We've already said it: the battery is to the solar system what the gas tank is to the generator, but in reality, how does it work? Reserve capacity, voltage, BCI group what does it mean and what impact it can have on your system.
Here is a practical guide to the technical particularities to consider before equipping yourself.
1. Capacity
As its name suggests, this is the capacity of a battery to store energy. It is calculated based on the time it takes to discharge according to a given consumption (amperage).
Take for example the Rolls S2 L16 Battery: its capacity is 1169A over 20 hours.
This means that if we consume 58.45A, it will take 20 hours before completely discharging.
Normally, advisors will base themselves on a 20H scale to recommend a battery. On the other hand, you will be able to see its consumption over 10-30 or even 100 hours in the technical sheet.
In any case, we do not recommend completely emptying your battery reserves so as not to cause them to wear out prematurely. Each device has an X number of complete recharges which we call a recharge cycle.
Normally, we will ensure that the reserve capacity of our battery bank is equivalent to 10 ~15% of the solar field in order to ensure its proper functioning.
Below that, lead-acid and AGM batteries are at risk of early sulfation. Above that, we would come to what we call oversizing: we would have more battery than we really need, which would mean that we would have more slack in our energy reserve.
2. Voltage
2, 6, 12 volts: what is the difference?
In fact, voltage is the energy that is pushed from the battery to the system.
The lower the voltage of a battery, the greater its reserve capacity will be. This is due to the size of the lead plates inside. The bigger it is, the lower its voltage and the greater its reserve capacity. A good trick to see the number of lead plates in a battery is to count the number of caps.
Normally, one lead plate can be counted as 2V. If the battery is 6V, that makes 3 plates, 12 volts, 6 plates and so on.
Battery Voltage vs System Voltage
To take the Rolls S6 L16 battery again, you will notice that it is 2V. As there is no system taking this type of voltage, we will join it with other batteries of the same model to create a 12, 24 or 48V system, depending on needs.
We recommend not exceeding more than 2 sets of batteries connected in parallel. If this is not possible, the solution is to add a terminal block (see photo) which allows you to connect different sets of batteries connected in parallel.
The choice of battery voltage will depend on your needs. For example, many RV or Van owners will turn to 12V batteries. In addition to saving space, the device already complies with the electrical system in place and requires less handling for connection.
3. BCI Group:
The BCI group refers to the battery format. GC2, 24, 27, 31: these different groups meet standards which allow a battery to be classified according to its weight and size.
4. Battery type
Lead acid, AGM, Gel, Lithium, this is the technology used to design the battery.
Normally, this does not affect the battery capacities. On the other hand, it can affect, among other things, its size, its capacity to be unloaded and its weight. To find out more, we invite you to read this article which talks about the different particularities of battery types.
Earlier in the article, we talked to you about solar system sizing. To get an idea of how to estimate your energy needs, you can read The sun as a horizon point who gives tips and advice.
If that doesn't mean anything to you, you can also fill out a custom solar kit form. A member of our technical team will be happy to give you an estimate and explain what went into designing your system.
If you already have an idea of how big your system will be, you can also check out our pre-designed kits.
Here are the links:
Form to obtain a tailor-made kit: https://www.altenergie.ca/formulaire
Pre-designed kits section: https://boutique.altenergie.ca/kits-solaire
*Each kit comes with an installation plan.
**If you are not comfortable with the connections or basic electrical elements, you can write to us so that we can carry out the installation.
