My 55gal. rain barrel turned to a 55gal ice cube last winter. I was lucky that it didn't split. I would suggest emptying it and maybe bringing it into a heated basement and fill it with tap water for emergency use in the winter.
oh yeah...I put about a half gallon of plumbing antifreeze into it too and it still froze solid!

One of mine did split, despite that I drained it, next winter its upside down.

i do the same as ranger. drain it turn it upside down

I agree, drain and flip or put a stock heater in it, but only do that if its a big metal tank or cistern (cement) not plastic..

😳 guess I must have been lucky....never did anything with my tanks

I have used stock heaters in plastic containers for years and only have problems if tank goes below about 6" of water.
They have a wire ring around them to prevent contact to tank wall and sit above tank bottom if tank gets emptied,but will soften plastic at bottom if tank goes dry.

I have a large plastic rain tank. 1000L. To large to flip over in winter. Maybe the stock heater would work. Where can I find them?

Almost all feed stores or farm co-ops should have them.

TSC stores they will have what your looking for and much more

Remember that using a heater implies the availability of electricity. If that availability isn't guaranteed, then you may need to set up the tank inside.

I have a large plastic rain tank. 1000L. To large to flip over in winter. Maybe the stock heater would work. Where can I find them?

Fish pond heater will work and you can adjust the temperature. Just have to make sure that it does not touch the sides. You can use a regular fish tank heater as well. They start at about $15.00 but go up for the size of the tank that you want to heat.

I don't know if it would work, but I believe that they use aerators up north to keep boat house moorings from freezing in the winter. If that's the case, then moving the water around would use less electricity than trying to heat it. I also remember my mother in law used to bring her Koi fish from the outside pond into the unheated barn in the winter. She would put them in a big horse watering trough and then put a bubbler in the water. The water got really cold, but never froze. She wouldn't feed the fish or anything, just let them hibernate.

I just checked a couple of the heaters in my fish tanks and they are 200 watts and up. That is fairly heavy on hydro.

Hi there
In the past I have used an inline block heater running off of 12
All you need is a battery and a single solar panel they sell for ataching to you car in the winter
Hope this helps Hobo