Can I start with a small system and grow it over time?
In some instances you can grow a system over time, but you need to consider that in order for a solar system to work optimally, all components need to be of the same make, size and age. It is not advisable, but certainly possible to grow a solar system over time. However performance is going to suffer.
Some factors to consider:
The solar panels you buy now might not be available in 6 months time,
the batteries you buy now will degrade a little bit every day,
by the time you add another battery to your battery bank, the used batteries may be only 98% good while the new one is brand new,
the software in your inverter and/or charge controller will become outdated and when you buy your new component, it will come with newer (possibly incompatible) software.
If you absolutely have to buy the components in stages, it would be best to keep them in storage and not install them or commission the system until you have everything ready at once.
What size solar system do I need?
To make an accurate assessment of how much solar power you need, many factors need to be considered. Here are some questions to consider:
How many electrical appliances do you wish to run off of this system?
For how many hours do you need to power these appliances?
Do you want to be totally off-grid or purely have power during load shedding?
Do you want to run large appliances like a geyser or a tumble dryer off the solar system?
What kind of battery should I choose?
You have the choice of lead acid and its variations like: AGM, VRLA and Gel. Then you have lithium which we call LiFePO4 or LFP.
All these battery chemistries have advantages and disadvantages.
Lead acid is cheap and easy to charge, but doesn’t have a long life. Lead acid is also large and heavy. If used carefully these batteries can last from 3 to 5 years. Usually lead acid batteries have a 1 year warranty.
Lithium is expensive and has strict charging parameters, but gives a long life.
Lithium batteries are smaller and lighter than lead acid. If used carefully these batteries can last from 5 to 20 years. Our lithium batteries have a 5 year warranty.
When comparing lithium to lead acid, you would likely have to buy 2 to 4 sets of lead acid batteries in the same time that you would need 1 set of lithium batteries.
What all can I run off a solar panel?
A solar panel is just one component of many in a solar system. The role of the solar panel is to use sunlight to charge the battery. You cannot run anything directly off a solar panel as you first need to step the power down to an acceptable level by means of a charge controller (solar regulator) in order to charge a battery.
How do I charge a lithium battery?
Unlike lead acid batteries, lithium batteries favour particular charge parameters. Ideal charging for a lithium battery would be a constant current/constant voltage (CC/CV) charge. These batteries want to be charged up to 3.5V per cell, and then charging must stop. So for our 16S batteries, you would charge up to 56V and allow the current to taper to about 12A per module, and then stop charging. Lithium batteries do not want to be float charged. If you cannot disable your float charge, it needs to be set to anything below 3.3V per cell or under 54V on most 16S lithium batteries. The lower the float voltage the better.