Chobe Game Lodge’s FIRST Electric Game Viewing Vehicle, converted by Freedom Won, has been ‘released back in to the wild’ at her home in Botswana

There were heavy hearts and some tears (ssssh), when Team-Freedom Won ‘released Freedom3 back in to the wild’ this morning, waving her a very fond goodbye at 3.45 am (21/8/14). She’s now on route back to her Botswana Chobe home, where after her Gauteng Launch she’ll no doubt also create quite a stir! We took solace in knowing that at least we will see her again (strutting her electric stuff) when we spend some time at Chobe this October (2014) commissioning Freedom5 - Chobe’s First Electric “skimmer” River Boat…

Freedom3, the special Electric Land Rover created by Freedom Won is a Defender 130” Pickup with Crew Cab. It was originally fitted with a 2.5L Td5 engine and a 5 speed manual gearbox. The model year is 1999 with serial no. 833359. It was modified for game viewing duty by removing the roof and installing three rows of three seats each with a canvas roof, making it an 11-seater.

The Land Rover has been transformed almost beyond recognition under the bonnet, but the exterior remains unaltered and distinctly Land Rover. The magic lies in the 80kW permanent magnet motor that is coupled directly to the original transfer case, which delivers 600N.m at low speeds thus effectively eliminating the need for a gearbox. We have retained the High/Low and Diff Lock functions in the transfer case so it is still a very rugged off-roader…

The motor is driven by an advanced technology inverter specially designed to run permanent magnet motors. This unit manipulates the 580 Volt (V) Direct Current (DC) power source into a precision controlled variable frequency three-phase Alternating Current (AC) sign wave, which in turn accurately and smoothly delivers the exact amount of torque “requested” from the driver to the motor.  To the non-engineering types – forget all this, it is awesome to feel and experience the electric exhilaration without knowing exactly how it works!

The heart of this tamed beast is of course the long life and lightweight lithium iron phosphate cells. The battery pack boasts 35 kilowatt hours (Kwh) of energy and operates at a nominal 580V. This voltage, being relatively high in most people’s books allows greater efficiency all round, in the conductors, cells, inverter and motor. It also aids with preserving the expensive lithium cells for a longer life because the average current draw is well below the cell’s design limit. Driving with such high voltages in your car might be disconcerting to some, but there are various features that contribute to a safe experience such as fully enclosed battery boxes, double layered insulation on power cables, fused power circuit and contactors that isolate the inverter when the vehicle is switched off.

The game viewing experience is very special, especially in the Chobe National Park where the game are abundant and the Chobe River presents a setting that drags you softly into a bush Nirvana of flowing waters and tweeting birds. That is of course until the game guide starts up that riotous diesel engine again and puffs black smoke over guest and game alike…enter Freedom3, Chobe Game Lodge in Botswana’s first electric game viewing vehicle, and with Land Rover appeal to boot.

Freedom3 is the first of several electric conversions that Chobe has set out to accomplish with Freedom Won. It is capable of creeping along sandy rutted tracks and climbing rocky ascents, then setting out on the open road at speeds up to 120km/h… Chobe Game Lodge intends to use Freedom3 for two/three game drives per day, the traditional early morning and late afternoon drives around the park and along the river. Freedom3 will also be used daily to commute guests to and from the Kasane International Airport, which is a 30km round trip. Each game drive amounts to a similar distance.

Given that most of Freedom3’s driving will be on sand tracks a typical range is estimated at 120km. On the open road she will manage 150km if driven carefully – remember she has a large drag coefficient with all the guest seating paraphernalia mounted on her.

In Freedom3’s off time she will be receiving a charge in the lodge’s dedicated Electric Vehicle (EV) charging bay, which takes prime location in front of the lodge. A simple 30 ampere (A) 230V single phase source is all that is required to power up the 5kW charging system, with all control managed on board by the advanced Battery Management System (BMS). An average charge will be two to three hours, although if Freedom3’s cells have been fully depleted she will need 6 hours to ‘fill her tanks’. The electricity consumed at CGL originates from the Victoria Falls hydroelectric power scheme and is thus environmentally friendly. Solar panels are however a natural “Phase II” proposition for Chobe Game Lodge (CGL) and any other lodge not fortunate to have access to clean energy. Clean and quiet transport is not the only draw card for CGL. They will achieve substantial savings in diesel consumption. There is no maintenance required on the EV drive train, so the difficulties of maintaining a vehicle in a remote area will also be reduced to looking after the Land Rover transfer case and differentials, which will inevitable leak some oil at some point…  

We have found Freedom3’s performance to be superb. She accelerates faster than the original would have – we would say – and only stops at 120km/h because that is where the electronic limiter reminds us we are driving an open top Land Rover Pickup! The torque is adequate for most driving in Chobe and low range will only be needed in rare and extreme circumstances. There is one improvement we seek however, the synonymous Land Rover final drive unit (differential) backlash shows up more than ever on an EV with instant motor response and no clutch!

Freedom Won was inspired over ten years ago to develop electric car conversions. Our prototype Freedom1, an electric Jeep Grand Cherokee (do we hear jeers or cheers from the Landie owners?), has been running since December 2011 and has covered 45 000km of ‘almost free’ driving. Freedom1 is expected to continue at this pace for 10 years before the batteries show signs of age and warrant replacement. We are excited about revolutionising environmentally conscious game lodge’s transport, which is not limited to Land Rovers, we can convert almost any vehicle, and in fact

we are building an electric river game viewing boat (Freedom5) also with CGL. The opportunities are immense…

The Land Rover has been fun to work on, it is simple (we fondly use the word ‘agricultural’) and there is lots of space amongst the chassis members for installing the electric motor.

Converting this vehicle was special to us because it combines in the Land Rover Defender an old, loved, and sometimes quirky brand with the new high tech ‘green’ Freedom Won brand of the future. It was a mainstay vehicle in the game viewing arena and with Freedom Won’s environmentally conscious technological revival the Defender could regain its historical place from the Land Cruiser, which seems to have encroached on its game viewing territory…

Johan Bruwer (Chobe Game Lodge), Team-Freedom Won SALUTES YOU for pioneering the way with Freedom Won and sharing our green vision, commitment and determination to keep electrifying for a quiet clean future!

Plug into the future… with Team-Freedom Won

Chobe Game Lodge’s pure electric Landie conversion - Freedom3 is now in full swing and will be gracing Botswana with its presence soon…

Team-Freedom Won has spent the last six weeks refining the design, producing drawings and managing the specialist engineering fabrication of the Landie’s key conversion components.

Landie stripped… eagerly awaiting it’s ‘make-over’ to pure electric drive AND Team-Freedom Won is growing… Welcome Daniel and Miguel. Happy converting!

After the battery boxes’ design and positions were finalised, all the aluminium sheet sections were cut and welded together.

Battery box 2 and 3 are installed with batteries. Battery box 1 has been fabricated and will be installed after motor installation.

Battery Box 1’s support brackets have been fabricated as well as the power steering and vacuum pump anti vibration adaptor plate.

Brake and accelerator pedals have been reinstalled with position sensors attached.

The electric motor mounting position was determined in relation to the correct transfer case position which lead to the design of the adaptor housing. An extension shaft to match the motor shaft to the transfer case was also designed.

There’s been much excitement after collection of the motor adaptor housing and the extension shaft. .. which has now been fitted with the motor and transfer case, an integral unit ready to go into Freedom3.

Motor mount fabricated.

The Final ‘Say’ on Freedom3 & 4

We have now done just over 3100 km with Freedom3 over the past three months since we took delivery in August ‘14 of our “electrifying” Landrover 130 Defender game viewer.

To put things into perspective - that’s a Diesel saving of 564 Lt already, at 5.5 km per litre in our harsh environment - this in turn equates to a fuel saving of P 5617.00 (approx. ZAR 6684.23) and not taking into account fuel transport costs.

Lebo and Lynn, our two lady guides responsible for Freedom3, have done many game drives with our guests and the feedback from all have been overwhelmingly positive. We have been experimenting with Freedom3 and at one stage I drove F3 to our local international airport with nine passengers and a luggage trailer packed to the hilt. The 600 N/torque came in handy and made light work of our thick sandy tracks. We are looking forward to February 2015 with the addition of a second electric game viewer.

Our FIRST electric skimmer, Freedom4 has done 55 hours since our official launch on the 7th of November ‘14. With our conventional 40hp 4 stroke outboard motors we manage a fuel consumption of 2.15 Lt per hour, making a saving of 118 Lt petrol in this short time. With our 180 x 60Ah Lithium Iron Phosphate batteries and 30kW permanent magnet electric motor we discovered that this boat can now actually go further on a “tank” than in its previous guise without loss of performance to boot!

All our guests are blown away by the “magic carpet ride” you get on this craft, the only noise you hear is the rush of water in its wake, at speed. As with our electric game viewer, our guides and guests agree, that spending time on these game viewing platforms are much more relaxing for them and the animals they come to see on our slice of heaven, here on the banks of the iconic Chobe River.     

Johan Bruwer
Chobe Game Lodge


“It was an awesome experience to be part of a great team of unparalleled and talented creative men. For me it was a first. An exciting expedition and fascinating tour on a unique & exquisite design of an electric car. Naturally animals hate noise particularly that associated with human’s craftsman & therefore the best ingenuity to get as close would be none other than by means of a mute mobile conveyor. The launch itself was marvellous showing a high sense of planning & purpose. It is through such outings that one learns the outside world & comes to appreciate what other people are made of.”

I would like to express my heartfelt appreciation for being part of the launch, without which l could have not had this lifetime incredible experience, to that l will always remain grateful to FreedomWON.

Omega Masuku
Literally Tax Consulting (Pty) Ltd


We would love  to share our experience in driving with Freedom3 (Electric game viewer vehicle)!

Being in the tourism industry for almost 20 years, we felt very honored to be some of the first to experience this in Africa.

We would describe it as unreal!  Usually with starting your game drive, one has to exhilarate a bit to reach the required gear for the drive which is usually quite low, but the problem is stopping and starting with each sighting:  This vehicle has to go through  the same routine.  With the electric vehicle it is a smooth quiet start and finish.  It is wonderful to drive in the bush without hearing  engine noise and without exhaust emissions  – especially present with diesel powered game viewers.

We loved the experience and would definitely recommend it to all in the Game Industry.

Deon and Crystal Cuyler
Afric Reservations


"After almost a decade in the bushveld and 100's of game drives to boast, when it comes to FreedomWON's Electric Game Drive Vehicle it is definitely more a case of 'feeling is believing'. I wish you all the success in this passionate and necessary endeavour."

Justine Engelbrecht
Publishing Editor TravelmagSA & TOPBIZ Magazine


I imagined the whole week before the visit on how it would feel like to drive an electric car? Obviously I drove a golf cart before with an electric motor and also scalextric cars. HaHA! I imagined that stupid sound of a DC motor with the whistling armature to be flying about within the cab, I also imagined that the passengers would have to make peace with the ugliness similar to the sound of a dentist drill. Surely the driver “would” be used to it. HaHA!

Then when it all happened, __________nothing, except brute power with massive torque and speed, did you ever imagine going on a Roller Coaster with no sound? No, well that is it! The WEG permanent Magnet motor with no brushes and the pure genius from the designer ensured something unimaginable. I mean how can you reach that speed in a  2.5 ton vehicle without the racket of a combustion engine in such a short space?

Freedom1, what an amazing experience!

GO “Greenie” GO!

Fanie Steyn
ZEST WEB Group


I was surprised by the power and torque of the motor; as well as the way in which the weight of the JEEP although substantial, did not seem like a big deal for the battery powered motor.

It was certainly a trip to be remembered. Thanks to Freedom Won for my first experience in a battery powered vehicle.

Carel Ballack
Project Consultant


My perceptions have been changed after test driving Freedom1. I experienced a battery operated 4x4 vehicle with loads of power far beyond my expectations.

You have to drive it yourself to understand it. Well done and all the best for the future.

Trevor Roberts
Conserv Security cc


I must say for me, it definitely was a wonderful/interesting experience and so amusing  to see the petrol light staying on, hahahahahaha. Happy that I’ve had the privilege to have had experienced Freedom won.

Levine Warries
Copper Development Association Africa


My first impression was the amazing torque.
I was also surprised about the comprehensive control system and how quiet the ride was.

Evert Swanepoel
Centre Director
Copper Development Association Africa


Ek is al my hele lewe in die elektriese bedryf betrokke, ek was 4 jaar oud toe die gogga my gebyt het.

Maar in 46 jaar het ek na die toetsrit met Feedom no1,die grootste ervaring in my loopbaan geondervind.

Maar ek wil net noem dat die woord vryheid nie net as n woord gesien moet woord nie, n mens kan nie se dat hy of sy vryheid het nie, as hy of sy nie di’t self ervaar het nie.

Dit is ongelukkig n ervaring wat baie moeilik beskryf kan word, maar ek gaan probeer dit beskryf soos ek dit ervaar het.

My toetsrit het begin met n beskrywing van  hoe Freedom1 ontstaan het asook n verduideliking.

Wat verander is en waar wat geinstalleer is, dit is om die minste te se baie profesioneel en top vakmanskap wat op Freedom1 gedoen is al hoewel dit nog net n proto model is, is dit met die hoogste gehalte gedoen.

Ek het  dadelik die gemoedsrus gekry. Die plasing van toerusting is volgens my prefek gedoen.

Daarna is ons met Freedom1 in die pad. Die toetsrit het begin op ‘n grond pad vir 3 -4 km, helling op en af , ons het motors verby gegaan op n spoed van 100 tot 110 km per uur vir om en by 30 tot 40 km. Dit is in hierdie stadium waar ek regtig die ervaring gekry het wat dit was wat !!vryheid!! Beteken. Dit voel of ‘n mens in ‘n droom lewe, my hare het van opwinding gerys.

‘n Mens kan nie se dit is verniet nie, maar dit is baie naby daar aan. Amper so naby as my onder broek aan my lyf is as jy kan verstaan wat ek jou wil verduidelik. Ek moes my weg skeur van die ontwep en terug beweeg na my diesel voertuig, Ek wou hom net saam vat.

Die elektiese voetuig het my geamuseer, en ek voel na die berekening wat ek gedoen het met my diesel engin in my voertuig, sal ek in die lewens duur van die battery, die geld wat ek gaan spandeer op die ombouing, dubbel terug kry in hierdie tydperk.

Moet aseblief nie my woord vat van die ervaring wat ek gehad het nie , toets dit jou self! En oortuig jou self. DIT IS FREEDOM EN DIT IS SO TE SE VERNIET EN DIT IS MEER AS GROEN EN GOUD VIR DIE VOORT BESTAAN VAN ONS NATUUR. SO DOEN JOU DEEL EN DOEN NET EERS DIE TOETS RIT... DIE RES SAL VAN SELF KOM.

Antony ek dink jy moet n nobel prys kry vir jou deel van die beskerming van ons planeet se voort bestaan deur hier die stap met freedom 1 te neem. Ek gaan my deel doen en dit is om hierdie projek met alles wat ek kan,dit te ondersteun. Daarom gaan ek Freedom No ... my volgende voertuig maak.

En daarom kan ek dit wat ek ervaar het met sterkte aanbeveel.

Piet Vorster


With the recent announcement to mothball South Africa s first electric car to be mass produced, the Joule, what can we do if we want a pure electric car without having to travel the world?

Well that’s what one ordinary guy from Krugersdorp asked himself and came up with his own solution. It’s called Freedom1, and yes it’s an all-electric car. What amazed me about this car, is that this guy took an ordinary everyday car - an old Jeep Cherokee 2000 model and converted it to electric!

OK I’ll admit, I was sceptical when I first met Antony a couple of years ago, and saw the car standing under a makeshift roof with gearbox on the floor. Being a technical person myself, I thought this guy is crazy, it will never work… electric cars should be built by car manufacturers who spent hours with some of the best engineers and designers in the world building this stuff. But sometimes in simplicity there is an answer.

Antony English is the name of the guy, an Electro-Mechanical Engineer from Krugersdorp. When after the motor of the Jeep Cherokee gave its last breath, he decided why not try to convert it to electric? It sounds easy but it was not. He started about ten years ago with the project and it involved a lot of blood, sweat, money and tears. After a successful prototype in 2011/2012, the company Freedom Won was started in the view of being able to take any normal petrol aspirated car and converting it to electric.

So how long does a conversion take and what are the costs? Well if you supply the car yourself (they will also source a “One” for you) it can take up to four months, with shorter lead times envisioned in the future. The cost can be anything up to R350 000, also depending on the car and specific requirements. The batteries will last 10 years, but this is currently normal for any electric car using batteries.

Cost calculations are under way to determine what is the cost of running an electric car compared to a fossil fuel car, but initial calculations indicate that it can be up to 60/70% cheaper based on current electricity and fuel prices. But in my view, as an environmentalists the biggest advantage is the saving in greenhouse gas emissions which is significant, not only CO2 but also other chemicals which effects our health are reduced.

This year the first “One” was displayed at the Minex show at NASREC with huge interest, not only from the public, but also industry, who want to lower their carbon footprint, and talks are underway with one of the biggest mining houses to convert all their cars used on site  to “One’s”.

I have seen the car in motion and what also impressed me the most was the lack of noise from the engine, that we have become so accustomed to and take for granted. Also everything is neatly built and packaged, and easy to use, which I think the car manufactures sometimes forget.

I was definitely impressed and convinced that the “One” is the way to go, with most South African families needing two to three cars for mom and kids, why not consider making your second or third car a “One” and start saving?

Jacques Krog
Operations Manager for BPW Axles, responsible for Safety, Health, Environmental, Quality and Production Management

Chobe Game Lodge’s electric conversions  kick off...
Phase1 – Electrify 1st of 3 Landies + 1st of 7 Double Hulled Game Viewing Boats

At the crack of dawn on Saturday morning, 5 Apr ‘14 the wheels started rolling…  Chobe Game Lodge’s GM, Johan Bruwer with Landie TD130 and Game Viewing Boat’s 40hp petrol outboard motor in tow, bit the bullet and started the 2-day trek from Botswana to Freedom Won’s home base in South Africa…

Johan, man-alone determinedly persevered. After many a good old wimpy coffee, old fashioned bubble gum (Johan’s tried and tested stay-focussed-formula) and Freedom Won’s regular ‘cheering on’ via cell phone, Johan and his heavy entourage arrived exhausted but safe and sound at Freedom Won at 7pm on Sunday, 6 Apr ‘14.

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Long into Sunday night and some early hours of Monday morning conversations were inspired and on fire… fine tuning and driving the collaborative electric visions forward.

After only 4hrs of sleep, Johan was up and ready on Monday morning,

8 Apr ‘14 at 5.30am to tackle the ‘great trek’ back to Botswana again.

Go Johan!

Coffee in hand, at 5.30am Johan takes a last admiring look at the Landie’s lithium iron batteries and 80kW electric Permanent Magnet Motor… the next time he sees   these babies, it’ll be inside the converted Landie – a pure electric Game Viewing Vehicle

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Johan Bruwer and Jonathan Gibson ( Chobe Game Lodge), Team-Freedom Won SALUTES YOU! Together, we’ll keep pioneering the current future, enthusing the Game Viewing Vehicle Industry to electrify …

Idle a while’ for progress updates on Freedom Won’s Chobe electric conversions ….

Optimise your Stationary Power by using LiFePO4

Lithium Iron Phosphate Cells (LiFePO4) – No one can afford to be outside of this revolution!

It is not a case of LiFePO4 being affordable, it is a case of can one afford to use lead acid? The life cycle cost of LiFePO4 cells is a quarter of lead acid batteries. The upfront costs for a pack vary from similar to double depending on the application, but one must consider that in 3 to 6 years’ time the lead acid batteries must be replaced and the LiFePO4 cells will last 13 to 20 years depending on the application and pack design.

LiFePO4 cells have revolutionised the potential and life cycle cost of operating battery based power systems. These cells have a cycle life 10 times that of typical deep cycle lead acid batteries. They only cost approximately 50% more to purchase upfront, however the saving on life cycle cost is substantial.

LiFePO4 cells are available in a wide range of sizes to accommodate loads of a few amps to over 1000 amps. They can deliver sustained high power without excessive heat generation. There are no gases released and LiFePO4 cells are also thermally stable. They can be charged repeatedly to full capacity in less than 60 minutes with no appreciable loss in performance.

LiFePO4 Batteries  vs Lead Acid

Backup and Off Grid Battery Packs Using Superior Lithium Iron Phosphate (LiFePO4) Cells – the next Generation of Energy Storage

Antony John English
Co-founder Freedom Won Pty Ltd

Backup and Off Grid Battery Packs Using Superior Lithium Iron Phosphate (LiFePO4) Cells – the next Generation of Energy Storage

Lithium Iron Phosphate cells,  or LiFePO4 for short,  are beginning to dominate the alternate energy storage sphere amongst the more discerning designers and customers in Europe and some other parts of the world. Freedom Won has been using these cells in electric vehicles for nearly four years already and the company is now also providing this superior technology for stationary power applications or all sizes.

Freedom Won provides competitive prices made possible by bulk imports as well as comprehensive technical backup and design assistance. Freedom Won has also now extended the battery warranty in most applications to 5 years spurred by our confidence gained from our own test programme in electric vehicles, which is far more demanding on the batteries than stationary power systems. The expected life in off grid systems is more than 10 years, and as much as 20 years in grid tied back up installations with occasional cycling. The end of life is defined by the cells containing 80% of their Beginning of Life (BoL) capacity. The capacity deterioration over time is linear (the deterioration does not become substantially more rapid with extended use), and the cells could therefore be used for much longer periods if a lower end of life capacity is acceptable.  

The initial higher cost of installing a LiFePO4 system as compared to Lead batteries is dramatically overshadowed by the savings in the total life cycle cost, calculated as a cost per kWh delivered by the battery pack during its lifetime. Even Lead Crystal batteries cannot compete on life cycle cost. The lifetime cost per kWh can be as low as 25% of the cost of typical lead acid deep cycle batteries. The main reason for this is that the cells offer up to 10 times the number of cycles than your average deep cycle lead battery and as much as 5 times that of the more robust single cell types. This is especially apparent in cases of high current discharge and charging scenarios, further contrasted by high ambient temperatures, both of which are not suitable for lead batteries.

Another top benefit to the customer is the far greater efficiency of the LiFePO4 cell, which is typically better than 96%. A typical efficiency for lead batteries is 65%, although empirical data has demonstrated as low as 55% in a house PV system where the Depth of Discharge (DoD) is limited to 20% as a measure to lengthen the life of the lead acid cells. In a grid tied back up scenario this results in significant energy savings when recharging the batteries, and in a Photo Voltaic (PV) installation it enables a reduction of the size of the array by as much as 30% with the same usable energy.

The advantages of LiFePO4 cells over lead cells are extensive so a full elaboration is not included in this article. A summary is however provided in the table below, and further questions posed to Freedom Won will be welcomed.

Table: Summary of Benefits of Using LiFePO4 Cells in Stationary Power Applications

Comparison Aspect Lead Acid LiFePO4
Cycle Life (50% DoD with 80% remaining capacity, 30 deg C ambient temperature) 500 to 1300 cycles depending on manufacturer and model Up to 5000 cycles
Calendar Life Average (poor in high temperature or partial/full discharge condition or infrequent cycling) Excellent – no sulphation, partial charge storage is no problem, regular cycling is not required, heat tolerant
Charge – discharge efficiency 60-70% typical depending on current. Typically rated capacity is based on 10 hour discharge (C10) 96%, consistent throughout current range. Rated capacity is based on 20 minute discharge (3C), a one hour or longer discharge will actually give 10% more than the rated capacity.
Temperature resilience Poor – temperatures above 25 deg C significantly reduce the calendar life Excellent – ambient temperatures up to 45 deg C will not affect the life of the cell at all.
Up Front Cost Cheaper 20 to 50% more expensive up front than Lead Acid depending on what lead acid cells are used for comparison
Life Cycle Cost per kWh R2.50 to R6 depending on battery type and model R1,50 (approx.)
Quick Charge Time Typically should not be done in less than 5 hours 1 hour standard, 30 min quick
Discharge Current Higher discharge than C10 (10 hours), or 0.1xC rating causes substantial loss in efficiency and affects life C1 (one hour discharge) is standard, higher currents are also acceptable up to 3C (3 x Ah rating) continuous with negligible loss in efficiency and cell life
Gravimetric Energy Density Poor

Weigh 3 to 4 times less – reduced transport costs and installation effort.

Volumetric density more than 2 times higher – less than half the space required

Pack Capacity

Loss of 30% in heat (70% pack efficiency) means pack must be larger to meet a specific output objective

Max practical DoD is 50%, which requires a larger pack to stay above this DoD to prevent rapid life deterioration

Pack can be sized to 60% of the “rated” capacity of a lead acid pack because of 96% efficiency and ability to discharge on regular occasion to 80% DoD with much lower effect on life reduction
Charging Energy Source Size The charging energy source must provide an additional 30 to 40% energy to overcome the inefficiency of the pack at substantial cost Only about 4% of the energy is lost to heat – big savings in charging energy and capital on PV installations etc

When sizing a LiFePO4 pack, the rating of the cells cannot be compared to a typical lead acid rating without making some adjustments. Owing to the much higher efficiency and the ability to discharge more deeply without rapid capacity deterioration means that a LiFePO4 can be sized to about 65% of the lead acid rating if the same DoD is desired. This factor originates simply from the fact that only 65% of the rated energy is available from a lead acid battery in most backup applications, whilst 100% of the rated energy is available from LiFePO4 cells (LiFePO4 cells can deliver more than the rated capacity for moderate current applications hence the use of 100% instead of the 96% efficiency mentioned earlier). Because it is practical to use a lower DoD in LiFePO4 cells and still achieve an excellent cycle life the designer can reduce the LiFePO4 pack size even further and still provide superior performance over a lead battery pack. A typical scenario could be 50% DoD for a lead acid pack compared to 70% DoD for a LiFePO4 pack. This ultimately makes the LiFEPO4 pack energy capacity rating 46% of the lead acid rating. It is a rule of thumb to work on 50%.

LiFePO4 cells maintain their rated nominal voltage for about 95% of the discharge, whilst a lead cell voltage drops continually. When working out the Wh of a lead 12V battery one must use about 11V for the average voltage (1,8V per cell). The nominal voltage for LiFePO4 is 3.2V.

An example comparing a 200Ah LiFePO4 pack to a 520Ah lead pack is included in the below table. The theoretical energy capacity for the lead battery is reduced to 65% of the rated capacity in line 8. In line 9 the capacities are adjusted to the typical DoD expected in the design.  For this scenario the LiFePO4 pack rating is 45% (just less than half) of the lead battery rating. The LiFePO4 pack costs 65% more than the Lead battery, however as shown in line 15, after taking into account the cycle life and the kWh produced in the lifetime of the packs it is clear that LiFePO4 costs only 30% of the Lead batteries used in this example.

 

Table: Comparison Example of Lead Battery vs. LiFePO4

Line Lead LiFePO4
1 4 No. of Typical Solar Deep Cycle Batteries 8 LiFePO4 cells
2 260 Ah each 200 Ah each
3 12 V per battery (6 cells) 3.2 V nom per cell during discharge
4 520 Ah total (two strings in parallel, two per string) 200 Ah total (one string of eight cells)
5 22 V nom during discharge total 25.6 V nom during discharge total (3.2VX8)
6 11440 kWh rated (520AhX22V)    
7 65% efficiency of lead acid battery    
8 7436 Wh available for 100% DOD (11440kWhX65%) 5120 Wh available and rated for 100%DOD (200AhX3.2V)
9 3718 Wh available for 50% DOD 4096 Wh available for 80% DOD
10     45% Percent of LiFePO4 pack rated capacity to equivalent Lead Acid with optimal CAPEX DoD (50% vs 80% DoD)
11  R 16 000 Pack Cost  R 26 400 Pack Cost including delivery
12     1.65 ratio for upfront cost
13 500 cycle life (50% DoD) 2500 cycle life (80% DoD)
14 1859 Kwh in lifetime 10240 Kwh in lifetime
15 R 8.61 cost per kWh R 2.58 cost per kWh
16     30% Percent cost per kWh

The Freedom Won LiFePO4 cells can be provided in various sizes. The 200Ah cell is the most popular. They can be connected in parallel strings to suit the ampere hour requirements and in parallel to suit the voltage of the system. The LiFePO4 pack must be connected to a Battery Management System (BMS) that is able to monitor the voltage of each cell and prevent any cell from exceeding the upper and lower limits. The BMS must also balance the cells to ensure that the pack can perform at its best. LiFePO4 cells do not naturally balance themselves. Freedom Won supplies the BMS configured for each application and will also supply plug and play battery packs with the BMS pre-connected if requested.

For further information, assistance and sales of LiFePO4 cells please contact Antony English at Freedom Won Pty Ltd via the website www.freedomwon.co.za.

 

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Enquiries:

enquiries@freedomwon.co.za

Unit 20, Muriel Road (Cnr. Doreen Road)
Amorosa
Ruimsig, Roodepoort
1724
South Africa

(Situated behind Ruimsig Boulevard Shopping Centre)

Sales: +27 (0)71 890 9958
After Sales Tech Support:
+27 (0)83 258 3444
General Enquiries: +27 (0)82 256 7430

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