- Customers should expect a lithium battery with an inbuilt BMS to last 5 to 10 years. By comparison a recent user polls showed that over 21% of lead acid batteries fail in the first two years and 37% had failed within just 3 years! By comparison warranty records show the failure rate for LiFePO4 motorcycle batteries was less than 2% in the first two years.
- Extremely light weight! For example a typical 16 amp/hour battery weighs 5kg. A replacement Lithium battery weighs an amazing 860 grams complete with the built in Battery Management System.
- Very small size.
- Very high cranking power relative to size and weight.
- Very low self-discharge rate (about 3% every month).
- No internal liquids or acids that can spill – can be mounted in any orientation.
- Unlike lead acid batteries LiFePO4 lithiium batteries do not produce explosive gasses like hydrogen when charging or discharging.
- Very fast charging times typically a discharged battery can be fully recharged in 1-2 hours. By comparison a discharged lead acid battery will take over 12 hours to charge to full capacity.
- Lower per year cost of ownership than legacy lead acid batteries.
Are there issues with Lithium batteries I should know about? Many brands on the market are just interconnecting raw lithium cells in a plastic case to create a crude and unreliable battery. With this simplistic approachh there are several potential issues that are not being mitigated, such as:
- Potential short lifetime, due to physical cell separation.
- Bricking (becoming so flat that it cannot be recharged)
- Rapid temperature build up if short circuited
- Short cell life due to the individual cells within the battery not being evenly charged every time the battery is charged.
- Excessive and rapid temperature build up if charged at excessive voltages
- Decreased performance in colder temperature
- Rapid and destructive overheaating in the case of a short circuit.
How to select the correct battttery size for a bike? You should select a replacement battery that has at least the same or more CCA as your existing battery. Be aware that because there are practical issues in testing the CCA rating of a Lithium battery, many lithium battery manufacturers will advertise a CCA rating it is actually more likely to be a PCA (Pulse Cranking Amps) rating. If you live in a location where the temperature routinely drops to zero degrees celsius or below you should condider choosing the next size up battery.
- The UB200 – 120 PCA is designed for 125-250cc bikes. It is also ideal for Moto2 bikes and other 600cc racing bikes not fitted with a starter motor.
- The UB400 – 240 PCA can be seen as a replacement for 7-14 A/h lead/acid batteries. The UB4000 is suitable for 600cc-1000cc, 4 cylinder bikes and V-twin bikes greater up to 850CC.
- The UB600 – 360 PCA can be seen as a replacement for all 14-20 A/h lead/acid batteries. Suitable for most 4 cylinder bikes greater than 1000CC and V-twin bikes greater up to 1400CC.
CCA stands for Cold Cranking Amps. The higher the number the bigger the kick your battery can give your starter motor. It is the maximum current a lead-acid chemistry battery can provide at −18°C for 30 seconds while maintaining a minimum voltage of at least 1.2 volts per cell (7.2 volts for a 12-volt lead acid battery). This is the most widely used cranking measurement for comparison purposes of lead acid batteries. However lithium batteries generally stop working before the voltage drops to 7.2V so measuring the CCA of a lithium battery is not practical although some vendors do provide a theoretical ‘equivalent’ CCA as a comparitive indication. The problem is that different vendors derive their theoretical CCA ratings using different measurements and calculations ….and sometimes the marketing departments have influence! So the CCA ratings from different lithium battery manufacturers may not be directly comparable. Also for engine starting purposes, a 30 second discharge measurement is irrelevant. Normally we want an engine to start in the first 10 seconds of cranking!
PCA stand for Pulse Cranking Amps. Again the higher the number the bigger the kick your battery can give your starter motor. PCA’s are usually measured over a short duration (typically between 3 and 10 seconds). Because the pulse time is comparable to the time it actually takes to start a bike, a PCA rating is a better measurement of the abiity of a battery to start your vehicle. The problem is some vendors use a PCA pulse of just 3 seconds while other vendors use a PCA pulse of 10 seconds. A PCA of 200 over 10 seconds indicates a lot more power than a PCA of 200 over 3 seconds. So the PCA ratings from different lithium battery vendors may not be directly comparable.
Amp Hours is a measure of the storage capacity of a battery or how much charge it can hold. It is of little importance unless you operate the electrics of your bike while the engine is not running and charging the battery on your bike. If your motorcycle has current draw when the bike is not being ridden due to being fitted with an immobilizer system, clock, electronic dash, or other accessories that continues to consume your batteries capacity when the key is turned off then you may need to select a battery with a higher amp hour storage capacity or alternatively just connect the cable from the negative lead of your battery.