As a company that sells products to a lot people that don’t have any access to mains power we get a lot of questions regarding batteries and green off-grid solutions. Whether you are powering equipment just from batteries and charging them regularly at home or you have a solar off-grid system, batteries are a very vital part of our lives and having a greater understanding these batteries can only be a positive. So buying the right battery for your needs can not only save you money but also time.
As a general rule batteries can be divided into 2 categories
1) Large amount of current ( amps ) for a short period of time, eg. your car battery.
2) Small amount of current ( Amps ) for a long period of time, eg. leisure battery.
Something many people don’t know is that batteries have a life span, and the life of a battery is very much determined on how much you discharge them. This is called the charge cycle. A charge cycle is the process of charging a rechargeable battery and discharging it as required by powering equipment. The term is typically used to specify a battery's expected life span, as the number of charge cycles affects life span more than the mere passage of time.
We do see and hear of people using car batteries to power equipment that requires a small amount of current for a long time ie. electric fencers, lights and 4G cameras. While this will power your equipment it will have a massive negative effect on the life span of your battery and because batteries only have a certain amount of times that they can be charged and discharge before it will need replacing. It is always going to be better and in the long run and cheaper to buy a good quality leisure battery than using car batteries for these uses.
So if we look at the two categories listed above and look at how discharging them to different levels effects the life span of the battery.
Just for an example if a car battery has a charge cycle (life) of 300 charges with the battery never dropping below 90% rated power, then if you were discharge the battery to 70% rated power this would drop the charge cycle and effectively the life span dramatically for example to 150 charge cycles and so on as you discharge it further.
Now if we look at a leisure battery these are specifically designed to be discharged regularly to 50% of its rated power however if you then start discharging them past this point it will then have an effect on the life of the battery.
As it is very hard to determine how much charge is left in a battery we would always advise having two batteries that you can change regularly to avoid discharging them completely.
Also to consider is the longer you leave the battery in a discharged state will also have a massive effect on the life of a battery, so if you no longer require the battery it is alway better to leave it fully charged and out of the weather.
Voltage can be an indicator of how “good” the battery is however this is not a hard and fast rule. The only way to really determine if the battery is “good” is to purchase a battery analyser which can be quite expensive. Some of the expensive battery chargers have built in analyser and these test the individual cells of the battery and charge accordingly.
If all this sounds like a lot of hard work then a well designed off-grid solar system can make life a lot easier. I will cover this in a lot more detail in the next blog however in essence the energy produced from the solar panels will replenish the amount of energy you use in day, meaning the battery wont get overly discharged taking away the need to keep buying expensive batteries every year and the chore of charging batteries all of the time.
Thanks for reading and I hope this helps