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Solar query to run small office - EasySolar Vs MulitGrid Vs other options

I have a small office with fairly low daily electricity use apart from the depths of winter where we might run a electric heater.

Basically just two desktop PCs, a laser printer, router, cordless phones, a few LED lights, kettle, occasional microwave use if want something warm for lunch, 8 hours a day Monday to Friday.

Its got a mono-pitched south facing roof, so plenty of useable space for panels.

The building is only rented, so don't want to spend a vast amount on some feed-in type setup with export meter selling the excess, I just want to try and make the majority of what I use, and at the same time save a bit on the electricity bill.

I am struggling with what option to go for, as want to try and get the biggest benefit from what I have to spend.

I am tempted to go for a SmartSolar 100/20 (on 48V) and going as close to the full 1160W as I can on the panels, 4x 12v 100Ah-ish batteries, and then use a Phoenix 800VA (on 48V) inverter to run all the low powered stuff, PC's, Phones, Lights, etc... and leave the Printer, Kettle, Microwave and Heater on the grid. And in the winter if I struggle for solar power I could move some or all of it back onto the grid.

Is the fact I will be using the power during daylight hours going to give the batteries a problem? As they are probably only going to get back up to float during the weekend when there is no drain for a couple of days.

Or is it one of those things where I just need to bite the bullet and do something, and if its not enough I will have to swap something out for something bigger, or add another MPPT controller at later date.

I really do like the idea of the EasySolar how its all in one box, but unless I spent serious money and went for the 3kVA one, the 1600VA (on 24V) doesn't really let me run much more PV than the 100/20 (on 48V) but obviously could pull from the grid automatically if there wasn't enough PV or Battery, rather than me having to manually plug stuff into another socket.

Or to really throw a spanner in the works, when I look at the example layouts the Multigrid seems ideal as has enough power to run everything through it, and I could run a surplus of panels on a normal Grid-Tie AC type inverter, but set the Multigrid not to export the excess, and it would use the battery bank to fill in the gaps in the solar, and would only fall back onto grid if there wasn't enough solar or battery.

Any ideas or advice is greatly appreciated.

MPPT ControllersEasySolar All-in-Onemultigrid
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2 Answers
wkirby avatar image
wkirby answered ·

If you have grid available then I think ESS would be what you want. You'll need a VeunsGX or CCGX to do this though.
ESS will allow you to run most of your equipment from a smaller size inverter and then any extra for microwave can be imported from the grid.
Solar will go to loads and then battery. Excess could be exported if you did decide to get a FIT.
Battery discharge limit can be set at a certain percentage whereupon energy will be imported from the grid.

There are a multitude of options.
A 3KVA EasySolar would include everything you need for ESS. Just add PV and a battery. The 24V model will accommodate up to 2KW of PV. 4KW for the 48V model.
The smaller EasySolar models will need either a VenusGX or CCGX in addition.

You can have a system without ESS, but you have to switch things on and off manually. If the battery runs down you'll suddenly loose power unless you manually switch the grid back on.

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partpilotuk avatar image
partpilotuk answered ·

Hi, I have had a similar problem for a few years. I started by adding 6 x 150W Solar Panels on the Roof of my Workshop Portakabin, linked to a used eBay 2500W Mastervolt Grid Tied Inverter. I have the usual Office loads, plus I run Radios and Transmitters all day long and all my Network Switches etc running. I don't have FIT arrangements as it is rented. However, this has been great for a number of Years and has been good for two reasons. I have saved more than the cost of the equipment already. Secondly, I have learnt how it all works and really improved my knowledge of Solar Power.

However, two years ago, I realised that even with all this kit, when the Grid goes off, as it did regularly, then all the Solar goes off too, along with al my Network and Comms Radios.

I decided to explore Energy Self Store (ESS). I went all out and bought a Victron Easy Solar 3KW at 24V. It has been great. Plugged the Solar Panels in to the Easy Solar. Bought the Software adapters and changed it from a HUB arrangement to an ESS unit. It has an amazing WIFi/Bluetooth Dongle so you can see it all working on my iphone Ap and through the Internet via the Victron VRM.

I now have an amazing system that takes power in from the Grid and works as a fantastic UPS. I plug all the essential Mains Kit into the Easysolar and leave the Electric Heaters on the Mains Grid direct. That way, when the Grid fails, I lose just the Heaters, but all else just keeps on running, Broadband, lights, Radios, Network and all.

Big problem was Battery choice. I tried several big slabs of lead acid - both wet/Traction and Sealed. Problem was once you had a power cut, they took forever to charge and the Easy Solar was running at a high Grid loading to charge them via the built in Charger. This negated the Solar input somewhat.

I have just found 24 Lithium and now all the big slabs have gone and I have a small footprint LifePo4 160A/H Battery which is just incredible. I only allow it to discharge to 80% to supplement mains grid at sunset and keep the rest for UPS purposes. It charges rapidly off solar in the morning and shuts off at 95% SOC, set manually.

Now I have learnt about Lithium, which I use in the rest of my business and about BMS. Incredible technology and thoroughly recommend it. The Victron Kit is incredible. The Easy Solar 3000 is ideal as it is all integrated. Takes a little sorting out at first, lots of fiddling with Laptops and Cables, but got there in the end. I have it set to ESS with battery charge off Solar.

Waiting now for Victron to make a range of Lithium Battery Cell BMS Units so that I can dump the aftermarket Units I have had to use at present.

Have fun!

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