Questions tagged [lifepo4]

All related to lithium iron phosphate (or LFP) batteries

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54 views

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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32 views

Can we estimate the remaining lifespan of a Lithium (Iron Phosphate) battery by its energy efficiency?

All manufacturers that publish the energy efficiency of their lithium (iron phosphate) battery claims that it's 99%. https://www.sciencedirect.com/ claims that: Lithium Battery - an overview | ...
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137 views

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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13 views

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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1answer
60 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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16 views

Will running a tab between the positive terminals interfere with a 4S BMS?

I have 3 12V, 64AH battery packs with a 50A MPPT solar charge controller and 3 50A balancing boards. The rest is theory because I'm still waiting for components to arrive but... Normally, the ...
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1answer
69 views

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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1answer
48 views

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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1answer
22 views

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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20 views

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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1answer
50 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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1answer
68 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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45 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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45 views

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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130 views

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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1answer
112 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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1answer
59 views

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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1answer
150 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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1answer
241 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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20 views

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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1answer
550 views

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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1answer
58 views

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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94 views

How can I balance 2 separate LiFePo4 batteries?

On my boat I've got devices that run on 24V and others that run on 12V. Seeing as how the alternator, wind generator and solar panels are all generating 24V, I guess it's fair to say that this is ...
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2answers
195 views

charging 24v LiFePO4 with DC power supply intended for LED strip lights

I want to charge my 200Ah, 8 cell GBS LiFePO4 using my Honda 2000 watt generator. (I live on a boat). I have a BMS, active monitoring and all that. I just want to make sure the below power supply is ...
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1answer
23 views

VDC booster effect on LiFePo battery run time?

Looking for info to devise a solution for a mobile video rig. I work in the film industry and it would be VERY beneficial to run my video cart from battery power, as opposed to always having to plug ...
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1answer
27 views

changing 6v lead blocks by 3,2v LiFePo4 cells

I need to replace a lead battery system with a LiFePO4 element system. the existing system is 48V 240Amp and consists of 8 Trojan T145 6V Batteries with 240Amp in the C20, the idea is to replace this ...
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1answer
2k views

LiFePo4 Battery Charging for Maximum Cycle Life with Solar Panels

The problem is charging lithium iron batteries for "maximum Cycles" with a solar charge controller wile using loads? I have a PowerSonic 45 amp hour LiFePo4 battery for my Caravan house battery. I ...
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1answer
6k views

What is the maximum static voltage of LiFePo4 batteries?

I've been working with a pack of batteries from a DIY electric vehicle. The batteries in the pack are LiFePo4 chemistry and were chosen for safety (greater resistance to thermal run-away), flat ...
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0answers
334 views

Help needed with over discharge circuit on LifePo4 12V car battery replacement

I'm putting together a LifePo4 battery pack with the intention of replacing the 12V lead acid battery in my 4WD. So far, what I've got is the following. 4 x 10 Ah LifePo4 batteries (38120 Headway) in ...
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1answer
319 views

Load sharing between 3.3V regulator and LiFePo4 battery

I am trying to design a supply for a relatively low power (<100mA) device with a LifePo4 (14500 format) battery and a USB input. Everything is running at 3.3V, and therefore I would like to avoid ...
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1answer
115 views

How to drain LiFePO4 battery?

I am using a tracer battery BP2603(12V,3.5A) to turn on my camera. The camera needs 12V and it consumes max 3A. Maximum voltage the camera can accept is 13.5V. But I've found that when the battery is ...
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62 views

Dismantling 110v DC LiFePo4 Battery Pack

I've inherited a 110v battery pack that used to be used for a solar array made of 34 each 100 amp hour LiFePo4 3.2v for a nominal voltage of 108.8v all together. I'm getting about 90v total from the ...
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239 views

Load Sharing/Isolation Circuit with ADP5063

I'm designing the battery power/charging circuit for the Reform DIY laptop which uses a (big) LiFePo4 cell. For the charger IC I've now settled on ADP5063 as it seems simple and can charge with 1.5A ...
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1answer
113 views

LiFePO4 battery in sealed container

I'm making a project/rc boat to map the bottom of a lake and therefore I need a relatively big battery (say 12V 10Ah) for the operation and electronics of the small boat (propeller motor + telecoms + ...
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1answer
705 views

LiFePO4 BMS low charge rate disconnect

As my commercially purchased, 12V 4s3p LiFePO4 battery pack approaches full charge (3.65V per cell, 14.6V for the pack), the internal BMS disconnects the battery at a charge rate of 0.02C. What ...
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0answers
668 views

LiFePO4 solar charging problems (amateur question)

My application is primarily portable ham radio operation. I chose a self-balancing, 4.5 Ah, 12.8V, 4s3p LiFePO4 battery pack, a 28W panel and an MPPT solar charge controller with extremely limited ...
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1answer
387 views

Raspberry PI 3 - LiFePO4 power supply

I'm working on a mobile computer unit with a Raspberry PI 3 motherboard. The computer unit needs to run on battery so i can bring it with me anywhere. I'm going to solder both the battery pack and ...
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2answers
108 views

Determining Faulty Lithium Batteries in Battery Pack

I am having some difficulties with a 72V 200aH LiFePo4 battery pack that I am using in conjunction with an EMUS BMS. The BMS indicated some of the batteries were not charging properly, I corresponded ...
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2answers
78 views

LFP Cells - Case to internal thermal resistance

Semiconductors often specify thermal resistance from case to the junction, but LFP battery cells do not seem to specify this. Instead, they refer only to a generic 'maximum operating temperature'. ...
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1answer
986 views

Calculate LifePo4 charging amps

How do I work out the optimum charging amps for a life 2p4s battery? I have 8 x 66ah sinopoly batteries. http://www.sinopolybattery.com/userfiles/files/SP-LFP66AHA.pdf Charge Specs * Standard ...
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5answers
3k views

LiFePO4 in cold: charging

I have used LiFePO4 batteries, only in discharge mode, by down to -15 deg C (charging was done 'back to the warmth'), and they worked fine. But from what I read it looks like Li-* batteries do not ...
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2answers
651 views

Lifepo4 current limiter with supercapacitor in parallell

I am making a LiFePo4/supercapacitor-hybrid. Spike current draw can reach 300A for a few seconds. The LiFePo4 batteries I am using is rated for 100A max discharge rate. In order to make sure the ...
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1answer
288 views

BQ24650 or BQ24620 for LiFePO battery charger | Solar powered + Grid powered

I am designing a Battery Charge controller for our 12V LiFePo battery. Power input is: a. Solar Panel 80W @ 12V (Vopencircuit=21.33V, Vmaxpower=17.78V) OR b. 18VDC grid power. Either one power ...
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0answers
218 views

Switching in parallel high-capacity LiFePo4 battery packs during discharge cycle

I have two, possibly three 48V-nominal 50Ah Lithium Iron Phosphate battery packs used for E-bikes (16S cells, 2.5kWh capacity each). The packs have BMS circuitry which limits discharge to 50A (...
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1answer
572 views

Can I float charge LiFePo4?

Is it ok to take the output of a solar panel (no MPPT, but de-rated) and pipe it into a switching regulator at say, 3.45v? The output of the regulator would go into my micro, an STM32F103 and a ...
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1answer
504 views

LiFePO4 16-cell stack precision dc volt measurement LTC2400 MUX

I would like to build a highly precise volt meter (5 digits; e.g. +/- 1mV) to measure each cell voltage in a LiFePO4 battery stack of 16 cells (<60V). I am content with measuring the cell between 3 ...
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3answers
92 views

Massive Parallel Lithium Lead Wire Connection Point

I was wondering where the connection point should be on a "massive" parallel block of lithium batteries. Let's say there is a pack of 100 LiFePo4 18650 batteries all spot welded together with nickel ...
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1answer
603 views

Charging LiFePO4 at low voltage - how do you know when to stop?

I've read that the most typical approach to charging, is to provide as much current as you'd like (lower current causing less loss of capacity over time), and to stop when the cell reaches 3.6V. The ...
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1answer
162 views

Boosting Peak Draw spec on LiFePO4 using Capacitors

Attempt to replace a 4.5Ah 12V Pb battery with LiFePO4 for a Profoto Acute B flash generator I have a detailed writeup here... Previously I had used a Tenergy drop in Li replacement which worked for ...
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1answer
321 views

Using switching to control load sharing of DC?

I'm not sure of the right terminology for what I am trying to ask about. Feel free to suggest a better question title. Lets say that I have a fully charged LiFePO4 battery, which I do not want to ...