AC-DC battery chargers for 12V lithium batteries

Introduction

most people with 12V lithium batteries will need a AC to DC battery charger compatible with lithium batteries (ie. having algorithms to optimise charging of lithium cells)
- see 12V batteries and battery boxes for more details on lithium batteries
they range in how fast they can charge (this is the max. charging current which is usually 5-40A)
you can also get larger, heavier, faster chargers for RVs and caravans which also include AC inverter for powering 240V AC from your battery or from AC - see AC inverter / DC battery charger combo devices - but none of these are “plug and play” portable devices and are designed to be grounded to a vehicle chassis and many need hard wiring.

Check your battery's max charge current to see if it is compatible with the charging current options
- most LiFePO4 batteries have a recommended charge rate of 0.2C to 0.5C (ie. for a 100Ah battery this is 20A to 50A and absolute max is usually 100A)
- for most batteries under 300Ah you will need to be charging at under 100A or perhaps much less - 40-60A
- charging at lower currents is not harmful — just slower and may be more gentle on the cells
Charging at 50A or higher requires connecting to terminals of the battery
- Anderson plugs and wiring are generally limited to under 50A

main considerations for choice of a charger
- quality brand and preferably weatherproofed
- weight, size and price are important factors and each of these increase as maximum charge current capability increases
- maximum charge current capability
  - you do not want to be sitting in a camp ground laundry or kitchen for hours on end waiting for your battery to charge, hence the greater the charge capability, the less time you will spend having to supervise your gear and stop it from being stolen in a public place
  - if this is important, I would recommend a 25A or 40A charger - good quality portable faster output chargers are hard to find
  - Amazon do sell Chinese chargers with currents up to 100A and for the tech minded these may be useful for larger batteries however, they tend to lack safety features and may not be that healthy for your battery if left unsupervised which is NOT recommended
- ability to adjust charge current
  - if you have a range of battery capacities, you may wish to reduce the charge current for smaller capacity batteries
  - if you are charging at home, you may wish to select a slower charge current for better battery health
- a handy extra option is Bluetooth connectivity to a smartphone which allows you to monitor charge status and how much actually went into the battery

240V AC-DC chargers for 12V LiFePO4 batteries

NB. these are NOT needed for power stations as these generally have a built in charger
assuming you have a 100Ah LiFePO4 battery and you wish to charge it at the camp ground's laundry or other AC outlet and you don't want to be hanging around for many hours waiting for it to charge, then you should consider buying a high current (eg 25A) lithium charger albeit at higher cost, size and weight than low current chargers
you do need to check the max. rated charge rate for the battery to avoid overheating and damaging it but nearly all 100Ah LiFePO4 batteries should easily take a 25-30A charge rate.
you can potentially use two chargers in parallel for faster charge rates ¹⁾ however this may cause problems particularly as the battery is getting to full and needs cell balancing. Chargers generally turn output off momentarily to check voltage of the battery and if there is another charger going then it may not get an accurate reading, thus having multiple chargers running is probably not recommended, especially if each charger is not isolated to back current from the other charger by use of a schotkey diode to ensure current only runs one way. Do this at your own risk and with care!
these chargers will also charge lead acid, AGM, and lead calcium batteries
do not charge LiFePO4 batteries below 0degC or above 50degC.
Victron BlueSmart series have a smartphone Bluetooth app which allows you to change settings and monitor charging as well as retain a history of charging sessions. Plus the app lets you set them as DC out power supplies.

12V 50-100A chargers

this charge current is generally recommended for larger batteries such as 200-300Ah but will also work for most 100Ah batteries
see also AC inverter / DC battery charger combo devices

cheap portable versions

portable versions would be great for on the road campers who need to re-charge at camp ground camp kitchens or laundries as you want it done as fast as possible so you don't waste time minding them (they will get stolen if you are not there)
- safety and reliability may be issues
Shenzen E-fire Chinese 240V AC to 12V DC 100A charger
- minimal controls - you set the voltage via a screwdriver when the battery is not connected (default is 14.6V for Li batteries) and once the battery is connected you turn it on via a know and set the max. current
- no option to set charging profiles otherwise and no Bluetooth monitoring
- it does have a display which shows voltage, current and power in watts and when the battery is full the current will display as zero amps.
- “Uses constant-current and constant-voltage charging to manage the charging process from high-current charging through the final voltage stage. Current gradually reduces as the battery approaches full charge, helping provide a controlled charging process for LiFePO4 batteries.”
- I would probably only use it for a quick top up over 1-2 hours but would not leave it unattended for longer than that (use a better charger for overnight charging)
  - it comes with a couple of warnings:
    - do not use it at full current for a long time (not sure what they mean by this)
    - do not have it plugged into AC power for a long time (I am guessing they mean don't charge overnight)
  - even if it is turned off, if you accidentally connect the leads to the wrong terminals on your battery, the very high current will fry the charger instantly reverting it to a maximum 4.5V output and it does not appear to be a simple fix as it could be due to these which are hard to get to:
    - blown Anti-Reverse/Output Protection Diodes / MOSFETs
    - vaporised Current-Sense Shunt Resistors
    - fried Output Filter Capacitors
- https://www.amazon.com.au/dp/B0CM961HR6 ~$AU259
- there are cheaper versions with lower max charging currents but these don't seem to make sense to me - you will have to wait longer for it to charge

high end devices designed to be mounted in RVs or at home

Enerdrive 12V 100A AC Battery Charger
- takes 110-240V 50-60Hz AC (max 7.6A 240V, 15.9A 110V, max 1750W)
- fully automatic multistage battery charger with the ability to charge 3 separate battery banks - battery bank 1 can be programmed with a different charge algorithm over banks 2 and 3
- user adjustable current output (e.g. Dial the 100amp unit back to run off a 1kVA generator)
  - 4 stages - charge 14.2-15.5V; float 13.4-13.8V;
  - selectable battery type including lithium
- will regulate its output based on the loads connected to your battery banks
- LED display to adjust settings
- Silent Mode: disables the cooling fan for total silent operation at night or whenever required. Activation reduces charge output by half and locks out fan for 12 hours.
- 6.4kg; 425x236x102.7mm
- ~$AU1170
- recommended opt: Enerdrive 120Amp breaker
- if using AGM or similar batteries, must also buy the Temp Sensor EN#-TEMP (not needed for lithium)
Victron Skylla-IP65 12/70
- takes 120-240V 45-65Hz max 12A AC or 90-265V DC
- 7 stage adaptive algorithm outputs 14.4V absorption charge, 13.8V float charge and 13.2V storage charge
- 1 or 3 DC output models available
- designed for 350-700Ah batteries;
- 6kg; M6 bolts; IP65; 401x265x151mm; LCD display for status monitoring and changing charge algorithm
- for LiFePO4: simple charger on-off control can be implemented by connecting a relay or open collector opto coupler output from a Li-Ion BMS to the remote control port of the charger. Alternatively complete control of voltage and current can be achieved by connecting to the CAN-bus port.
- opt. Skylla-i Control Panel
- opt. BMV-712 Smart Battery Monitor
Victron Centaur 12/60
- takes 90-265V 45-60Hz AC via AWG6 screw clamps or 90-400V DC inputs
- outputs 14.3V absorption charge and 13.5V float charge
- designed for 240-600Ah batteries; 3 outputs;
- 5kg; M8 terminals; 437x239x110mm; IP20; designed for home use
Victron Centaur 12/100
- takes 90-265V 45-60Hz AC or 90-400V DC inputs
- outputs 14.3V absorption charge and 13.5V float charge
- designed for 400-1000Ah batteries; 3 outputs
- 12kg; M8 terminals; 514x252x123mm; IP20; designed for home use
- there is also a 80A version same weight and size

12V 40-50A chargers

iTechWorld iTECHBC40
- 12V 40A
- https://itechworld.com.au/products/bc40-battery-charger-40-amp-12v-itechworld-for-car-boat-caravan $AU229
Enerdrive EPower 12V 40A charger
- silent 20A mode for up to 12hrs; 2.6kg; 295 x 206 x 86mm;
- $AU599
- https://thebatterybase.com.au/categories/battery-chargers-and-accessories/battery-chargers/car-battery-chargers/epower-12v-40a-battery-charger/
Kickass 50A ACDC Flexicharge charger
- 2025-26 model
- 4A, 16A, 32A and 50A charging; alligator clips or ring terminals, Anderson plug; On Board LCD
- Lithium Recovery Mode
- Starter Battery Replacement Mode
  - Acts as a 12V DC power source when replacing your starter battery – preventing ECU resets, data loss, or interruptions to other electronics.
- AGM Reconditioning Mode
- Bluetooth smartphone app
- built-in vehicle alternator and starter battery tests - voltage, cranking performance, etc
- 3.05kg 338 x 232 x 87mm
- https://kickassproducts.com.au/products/kickass-flexicharge-12v-50a-acdc-smart-battery-charger-for-lead-acid-agm-lithium-batteries-integrated-bluetooth $AU349 on special

12V 20-30A chargers

Victron BlueSmart IP22 12V 30A chargers
- silent night mode which runs at half or quarter charge rate depending upon model
- conventional screw-down electrical connections and is not shipped with cabling
- 94% efficiency;
- $AU344 for triple outlet charger can charge up to 3 batteries at once to max. total current of 30A
- $AU329 for single output charger
Victron BlueSmart IP65 12V 25A
- better option than the above for most as has better weathersealing for outdoor use (IP65 not IP22) and comes with cables and connectors (alligator clips and eyelet) and it is easy to convert one of these cables to Anderson plug.
- 95% efficient
- low power mode to charge smaller batteries; 1.9kg; 240x140x75mm;
- $AU332 https://www.everybattery.com.au/online/product/victron-blue-smart-12v-25a-ip65-bluetooth-battery-charger-bpc122531014/
Renogy 20A charger
- 93% efficient; 1.7kg; 233 x 108 x64 mm; alligator clips;
- only for LiFePO4 batteries? not weathersealed?
- $AU146 https://au.renogy.com/20a-ac-to-dc-lfp-portable-battery-charger/
Kickass 32A ACDC Flexicharge charger
- 8/16/32A;
- 298 x 152 x 87mm;
- one reviewer suggested that “it really doesnt have a proper LiFePO4 charge profile. LiFePO4 cells should be charged purely bulk at a fixed Voltahe and fixed current to 3.65V per cell or 14.6V for a nominal 12.8V battery and then disconnect. This charger in Li setting, only charges to 14.4 and exactly the same as a Lead Acid battery, ie, bulk, then a reduced current absorbtion then a lower voltage float.” Response from Kickass “The lithium charge algorithm used in our Flexicharge 32A Smart Charger was custom-designed by our engineering team, specifically for use with our KickAss LiFePO4 batteries and their internal BMS. Our Li setting uses a proper CC-CV (Constant Current – Constant Voltage) profile - it charges at max current until the battery reaches 14.5V, then holds that voltage while current tapers off until the battery is full. While it may appear similar to traditional lead-acid charging at a glance, our Li profile does not include a float stage, which is key for LiFePO4 chemistry. This setup has been extensively tested to ensure it’s safe and effective for our battery range.”
- https://kickassproducts.com.au/products/kickass-flexicharge-12v-32-amp-9-stage-automatic-agm-and-lithium-battery-charger $AU249 on special

12V 15A chargers

Victron BlueSmart IP65 12V 15A
- as for the IP65 25A charger above but only 15A
- 0.9kg; 190 x 105 x 60mm;
- $AU239 https://www.everybattery.com.au/online/product/bpc121531014r/

¹⁾

https://www.youtube.com/watch?v=zROCzxXbuNo

Table of Contents

AC-DC battery chargers for 12V lithium batteries

Introduction

240V AC-DC chargers for 12V LiFePO4 batteries

12V 50-100A chargers

cheap portable versions

high end devices designed to be mounted in RVs or at home

12V 40-50A chargers

12V 20-30A chargers

12V 15A chargers