Q) What is the Type of Lithium Ion Battery in the HD and Novel Range?
A) Lithium Iron Phosphate also referred to as LFP or LiFePO4.
Q) Where Can I See the Technical Details of the Battery?
A) Each battery in the range has a full technical summary under the product description of each item on our website.
Q) What is the Normal Voltage of the 12V Battery? Is it Always 12V?
Lithium ion batteries have a very stable voltage through the majority of their operating state of charge. We recommend that the battery is used and warranted for a 20% - 100% state of charge. Within this range, the nominal voltage will approximately fall between 12.8V. - 13.6V
When the minimum working voltage is 10V below this, the BMS will disconnect the battery to protect the minimum safe charge of the lithium cells. If a lithium battery disconnects due to low voltage, it should be charged at the first opportunity to prolong the cycle life. Individual cells are protected at 2V each (minimum).
The maximum working voltage is 14.6V. Once the voltage exceeds 14.6V the BMS will seek to control the charge rate. Each cell has overcharge protection, this is set to 3.9V per cell maximum. 4 cells in series make up the battery. During the final stages of full charge, cell balancing occurs, this reduces charge to full cells while permitting charge to cells that have not yet reached full voltage (if any exist). Once they attain full voltage they too are disconnected. Unlike lead acid charging there is no absorption phase so this process can be completed very quickly.
Q) What Charge Voltage Should I Use?
A) 14.6V Constant Current Constant voltage.
Q) What is the Maximum Rate of Charge?
A) Please check the individual battery specification sheet as this depends on the size of the battery. For example a HD series 12V 40Ah battery std charge rate is 8A. For a HD Series 12V 300Ah battery std charge rate is 60A.
Q) Can I Use My Existing Lead Acid Battery Charger?
A) The best way to charge a LiFePO4 battery is with a dedicated LFP or LiFePO4 charger. It will be faster, safer and maximise battery life.
However, it is possible to use your existing charger sometimes. If you can be certain that the maximum voltage delivered is 14.6V or less at any stage of the charging program, but it is likely to be very slow for the bigger lithium sizes, as most lead acid/AGM or gel chargers are typically providing 4-20A maximum.
Some chargers have a 'boost' feature that exceeds 14.6V at the beginning of the charge process. This feature can not be used with LiFePO4 batteries. Check the model you have with the manufacturers of that model to see if the charger exceeds 14.6V BEFORE USE.
Some chargers have a desulphation program or 'repair' program, either of these could be more than 14.6V these are Not required and must not be used with LiFePO4 batteries. Check the model you have with the manufacturers of that model to see if the charger exceeds 14.6V BEFORE USE.
Q) Can I Use My Alternator to Charge the Battery?
A) If the alternator delivers no more than 14.6V then it may be suitable to charge the battery, However we strongly recommend either or an external regulator that can monitor alternator temperature and Battery Voltage, connected so that the alternator reduces charge rate and or cuts charge completely in the event that the alternator becomes over temperature and or the battery voltage exceeds 14.2V . If the battery reaches 14.6V the BMS will disconnect the battery and this could damage an alternator that is still charging as it will likely cause a voltage spike that will blow the diodes.
The best way to use an alternator to charge a lithium battery is with a DC-DC Converter that is designed for use with Lithium Iron Phosphate LiFePO4 batteries. These typically limit the rate of charge to 20 or 40 Amps and correct the voltage provided to ensure the battery receives 14.6V, this protects both the battery and your alternator.
Q) How to Charge Lithium Ion Battery with Solar Panel
A) You can charge lithium ion batteries with solar panels using a suitable MPPT Controller that has a Lithium Iron Phosphate or LFP Setting. Or one that can be programmed to charge at 14.6V, with a float voltage of 13.8V, and a high cut off no more than 14.6V (14.4V recommended).
Q) How Long Does a Lithium Ion Battery Last?
A) Our batteries are warranted to last for more than 2000 cycles when they are charged at the std charge rate and cycled/used between 20 - 100% state of charge. (0 - 80% Depth of discharge) 2000 cycles is equivalent to 5.3 years if you drain the battery 80% every day, 7 days a week!
You can typically DOUBLE the expected life of the battery if you reduce the maximum voltage when charged and discharged by 0.2V. For example, do not hold the battery at 100% state of charge and do not discharge the battery fully. LiFePO4 batteries last the longest when used in the 60 - 80% state of charge window (some quote upto 6000 cycles plus). For many people significant increase in lifespan will be possible using the battery in the 30% - 95% state of charge window. The temperature of operation and the rate of charge and discharge also affect total battery life.
Q) What is the Maximum Charge Rate for the Battery?
A) For most batteries the maximum charge rate permitted is 1C. This means for a 40Ah battery the maximum charge rate is 40A. For a 100Ah battery the maximum charge rate is 100A. The std BMS limits charge to 100Ah (On bigger batteries, more than 200Ah. The Uprated 160Ah BMS allows a higher charge rate of upto 160Ah) repeatedly charging at the maximum charge rate will reduce the life of the battery.
Q) Can I Use More Than One Charge Source to Charge the Battery?
A) Yes, so long as the total combined voltage supplied and the total current supplied are within the limits specified on the table for each size battery.