Questions tagged [lifepo4]

All related to lithium iron phosphate (or LFP) batteries

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What concerns should I have when using per-cell charging in a LiFePO4 design?

I've started looking at using 26650 LiFePO4 cells in various (personal use) systems. I've been learning a lot on the topic lately, including how cell balancing systems actually work. While passively ...
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42 views

Charger for a 32650 LIFEPO4 BATTERY PACK 4S2P 12.8V 10AH -12AH

Good day. I ordered a 4s2p LIFEPO4 battery online and it odes not come with a charger. I'm wondering what specific kind of charger do I need for this battery. Specs and the link of the battery are ...
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MOSFET heats up quickly in High power 14V DC-DC bidirectional charging circuit

I am currently design the following circuit to charge a 14V LifePO4 4 cells battery while running a high power motor at 14V 24A. There are some issues that I am currently facing: Without any diodes ...
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2 answers
98 views

My 15S BMS of LiFePO4 battery stack outputs 15.9 V (the entire pack measures 48 V)

I have a LiFePO4 stack of 15S and 3P configuration. Everything was working fine until I broke the pack and divided it into two packs of 8S and 7S, and connected both via jumper wires. Now the pack ...
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Adding 12V power supply to existing Solar MPPT load circuit

I have a camper which has a small 12v power system consisting of a 50w solar panel, a generic 20ah LiFeP04 battery, an a 15A Victron MPPT controller whose 12v load output feeds directly to a fuse ...
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Will it be safe to give 14.7 VDC to this network switch rated for 12VDC? [closed]

I have a number of video devices and a 1GbE network switch which are being powered by a 12VDC LiFePo4 battery via a DC power distribution module, using powerpole connectors. All of the devices are ...
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57 views

General design approach to LiFePO4 charging

I'm trying to design a charging circuit for a 12V 120Ah LiFePO4 battery pack from a DC generator. Part of the project that the battery powers contains a Pi, and I'm not sure whether it's clever to ...
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How to combine two 48 V DC power sources for redundancy?

CONTEXT: I am building a new system to power my servers rack. There will be 2 separate LifePo4 battery packs of 48 V 50 Ah, each with their own charger connected 24/7. This will act as a UPS. From ...
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Can DC DC converter (CCCV) + BMS charge Lithium Polymer batteries

I need some help in clarifying my understanding on charging Lithium Polymer batteries. Context: I am trying to build DIY vacuum cleaner bot. For that I need a LiPo batteries which bot could charge ...
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LifePO4 + regular charger

What happens if I try to charge a LiFePO4 battery from the car alternator? I have a X30 LiFePO4 battery (https://cara-tech-24.eu/en/electric/278-powerxtreme-x30-battery-lifep04-battery.html) in my ...
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LiFePO4 Battery, fuse, and resistor needs when using a 12V DC to 120V AC inverter?

I am new to micro power grids and learning how to use DC-power storage with AC-powered devices. In researching the topic I have read some unsubstantiated points I want to clarify. Battery: Apparently ...
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Charging 3.2V 6000mAh LiFePO4 batteries (32700)

I bought one 3.2 volt 6Ah LiFePO4 battery, which is called 32700: For charging, I have a lot of li-ion TP4056 charging modules, but I have read that these batteries differ from lithium-ion batteries. ...
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50 amp hour and 100 amp hour lifepo4 batteries in series

I have four 12 V, 50 amp hour lifepo4 batteries running in series, so 48 V. I need to increase the capacity of the battery bank. Can I get four 100 12 V amp hour batteries and create 4 sets of 150 amp ...
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102 views

Regulating 12.8 V, 240 W from a LiFePO4 to 12 V for computer

I have a LiFePO4 12.8 V, 20 Ah capable of 244 watts. I am trying to power a computer that needs regulated 12 V that will need 200 W. The regulators I find on Amazon don't cut it. The ones that handle ...
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LiFePO4 or 'Standard' lithium (Chinese cell) pack for e-moped build

I am trying to build my own e-moped for university in Hawaii and I am in need of some advise for the right pack. I currently have two orders awaiting payment on alibaba. They are both 48v 50ah and I ...
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Possibly connect second charger to Lithium Iron Phosphate battery

I have a sump pump system that includes a 12 volt backup sump pump. It is managed by this Pump Spy system: https://www.amazon.com/PumpSpy-PS2000-Battery-Internet-Monitoring/dp/B07N8FY4L9 I have a ...
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169 views

Current limiting at 100 amps

What options exist for limiting current in this scenario? I have been searching for an option and it looks like I need to reduce the field on the alternator but I don't understand enough to know if ...
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Can LiFePO4 BMSes be connected in parallel without causing charge/discharge issues?

I have two LiFePO4 battery packs in 4S configuration: one with 2x4 cells (4S2P) and one with 3x4 (4S3P) cells. Each pack has a 4S BMS. Are there any potential issues with connecting those two in ...
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1 vote
3 answers
213 views

Charging LiFePO4 with high voltage but low current?

I'm trying to charge a 230 volt 24 kW bank of LiFePO4 batteries. It's difficult to generate the right charging voltage because it needs about 250 volts and most inverters don't do that. It's usually ...
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Typical voltage range for a LiFePO4 BMS

I'm about to hook up some LiFePO4 (32650) batteries to solar panels. I bought a couple of noname BMS boards ("HX-4S-F30A") for a 4S configuration for the batteries online, and the ...
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Configurations for charging batteries of varying voltage from one source for RV

I have wired up a solar system in my travel trailer, using a 7s1p 48V (58.7V) pack from used Nissan Leaf battery modules. I am now making a 12 volt battery from a bunch of LiFePO4 18650 cells I have ...
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419 views

PWM and MPPT charge controller on same solar panels

I have two identical solar panels in series that are connected to an MPPT controller (EPEver Tracer 1210A), which is currently charging two SLA batteries connected in parallel meant to power some ...
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Solar LiFePo4 Battery sudden discharge at end of the night

Image above showed performance of the system over the past week. Blue is battery in W (this takes into account 2 230w/h batteries. Orange is the current from the PV. Grey is the W used by the LED ...
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790 views

DC-DC converter current limiting for charging LiFePo4 battery using SLA battery

I have a DC-DC converter which converts 9-36V to 13.8V with a 20A rating. I would like to use this converter to charge a 100aH LiFePo4 (with BMS, see: https://ca.renogy.com/renogy-smart-lithium-iron-...
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2 votes
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1k views

Can Lithium-Iron-Phosphate or LiFePO4 batteries be stored in cold?

According to this site, you can store in -40°C/-40°F just never charge them below freezing. I have a E-Bike in cold Canada and taking the battery out is a pain. The link says just make sure it's ...
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3 votes
2 answers
704 views

LifePO4 battery to replace lead-acid

I want to replace my cargo van's lead-acid battery with a LifePO4 battery. Never used any li-ion type battery for high amp burst. The current lead-acid is NAPA The Legend Premium Battery BCI No. 75 ...
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Is there a relativily simple way to determine state of charge (SoC) for LiFePO4 batteries?

I'm searching for information regarding this matter and I can only find academic papers. I am wondering if anyone knows of any (more accurate or less accurate) way to evaluate the state of charge for ...
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2 votes
3 answers
2k views

Charging circuit for LiFePO4 cell

I recently purchased this 32650 LiFePo4 6Ah cell, and I'm looking for simple ways of charging it. I am not able to find LiFePo4 specific chargers that charge single cells, and I was wondering if I ...
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201 views

What's the minimum discharge for a 12 V LiFePO4 Battery?

I just purchased two "SOK LiFePO4 12 V batteries", one of them after opening the box had a voltage of 7.9 V, the other was at 12.9 V. They haven't been used at all. What's the minimum safe ...
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Parallel BMSs with LiFePO4 Packs

I'm trying to design a BMS that allows for multiple larger packs to be connected together in parallel (say, multiple 4S LiFePO4 packs). Using an unconnected conventional BMS SOC there's obviously the ...
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1 vote
1 answer
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A fully charged 3.2 V DC cell used to power a 3.5 V DC light string gets discharged in 2 hours

A light string, normally powered by a 120 VAC to 3.5 V DC 800 mA power supply, when connected to a single 3.2VDC cell (LiFePo4 26650 3300 mAh), was bright at first, then dimmed and went out within 2 ...
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Why is my self built LiFePO4 battery pack not charging?

[NOTE] I understand that the adapter that I bought for my battery pack is not actually a charger. I also understand that it could be dangerous what I'm doing. I still wonder why there is no current ...
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Inamp to Measure LiFePO4 Battery Voltage

I know there are a few posts regarding the best way to measure battery voltage but I didn't see any that were focused on the most precise method possible. I am designing a battery analyzer to measure ...
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1 vote
1 answer
135 views

Need help designing LiFePO4 BMS disconnect alarm

I need help designing an alarm for a 12v LiFePO4 + BMS system. I am using an off the shelf BMS. The BMS has internal FET switching which may disconnect the battery for a variety of reasons to protect ...
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How to build a 18650 battery pack without a spot welder?

I'm building an autonomous boat (which needs to get me a bottle of fine whisky from Scotland) for which I want to build a battery pack. The boat is currently powered by a cheap Li-ion battery pack, ...
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BMS and Charger For LiFePO4 prismatic module

I just purchased a lithium battery module for an electric tractor project. I'm looking for advice on how to set up my BMS and charger. Here are the details of the module from the seller: "Prismatic ...
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1 answer
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Is ESP32-Pico D4 Kit able to charge batteries out of the box?

I was looking at this: https://www.digikey.in/product-detail/en/ESP32-PICO-KIT/1904-1030-ND I read somewhere that Dev boards like this have the ability to charge batteries (LiFePO4) when connected ...
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400VDC LiFePo4 charger?

I have a solar electric system from many years ago. The setup runs on 400 to 480VDC from a string of solar panels. I have a unit that converts 250 to 600VDC to 48VDC for charging lead acid ...
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128 views

Charging a LiFePo4 12v 40ah battery with 10A charger instead of 6A

I purchased a Bioenno Battery with 12v 40ah. I already have a 10A LiFePo4 battery charger. The new battery says charging current should be 6A. Can I charge it with a 10A charger since it has a ...
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2 votes
1 answer
155 views

Effect of Rapid Switching between Charge/Discharge of Lithium Batteries

I have made a DIY offgrid solar generator that utilizes an arduino to determine when to dump excess energy to a water heating load. I have programmed the arduino to activate the load circuit when the ...
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51 views

Can I use a rechargable battery with a PIR sensor designed to use two CR2032 batteries?

I use a PIR sensor that works with two CR2032 3v button batteries (in parallel). The main problem I face is that the batteries are only lasting for less than one month. ...
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6v reading on a LiFePO4 18650

I have 2 charged LiFePO4, which should be between 2.5v and 3.6v both reading 6v. I think my meter is broken, but I just want to check: Is that possible?
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Is there a good way to test your schematic before buying the parts and building it?

I'm trying to design a BMS that can handle 12 cells, be powered either with a isolated dc-dc converter or the batteries themselves and uses active balancing, but I'm not sure if my design will work:
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318 views

Multi-cell LiFePO4 charger ICs

I've been looking for a monolithic battery charging / load sharing PMIC that is designed to work with up to 3 or 4 LiFePO4 cells. I had a search on Digikey and could only find one ($6!) chip, and that ...
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Increasing TPS63001 Under Voltage lockout from 1.8V to 2.5V for use with LiFePO4 cell

The Under Voltage Lockout threshold for this chip ranges from 1.5 V to 1.8 V. I want to use this with a LiFePO4 cell, whose minimum voltage is 2.5 V. With reference to the datasheet here, the VINA ...
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562 views

Low current LiFePO4 battery charging

I have a portable solar panel capable of delivering 21W at 5V. I would like to be able to charge my 12V LiFePO4 battery with this panel. My AC-powered charge controller is rated at 14.4V 4A which I ...
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3 votes
1 answer
462 views

Boost converter voltage drop when charging battery

I made a 4s battery pack made of 18650 LiFePO4 cells that I'm planning to use for a mobile computing hobby project. My plan for charging it is to use a salvaged power supply from a computer along ...
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Using SLA in place of LFP to test an LFP charging device

I'm testing a solar charge controller for LiFePO4 that uses absorption and float stages. By design, power-on initiates the absorption stage, and a timer terminates absorption and initiates the float ...
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2 votes
1 answer
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LiFePO4 cells - self-balancing in series or parallel?

I am building various banks / packs from individual prismatic LFP cells, nominal 3.2V each. New and pretty large, 60-400AH. I have a good power supply, charge each cell independently, Bulk stage CC ...
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3 votes
1 answer
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LiFePo4 cell risk of explosion during cool down

A 3 Ah LFP cell is charged to 100% at 25°C temperature. What happenes if I cool down the charged cell to -20 °C temperature? At -20 °C the cell can store only 2 Ah. Does it mean, the cell is ...
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