How to Calculate the Size of
Solar Power Battery?
Hi. Ever wondered how street lights always light at night? Where do they get their power from? I have one word for you. Solar power battery. Power and energy maintain life.
There are different options for batteries available. You should really be careful when choosing the storage devices. It is not a one battery fits all situation. If the solar power battery is undersized, it will cause the depth of discharge to get deeper than normal. This will, in turn, reduce the lifespan of the battery. If it is over-sized, the batteries will not fully recharge. The PV panels will not be able to replenish the large deficit.
Power Today is Integral to the Continuation of Life
Would you like to have a battery of your mobile phone that will last more days? Remaining without batteries is a problem for devices that are not connected to the grid. The same is valid for the solar street lights. We will remain without light, not without a mobile phone. It is therefore important to configure solar street lights carefully.
Now you will discover how to size the solar batteries.
Of course the more is the power, the more is the consumption of electricity and the more batteries we need.
Standard solar street lights work at 12 or 24V. We need to know the exact voltage of our street light to determine the correct battery power.
A light at 100% power for all the night consume much more than a light that is 100% for first 6 hours and 50% for remaining 6 hours.
Not all the days are sunny. We need to have the batteries support also when there is no sunshine and the solar panel cannot charge our batteries.
Type of batteries used
Different battery types have different electrical properties. Examples include Lithium LiFePO4 or GEL batteries.
How To Calculate The Size Of Solar Power Battery
In order to calculate the size of the battery, you will need to provide:
- Amp-hour rating
- Voltage rating
- Depth of discharge of the battery
- Weather condition
- Daily watt-hour usage
- Number of batteries needed
So, let’s make an example
•60W led power at 24V
•Dimming 1 hour 50% + 5 hours 100% + 6 hours 30%
•3 days backup (that is 1 + 2 days)
•The led lamp has a consumption of 60W/24V = 2.5 Ampere
•The dimming mode has the same consumption as 7,3 hours at 100%
•The total daily consumption is 2.5 Ampere * 7,3 hours = 18,25 Ampere-hours (Ah)
•If we need 3 days backup, the total consumption is 18,25 Ah * 3 days = 54,75 Ah
•LiFePO4 batteries has a DOD of 80%, so 54,75 Ah / 80% = 68,44 Ah at 24V .
•Batteries are normally at 12V so we need 2 batteries at 68,44 Ah.
In case battery is GEL;
•The DOD is 50%
•So we need 54,75 Ah / 50% = 109,5 Ah at 24 V.
•Since batteries are normally at 12V we need 2 batteries at 109,5 Ah.
Do not hesitate to contact us if you need an expert on your solar street light system. We are here to serve your lighting needs that are also environment-friendly. Hit us up anytime.