Our most Frequently Asked Questions on Lithium-ION Batteries Part One

We know that when compared to a conventional lead-acid battery, lithium-ion batteries in industrial trucks provide many advantages. Over the years we've received frequently asked questions regarding our lithium-ion battery systems, so we decided to put together a three-part series to explain this technology further. We hope you enjoy part one!

1. Can I treat lithium-ion batteries like lead-acid batteries?

No, lithium-ion technology is very different from traditional lead-acid technology. Lithium-ion batteries have significant efficiency advantages, e.g. a much longer service life, highly efficient charging and reduced maintenance costs but are subject to special requirements for storage and transportation.

2. How many charging cycles is a lithium-ion battery designed to last?

The Li-ION batteries guarantee a minimum of 2500 charging cycles (one cycle is considered to be the complete charge and discharge of the battery). This means that, up until this point, the battery retains approx. 75% of its original capacity for warehouse trucks (24V) and 80% for electric forklift trucks, reach trucks, and VNA trucks (48V and 90V products). In many cases, it is therefore possible to use the lithium-ion batteries for a second truck life.

3. What effect do opportunity charges have?

Unlike traditional batteries, opportunity charging has no discernible effect on overall service life. Lithium-ion batteries are also not subject to the so-called memory effect. This means that the full energy capacity is always available and not reduced to the range within which the battery is regularly charged and discharged. Batteries “feel most comfortable” in a range between 20 - 90% SOC.

4. What are the key benefits of the Li-ION technology?

• Higher battery efficiency compared to lead-acid: Due to the higher degree of system-efficiency (battery + charger), the Li-ION battery has up to 20% higher electrical efficiency compared to the lead-acid battery. As a result, the higher battery efficiency causes less energy losses and less heat development inside the battery which leads to lower energy costs for the customer. The Li-ION battery can be fully used down to 5% State of Charge (SOC).

• Intermediate – charging possibility: One main advantage of the Li-ION technology is the possibility of intermediate charging which means higher flexibility. It is possible to charge whenever it is necessary (e.g. “lunch & charge”). In addition, the charging is not place-specific, customers can charge their trucks wherever they want, near their application. The intermediate charging ensures high truck uptime and multi-shift availability.
• Fast charging possibility: The charging times of Li-ION batteries are shorter than the charging times of lead-acid batteries. Customers can use this in an economical way and charge the trucks in regular breaks. Moreover, the accelerated charging allows to serve several trucks with just one charger, reducing charging installation cost and space.
• No battery change necessary: For most 2-shift applications, no battery change is necessary because of the intermediate and fast charging possibility. Therefore, costs and time are saved (e.g. no personnel costs for battery change, no storage costs for a second battery). Besides, there is no need for a charging room.
• Emission-free battery: Due to the closed battery system, no hazardous battery gases (hydrogen) or acids are evolved. An extraction unit (ventilation) is not needed. In addition, the Li-ION battery does not contain toxic substances like Cd, Pb or Hg.
• No more daily battery-maintenance: The Li-ION battery is maintenance–free in daily application. For instance, no water-refilling or battery cleaning is necessary. In addition, no regular battery control is required and there is no need of electrolyte circulation or other add-ons.

5. What advantages do lithium-ion batteries bring me in daily operation?

The high energy density, fast charging, long service life, low self-discharging rate and the option of discharging the battery down to approx. 5% of residual SOC without affecting performance all mean a significant rise in efficiency. In comparison to the full 6 – 12 hours charging time of traditional batteries, the lithium-ion battery can be fully charged in less than 90 minutes. The charging-time strongly depends on the used battery and charger combination. Quick interim charging is also possible, which means there is no battery change needed — a decisive advantage, particularly for intensive multi-shift use. Maintenance costs and effort are also reduced: no need to refill with water, no gases/acids are emitted and therefore no associated investment for battery charging is required. In summary there's:

• No second (or third) battery needed
• No battery change
• No battery maintenance (clean-up, water-refilling, etc.)
• Very high truck availability, less downtime
• Efficient use of each break (lunch & charge)
• No battery room needed (no emissions inside the battery and no ventilation system needed)
• Energy savings due to higher battery efficiency (up to 30%)
• Longer battery-service life (guaranteed 2500 full charging cycles)
• Residual value of battery (after 2500 full charging cycles at least 75% (24V) or 80% (48V and 90V products) residual capacity)

6. What effect does the weight of a Li-ION battery have in comparison with lead-acid in terms of counterweight?

Additional weight is added to Li-ION batteries to retain the residual capacities.

7. Can I charge lithium-ion batteries with my normal battery charger?

No, when charging Linde Li-ION batteries, only the corresponding Linde Li-ION charger is suitable and has to be used as the battery and charger communicate via a CAN-Bus interface.

8. Can we have on-board chargers with Li-ION batteries?

Some 24V Warehouse truck models have onboard charging available with Li-Ion batteries.

9. Could we have a mains current draw charger guide?

The battery and charger data sheets show the ‘Max AC current’ figure as well as the primary peak power draw for each charger type.

10. What are the charging-times?

See the datasheets for 24V, 48V and 90V batteries or use the Linde World Li-ION calculator.

11. What are minimum 20% to 100% charging times?

The 20% discharge level refers to a lead-acid battery. For Li-ION 95% of the energy in the battery can be used. The battery and charger data sheets show the charging times from 95% discharged to fully charged for each battery and charger combination. As a general rule, Li-ION chargers charge the batteries at a constant rate to a certain SOC. The last 10-15% SOC need a bit longer to be charged as the chargers decreases its power to avoid a cell overcharge. You may know this effect from your smartphone where the last 10% often take as long to charge as the 30% from 50% SOC to 80%.

12. How much current does the Li-ION charger draw compared to a HF charger?

Generally, chargers for Li-ION batteries have a higher output, thus requiring a higher input current than chargers for lead-acid batteries. This is an inevitable result of the fast charge capability of the Li-ION battery and charger. The difference in current draw mainly depends on the power rating of each respective charger. Moreover, thanks to the CAN-Bus communication between batteries and chargers, the most powerful chargers in each voltage range can also charge the batteries with the smallest available energy content. Only in the case of warehouse trucks (24V products), such a combination will automatically reduce the input power demand as compared to charging batteries with the largest available energy content.

13. Can Li-ION batteries be charged via either 3 phase or single phase supply chargers?

• For 24V batteries (warehouse product) we have one single phase charger, the rest are 3 phase
• For 48V/90V batteries (counterbalance and Reach) we have only 3 phase chargers

14. Do I need to make any changes to my electrical supply to accommodate the chargers?

We would need to work with you to check what your current system can supply. Things we'd need to consider:

• Current energy consumption at your site
• Infrastructural conditions (eg, cable cross-section, number of free grid connections)
• Possible effects on the peak power demand

15. Are there any differences between a Lithium compliant charger and a standard charger that I should be be aware of?

The main difference is the higher current draw from Li-ION chargers. Further to that, is the different circuit breaker and connector types that may be required.

16. How much energy will this technology need?

When evaluating whether your site is able to accommodate Li-ION batteries, we will need to do an energy survey.

Li-ION batteries require a different approach to lead-acid batteries. With lead-acid batteries, multi-shift applications typically use more than one battery per truck, allowing extended working periods by changing batteries. In most of all applications, lithium-ion batteries do not need to be changed therefore, we have to ensure that the utilisation of the trucks and the opportunity charging periods available will satisfy your application.

In order to accurately determine the correct battery and charger for the application we need to know:

1. Maximum power supply available in the building for the truck fleet, ideally, for every individual charging position
2. Peak power draw vs. terms and conditions of the current power supply contract
3. Operating time vs idle time vs charging time
4. Pricing regime for energy (day/night cost, etc.)
5. Energy infrastructure (cables and sockets available for high power chargers?)

If you require further clarification on any of the above FAQs or would like to talk to us about upgrading to Li-ION battery technology, please contact us by clicking on the button below.

Stay tuned for part two in our three part Lithium-ION batteries FAQs series.

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