Ok, everyone, here's my setup - not only for the tank, mind you...
After doing some research, and calculating my needs, I decided to set up an inverter based standby power supply for when Eskom starts again with their power cuts. I also planned the setup to be able to accept solar panels in the future, if/when the national electricity supply becomes so bad that there is no reliable electricity supply to re-charge the standby batteries. Finally, I designed the system to provide a long "operating life" with the batteries lasting for at least 5 years (and hopefully more than 10 years) before I need to replace them.
My "critical" electrical requirements are as follow:
Early in my research, I discovered that an inverter is only as good as the batteries supplying it with DC power. I wanted a system that would be able to give me a reasonably long back-up supply, and not cause the batteries to fail prematurely by discharging them too deep (or not charging them sufficiently). I thus calculated my requirements as follow:
Power requirement = 2kVa = 2000W @ 230V
Assuming an inverter efficiency of 90% (the Studer is rated at 95%), and given that it is a 24V unit, I thus need an input current of 2000W / 0.9 / 24V = 92.6A @ 24V.
After studying various makes and types of batteries' data sheets, I settled on using the TPL 121600 batteries from CSB (a well known, reputable Chinese manufacturer). These batteries are rated at 160Ah, and has a nominal "stand-by" life of 10 years. The data sheet of this battery indicates that a discharge down to 1.8V/cell (10.8V) can supply 44.1A for a period of 3 hours. Using two batteries in parallel would thus give me a capacity of 88.2A for three hours, or 96.6A for two hours and 45 minutes. With a combination of two batteries in series (to give me 24 Volt) and two batteries in parallel (to double the Amperage) I can thus run the inverter for slightly less than 3 hours at full load.
The inverter's built-in charger supplies up to 37A of charging current at 24 Volt, which is also within a safe range to recharge all four batteries at the same time without over charging them.
OK, enough info - here are some photos:
The inverter:
The batteries:
Notice the thickness of the connecting cables, to be able to handle nearly 100 Amperes:
Hennie
After doing some research, and calculating my needs, I decided to set up an inverter based standby power supply for when Eskom starts again with their power cuts. I also planned the setup to be able to accept solar panels in the future, if/when the national electricity supply becomes so bad that there is no reliable electricity supply to re-charge the standby batteries. Finally, I designed the system to provide a long "operating life" with the batteries lasting for at least 5 years (and hopefully more than 10 years) before I need to replace them.
My "critical" electrical requirements are as follow:
- All the tank's circulation pumps, including the sump return pump and skimmer pumps
- Lights throughout the house (but not all burning at the same time)
- Supply to the deep fridge
- Supply to the computer in my study
- Some spare capacity to be able to run either a kettle or the microwave oven if I turn off most of the lights
Early in my research, I discovered that an inverter is only as good as the batteries supplying it with DC power. I wanted a system that would be able to give me a reasonably long back-up supply, and not cause the batteries to fail prematurely by discharging them too deep (or not charging them sufficiently). I thus calculated my requirements as follow:
Power requirement = 2kVa = 2000W @ 230V
Assuming an inverter efficiency of 90% (the Studer is rated at 95%), and given that it is a 24V unit, I thus need an input current of 2000W / 0.9 / 24V = 92.6A @ 24V.
After studying various makes and types of batteries' data sheets, I settled on using the TPL 121600 batteries from CSB (a well known, reputable Chinese manufacturer). These batteries are rated at 160Ah, and has a nominal "stand-by" life of 10 years. The data sheet of this battery indicates that a discharge down to 1.8V/cell (10.8V) can supply 44.1A for a period of 3 hours. Using two batteries in parallel would thus give me a capacity of 88.2A for three hours, or 96.6A for two hours and 45 minutes. With a combination of two batteries in series (to give me 24 Volt) and two batteries in parallel (to double the Amperage) I can thus run the inverter for slightly less than 3 hours at full load.
The inverter's built-in charger supplies up to 37A of charging current at 24 Volt, which is also within a safe range to recharge all four batteries at the same time without over charging them.
OK, enough info - here are some photos:
The inverter:
The batteries:
Notice the thickness of the connecting cables, to be able to handle nearly 100 Amperes:
Hennie
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