Solar Power Battery: To find the right memory – Wirtschaftswoche

by Dieter Dürand

If you want to make sure that the battery for the power from the photovoltaic system really counts in the end, can not alone stare at the price. The overall system performance has to be right, the experts emphasize the Karlsruhe Institute of Technology (KIT). Only then it can be operated economically. Here are the key points that you should look for when buying.

Reliability: In order for a solar power storage pays for itself with the current prices, it must be by the end of its useful life at least 3000 times allow loading and unloading. Although the manufacturers promise consistently full cycles 3500-10000 – depending on battery type. But beware !, warn KIT professionals who check in their laboratories practically all common market models through their paces. Buyers should thoroughly inform in advance if the batteries really fulfill the promises. Quite a few cells lost after 1,000 full cycles 30 percent of their storage capacity. This makes them uneconomical criticized KIT expert Andreas Gutsch. “There are systems sold that are not worth the money in terms of performance. Compared to photovoltaic modules, the performance margin is extremely large. “

The best techniques for using and storing solar power

• solar system

  Provides in sunlight into electricity, regardless of consumption. Excess electricity is far sold to network operators

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  home electronics management system (HEMS .)

  Distributed solar power to battery, pump and other consumers

• battery

  Saves the day generated solar power to meet energy needs in the evening.

• pump

  Uses electricity from solar energy to heat . create / shower water for heating or washing

• hot water tank

  If the heat pump or directly heated with excess solar electricity

• Variable consumers

  devices like washing machine or dishwasher to be activated by HEMS and coordinated as soon as the solar system provides enough power.

• Electric Car

  Saves the day solar energy in its own battery or is loaded in the evening on the house battery.

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aging: Poor batteries lose power early on, because it is increasingly warm soon after installation if you are loading or electrified. It lost electrical power. Put another way: The battery heats up its environment, rather than provide electricity. The phenomenon occurs when the internal resistance of the cell increases. Gutschs advice: “Buyers should ask the manufacturer how good counteracts the temperature management of the battery when the heating effect starts with the aging of the battery.” A good control can limit the power loss.

control without a digital smart energy manager, even the best memory is only worth half. The software should be easy to be adjusted to the habits of the residents; very good programs to learn the daily routine over time and optimize their own business. Are residents, for example, at noon at home and put dishwasher, washing machine and dryer on, it makes sense to use the watts from the solar system directly. The family returns only towards evening, the current flows better in the battery

interaction:. It is crucial that the individual components: solar panels, inverters, memory, control software and wiring, are precisely coordinated. Whether the artisans, the system reinstalled or retrofit an existing photovoltaic system with a rechargeable battery. Does it not only at one point, the efficiency of the system immediately rushes to the basement, KIT warns expert Gutsch. “With a bad connection technology, for example, is a good fast a lousy memory.”