Page 59 - QH Battery Application Guide

Digital Conductance Testers Explained (cont...)
Essentially these testers have been developed as a
tool to assess if a battery has failed totally or can be recovered to continue in service. The intended use being “end of life assessment” not as a goods inwards check. The readings of CCA and capacity are at best estimates.
Users of these testers have sometimes complained that new batteries do not appear to achieve the CCA performance that is on the label (according to the tester read out).
• Electronic Conductance testers were NOT developed to test new and unused batteries.
• They have been speci cally developed to assess the condition of USED batteries, and to establish if a battery
has some useful life left or is at or close to failure.
• The aim was to determine quickly and with no skill if a battery is capable of continuing useful service or if it’s at the end
of its useful life.
• Why cannot new batteries be tested like used batteries? New and unused batteries have not always achieved their operating conductance level at the point of delivery; this creates a problem for the electronic tester.
EN 50342 requires a number of charges and discharges are carried out, to assess a battery’s performance. This is also the case when assessing any new battery. Basically all batteries require “Conditioning” prior to testing.
• Batteries at the point of delivery have necessarily been in storage for various lengths of time thus the state of charge will be quite variable. State of charge is a crucial part
of the instruments algorithm the battery has to be in
a known condition.
Different manufacturing operations and different battery designs will create different states of charge for the same voltage. This makes assessing battery condition and performance potential, with variable constructions and states of charge, very dif cult.
A Conductance tester can normally con rm that a battery is unserviceable. Their ability to assess the real performance of a battery is limited for the many reasons stated.
Any “CCA READING” given by one of these testers should at best be considered only as a guide to actual performance.
It is our experience that when testing a batch of batteries with these testers that the results appear to be “VARIABLE”. Some show the batteries as OK, some will be low, and rather strangely some will be high. And if the same tests are performed on the same batteries a few hours later, different results are
often obtained.
It is unlikely that batteries will perform at levels signi cantly in excess of the label ratings. It is not in the manufacturer’s interest to underrate a battery.
The equipment that any good battery supplier would recommend for the testing of batteries is:
• A voltmeter to check open circuit voltage.
• A variable high rate discharge tester to check the products
ability to supply a high current to replicate that required by the starter motor applying a real load to the battery.
• A hydrometer to check the speci c gravity and condition of the electrolyte.
• A good quality charger to enable discharged units to be correctly and fully recharged .
With these 4 pieces of kit it is possible, with some training,
to con rm that batteries are either fully charged and serviceable, discharged and requiring recharge or further testing, or service abuse not covered by warranty or have unusually failed due to
a manufacturing defect.
Please Note: Whenever you are using any testing equipment, please ensure you are using the correct safety equipment, such as eye protection goggles.
S.A.E.
Society Of Automobile Engineers) UK Norm
-18oC
Time = 30 sec
End voltage = 1.2 vpc (7.2 volts)
E.N.
(European Norm) New European Accepted Standard
-18oC
Time = 10 sec + Total Time at 60% of CCA = 90 secs End voltage = 1.2 vpc (7.2 volts)
End Voltage = 1.0 vpc (6 volts)
D.I.N
(Deutsche Industrie Nationale)
-18oC
Time = 30 sec + Total Time = 90 secs End voltage = 1.5 vpc (9 volts)
End Voltage = 1.0 vpc (6 volts
I.E.C.
(International Electrotechnical Commission) -18oC
Time = 60 sec
End voltage = 1.4 vpc (8.4 volts)
C.A.
(American BCI standard)
Also known as M.C.A (Marine Cranking Amps) 0oC
Time = 30 sec
End voltage = 1.2 vpc (7.2 volts)
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DIGITAL CONDUCTANCE TESTERS EXPLAINED (CONTINUED)