Batteries / Energy for planes

A little battery lore
Not all lead-acid batteries are the same. The frequently used glider batteries from the manufacturers Panasonic, Yuasa, ... are inexpensive AGM (fleece) batteries and are mass-produced for use in alarm systems, fire alarm systems and UPS systems. This means that they only have to supply battery power in the event of a power failure. They are therefore not designed for a high number of charging and discharging cycles.

The Sonnenschein Dryfit series is designed and built for a high number of cycles. By using gel instead of acid-soaked fleece mats, there is always sufficient electrolyte between the lead plates, which allows a considerably higher number of cycles than with lead-acid fleece batteries.

AGM (fleece) batteries have impregnated fleece between the lead plates. They are therefore cheaper and have a higher capacity when new, but this usually diminishes quickly afterwards.

In technical terms, this means that the chemical reaction causes sulphate to form on the lead plates when a lead-acid battery is discharged. This sulphate pushes the fleece away from the lead plate. When charging, the sulphate is converted back into lead, but the fleece no longer fully adheres to the lead plate. Where there is no fleece on the plate, there is no chemical reaction. The result is a loss of capacity, which is often only noticed after a longer flight. A lead-gel battery from Sonnenschein does not suffer from this effect.
We therefore recommend checking the capacity of the battery regularly (annually in winter) or replacing it as a preventative measure

The LiFePO4 supply and avionics batteries
Lithium iron phosphate cells (LiFePO4) have almost twice the energy density of lead cells. Compared to classic lead (glider) batteries, this means: only half the weight for the same size. They have a very low self-discharge rate and are therefore perfect for mobile use.
LiFePO4 batteries may only be charged with special chargers (e.g. lead-acid battery chargers with IUoU characteristic and suitable end-of-charge voltage), which switch off in good time when the end-of-charge voltage is reached. The right charger guarantees perfect battery care and, above all, a long service life. The chargers we offer in our shop are programmed for charging lead-acid batteries AND LiFePO4 batteries, so that nobody in the club can make a mistake when connecting the charger in mixed operation (an important aspect from our point of view).

Installation in aeroplanes
In gliders, the battery type is often prescribed by the manufacturer of the aircraft, so it is not easy to change.
Since 2019, CS-STAN Issue 3 has provided a simple way to do this. The AIRBATT avionics battery, tested in accordance with UL2054, fulfils all the necessary requirements and can therefore be used in compliance with all regulations. The documents for registration in the aircraft documents are available in the download area of the article.

Chargers
The majority of prematurely defective batteries could still live for a long time if they had been charged with a suitable charger. Due to the often unsuitable chargers, some of which are home-made, the plates of the batteries sulphate. This slowly but surely loses capacity. Annoyingly, you only notice this during a longer flight, when the logger fails shortly before completing the beautiful FAI triangle on the final approach to the home airfield. Our chargers are optimised for the batteries we sell and therefore guarantee a long battery life.

Warranty
For batteries that have ‘died’ due to incorrect charging technology within the warranty period, you must send in the charger for the above reasons. If the charging technology fulfils the requirements, we will of course replace the battery immediately. If the battery has lost its capacity due to incorrect charging technology, we cannot replace it. We ask for your understanding.

Transport of LiFePO4 batteries
The transport of LiFePO4 batteries is subject to strict rules. The typical sizes for aircraft must be labelled as dangerous goods and may only be shipped by appropriate carriers/forwarding agents/shipping service providers.