Large Pulse Resistance (LPR) Technology

 
Large Pulse Resistance^® (LPR) battery testing technology developed by Argus overcomes a number of significant shortcomings of conventional testing technologies such as simple load testers and AC conductance testers.

Load testing (carbon pile tester)

A carbon pile tester is relatively inexpensive, but has correspondingly limited value. To achieve limited results is difficult and time consuming.

• No state of health information possible, only pass/fail
• Large and long test load causes singificant battery dischage
• Test can only be performed on fully charged batteries
• Test load must be set for each battery size
• Results must be manually adjusted for temperature

AC Conductance testing

AC conductance testing applies a small AC signal (around 1Amp) for a period of time and measures the resulting signal response from the battery.  Electronic conductance testers overcome some of the limitations of the simple load tester, but significant shortcomings remain. 

• Test must be performed when battery is off-line (functionally removed from the vehicle)
• The tester signal is confused by electronic noise present in the system, preventing accurate readings
• Small test signals fail to expose some mechanical battery defects such as broken plates, or straps

Large Pulse Resistance

Argus' LPR technology draws a large current (~100A) pulse from the battery for a very short period of time (<1msec) and simultaneously measures the voltage drop of the battery during the test. By determining the amount of current that was drawn from the battery during the test and using ohms law -- the internal resistance of the battery can be quickly and accurately determined. The internal resistance value can then be correlated reliably with a capacity value or to cold cranking ability. From one perspective, the LPR test is similar to a traditional load test, but a very fast load test combined with very fast measurement and calculating capability.

The benefits of LPR testing over traditional methods are:

• the 100A test load of the LPR method exposes more defects than other methods
• the short duration of the test load (<1ms) does not produce any detectible battery discharge, and is very safe
• the 100A test load is close to the 'real life' DC loads that are typically applied to most automotive and heavy duty batteries in service
• the LPR method is largely immune from electronic noise on the battery allowing testing while the battery remains in service
• advanced software algorithms can adjust for extreme temperature and adjust results to allow testing discharged batteries

Because the duration of the impressed load is so short and the internal resistance is determined over such a short period of time, it does not matter if there is a dynamic duty load (or a charger) applied to the battery. The voltage of the battery can swing dynamically up and down as demanded by the duty load or charger without significantly affecting test results. This characteristic allows LPR testing to be applied to batteries while they are being used -- a breakthrough for battery monitoring applications. 

The Argus AA Series diagnostic testers models AA350, AA360, AA400, AA500P and AA1000 use LPR technology for capacity testing.