Test Equipment for Low-Conductivity Coolants (LECC/LCC)

Frequently Asked Questions About LECC/LCC and Low-Conductivity Coolants

Low-conductivity coolants pose special challenges in terms of testing, purity, and workshop handling. The following questions explain the terms LECC and LCC, the importance of electrical conductivity and pH, and the proper handling of these coolants in electric and hybrid vehicles.

• What does LECC stand for?

  LECC stands for Low Electrical Conductivity Coolant.

  This term refers to coolants that have low or controlled electrical conductivity and have been developed for appropriately designed cooling systems in electric vehicles.

• What does LCC stand for?

  LCC stands for Low Conductivity Coolant.

  This term is also used for coolants with low electrical conductivity.

  However, it is not just the name that matters, but the specific specifications and vehicle manufacturer approval of the coolant used.

• Are LECC and LCC the same thing?

  These terms are sometimes used for comparable coolant systems.
  
  However, this does not mean that different LECC or LCC products are automatically compatible or interchangeable.
  
  The relevant coolant specifications and the vehicle manufacturer’s approval are always decisive..

• Where are low-conductivity coolants used?

  Depending on the vehicle design, LECC/LCC can be used, for example, in thermal management systems for:

  • High-voltage batteries
  • Power electronics
  • Inverters
  • Electric motors
  • On-board chargers
  • Other electrical or electronic components

  Which components are actually connected to the cooling circuit in question depends on the vehicle architecture.

• Is every electric car filled with LECC or LCC?

  No.
  
  Electric and hybrid vehicles use different cooling systems and coolant technologies.
  
  Not every electric vehicle requires a special coolant with low conductivity.
  
  Therefore, only the coolant specified or approved for the specific vehicle may be used.

• Why are low-conductivity coolants used?

  In addition to traditional functions such as heat transfer, freeze protection, and corrosion protection, these coolants have a deliberately low or precisely defined electrical conductivity.
  
  This property can represent an additional technical requirement in appropriately designed high-voltage cooling systems.

• Is LECC a standard water-glycol coolant?

  LECC can be based on a water/glycol-based system, but is specifically tailored to meet additional requirements, such as low or defined electrical conductivity.
  
  Therefore, LECC must not simply be replaced with just any conventional glycol coolant.

• Does LECC always have to be diluted with water before use?

  No.

  Depending on the product, coolants with low thermal conductivity may be sold as a concentrate or as a ready-to-use mixture.

  Dilution is permitted only if expressly recommended by the coolant or vehicle manufacturer.

• Can tap water be used for diluting or refilling?

  Not without express authorization.
  
  Tap water contains dissolved minerals and ions and can therefore alter the electrical conductivity of a low-conductivity coolant.
  
  In the case of a ready-to-use coolant, additional dilution is not intended anyway.

• Can LECC/LCC be mixed with another type of automotive coolant?

  Only if this has been expressly approved.

  Unintended mixing may alter the following properties, among others:

  • electrical conductivity
  • pH value
  • freeze protection
  • corrosion protection
  • chemical stability
  • material compatibility
• Can LECC be identified by its color?

  No.
  
  The color of a coolant is not a reliable indicator of its technical specifications or compatibility.
  
  The product name, manufacturer's approval, and vehicle specifications are the decisive factors.

• Why is electrical conductivity important in LECC/LCC?

  Electrical conductivity describes how well a liquid can conduct an electric current.
  
  In LECC/LCC systems, low or defined conductivity is one of the intended properties of the coolant.
  
  If the conductivity changes significantly, this may indicate, for example, contamination, mixing, or changes in the medium.

• In what unit is electrical conductivity measured?

  Electrical conductivity is typically expressed in:

  • microsiemens per centimeter (µS/cm)
  • or millisiemens per centimeter (mS/cm)

  For low-conductivity specialty coolants, the µS/cm range is particularly important.

• Is there a general maximum conductivity value for all LECC/LCCs?

  No.
  
  A universal threshold value for all low-conductivity coolants would not be technically correct.
  
  The permissible electrical conductivity must be taken from the specifications for the specific coolant or vehicle.

• How is the electrical conductivity of LECC/LCC measured?

  A suitable conductivity or conductance meter is used for the measurement.

  Leitenberger offers the following models in particular:

  • LWM 01_LR
  • LWM 02_LR

  The measured value is then compared with the respective manufacturer’s specifications.

• What is the LWM 01_LR?

  The LWM 01_LR is a professional conductivity meter for suitable coolants and other liquids.

  It is suitable for monitoring and documenting electrical conductivity and can be used, for example, in workshops, R&D, and quality assurance.

• What is the LWM 02_LR?

  The LWM 02_LR is a compact handheld conductivity meter.

  It is particularly well-suited for mobile measurements directly on the vehicle or in the workshop and can also measure low conductivity levels.

• What is the difference between LWM 01_LR and LWM 02_LR?

  Both devices are used to measure electrical conductivity.

  The LWM 01_LR is particularly suitable for applications that require extensive measurement data documentation and more stationary workflows.

  The LWM 02_LR, as a compact handheld meter, is particularly suitable for quick, mobile measurements directly on the vehicle or in the workshop.

  The choice depends on the measurement task and the desired workflow.

• Why is it necessary to take temperature into account when measuring conductivity?

  The electrical conductivity of a liquid depends on temperature.
  
  Therefore, the same coolant can exhibit different conductivity values at different temperatures.
  
  To ensure comparable measurement results, the temperature should be taken into account or compensated for by the measuring device.

• Can a rising conductivity indicate contamination?

  Yes.

  A conductivity value higher than specified can be caused, for example, by:

  • Mixing with another coolant
  • Unsuitable make-up water
  • Residues in tanks or equipment
  • Contaminants
  • Material or ion carryover
  • Aging or changes in the coolant

  However, the measured value alone does not automatically indicate the exact cause.

• Does an elevated specific resistance automatically mean that the coolant needs to be changed?

  No.
  
  First, you must check whether the measured value falls outside the specifications applicable to the specific coolant or vehicle.
  
  The steps required afterward depend on the diagnosis and the vehicle manufacturer's guidelines.

• Can a conductivity value that is too low also be a problem?

  Even an unusual measurement should always be evaluated based on the manufacturer’s specifications.
  
  With coolants that have low electrical conductivity, “the lower, the better” is not necessarily the correct conclusion.
  
  The key factor is whether the coolant falls within the range specified for the specific product.

• Why is the pH value also measured in LECC/LCC?

  The pH value describes the acidic or alkaline nature of a liquid.
  
  Changes in the pH value can indicate changes in the chemical state of the coolant.
  
  pH measurement can therefore complement conductivity measurement.

• Which device is suitable for measuring the pH of LECC/LCC?

  The PHM 01_LR is a professional pH meter designed for use with compatible coolants.

  Among other things, it can be used to test coolants in electric, hybrid, and fuel-cell vehicles.

• Is there a general target pH value for all LECC/LCC systems?

  No.
  
  The acceptable pH range depends on the specific coolant formulation.
  
  A measured value must therefore be compared with the specifications for the specific coolant or vehicle in use.

• What is the difference between pH and conductivity?

  These two measurements examine different properties of the coolant.

  Electrical conductivity:
  describes how well the liquid conducts electrical current.

  pH value:
  describes the acidic or alkaline nature of the liquid.

  Both values can therefore provide different insights into the condition of the coolant.

• Is a conductivity measurement alone sufficient to evaluate the coolant?

  Not always.
  
  Electrical conductivity is a particularly important parameter for LECC/LCC, but it does not account for all of the coolant’s properties.
  
  Depending on the coolant and the manufacturer’s specifications, other factors—such as pH, freeze protection, age, contaminants, or other chemical properties—may also be relevant.

• Is a pH measurement alone sufficient to assess LECC/LCC?

  No.
  
  The pH value is also just a single parameter.
  
  In particular, it does not replace conductivity measurements if low electrical conductivity is required for the cooling system in question.

• Why is it especially important to work cleanly at LECC/LCC?

  Coolants with low conductivity can be sensitive to contaminants.

  Residues from:

  • other coolants
  • tap water
  • cleaning agents
  • metal particles
  • unsuitable containers
  • other liquids

  can alter the properties of the coolant.