Questions tagged [lifepo4]

All related to lithium iron phosphate (or LFP) batteries

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2answers
65 views

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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50 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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0answers
45 views

Charging LiFePO4 with car alternator [migrated]

I currently have this setup in my van: Alternator -> Car Battery -> Voltage Sensitive Relay -> Leisure Battery (AGM) I'm thinking of changing out my AGM battery with a LiFePO4 battery instead,...
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1answer
41 views

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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1answer
34 views

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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1answer
116 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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42 views

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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2answers
62 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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40 views

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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22 views

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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1answer
51 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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60 views

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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1answer
336 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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40 views

LiFePo4 BMS recommendation

I am trying to design a backup power system around the LTC4015 battery charger. I am looking for a battery balancing circuit to balance the charges in the batteries. 4 Batteries used are with 3.2v ...
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1answer
527 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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2answers
244 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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31 views

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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3answers
729 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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1answer
78 views

Whats the minimum discharge for a 12v LiFePO4 Battery?

I just purchased 2 "SOK LiFePO4 12v batteries", one of them after opening the box came with a charge of 7.9v the other came 12.9v. Haven't been used at all. What's the minimum safe discharge ...
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0answers
25 views

LiFePO4 BMS purchase and wiring

I have 48 new CALB LiFePO4 batteries coming in. I want to build a 24V bank in a 8S6P configuration. I have enough room to build the 6 sets of 8P and connect the 6 sets together using the same bus ...
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37 views

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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1answer
68 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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52 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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1answer
426 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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18 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
101 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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1answer
183 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
299 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
57 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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24 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
91 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
99 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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48 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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50 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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1answer
142 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
220 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
72 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
303 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 ...
3
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1answer
371 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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0answers
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
819 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
64 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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0answers
140 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
348 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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2answers
3k 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 ...
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1answer
9k 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
348 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
468 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 ...