Page 58 - QH Battery Application Guide

58
Battery Care
& Maintenance (cont...)
Battery Maintenance In Non-Automotive Float Applications
1. Typical applications are motor generators, stand by
applications etc. The Leisure/SLA/GEL battery range is recommended for these types of applications; standard vehicle batteries are not suitable.
2. Batteries used in these applications should be charged every 2 years or more frequently (Continuous charging, even from a well-controlled charging system, will result
in internal degradation of the battery. This could result
in the battery not giving its predicted output when required even though the battery appears to be fully charged).
3. Ensure that the battery is always kept in as high a state of charge as possible without causing excessive overcharge. Always recharge immediately after use.
4. Check the electrolyte levels on a regular basis dependant upon use, but not less frequently than monthly. Charging batteries continuously on a nonvehicle charging system may result in a higher rate of water loss.
5. Check that the battery is clean and dry and that the vents are not obstructed.
6. If the battery is not to be used for an extended period (more than 1 month), fully charge it before storage, and give it a refreshing charge every 3 months.
7. Best practice is to de ne a regular maintenance routine and to record the results. This should include such variables as the amount of de-ionised water added to
each cell, speci c gravities in each cell, battery voltage etc.
Use Of Battery Additives
1. We do not recommend the use of battery additives. 2. The use of these invalidates the guarantee.
Digital Conductance Testers Explained
The electrical performances given on a battery’s label provides information as to its ability to supply suf cient current to start the engine and to run the various electrical loads. The rate are in accordance with EN 50342 the speci cation for lead acid starter batteries.
The Cold Cranking Amps (CCA) is relevant to the current required to turn the engine over (particularly in cold conditions when a battery needs to work harder).
The Ampere hour capacity or reserve capacity measures the stored energy available for ancillary equipment and periods of inactivity of the vehicle.
There are various national and international standards which are used to illustrate the batteries ability to perform as required and perform the tasks they are designed for.
As clearly visible from the later text there are very strict and speci c tests to which the batteries must comply with.
There are many testers now available within the automotive industry which claim to be able to evaluate batteries to these speci cations and supply results in accordance with these speci cations and in many cases these are relatively low
cost (£200 - £300) per unit.
None of these testers carries out the speci c test requirement. The testers work on either the impedance or internal resistance of the battery. The testers then rely on the use of an internal algorithm (developed by the manufacturer and different in every case) which attempts to compare the impedance to state of health. Then to use this to estimate the batteries potential
CCA or available capacity.
Most testers require the battery to be in a fully charged condition to give the most accurate reading, when a battery is in a partial state of charge (as most batteries are) it is more dif cult to assess the battery “Performance rating” as these testers claim to.
These Readings Are Often Misleading Due To The Following:
• Battery temperature is crucial when testing. None of the testers assess battery temperature (Some claim to have temperature compensation but this is generally not graduated and relies on user estimates).
Different battery manufacturers make batteries in different ways (grid technology and design, separator material and manufacturer etc); this creates different impedance and internal resistances for the same battery rating. Testers ideally need to be calibrated to speci c battery suppliers. True battery capacity and CCA can only be assessed by carrying out the tests as laid out in the EN (European Norm) JIS (Japanese industrial Standard) or SAE (US society of Automotive Engineers) speci cations at the speci ed temperatures and currents listed.
Any tester using an algorithm to try and match actual readings will have dif culty in producing accurate and consistent performance data in an instant test with no loads applied.
• These testers do not actually discharge the battery at all, so no current is drawn
• These testers do not actually discharge the battery, so no end voltage can be measured and no period of time elapses
• The test only lasts a few seconds
• The battery temperature is not at -18C, it could be anything
from below zero up to 40C
The equipment required to test these correctly to the above ratings costs in excess of £25,000, the two main suppliers being Bitrode and Digatron.
It is advisable to refer to the document ‘EN 50342’which explains in great detail the rigorous tests that the batteries must comply with in order to be classi ed with regards to CCA Ah Capacity and reserve capacity all of which are relevant to a batteries state of health.
BATTERY CARE & MAINTENANCE / DIGITAL CONDUCTANCE TESTERS EXPLAINED