Power failure solution

I have just lost a few fish and stressed many more after a long power cut. By the time the power came on again most my tanks had dropped 10 degrees C and ammonia was starting to build because the filters had stopped. I had a couple of battery air pumps so I put a stone in each tank to give them a little air exchange ( 2 small pumps and 7 tanks so not a lot of air each)
As I have been in this position before and likely will be again I am considering building a backup power system. I'm thinking of a couple of truck batteries connected to an inverter and two 150W photovoltaic panels placed outside connected to a charger to top the batteries up keeping them full ready for the next power cut.
Has anyone built anything like this? Can anyone see a problem I'm overlooking?.
Any other ideas to get your tanks through a power cut?
I would appreciate any thoughts
Thank you

 

Get deep cycle batteries instead of truck batteries(unless the truck ones are deep cycle of course). Also you probably don't exacly need both panels to charge the batteries, but that could also depend on how long power would be out for among other related things so it doesn't hurt running both.

 

Get deep cycle batteries instead of truck batteries(unless the truck ones are deep cycle of course). Also you probably don't exacly need both panels to charge the batteries, but that could also depend on how long power would be out for among other related things so it doesn't hurt running both.

The last cut we had was a few days so I need enough power to keep 7 tanks going for a few days. The reason I was going for truck batteries is I know a good HGV breaker who can get me cheap second hand ones.

 

I bought one of these a few years ago.

Sportsman 4,000/3,500-Watt Dual Fuel Powered Portable Generator, Runs on LPG or Regular Gasoline-803266 - The Home Depot

 

How long will

I bought one of these a few years ago.

Sportsman 4,000/3,500-Watt Dual Fuel Powered Portable Generator, Runs on LPG or Regular Gasoline-803266 - The Home Depot

How long does it run on a gallon of petrol/ gasoline?

 

How long will

How long does it run on a gallon of petrol/ gasoline?

 

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I will look into a generator, I would try to get a diesel one because petrol is expensive here in the UK and we get diesel for the tractors anyway.