Off Grid Shed Kit

The off Grid shed kit is a man thing and we have kits that should meet your needs.

Your first consideration is the power you need and this is diluted to what you are using in the shed, if your shed is a work shop or play room.
Workshops need to have a LF type inverter, Victron are LF, the LF can handle motor start up better than HF inverters. so bench saws, CNC, mills and welders will need to have LF unless they are small.
You need to consider the “Start up current” of all machines…

Whats the start up current?
a motor stood still needs to have move power to start spinning than it does to spin and when working normally. if you have a smart meter stand in front of it with the freezer door open and wait for the motor to kick in. you will see a spike of around 1500w and then it will drop to 200w. the 1500w is the start up (surge) current of the device and this can catch people out. these are inductive loads, just in case I mention the inductive and resistive loads again…

Solar Panels

ideally solar panels should be all you can get in the space. They are cheap, so no excuses to not going all out. You will need to take a measure of the roof and then look at the solar panels sizes to see how many you can fit.
Tip: you can extend most shed roofs to make a canopy to the side or over the door, or you can add joists to the roof and continue down.

You need to read the battery section and then return to work out how much solar you will need…

Mounting the panels is a personal thing, and a worry for some due to leaks. Proper mounting do not leak. having seen some sheds, weight would be more a concern.
There are a number of ways to “hang” the panels or frame them. so here are a few options:

• Loaders: Fix timber running down the roof to the roof with sealant and screws from top to bottom. then fix the panel to the loader, Z Brackets or mini rails work.
• Hangers: Hangers are a screw bolt with rubber washer and metal washed that compress to form a seal, I would not recommend these for felt or edm roofs but on hard roofs they work.
• Mini Rails: Mini rails have a flat bottom and seal which are bolted to the surface, they can be used on a wide range of roofs.
• Z Brackets: Z brackets bolt to the bottom of the panel ( which has mount holes) and then fix to the surface, you would be advised to sealant the bottom of them, typically used on caravans.
• Over frame: Used by those who have a weak structure and worry about leaks… the frame goes on the outside of the shed and bridges the roof so that the panels are not fixed to the building but the frame around it. you can fit standard rails to this or any other mounting system you like.
• Legs/feet: you will fid we also sell big rubber feet used for flat roof non invasive installations in the shop.

Battery storage.

The battery you select is important if you want to use the system in winter then LFP may not be the right choice as you cannot charge them at 0oC and they perform fairly lesser below 10oC. you may want to look at Sodium or lead acid.
The battery size is going to be down to what you use, in winter you may have a heater that’s 1kw running for a few hours, if your insulated then this wont be on constantly, but if not then it will be on more of the time. lets say you want 4 kwh which should be about 8 hours of heating.
You will want lights and tv, radio and this all adds up. – you will have to do this part to get the total power used.

With lead go over by 50% and LFP over by 40% For the purpose I will say 3 kwh of tools and lights, plus the 4kwh of heating. that’s 7kWh total
So we would look at 14kWh from the battery capacity.

Our 24v 400Ah lead solution is £700. with a little over 4.8 kWh
Our 24v 200Ah LFP solution is £600 with around 5.2 kWh
there is nothing stopping you going to the breakers and buying batteries from cars for about £40 each.. but the miles you get from them will vary. ( note the technical requirement and use of lead or any other battery must match or exceed the system requirements.)

Why 24V?

24 volts is a safe range for most people without the risk of shock, this occurs in the 48V systems with voltage over 50v. (usually 54v on a 48v system) With 24V your power out put would be able to reach 3000W and the DC load would be 125 amps. This nominal power is fairly safe and familiar.

With 12v systems, the nominal output power would only be 500w, going higher has a number of requirements which some may not view or be aware of.

12v system with a 1kw inverter is 1000/12 – about 84 dc amps.
12v system at 3kw is 125 amps.
As you can see the scale is different. a 3kw 12 v system would be in the region of 250amps.
With a 12v lead battery the peak current for the battery would be 55amps meaning that you would need to have 5 batteries to support the load, and you would have to maintain and balance the batteries.

If we take two 24v LFP batteries, you would have 200 amps of power DC to go to the inverter, as you would run at 125 amps you are within spec running each one around 62 amps.

The Victron MultiPlus-II 24/3000 is a multifunctional inverter/charger that combines the capabilities of the MultiPlus and the MultiGrid. It’s designed to work as a powerful true sine wave inverter, a sophisticated battery charger, and a fast-acting transfer switch in a single compact unit. Here are some key features:

• PowerAssist Technology: This feature prevents overload of a limited AC source, such as a generator or shore power connection. It can reduce battery charging or boost the output with power taken from the battery to prevent an overload¹.
• Uninterrupted AC Power (UPS Function): In case of a grid failure or disconnection of shore or generator power, the inverter within the MultiPlus-II automatically activates and takes over the supply to the connected loads in less than 20 milliseconds¹.
• Remote Monitoring and Control: When paired with a GX device (like Cerbo GX), it allows for monitoring and control of the system locally or remotely via the internet, using the free VRM app and portal website¹.
• Energy Storage Systems (ESS): The MultiPlus-II is a key component in a Victron ESS system, allowing for flexibility to combine with MPPT Solar Chargers or Grid-tie PV Inverters¹.

Personally I do not like the “buy in” of Victron. but they are popular at around £1,450.
these do also work with the grid, so you could feed back and fall under G98.
You can buy a reasonable off grid inverter for around £450 in comparison. and buy that big LFP battery with the money you would save.

Here will be some links to buy kits….