The Radenite 24V (21.6V nominal) 6.8Ah Li-ion battery has the highest
commercially available capacity of any "6S 2P" 18650 battery.
The
battery's cells are those used by Tesla® in their Model S and Model X Electric Vehicles.
The battery can deliver 302W continuous and incorporates a protection BMS with balanced charging and short-circuit protection.
Spot welded pure nickel power connections are used throughout (not plated steel). The BMS provides additional protection with a thermal cutout should the pack tempertaure rise beyond 75°C. A water ingress detector will alert to any potential water damage.
The useful built-in LED State-of-Charge indicator lets you know when it's ready for a re-charge.
For important SAFETY information see "Using your Lithium-ion Battery" below.
Alongside the essential safety information, there are 5 additional considerations to understand:
Parameter | |
---|---|
Chemistry | Lithium-ion NCR |
Voltage | 21.6V nominal |
Capacity | 6800mAh |
Total Energy | 146.88Wh |
Max Continuous Discharge | 14A |
Max. Continuous Load | 300W |
Max. Charging Current | 7A |
Over Voltage Protection | 25.2V |
Over Voltage Recovery | 24V (Automatic) |
Under Voltage Protection | 16.8V |
Under Voltage Recovery | 20V |
Thermal Protection | 75°C |
Short Circuit Protection | 200μs |
Short Circuit Recovery | Remove short. Connect charger |
Charge/Load Connector | Female 3A 5.5/2.1mm Barrel |
Dimensions | 140*75*61mm |
Weight | 699g |
When using your rechargeable Radenite battery, it's important to understand the environmental and operating parameters within which the battery must be maintained to ensure safety and good performance.
The power density of Lithium-ion batteries has revolutionised portable power applications, energy capture/storage and transportation. When used incorrectly however, rechargeable Li-ion cells and batteries are less "forgiving" than the NiMH, Ni-Cad and Lead Acid alternatives. Cells have a very narrow tolerance level for their charge and discharge currents. The cells must also be kept within a defined voltage range. Radenite's batteries provide some protection against voltage and current anomalies, but much depends on how the battery is deployed to ensure safe use, extended life and optimum performance.
The following sections provide additional essential information on the safe use of your Li-ion and LiFePO₄ batteries.
If you are unsure about the safe use of your Radenite battery, disconnect it from any charger and/or load equipment and contact Radenite immediately.
If a Li-ion battery overheats, hisses or bulges, then it's possible that one or more cells are in "thermal runaway". If it's safe to do so, immediately move the battery away from any flammable materials and place it on a non-combustible surface. (Use oven gloves or tongs if available). If possible, place the battery outdoors to burn out. If a fire is uncontrollable, contact fire emergency services. Disconnecting the battery from a charger may not stop thermal runaway.
A small Li-ion fire can be handled like any other combustible fire. Ideally, use a foam extinguisher, CO2, dry chemical, powdered graphite, copper powder or sodium carbonate to extinguish any fire. If no foam or powder based extinguisher is available, use water to extinguish a fire. (There is very little lithium metal in a lithium ion battery to cause a significant adverse reaction). Water also cools the adjacent area and prevents the fire from spreading. Covering the battery with a fire blanket may help contain the combustion.
Adhering to the recommended Charge and Discharge (Load) currents is essential to avoid battery failure and fire risk.
Note: Never leave a Li-ion battery charging unattended.
Check the specifications of your battery and ensure that you do not exceed the load limits during discharge (usage).
The same applies to charging rates. Radenite batteries are marketed with matched chargers that will deliver current within safe limits and the correct final voltage to your battery. For example, the Radenite 1500mAh 12V LiFePO₄ battery should not be charged with a current higher than 1500mA. Common domestic "wall-wart" chargers will often be rated at 2A (2000mA). These should not be used. Moreover the voltage of a fully charged 12V LiFePO₄ battery is 14.4V (3.6V x 4). A standard "12V charger" typically delivers 12.8V. This may result in a battery charged to only 50% of its capacity.
Do not attempt to charge the battery with a voltage higher than the battery's specification.
Furthermore a 36V Li-ion battery requires a 42V supply to reach full capacity. A 36V charger will take your 36V battery to only ~50% of its useful capacity.
• Never use a battery charger that exceeds the charge current specification of your battery
• Never connect your battery to equipment that draws more current than the battery's discharge current specification
Radenite batteries are not waterproof and should not be exposed to liquids or damp environments. Ensure that the battery is deployed where the ambient temperature does not exceed 60°C.
All Radenite Li-ion batteries are fitted with an electronic Battery Management System (BMS). One of the features of the BMS is "short circuit protection". If a short is detected on the battery terminals, the current is disconnected. In most cases, the battery will need to be connected to a suitable charger to reset and restore the current to the discharge (load) terminals.
A similar situation arises when a cell in the battery becomes "over discharged" past its low-voltage cut-off threshold; at this point the power to terminals will disconnect. Cells will naturally recover some voltage after the load is removed and power to the terminals will be reactivated usually within a few minutes. In fact a cell's voltage will usually recover within a few seconds but the BMS has a delay before auto-recovery to prevent continuous oscillation of power to the terminals.
Whether a cell is able to recover a threshold voltage or not, it's important that the battery should now be recharged.
If your battery has built-in thermal cut-out, then the battery temperature may have exceed operational limits. Restore the battery's temperature to within its specified operating range; recovery is automatic.
Aside from following the preceding essential safety advice and the required parameters related to charge and discharge currents, there are two significant contributions you can make to extending the operating life of your battery.
LiFePO₄ batteries can endure regular 100% DoD before recharging. This gives them a singular advantage over Start Light Ignition (SLI)
batteries. Radenite LiFePO₄ batteries are NOT a substitute for SLI batteries; they are incapable of delivering the cold cranking amps to start a car engine. Using them for these purposes may damage cells, the battery or the BMS and void your warranty.
Ensure the batteries are in a 50% charged state (An approximation may be used from the battery voltage: 3.2V per series cell for LiFePO4 and 3.6V per series cell for Li-ion). Then cover the terminal connections in electrical insulating tape and store in a dry environment between 10°C and 25°C. Check each month if the battery is approaching lower voltage threshold (all cells discharge naturally over time) and charge if necessary to 50%.
If you are replacing a lithium battery, then the specifications of the existing battery will help guide you to the right type of battery (eg Li-ion vs LiFePO₄) and whether it will fit in the space you have allocated (form factor).
But whether you are replacing or purchasing for the first time, ensure that you know the correct voltage of the battery you require, the maximum current that the battery will be expected to deliver and the capability of any new (or pre-existing) charger to ensure that battery charge currents are not exceeded.
Special consideration must be given to the current with which you will charge your battery and the current which you expect your battery to delivery. Again, unlike their lead-acid counterparts, lithium batteries are less tolerant of excessive currents. Make sure you understand the specification of the battery you are buying and verify that it will deliver the continuous current you are seeking.
In particular, although LiFePO₄ batteries will meet the voltage requirements for most lead-acid replacements (6V, 12V, 24V etc.), lead-acid batteries have an extremely low internal resistance and can deliver very high currents in comparison to most LiFePO₄ equivalents. Therefore, while the capacity (Amp Hours(Ah) or Watt Hours(Wh)) and voltage of a LiFePO₄ battery might seem a good match, it may not be able to deliver the current (or Cold Cranking Amps) required to start an engine.
Lithium-ion batteries have more than twice the energy capacity of LiFePO₄ batteries on like-for-like volume and weight comparisons. Many Li-ion batteries can deliver higher currents and can accept a higher charge current compared to LiFePO₄. There are specialist LiFePO₄ batteries that can accept and deliver higher currents (for example, those designed for starting car engines that require 100s of CCAs), but in the non-specialist category, Li-ion exceeds LiFePO₄'s capabilities.
However, LiFePO₄ batteries have several unique advantages over Li-ion:
The table below gives general guidance on voltages, capacities and thermal stability; energy density figures are given for Radenite's own cells.
Li-ion Battery Type | Cell Voltage Multiples(nom./max./min.) | Energy Density (Wh/Kg) | Energy Density (Wh/L) | Unprotected Thermal Stability* |
---|---|---|---|---|
Li-ion NCM | 3.7/4.2/2.6 | 266 | 730 | Poor * |
Lithium Iron Phosphate | 3.2/3.6/2.6 | 104 | 322 | Good |