In order to correctly size the batteries of a solar installation, it is necessary to base it on the C10 value, which represents the energy that the battery will offer if it is discharged in 10 hours. This value is the most realistic and is close to the daily electricity consumption of 24 hours. Using the value C100 is wrong and will mean that the capacity of the batteries falls short and problems for its owner. At Damia Solar we always use the C10 value to size the batteries of each solar kit.
What do the C10 and C100 values of a solar battery mean?
To indicate the capacity of each battery model, battery manufacturers use nomenclatures such as C5, C10 and C100, written behind the information in Ah (amp hours). The C5, for example, is used exclusively in batteries for use in vehicles and cars for starting, so we must discard them immediately for use in solar installations. For a photovoltaic installation, batteries are used in which their capacity values are indicated by the nomenclatures C10 or C100.
This nomenclature refers to the amount of energy that each battery can offer in relation to the discharge speed that is made to them. In other words, to give a clear example, the VR OPZS 630Ah C100 (420Ah C10) stationary battery indicates that if it is completely discharged in 10 hours (C10), it will offer 420Ah to its user, while if this user discharges the battery more slowly, in 100 hours (C100), this battery will offer an amount of energy of: 630Ah. The solar battery we are talking about is the same, but as in all existing batteries, its performance capacity will vary depending on how quickly the electricity is extracted from its interior.
This detail is very important when correctly sizing a solar installation and it can mean that it works excellently, or that the user has nothing but problems. The reason is as follows: in a solar installation, the battery capacity is dimensioned according to the daily consumption that the installation will have, that is, the consumption in 24 hours. With which it is important to apply the C10 capacity to make the calculations since it corresponds to 10 hours, instead of the C100 capacity corresponding to 100 hours. The C10 value is much closer to the actual daily consumption and allows correct sizing.
In the kits already prepared in our Damia Solar store, as well as in each personalized solar kit that we make to measure for each client, we always take into account the C10 value to size the batteries and so that their size is optimal and capacity is never lacking. .
In the calculations, in addition to the C10 value, we then apply 4 extra days of storage capacity for security reasons in case there are rainy days or adverse weather conditions that do not allow the solar panels to receive the necessary energy on some days.
Example: a client contacts Damia Solar and after performing the calculations we see that he needs 100Ah of daily battery consumption, after dividing his daily consumption of Watts from his electrical appliances by the 12V voltage of the solar installation: 1600W / 12 = 133Ah. Then we apply the 4 days of safety margin and it will give us the necessary final battery capacity of 532Ah. So at Damia Solar we would size 3 units of 250ah C100 (200Ah C10) gel solar battery, which based on the C10 is equivalent to 200Ah + 200Ah + 200Ah = 600Ah C10.
An erroneous calculation used by other companies and that will be detrimental to the proper functioning of the client’s solar installation is to base it on the C100 capacity. With which the installations will always run out of battery because the C100: 250Ah will be taken as the value, when in reality for daily use it will only be possible to extract 200Ah from the battery. So in a wrong dimensioning they would only use 2 batteries: 250Ah + 250Ah = 500Ah C100. That in reality in C10 they represent only 400Ah, with which the solar installation of that client would fall short of batteries since it would lack more than 100Ah of battery. Because of this, that client will always have problems due to a small safety margin and because the batteries run out quickly.
For this reason, at Damia Solar we only rely on the C10 capacity to dimension the size of the batteries of our clients’ solar installations . In this way, your equipment will always work well and with optimal security days, guaranteeing perfect and problem-free use.
Damia Solar is the leading solar energy store in Spain with a large stock of products and solar kits for houses, flats, country houses, farms, swimming pools, motorhomes, boats, etc. We also make customized custom kits according to the specific electricity needs of each client. In addition, in our kits we offer the Easy Mount pre-installation, through which we carry out the installation of the most complex components of the kit, such as the inverter, regulator, fuses, circuit breakers, wiring and connectors, on a metal plate. In this way, once the customer receives the solar kit, they only have to connect the solar panels to the cable outlet coming from the Easy Mount, and do the same with the batteries. You will be able to finish connecting the kit easily, saving time and money.