TECHNOLOGY NEWSLETTER No. 2 - August 2010
QUICK TESTERS – THE CHANCES AND RISKS The rapid receipt of a situation report is one of the basic requirements in any business process. However, the starter battery of today largely constitutes a “black box”, which is either difficult or impossible to enter from the outside and is hard to judge with regard its performance capacity. Therefore, it is all the more understandable that quick testers are enjoying growing popularity. Risks Naturally, a quick assessment bears the inherent danger that important factors may be overseen. In the case of a battery, this problem is self-evident in view of the prevailing physical-chemical laws that prevent the short-term attainment of an overall picture for analysis. As previously, a reliable estimation can only be made following a laboratory test in line with the EN 50342 standard. The accuracy of quick tests is far below 100 per cent and a degree of uncertainty always exists. Statements concerning charging levels Quick test devices are extremely wellsuited to the provision of a fast and reliable statement concerning charging levels. However, a forecast concerning battery life expectation, or in other words how long it can remain in use, is only possible to a very limited extent. In addition, the fact that the appropriate performance level (cold start current, load current, etc.) varies in line with the charge state (open circuit voltage), i.e. the lower the charging state, the
lower the performance level, although this does not constitute a genuine benchmark of just how good the condition of a battery really is. Therefore, comparisons only make sense when made with uniform charge states. Ambient temperature influence In addition, there is also the problem that such measurements are highly dependent upon ambient temperature, which means that major differences can occur when cold and hot batteries are compared. Design influences measurement values The design principals of a battery can also affect measurement values in differing ways. For example, separators employing a glass fibre nonwoven demonstrate excellent cyclical resistance, but also a high level of internal resistance and therefore show lower measurement levels than batteries without such separators. The life of a battery with a glass fibre web separator will also certainly be longer, but even the best quick testing device is unable to give a prediction in this regard. Thus one is in danger of comparing chalk and cheese. The basic structure of a battery can also result in similar problems. For example, a large number of electrode plates leads to excellent quick testing values, but a quick tester cannot be used to determine whether the life of such a battery will actually be longer because a large
number of other factors (active mass density, alloying quality, general standard of craftsmanship, etc.) also play a major role. Measurement precision Last, but not least, the measurement precision and repeatability of quick measurements is also a familiar problem in scientific circles. The briefer the measurement, the greater the result spread because the volume of data is smaller and does not permit an exact evaluation. As in other areas, one can measure virtually anything, however understanding and interpreting the results constitute the main challenge. It is here that our team of technical experts (Messrs Diermaier and Kaminski) are more than willing to help. The Banner quick tester range We cooperate with leading quality manufacturers such as Midtronics and have an extremely up-to-date programme of Banner quick testers available. Our specialists complete regular checks on the quick testers, during which they are compared with laboratory test methods, in order to better assess the validity of the results. This is currently taking place with regard to AGM batteries. This know-how will soon be added to our product data sheets and will be part of instruction at Banner’s training academy. Therefore, we can also score points by offering our customers extra competence in this area.
Banner BBT 205
Banner GmbH, A-4021 Linz-Austria, Postfach 777, Banner Straße 1, Tel. +43/(0)732/38 88-0, Telefax Verkauf +43/(0)732/38 88-21599, e-mail: office@bannerbatterien.com Verfasser: Günther Lemmerer, Marketing und Öffentlichkeitsarbeit