12v timer switch?

[turf]

hey folks!

i just got a new heating pad for my black tank and i'd like to rig up some sort of timer switch for it.

https://www.etrailer.com/RV-Fresh-Wa...77-000164.html

it says it can thaw a black tank in about an hour. today, im going to install the heater and wire it back to my battery bank. at the battery bank, im just going to put 2 big battery clamp ends on it and plug it in then morning before i go dump.

what i would like is a button to push, that would turn it on for an hour and then turn off automatically so i dont kill my battery.

any ideas for a timer appreciated. something just 12v

thanks
Dave

[Rusty]

Originally Posted by turf

hey folks!

i just got a new heating pad for my black tank and i'd like to rig up some sort of timer switch for it.

https://www.etrailer.com/RV-Fresh-Wa...77-000164.html

it says it can thaw a black tank in about an hour. today, im going to install the heater and wire it back to my battery bank. at the battery bank, im just going to put 2 big battery clamp ends on it and plug it in then morning before i go dump.

what i would like is a button to push, that would turn it on for an hour and then turn off automatically so i dont kill my battery.

any ideas for a timer appreciated. something just 12v

thanks
Dave

ebay

[PNW_Steve]

Keep in mind that if you allow your tanks to freeze at any point they can crack/split.

Not a big problem until it thaws......

If you are in really cold weather you may want to consider running the heaters daily.

[Rusty]

Originally Posted by PNW_Steve

Keep in mind that if you allow your tanks to freeze at any point they can crack/split.

Not a big problem until it thaws......

If you are in really cold weather you may want to consider running the heaters daily.

It's be cool if there was a liner in or around the tank as backup...

[turf]

right now, we are seeing 40 degree days and about 10 degree nights. last week a solid 3" chunk of "black ice" was blocking my drain and it forced the blade valve open a bit. i had ice on both sides of the the blade, when i took the cap off. the tank drained but i think there was plenty of stuff frozen to the bottom that stayed.

ill find out what sort of drain this heater is on the batteries before i go hardwired.

[Jolly Roger bus 223]

I don't know about for 12v but if you have a form of shore power then they do make self regulating heat trace wiring that is basically plug and play.
I will talk to one of my suppliers tomorrow to see if they have anything 12v.
They make timers for everything else electrical but I don't see why you just can't wire it to a toggle/paddle switch except you would have to remember to turn it off/on.
Good luck

[turf]

yep, i need a timer. short term memory is gone!

i'm a stoner, living in a bus on a hemp farm.

here is a picture of the days work. as you can see, its running.

it didnt feel very warm by hand, like electric blanket on low, so to speak.

next week, i'll plug it the morning before i go dump, give it a few hours to work. temps are only going to get colder here, and i'll be lucky to have days above freezing soon enough.



its wired to the negative and i have a little spring battery clamp on the positive side until i get a timer.

[Robin97396]

I'm guessing you're going to need more than a couple hours of heat on that tank to be able to dump it. Maybe not now, but when it gets cold you're going to have a big cube of frozen... stuff. A couple hours of moderate heat in the morning is barely going to get the cube floating in its own juices during freezing weather.

Just today my waterlines finally unfroze with the recent 40 degree weather. I drained and rinsed my water tank before refilling. I'm glad I don't have to deal with a black tank, but then again I will have to be moving my outhouse after 10 years. An outhouse does mean sitting on a frozen toilet seat most mornings, but I don't have to empty it.

I usually get snowed in every year for as much as a month or even two. It's bad enough that I have to economize on water during those times. Not much way to economize on the use of a black tank.

My freezing weather returns in a couple days.