Drop in lithium deep cycle replacement leisure batteries

Leaders Lithium-ion Phosphate motor home & marine leisure batteries

Swapping deep cycle lead acid, AGM or Gel leisure with Lithium-ion phosphate batteries ??

Lithium-ion phosphate cells are electro chemical devices that all share and use identical chemical elements in construction. Since they are using identical chemical elements, they all have identical electro-chemical characteristics, there really is no magic bullet! Voltage, charge & discharge characteristics as well as environmental response in theory are identical. Where things begin to differ are cell packaging and how individual cells are arranged. KS Energy cells are all packaged in sealed cylindrical steel canisters who's size allows a for a very fine tolerance and fixed capacity of 3.2Ah per cell with high environmental and mechanical stability.

KS Energy batteries are designed as a drop in replacement for led-acid leisure batteries. Within each toughened ABS case, our batteries contain a state of the art battery monitoring system which ensures all of the individual cells remain finely balanced during charge and discharge and constantly protect the battery against over discharge and over charge currents and voltages.

All KS Energy batteries contain our advanced Mosfet BMS circuit boards which guarantees optimum performance, long life, the ultimate in active charge and discharge control, protection and safety. (100Ah specification).

There is certainly a lot of miss-information or confusion around the topic of lithium batteries and conflicting information. A situation exacerbated due to the involvement of many retailers and manufacturers, some making outlandish claims and in other instances, simply poor construction. For example using prismatic cells or cardboard packaged cells to no cell management circuitry.

There are a couple of key differences to be aware of when swapping old batteries for Lithium-ion phosphate leisure batteries. Firstly, Lithium cells have a very low self-discharge rate and do not require a trickle or float charge.

Secondly the peak required charge voltage of Lithium-ion phosphate batteries are 14.6 volts, this is required to reach a state of 100% charge capacity. Older lead technologies will generally not exceed 14.4 volts (unless there is complex temperature compensation circuitry).

What does this all mean? Well when your charger (or the engines alternator) is performing its initial and main charge it will continue to do so until 14.4 volts is reached. A conventional charger will then revert to float charge. At this stage your KS Energy battery will be approximately 95% charged thus in the case of a KS-100 battery, that is 95% of 105.6Ah or 100.32Ah of available usable capacity.  In detail, KS Energy batteries are constructed with excess cell combinations. For example the KS-100 consists of 4 series banks of 33 cells (4S33P) rated at 3.2Ah - maximum capacity thus 33 x 3.2 = 105.6Ah whilst our KS=200 contains 4S66P, that's 66 x 3.2 = 211.2Ah. Interestingly, since Lithium batteries are in electro-chemical devices with variable parameters, this has the effect of extending the Lithium-ion life span from our guaranteed 2500+ cycles to something exceeding 3000 cycles. In other words, you could probably add a few more years to your batteries service life!

Since the "float charge" is unnecessary a conventional lead acid charger can be manually switched off once the main charge has concluded. If the user fails to do this, then this is fine as the battery will be held at 13.8 volts and KS Energies internal battery management system will ensure all the cells remain balanced with no further charging taking place. However in many cases, a dedicated leisure charger will supply the interior lights and other user accessories and switching off may be unnecessary. The float phase remains until a current demand is once again placed upon the battery and the cycle will repeat. I.e. the charger will begin to charge again to 14.4 volts, reverting to the redundant float phase.

All the above information is of course applicable to the majority of 12V lead acid solar chargers. It is worth noting that many modern mains leisure chargers and solar chargers are now increasingly appearing with a dedicated Lithium-ion (LiFEPo4) setting to increases the efficiency and capability of fully charging lithium batteries. In essence since what is actually involved, i.e. An increase from 14.4 volts to 14.6 volts and removal of float circuitry, there really should not be any increased purchase costs for such devices. So do remain cautious of any unusually expensive products purporting specifically to lithium charging, and perhaps look closely at the the specifications to understand why! 

There is one very important difference to note however. Lithium-ion cells cannot be charged if their cell temperature is at or below freezing point (zero degrees centigrade or 32F). If charging takes place, Lithium-ion phosphate batteries start to become irreversibly damaged with the lower the temperature and higher the charge current resulting in an rapid acceleration of this damage. Since the current available from lithium battery is so large, conventional solid-state charge control switching is unfeasible and mechanical relay switching for protection is the only option. For this reason, KS Energy are the only battery manufacturer to offer a bespoke low temperature solution to a problem that up until now, the leisure industry has been ignoring.