An off grid solar kit is a significant investment, and with some careful planning and attention, you can maximise its output and longevity.
There are three key time periods to think about when you’re trying to get the most out of your kit: when you order it, when you install it, and when you use it.
1. Choosing and ordering your kit.
At this stage you need to consider how it will be used, and what your future plans are.
Sizing your kit for the future
Do you think you will use more power in the future (compared to your immediate plans), or do you think you might want to expand later? If so, you may benefit from oversizing your kit to give yourself more wiggle room, or getting a kit that will allow you to add extra panels or batteries later (without needing to replace any components). It will be more expensive in the long run to try to expand a kit that is not designed for expansion.
It's best to add extra batteries quite soon after you get the kit (less than 6 months for Gel and 12 for Lithium) as wiring them in with the older ones can prematurely age the new batteries, so make sure you have an idea early on if you want to add more.
Typically, the Bach and larger kits with a hybrid inverter upgrade will have the most room for expansion. You can learn more about what expansion is possible with our kits here, and you’re welcome to get in touch with any questions about what's best for you.
When it comes to choosing between Gel and Lithium batteries for your kit, it's usually a consideration of budget. Lithium has the greatest longevity, capacity, and resilience – although it comes at a higher price point. We recommend getting lithium batteries for all full-time setups if your budget can accommodate them, as they are better value in the long run.
Gel batteries on the other hand are more appropriate for part time settings, and they are necessary if you plan to run any 12V DC items.
If you will be off-grid full time but your budget doesn’t allow for Lithium, you may want to consider getting the standard Gel batteries now and replacing them with Lithium batteries in approximately 5 years (when the gel batteries degrade), as the lithium batteries are likely to drop in price as the technology improves. Keep in mind you'll need a hybrid inverter for lithium batteries, so it’s best to get a hybrid kit initially.
Optimising your home
You can also make some changes to your home at this stage too (in addition to the usual heating alternatives we recommend), by swapping out your appliances for more energy-efficient options. Swapping incandescent bulbs for LEDs, older whiteware for modern appliances with high Energy Star ratings, and corded power tools for battery powered ones are all recommended. Some people choose to transition things like lighting to 12V DC for increased efficiency. This is fine to do if you already have 12V appliances, although modern appliances using AC are just as efficient and are usually cheaper, so there is no need to buy any 12V DC appliances.
2. What to consider once you have it
Once you’re at the point of having and installing your kit, there’s a few things to think about. When you receive it, make sure you check everything for damage, note it down on the delivery slip, and take photos before the driver leaves. See our Terms and Conditions here.
If your kit won’t be installed immediately, and you have Gel batteries, you need to make sure you give them a top up charge about every 3 months to keep them in good condition. Lithium batteries are pretty happy to be left sitting partially charged for a longer time period. Make sure everything is out of the weather too!
Where you actually put the gear can affect the longevity of it. Everything should be kept in a ventilated spot out of the weather, but ideally not in your living space, so many people opt for a garage or a shed. This gear is not rated for any kind of moisture resistance, so it is essential that it is protected from rain as well as condensation. Occasionally the warmth of the electronics may attract insects and other pests, so some preventative measures may be needed.
Make sure your solar panels aren’t getting any shade where they’re installed. Even a tiny bit of shade, such as grass or a chimney shadow, can have a huge impact on how much solar power you can generate. You’ll need to either move the panels or remove the shadow to ensure you don’t lose out on power.
The positioning of the solar panels can also have a significant effect on their output. We recommend they face due north, with about 30 degrees of tilt. The ideal degree of tilt changes depending on the time of year and your latitude, with 30 being the average. You can either split the difference, err more towards the winter tilt, or adjust the tilt every 6 months. Each comes with pros and cons covered in this article.
Incorrect wiring is the most common cause of issues straight after installation, so make sure you double check all your work against the instructions before you turn anything on.
3. What to do when it’s running
Once your kit is up and running, it’s generally pretty maintenance free. Your daily usage is what will have the biggest impact on longevity.
We recommend cleaning the panels every 6-12 months, and checking all your connections when you do this. You can read this article for guidance on cleaning panels.
We’ve got a few best practices that apply to our kits to help you get the most out of them in your daily usage.
Gel batteries should not be discharged lower than 50% of their capacity – this is a resting voltage of 24.4V for the Weekend Warrior and Tiny House Kits, and 48.8V for the Bach and larger kits. Learn more about the difference between resting and charging voltage here. You can set a low-voltage cut-off on your inverter to prevent accidentally discharging your batteries too deeply.
It’s also important not to leave your Gel batteries sitting partially discharged for more than a day or two, as this can damage them. This is why we always recommend that people living off-grid full-time have a backup generator, so those batteries can be recharged even when the sun isn’t there to charge them, and you can keep powering your appliances without discharging the batteries past 50%.
Lithium batteries should not be discharged lower than 20%, but they are okay to be left sitting partially discharged. We still recommend a generator to allow you to keep using power and keep the batteries above 20%.
Avoid using very high draw appliances that are higher than the rating of your inverter. This will use your battery power much more quickly and runs the risk of you running out of power much sooner than expected, as well as risking potential damage to the inverter.
Reading your Gel battery charge using the bars (for standard charge controllers) or percentage (for hybrid inverters) on screen.
These are misleading as they are not a straight measure of how much energy is left in the battery like you might expect from your phone. You should instead refer to the voltage-percentage conversion table we have included at the back of the manual. (You can use the percentage reading on the hybrid inverter for lithium batteries, as the Battery Management System does the work of interpreting the voltage.)
Misunderstanding resting vs charging and discharging voltage.
Resting voltage is the true reading of the battery’s charge state. It refers to the voltage of the battery when there is no charge going in or out – the battery is at rest.
Charging voltage is the higher voltage the batteries will be at when they are charging. It’s easy to see this voltage and think the batteries are fully charged, but if the batteries are at a higher voltage and the battery amps are above 5, then it means the batteries are still charging.
Discharging voltage is the lower voltage the batteries will be at while you are using power. This may make you think the batteries are low, but if there is power being drawn, the batteries might not be as low as it seems. This is the reason why the cutoff voltage on Gel batteries is not set to 50%, as it might drop to past that while discharging and cause the system to shut off unnecessarily.
New users of the systems often have a slight panic when the sun goes down and they see the battery voltage drop down. This just means either they weren’t fully charged when the sun went down, or there is a load on the batteries drawing them down with no solar to offset it.
For the most accurate reading of your battery charge, turn off the breaker on the solar panels, and the breaker between the batteries and inverter (or from the panels and out to the switchboard for the hybrid), wait a couple minutes for the batteries to come closer to their resting voltage, then read the voltage of the batteries.
Continuing to use your normal amount of power when there is less sun for multiple days. If your battery bank isn’t fully charged at the end of the day because there is less sun than usual, trying to maintain your normal power usage the next day with continued poor weather will make the problem worse.
We recommend cutting back on your power usage as soon as possible when you know there are multiple days of less sun coming, and using a generator to top up the batteries if needed. This is the best way to ensure you have enough power to keep your essentials running, and your batteries don’t get damaged.
Running things that draw a lot of power quickly – while you can run most of the same things that you would be running in a grid-connected house, there are a few things that you need to be more mindful of.
Obviously, there’s the electric heating items that shouldn’t be used, but there are also things like power tools and pumps. These will draw a lot of power quite quickly, and the electric motors in these have power spikes, which can run the risk of overloading your inverter and causing it to shut off.
Sometimes these things are okay to do when the batteries are full and the sun is shining, but typically we recommend alternatives, like switching to battery powered tools.
Missing shadows. Shadows will change over the course of the day (and the year) so it’s possible that you could have missed them when the system was installed. If you notice PV input dropping off significantly when there’s strong sunlight, take a look for any shadows. Even quite small shadows can have a big impact due to the nature of solar panels.
Overestimating solar output potential. If your solar output is less than expected, it's not usually the fault of the panel. If your batteries are full or nearly full then it’s nothing to worry about. PV will be lower in the morning and afternoon, as well as on overcast days, but if it’s a very sunny day and your PV is low, it’s possible that your panels are catching some shadows. In rare cases the settings on your hybrid inverter may have been inadvertently changed during installation to limit the charge, so you’ll just need to change this back – we're happy to step you through that as it can be different for each unit.
- Running 12V DC loads from just one Gel battery. You should never run loads from just one Gel battery if it is wired in with other batteries as it will prematurely degrade the entire battery bank. Instead, use a 24 or 48V to 12V converter to use all the batteries equally. Keep in mind, the converter does not have any cut-off protections you can turn on (unlike the inverter), so there is a risk of accidentally draining the batteries too deeply if you’re not paying attention.
If you have any questions or concerns about how to get the most out of your kit, feel free to contact us and we’re happy to talk you through it!