Lithium as a replacement

Dec 2, 2021 | News

Quality & Design   Price & Power

Direct replacement:
Freedom Lithium batteries designed to be a direct replacement for lead batteries. They achieve this by having a terminal voltage similar to that of other lead acid variants of leisure batteries including wet, gel and agm types.


Our batteries are designed to charge fully to their capacity of 14.4V (+-0.2V) and as this is the same output level used by the charging circuits of all modern 12V existing split-charge engine wiring circuits. Whether the manufacturer has used a fixed voltage or smart alternator charging circuit, since they would have already taken this into account.

What about Solar Charging:
When solar charging, existing 12V MPPT chargers can charge existing wet, agm and gel batteries, and will therefore charge Freedom Lithium just as effectively in the same way. Existing 12V PWM solar chargers are also the same. Most modern PWM or MPPT variations have a separate selection for wet/agm/gel/lithium battery types to fine tune their charging efficiency. In the case of variations having no lithium settings it is recommended to select the setting nearest to a 14.4V charge voltage.

What about Mains Charging:
The existing mains charging/power supplies that were designed to charge existing wet, gel or agm batteries will also charge our batteries too and may have a setting to change between wet/agm/gel/lithium. Where this is the case, select either lithium or as in Solar select the voltage output closest to 14.4V.

Some very old chargers may have been designed with a fast charge or so called desulphurisation mode often called a rejuvenation setting. It is important to ensure these settings are never used since this could result over time to damaging the battery.

Charging from your alternator can damage it.
This is simply not correct. A Freedom Lithium battery has a similar resistance to a lead battery, and in a low state of charge it will only draw from the alternator what a discharged lead leisure battery would have done.

The question of upgrading the wiring is an option not a requirement. The normal current load on the alternator is comparable, indeed many motorhomes have a capacity to charge a lithium battery at a far higher rate and so it is a possible option to upgrade the wiring to overcome natural resistance and voltage drops of the original manufacturers to drastically increase the charge duration of your lithium battery

Can Lithium batteries just drop in and replace lead batteries?
The answer is, yes no additional components are required when you upgrade your battery power source to lithium. When you use Freedom Lithium batteries as a replacement for older AGM, GEL or lead acid deep cycle leisure batteries. There is no requirement for you to change or modify your existing mains or solar chargers as our batteries can be charged directly from the vehicles existing  standard fixed voltage Lead 14.4V alternator. Replacing with Freedom Lithium Batteries

A Lead battery is cheaper than a Lithium one. This is correct at first view, lead batteries have been manufactured commercially for more than 100 years whilst lithium iron phosphate only twelve years (see our Home Page “Why  choose Lithium?”). However there is a big proviso. Setting aside the several  benefits in use; manufacturing techniques have already greatly reduced the costs over the period and we are now well past a price point where the cost per KWh of stored energy over the lifetimes of each now means that lead batteries will always work out more expensive and less dependable, and are a total disaster for the environment The manufacturing carbon footprint of the lithium is less than 50% lower than lead acid batteries.

 A lithium battery needs a battery to battery charger.
Our lithium battery will not charge quicker or higher with a battery to battery charger unless the charger is increasing the current available to the battery by overcoming the natural voltage drop that was a draw down in the original wiring. If you do  then you must also check that the alternator can support the extra load demanded upon it by that charger argument that suggests it is needed to increase the life expectancy of a lithium battery, or that even without one the life will be dramatically reduced is incorrect

The benefits of installing Freedom Lithium batteries

No “Float charge” needed:
A lithium battery does not need a float charge since it is extremely efficient and does not self-discharge in the way a lead battery does. It does therefore not need any protection from self-discharge. If the charger were switched off at this point, the rest voltage of the battery would fall to 13.3V. However, if the charger is left to its own devices to float the battery, the fully charged lithium will fall back to the float level, instead of its natural rest voltage. Within the context of normal leisure use, this is completely harmless to the battery,

Vehicle charging:
Lastly, we look at split charging, in other words charging from the engines alternator whilst driving. Till recently, all RV’s were fitted with a simple relay which simply connects the leisure battery to the alternator when the engine is running. The alternator has a fixed voltage output of 14.4V and this is the perfect level to charge our lithium batteries at. Since it has a low resistance, similar to the level of a lead leisure with a low state of charge, it will recharge extremely efficiently from the alternator because it will effectively be in what would have been the bulk charging stage of the lead over the majority of its charge cycle. Once fully charged, the terminal level will be brought up to and held at 14.4V as the journey concludes. This is also completely harmless within the parameters of normal leisure use.

Smart alternators:
Increasingly, vehicles are switching to smart alternators. There are several different versions of this technology. The most popular involve monitoring the vehicle battery temperature and voltage and using a pulse charge current to accurately maintain a constant state of charge. This reduces engine load by saving wasted energy the alternator would otherwise have been generating, thus reduced unwanted emissions. There are others including regenerative breaking. It has meant that RV coachbuilders and van convertors are increasingly finding they are having to use what is known as DC-DC charger to charge the leisure battery instead of the conventional split charge relay. This system is a little more expensive for the manufacturer, however it is by no means less efficient than the former system, in fact it is possible to tailor the output current to better suit the manufacturers alternator and has meant for installations where the habitation electrics are fitted some distance from the alternator, natural voltage drops over wiring runs can easily be overcome. This can allow for greater efficiency in leisure battery charging. In the case where a vehicle has one of these types of chargers (some times also know as a B2B or battery/battery charger), the user should ensure it is set to a 14.4V

Lithium batteries are dangerous.
This statement can be correct, for less well designed batteries.
However Freedom Lithium batteries are designed to be safe.

All our batteries have a BMS or a Battery Management System installed with a range of features that guard against the dangers. Most important from an external short circuit which a lead battery does not have. Additionally, in the unlikely event the cells themselves were shorted, for example externally pierced or crushed, the cells would not achieve a high enough temperature to combust and any gases given off during this process are inert. A high enough temperature could not be achieved if the cells were electrically damaged, for example by over voltage charging, or charging at a low temperature (below freezing). Our battery management system prevents low temperature charging or high voltage charging. On balance, lead batteries would normally be more dangerous since gases given off in fault conditions are explosive and there is no internal short circuit protection or BMS equivalent to protect them


Advantages of a Lithium Battery

Providing more power.   
Up to 50% more than a managed lead battery and preventing a diminished life. Regardless of the load, lithium provides virtually all the available power at a constant voltage with no slow fade out.

Ultra-long life.   
Several thousand cycles are possible. Lead batteries fail prematurely when they operate in deficit for long periods. If left partially charged or discharged, failure is even quicker. Lithium batteries do not need to be fully charged. Service life even improves in case of partial charge. This is a major advantage and why we are able to offer a guarantee of up to 10 years.

Highly efficient 96% power cycle.
Efficiency is extremely important, a discharge from 100% to 0% and back to 100% of an average lead-acid battery less than 80%. The efficiency of a Lithium 96%. Lead batteries become especially inefficient from above the 80% charge. Over several days, such losses can compound to lower than 50% in losses or even worse in systems where batteries are operating between 70% to 100% charged state. In contrast, lithium’s achieve over 90% efficiency, even under shallow charge/discharge cycles.

Faster charging.
Once a Freedom Lithium battery is installed what occurs next is the same  as with a lead battery, at the onset the internal resistance of the battery is low. But the difference is that the resistance also remains low. So, the charge remains in the bulk phase just as with lead, but importantly it continues to remain in the bulk phase for much longer thus permitting a faster time to fully charged. In fact it does so until the battery is almost fully charged. It is only once it reaches around 95% of its entire charge that the constant voltage (or absorption phase) can begin and the remainder of the cycle completes. The charger then reverts to its float phase.

Due to lower resistance. Lead batteries have an increasing resistance as they take on charge, resulting in longer charge cycles. Lithium’s do not suffer with this increasing resistance meaning they stay in a constant current (bulk charge) phase for most of the charge duration leading to a naturally faster charge cycle. This is particularly significant when looking at the time taken for the last 30% of the charge of a lead battery

Around 40-50% lighter
Reduced axle weight creating increased load carrying capacity. A 100ah Freedom Lithium SAFE POWER / BLUETOOTH / ARCTIC weighs just 15 kgs.

Orientation in any direction.
We use 32700 type premium cylindrical cells which can be orientated in any position, even upside down. This is especially advantageous in confined areas such as under seats of cupboards. Many lead batteries and cheaper prismatic cells can only be orientated standing.

Abuse proof, our lithium’s switch off in the case of over charge or under charge conditions, or attempted charge at low temperature (except our ARCTIC super series)

Environmentally Friendly
There are no poisonous heavy metals or environmentally damaging chemicals in Freedom Lithium iron phosphate batteries which are recyclable. In contrast lead batteries are toxic to all life and lead pollution is damaging to the environment. The simple fact that lithium significantly outlast lead batteries result in a reduction of repeat manufacturing and recycling. Thus there is a dramatic reduction in our products carbon footprint.