Save money on your electricity bills by running your house on cheaper overnight economy 7 electricity during the day.
All you need is a leisure battery, an inverter and a charger to run at least part of your house on cheaper economy 7 electricity during the day. Here I'm going to show you what I have successfully done to help inspire you to get one over the robbing swines that control our energy supplies.
In 2024 we start trading at outdoor festivals so we needed to buy a leisure battery, inverter and charger to allow us to run our computers and cutters in a field. It occurred to me that with a little bit of thought and work I just maybe able to plug the battery into my home and, when we are not in a field, we can charge the battery with cheap overnight electricity or during sunny days with free solar power and use the power at other times when the electricity is a lot more expensive.
I did a bit of research online and could not find much information at all to help me so I've had to do my own thing so I want to put what I have done here so anyone out there can do something similar.
Most of our Hippy Motors customers have a camper-van, motorhome or even a caravan with a leisure battery and inverter so, as far as I can tell, it's no great investment to bring them indoors and use when the vehicle is not being used.
My initial thought was to plug it into my existing solar panel system but that, for me, was not possible but if you have solar then please check first if you can as that makes it really easy. If your system is newer than 2019 then your existing inverter in your system may already take any leisure battery so check with whoever installed it and ask. Then all you'll need is a pair of leads to plug in directly.
If like me you can't it's a bit more work, a bit more untidy but it's very possible and not really very expensive to do. I expect the equipment will pay itself of in maybe a year, after that it's all money in my pocket and not going to shareholders and utility companies. This is what I had to do...
Our house is 100% electric, we do not have gas, and our solar output from our panels is great during the day but in the evenings and mornings, even in the summer, using the kitchen for cooking is not usually covered by the sunshine. It's always frustrated me that just as the output from the system is tapering away I need to use the oven, kettle, microwave etc. and I get that back from the mains at a high cost. So an easy option for me was to target the kitchen to power with a battery.
As I couldn't plug a leisure battery into the solar panel system I created an independent, off grid, electrical supply for the kitchen. Off from the kitchen we have a toilet so I decided to put the battery in there. The inverter must be as close as possible to the battery with plenty of room around it as it will require air flow to prevent overheating. The charger needs to be close by as well.
Initially it is important you understand your own needs so look at the appliances to want to power with an inverter. Very high wattage appliances like a built in oven or hob is most probably out the question but other lower power ovens like microwave, halogen or Ninja (style) multifunction ovens can. Kettles consume a lot of power so be aware what you want and work around them.
For our trading away from home we didn't need to buy a large inverter; a 1000W unit would have done for what we need but looking at the appliances though I considered the minimum I needed was a 3000W inverter. It can handle a kettle, toaster and the like and is a small, light unit so it's still a practical option for taking to festivals to trade. Pure sine is best as well.
Then I had to consider the size of battery. The bigger the better but the bigger they are the more expensive which obviously takes longer to pay itself off. Also they get physically bigger so it's also a play off as to being easy to transport. If you own a campervan or motorhome you'll also know you'll have a certain space to work with in there.
I decided to buy a 3.8KW/hr 12v 300Ahr lithium battery. The cost is extortionate and, to be honest, was beyond our budget. For that reason we took a chance and purchased directly from China rather than a rebranded battery. We felt it was a bit of a risk as we know of the well publicised faults on cheap lithium batteries. Reading up though it seemed the main issue is charging so we took a chance buying a cheap battery but made sure the charger was a good one. We waited a few weeks for the delivery from China but we are pleased with the unit, I'm sure it's as good as anything I'd have bought in the UK for twice the cost.
The final big purchase is the charger. As I said we got a good one that I felt confident in. We got a Victron Phoenix Smart IP43 50A Charger, not the cheapest but defiantly a good unit. We needed the 50A model as lower value models take more time to charge and if you are using large wattage appliances you'll need to recover that in a few hours overnight or in sunny spells.
Once you get the equipment, and I feel quiet a few of you reading this will already have these things, it's a case of installing in the house and then creating a simple circuit of sockets in the house; in my case, the kitchen.
To connect the battery to the inverter you need to be aware that the size of the cable is very important. The distance to the inverter from the battery must be as short as possible and the cable thickness must be right. Too thin and they get as hot as a heater which is very inefficient and dangerous. This took a little messing about for me to get right. The inverter came with cables so I wrongly assumed they would be adequate for a 3000W unit but they were not. They got so hot they melted the insulation. I purchased 50mm² cable with the relevant crimp connectors (in my case for 8mm bolts). It seems this can handle all I can throw at it for a 3000W powering things like a kettle so that's what you want to have.
You will need a programmable mains switch to switch the charger on during cheap economy 7 times. You can get very complex and expensive array of devices for this but in the end I opted for simple and cheap. I went for a very cheap mechanical timer with an override switch. The override switch is needed for me as on sunny days I wanted to charge the battery via the solar power as, for me, that's free electricity. If you don't have your own free electricity I imagine you don't require an override switch.
That's everything, except for the sockets and cables you need. This is far less complex than rigging up the inverter and battery and the equipment you need is standard household stuff. Work out the amount of double or single sockets you want. Work out the metreage of cable. Usually for the sockets you need that grey rectangular ring-main cable but going from the inverter to the circuit normal white round extension lead is fine as it's more flexible so it's better for snaking around to the first socket. After that go for the ring main cable between sockets. You'll also need thicker gauge cable for powering the likes of a kettle so don't get the thinner light circuit cable.
I have very little experience of domestic household wiring but it was simple enough and easy enough to do. If you don't want to then obviously get an electrician to do the install for you.
That's it. You'll be able to allow your battery to charge overnight with cheap power or from solar panels for free so you can use it during the day saving you money. Looking at it over a year it should be a significant saving.
Closely monitor your system when you first start to use it. Make sure the cables to the battery are secure and do not get hot when in use. Slightly warm will be acceptable but if they get hot disconnect them and look at the size and length of the cables; as short and fat as you can. Use any technical support you will have with your inverter or battery supplier; always try to pick the brains of someone who has experience.
With my 3000W inverter it works great for what I need except if I have the kettle on with another big appliance. If the inverter gets overloaded it will do a restart that stops the other appliance -p not really a problem. I could have gone for a 4000W inverter but I really couldn't justify the additional cost but if that's fine for you then go for it. Up to 6000W and you could even power a washing machine.
With care you can save a lot of money with this setup. As it seems costs are just ridiculous for electricity if you can make a saving then do it. I hope you found this article useful. I wish I'd have had this information when I was scrabbling around for advice.
I have videoed my system as I believe seeing it will help you. Click the link below...