History of Lithium Ion Batteries

The term “lithium battery” refers to a family of different lithium-metal chemistries, comprising many types of cathodes and electrolytes but all with metallic lithium as the anode. The battery requires from 0.15 to 0.3 kg of lithium per kWh.

In 1980, the American physicist Professor John Goodenough invented a new type of lithium battery in which the lithium (Li) could migrate through the battery from one electrode to the other as a Li+ ion.

Lithium is one of the lightest elements in the periodic table and it has one of the largest electrochemical potentials, therefore this combination produces some of the highest possible voltages in the most compact and lightest volumes.

This is the basis for the lithium-ion battery. In this new battery, lithium is combined with a transition metal – such as cobalt, nickel, manganese or iron – and oxygen to form the cathode. During recharging when a voltage is applied, the positively charged lithium ion from the cathode migrates to the graphite anode and becomes lithium metal.

Because lithium has a strong electrochemical driving force to be oxidised if allowed, it migrates back to the cathode to become a Li+ ion again and gives up its electron back to the cobalt ion. The movement of electrons in the circuit gives us a current that we can use.

Types of Lithium Ion Batteries

  1. Lithium Cobalt Oxide: Used in cellphones due to very high capacity
  2. Lithium Manganese Oxide: Used in medical equipment due to high safety and stability
  3. Lithium Iron Phosphate: Used in energy storage and electrical vehicles due to high cycle life and safety
  4. Lithium Nickel Manganese Cobalt Oxide: Used in power tools due to good balance of specific energy and specific capacity
  5. Lithium Nickel Cobalt Oxide: Could be used in electric vehicles in the future as prices come down
  6. Lithium Titanate: Used in military and aerospace due to incredible fast charge and high energy density

Overview of Lithium Ion Batteries

High Performance

High energy density: More energy with less weight
High charge currents: Shortens the charge period-essential for solar applications
High discharge currents: enabling for example electrical cooking on a small battery pack
Long battery life: Up to six times the cycle life of lead acid battery
High efficiency between chargeing and dis-charging: Very little heat generation
Higher continuous power available


A lead acid battery can fail prematurely due to sulphation if it is left partially charged, fully discharged, or rarely fully charged for long periods of time. A Lithium Iron Phosphate battery does not need to be kept fully charged, has a wide operating temperature range and excellent cycling performance. They are therefore THE battery for very demanding applications.


A typical “round trip” energy efficiency (energy that can be taken out of the battery compared to the energy required to -recharge) for lead acid batteries is ~70%. For a LiFePO4 battery it is >96%. The final 20% charge of Lead Acid battery is particularly inefficient with efficiency dropping to ~50% and can take a long time for the battery to become completely charged. In contrast, a LiFePO4 battery will always achieve >96% efficiency and can therefor be charged more quickly while wasting less energy.

Size and Weight

LiFePO4 batteries save up to 70% in space and 70% in weight compared to lead acid.

Battery Management System

It is vital that an advanced Battery Monitor System (BMS) is used to control the battery charging. This is important to actively balance the individual cells that make up the battery and prevent under or over voltage which can otherwise destroy the battery. It is also important for the battery to be able to communicate with the rest of the system.

Lithium Batteries Compared to Lead-Acid



Lithium Ion

Lead Acid

Cycle Life
Cycle life refers to the amount of charge and discharge cycles a battery can last, before reaching a fixed percentage of its original capacity. This is usually 60, 70 or 80%
Lithium Ion batteries will last between 5 000 and 7 000 cycles before reaching 70% of their original capacity.
Lead Acid batteries will last between 1000 and 2000 cycles before the need to be replaced.
Depth of discharge
Depth of Discharge (DOD) is how deep a battery can be discharged per cycle.
Lithium Ion batteries can be cycled up to 90% (and even 100%). Typical systems are sized to cycle the battery to 70% for optimum life.
Lead acid batteries shouldn’t be discharged too deep before the cycle life is drastically impacted. Most systems are sized for a maximum of 50%.
Discharge Efficiency
Discharge efficiency is the energy that can be extracted and used in a battery, measured as a percentage of the energy stored in the battery.
Lithium batteries typical have discharge efficiencies around 98%. That means, for every 100W.h in the battery, you will be able to use 98W.h to power the inverter. To use 100W.h, you need to store about 102W.h.
Discharge efficiencies of lead acid batteries are around 70 to 80%. This means for every 100A.h stored, between 20 and 30 W.h is wasted as heat. To use 100A.h, the battery needs to be oversize by an additional 20 to 30% to compensate for the losses.
Charge Efficiency
Charge efficiency is an indication of the amount of energy needed from the source, in order to store the desired amount of energy in the battery.
Typical charge efficiency of a Lithium battery is also 98%. In order to store 100W.h of energy, you would need to produce a little more than 100W.h from your panels.
Charge efficiencies of lead acid batteries are around 70 to 80%. This means for every 100A.h stored, between 20 and 30 W.h is wasted as heat. To store 100A.h, the panels need to be oversize by an additional 20 to 30% to compensate for the losses.
The purchase price of Lithium Ion is steadily dropping due to improvements in technology and the distribution network world wide. Prices of Lead Acid batteries are steadily increasing due to the ever rising price in lead.
For a 52V, 100A.h Lithium battery, the price is between 2 and 3x more expensive than the equivalent Lead Acid battery bank with the same A.h rating and system voltage.
4x Lead Acid batteries in series are required to have the same system voltage as an equivalent Lithium battery.
The below table compares the levilized cost of storage for a selection of batteries over the usable life of the battery. The initial cost price is compared to the price of a Gel battery.

All systems are sized to have about 4kW.h of usable power.

Type Relative Cost AH V Qty kWh η N (Cycles) DOD Usable Energy Cost/kW Cost/kWh
Freedom Mini 5/4 8.0 100 52 1 5.2 96% 5000 70% 3.64 1.53 2.00
Lead Carbon 1.0 200 12 4 9.6 80% 2200 50% 4.8 0.41 2.05
Lithium BN13V-310-4K 10.6 310 13 2 8.06 92% 7000 70% 5.642 2.63 2.56
LBP4k4 10.0 86 52 1 4.472 95% 5000 80% 3.5776 2.23 2.57
15S20P 12.5 100 52 1 5.2 95% 6000 70% 3.64 2.40 2.63
Lead Crystal 1.0 200 12 4 9.6 80% 1700 50% 4.8 0.42 2.70
OPzV 1.6 200 12 4 9.6 80% 2500 50% 4.8 0.67 2.95
Freedom Home 5/4 12.8 100 52 1 5.2 96% 5000 70% 3.64 2.46 3.21
cMax AGM 0.8 200 12 4 9.6 75% 1000 50% 4.8 0.32 3.69
Gel (Reference) 1.0 200 12 4 9.6 80% 1100 50% 4.8 0.42 4.15

Pylontech Lithium Ion Batteries

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The Pylon US range is an HESS battery system provided by Pylontech, developed with their own lithium iron phosphate cell to ensure the highest safety value and most promising life cycle. A self designed BMS protects the cell from abnormal temperature, current, voltage, SoC and SoH.

Brand: Pylon Tech
Type: LiFePO4
Voltage: 51.2V (For 48V systems)

Warranty: 10 Years

Available in 2.5kWh, 3.5kWh and 5.0kWh blocks

  • Vertical industry integration ensures more than 4500 cycles with 95% DoD or 6000 cycles with 90% DOD (please note most devices will set the DOD at 90%)
  • Compact and fashionable design fits in your sweet home environment
  • Deliver up to 5KW* with single module (2.4KWh) – * please note this value is inverter/charger dependant, typically the maximum achieved value is 1.2kW per battery 50Ah and 1.8kW for 73Ah battery.
  • Modular design gives the end customers the power of choice of capacity
  • Compatible with large number of Hybrid inverters
  • Simple buckle fixing minimize the installation time and cost
  • Safety Cert.TÜV CE UN38.3
  • You can now register the Pylon US2000B, US3000B and US3000C for an additional 3 years of manufacturer warranty for free. Go to http://www.pylontech.com.cn/service/support and complete the information in the ‘sign up battery’ page.
Stock Code Pylon Batteries Voltage
Max Energy Usable Energy (@90% DOD) Max Power
(kW Continious/ Max/ Peak 15sec)
(W x D x H)
Weight (kg) Lifecycle cost (k/kW.h)
BLPY20P US 2000 Plus 2.4kW.h 48 50 2.4kW.h 2.2kW.h 1.25/2.5kW/5kW 6000 4500 3500 442 x 410x 89 24 ZMW 2.26
BLPY25 UP2500 24V, 2.5kW.h 24 100 2.84kW.h 2.55kW.h 1.4kW/2.7 (15 sec) 6000 4500 3500 442 x 420 x 119 27.5 ZMW 2.78
BLPY30C US3000C 3.5kW.h 48 70 3.5kW.h 3.2kW.h 1.8kW/3.5kW/4.5kW   6000 4500 442 x 420 x 132 34 ZMW 2.09
BLPY50 UP5000  48 100 4.8kW.h 4.3kW.h 2.4kW/3.6kW/4.3kW   6000 4500 443 x 420 x 132 45 ZMW 1.89
Stock Code Pylon Extras
BLPYCP Cable Pack
BLPYB20 Bracket US2000B
BLPYC22 Pylon US2000 x 2 Cabinet
BLPYC23 Pylon US2000 x 4 Cabinet
BLPYC25 Pylon US2000 x 5 Cabinet
BLPYB30 Bracket US3000B
BLPYC32 Pylon US3000 x 2 Cabinet
BLPYC33 Pylon US3000 x 3 Cabinet
BLPYC34 Pylon US3000 x 4 Cabinet
BLPYC51 Cabinet for 2x Giter or 1x UP5000
BLPYC52 Cabinet for 3x Giter or 2x UP5000
BLPYC53 Cabinet for 4x Giter or 3x UP5000
BLPYC55 Cabinet for 6x Giter or 5x UP5000
BLPLVH01 LV-Communicaton Hub
BLPY21 Replacement PMU

Freedom Won 

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  • Aluminium enclosure, powder coated white front and sides, with aluminium back-Rated for indoor use.
  • External interface through multi-core cable – Remote Enable for inverter, Charger, Solar Charge Controller, multi purpose programmable output. Analogue Outputs – 0 to 5V for Charge Current Limit and State of Charge. CAN Bus – RJ45 Socket
  • Protection through a Sunt Trip Circuit Breaker, sized to suit maximum current, can be tripped by BMS if critical fault, manual reset. Includes over current, cell under and over voltage, temperature, weak cell detection.
  • State of Charge Display (0 to 100%), Error light, Error Reset Button, Serial RS232 Plug for Programming, WiFi Remote Monitoring (Optional)
  • Warranty: 10 Years (or 3500 cycles) warranty for average 70% DoD, and Maximum 90% DOD
  • Service life : 15 Years (5 000 cycles) expected life at 70% DoD, 20 years (7 000 cycles) at 50% DoD
  • 1 to 30kW.h: Wall Mount, 40kW.h< Floor mount
  • Online monitoring
  • High Power and High Current package available
  • Extra High Power and Extra High Current package available
Stock Code Model Voltage
(AH @ C10)
Max Energy Usable Energy (@70% DOD) Max/Continious  Power (kW) ᵃ 50% DOD 70% DOD 90% DOD Dimensions
(H x W x D)
Weight (kg) Warranty
BLFH05 Home 5/4 52 100 5kW.h 3.5kW.h 6/5 7000 5000 3000 550 x 372 x 265 56 10 Years
BLFH10 Home 10/7 52 200 10kW.h 7kW.h 6/5 7000 5000 3000 916 x 372 x 265 104 10 Years
BLFLH15 Home 15/11 52 300 15kW.h 11kW.h 12/10 7000 5000 3000 916 x 540 x 265 154 10 Years
BLFLH20 Home20/14 52 400 20kW.h 14kW.h 12/10 7000 5000 3000 916 x 712 x 265 207 10 Years
BLFLH30 Home 30/21 52 600 30kW.h 21kW.h 19/15 7000 5000 3000 953 x 1044 x 265 306 10 Years
BLFLH40 Business 40/28 52 800 40kW.h 28kW.h 19/15 7000 5000 3000 1776 x 584 x 310 404 10 Years
BLFLH60 Business 60/42 52 1200 60kW.h 42kW.h 25/20 7000 5000 3000 1776 x 859 x 310 601 10 Years
BLFLH80 Business 80/56 52 1600 80kW.h 56kW.h 25/20 7000 5000 3000 1858 x 1142 x 310 798 10 Years

Home&Business Range is a Lithium Iron Phosphate (LiFePO4) type battery. These units can be configured for high power as well as extra high power.

LithTech Lithium Ion Batteries

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Drop-In replacement Batteries


  • Nominal Voltage: 12.8
  • Efficiency: 99%
  • Maximum continious discharge current: 50A (120A for 5sec)
  • Recommended charge current: 5A – 20A (25A max)
  • Three year wararanty
  • Max 4x modules in serie or parallel- N
Stock Code Model Voltage
Max Energy Usable Energy (@90% DOD) Max Power
(kW Continious/ Peak 5sec)
(W x D x H)
Weight (kg) Lifecycle cost (k/kW.h)
BLLT12100C Lithium Drop-in 12V 100Ah 12 100 1280Wh 1.2kW.h 1.2kW/3.12kW 3000 325 x 175 x 215 13kg ZMW 2.95
BLLT12150C Lithium Drop-in 12V 150Ah 12 150 1800W.h 1.6kW.h 1.2kW/3.12kW 3000  483 x 168 x 209 19.5kg ZMW 3.59

Rack Mount


  • Efficiency 99%
  • Maximum modules in parallel: 15
  • Low voltage disconnect: 42V
  • RS232, RS485 and CAN communication
  • Prismatic cell type
Stock Code Model Voltage
Max Energy Usable Energy (@90% DOD) Max Power
(kW Continious/ Peak 3sec)
(W x D x H)
Weight (kg) Lifecycle cost (k/kW.h)
BLLTE2000 48V, 2kW.h 48 50 2400Wh 2.0kW.h 1.25kW/3.75kW 6000 440 x 420 x 90 25kg ZMW 2.17
BLLTE4000 48V, 4kW.h 48 100 4800W.h 4.0kW.h 2.5kW/7.5kW 6000 482 x 420 x 178 48kg ZMW 1.97
Stock Code Model
BLLTBTE2000 Bracket for TE2000

Giter Lithium Battery (Works with Kodak Inverters)

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– Nominal Voltage: 24 or 48V
– Efficiency: 99%
– Maximum continious discharge current: 50A (120A for 5sec)
– Recommended charge current: 5A – 20A (25A max)
– Three year wararanty
– Up to 6x modules per bank
– CAN and RS485 communication
– 3 Year Warranty

Stock Code Model Voltage
Max Energy (5s) Usable Energy (@90% DOD) Max Power
(kW Continious/ Peak 5sec)
(W x D x H)
Weight (kg) Lifecycle cost (k/kW.h)
BLGT2425 24V, 2.5kW.h LFP 24 100 2.56kW.h   1.2kW/1.44kW     4000   29kg ZMW 2.30
BLGT4825 48V, 2.5kW.h LFP 48 50 2.56kW.h   1.2kW/1.68kW     4000   29kg ZMW 2.30


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Prices are subject to change without notice
Errors and omissions excepted
Prices published does not constitute a final quotation

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