is all coming up because we're taking the camper to family thanksgiving and that night we'll be in the 20's. Water isn't as important for the trip, as we'll have the house bathroom. Its all about not having to winterize then break winterization when we get home.

@dirty6 - you're right though. The thermal mass of a filled tank is pretty high, and I'm 99% sure @Cary Winch said these are freeze-safe tanks, so even if they froze it wouldn't damage them --- especially just on night.

I'm curious now...How does water freeze in a tank? Would it freeze from the bottom up since the cold surface is the bottom, or the top of the water line down? I know its said water freezes on the top first....but if the primary cold is the tank bottom...I don't know.

For a 1 nighter, it may not be as big of a deal --- 99% of the time we don't eat breakfast -- we only need water in the evening before. Which would still be liquid as it hasn't seen the over-nigth low.

You would need to keep the web bay warm though....

Two thoughts...

1. The sink is probably your least insulated. Two ways you can mitigate this...Fill it with water to add a thermal mass. Alternatively, use a plastic bag and expanding foam to make an insert. Like some shippers use on delicate parts...cutom form-fit packaging. One of these would be required because cold would transfer into the wet bay quickly through the uninsulated metal.
   
   
2. To keep the wet-bay warm you only need ot keep it a few degrees warmer than ambient. So if you can take care of the sink, maybe a couple or four of hot-hands slipped into the bay would do the trick? No fire risk, no drilling, no power requirement at all --- and they are cheap.
   

Of course, none of this will help if you spend days in the cold But it might not be too bad for a 1 nighter at 20 degrees...

Of course --- you would HAVE to drain the water out of the spigot snd sprayer...that would be 100% necessary regardless.

 

[DerekD]

If it's just one night in the 20's ... I would say you should be ok with a full tank, drained sink and sprayer lines, and galley door closed with the under-counter doors open and the furnace in cabin on ... the lack of insulation between the galley and cabin should keep things warm enough for one night.

This is, of course, assuming you have a furnace.

Also ... if you have a fridge ... keeping that on in the galley will produce a little heat as well.

Maybe something as simple as a 12V electric blanket on and laid out in the galley overnight?

Definitely keep us posted.

-Derek
#1098

 

[Lipster]

Gonna freeze from the top down, like ice cube trays in your freezer.

 

[Sweeney]

If it's just one night in the 20's ... I would say you should be ok with a full tank, drained sink and sprayer lines, and galley door closed with the under-counter doors open and the furnace in cabin on ... the lack of insulation between the galley and cabin should keep things warm enough for one night.

This is, of course, assuming you have a furnace.

Also ... if you have a fridge ... keeping that on in the galley will produce a little heat as well.

Maybe something as simple as a 12V electric blanket on and laid out in the galley overnight?

Definitely keep us posted.

-Derek
#1098

LOL --- I was thinking of buying a reptile rock and dropping it in the left side bay as well, since we'll have 120 volt while were there. Probably remove the divider below the sink....that will certainly do the trick.