When planning out your off-grid power needs, it's important to consider how your power needs, usage, and generation will change across the year. Specifically, it's important to consider what these will look like over the winter months, as the summer sun typically allows you to live without much consideration for energy conservation.
Over winter and the shoulder seasons, you may find that there are extended periods of weather that don't allow for solar power generation - whether that's storms and rain, or simply days and days of overcast skies. If you're not prepared for it, you might suddenly find yourself without power, so it's likely that you've seen advice to get a generator to allow you to top up your batteries over this time. But are there alternatives? What's the best way to get through winter?
Well, there are three ways to realign your power use and power generation: adapt your power usage to conserve energy during these periods, upgrade your kit, or have a generator on hand to top up the batteries, allowing you to continue using your normal levels of power.
Should I just adapt my power usage during winter?
If you're not going to be using the solar much over winter (eg it's a summer holiday location) then this may be the way to go. However, if you're there full time and using power everyday, you need to work out if it's even possible to do this.
You are likely to have certain baseline power usage (things you can't cut turn off or switch to day time only) you'll need to account for before seeing what you can cut back on. This might include a fridges or freezers, water pumps, modems, or non-compliant children for example.
This exercise may highlight inefficiencies in your system that you need to address as well, such as a power-hungry fridge or incandescent lighting.
Our kits are spec'ed on getting 3 hours of sun during winter, so if your winter usage is already on the conservative side, then cutting back enough could prove to be a quite a hinderance to your daily life, or simply not possible. You can read more in this article about how you may have to change your habits.
Even if you are able to adapt your usage, you may still run into the issue of running out of power completely without sufficient sun - but more on that later. And if you can't adapt your usage to manage this, you need to increase your power generation.
So when should I get a bigger kit?
There are a few different choices you have here: jumping up to the next kit, or adding on batteries or panels.
If you're looking at a kit that suits your needs, but you've been told you need a generator, a bigger kit will not erase the need for it completely. Jumping up a kit size is only recommended if you don't think the kit will meet your needs when the weather is fine - the panel to battery ratio will be the same so you will have more panels, but a bigger battery bank to charge as well. This can also be done to future proof your set up if you think your power needs will increase down the track.
If your kit is appropriately sized to your needs, a possible alternative to adding a generator is to add more solar panels to your kit (without adding any more batteries). This will offer increased power generation capacity to make up for less sun, and make the most of what you are getting so you can fully recharge your batteries each day. When the weather is fine you will also be able to increase your usage during the day, as there will be plenty of power generation capacity - your usage overnight will be same. This is not a fool proof method however. If you want to upgrade a kit before you buy it, chat to us, and to upgrade an existing kit, read this article.
If you want to add more batteries, keep in mind these will offer more night time usage (useful if you find your batteries are very low in the morning) but you must make sure you can fully recharge them during the day. Adding more batteries will compound the problems of lowered power generation.
And when should I get a generator?
If you won't be using your kit over the winter, or you will only be using it some of the time (eg just the weekends), then you will likely be fine without a generator.
No matter how many solar panels you have, there are always going to be times when there is no sun for several days, or such a small amount that it is not able to sufficiently recharge the batteries. In addition to the obvious benefit of having power, recharging batteries is important for the batteries' warranty and longevity - discharging past 50% or leaving them in a partial state of charge for an extended period of time can damage them.
A generator is highly recommended if you normally have enough power, and only struggle to generate enough during these bad weather periods, and will make up for times when even a huge panel array can't keep up. If it is crucial that you always have power, a generator is required, otherwise you run the risk of being without power or damaging the batteries by over-discharging them.
Without a generator (if you haven't reduced your usage in advance to prepare for these low-sun periods), you would likely need to completely stop using power to allow the batteries to fully recharge - if you're unlucky with weather, this could take multiple days to accomplish. This article goes more in depth about how this happens.
We also typically suggest having a generator if you will be using any items with a high, short power draw such as drop saw. This will allow you to run them without fear of the inverter overloading and shutting off, or accidentally drawing your batteries too low.
If you do get a generator, you will need a method to switch to the generator so it can charge the batteries. This either requires a separate battery charger to be wired into the battery bank, or a hybrid inverter upgrade - this allows you to have something like a caravan plug, or wire the generator directly into utility input with either manual or auto-start, and use it to charge the batteries to directly power your home. If you've already purchased, or are planning to purchase, a GridFree Kit, we can get you 5% off a GT Power generator - just get in touch.
Can I supplement with other energy sources?
If you live in a particularly windy area, a wind turbine may be a good option, however many people find them to be a bit more trouble than they're worth, so do your research on this one. If you have access to running water, a water turbine could be a good supplement too. These are just as susceptible to changes in the weather as solar is, and are not a foolproof solution like a generator.
In both cases, you will require a separate charge controller for each of these turbines.