5 years ago I picked up a set of 8 solar powered lawn lights (the kind on a small post you stick in the ground). They're powered by one 14430 LiFePO4 each. They've been out there through Upstate NY winters, summers, 365 days a year. 6 of them them will still, given a fully sunny day, burn brightly for at least 8 hours in the summer, around 4 hours in the winter. 2 have significantly weakened. Call me a LiFePO4 phan.

I have been watching your videos for the last 6 months or so. I really am shocked at how much I have learnt you're a fantastic teacher.

I've actually been building a portable solar system with a 65x55cm 50W panel and a pelican case housing a controller, a 12Ah LiFePO4 12V battery and water proof connectors so it can withstand rain. I'm glad that I went with LiFePO4 instead of Li-ion

I think you didn't mention it, but LiFePO4 cells also allow discharge at freezing temperatures, which might be a huge bonus for outside installations.

LiFePO4 delivers a much higher number of charge-discharge cycles while also degrading the least of any lithium chemistry while they're held at full charge. They're the only lithium chemistry I'll consider for backup power because of this and their immunity from need for an explosion containment pie tin around installations.

Thank you for the great videos. This is my favorite channel and has increased my knowledge so I’m not just replacing and re soldering broken components but actually understanding what the components do and why they broke. Thank you so much for taking the time to do this.

I have an e-bike originally designed to run on 24v of SLA batteries, and it's been retrofitted with a stack of two LiFePO4 (i like to pronounce them 'life po four') which have 4 cells in series each, which for all intents and purposes makes a great drop-in replacement for a 12v lead acid battery.

When BigClive and TechMoan upload a video at the same time.... Today is gonna be a good day

one thing everyone in the comments seems to be missing is that, while LiFePO4 is less energy dense than other chemistries, it has greater *power* density. the electricity within can be discharged faster than other kinds of lithium ion batteries.

Rich rebuilds used a defective charger on the Tesla 18650 pack which made it go above 4.2 volts per cell. Then bang. It was a great example of how important good electronics are for managing a lithium ion pack.

I have an LiFePO4 starter battery in my FJR-1300 motorcycle, made by Shorai. It's been in there for 11 years now, and it starts the big 1300cc motor with no problem, even after 3-4 weeks of sitting. It's strange how light it is. It honestly feels like an empty plastic case. It's also about 20% smaller than the OEM AGM lead-acid, so it has foam padding sheets to make it fit. It was rather expensive, but it's probably saved me buying several lead-acid batteries, so it's probably not that much more money after all. The only issue is if it's cold (30F or so) then it takes a crank cycle for the battery to warm up internally and generate more current. I loved the MBC New Year's stream! I'm in Orlando, FL, so your midnight was my 7pm.

I would venture to say that Rich's battery accident had more to do with his battery pack not having a BMS and possible overcharging rather than the types of cells he had. But nevertheless great video once again!

I really enjoy your videos. I am a novice with electronics but have learnt a bit watching your videos. Also found your recent video on Alzheimers disease and caring for your mother very informative. Keep up your good work.

Appreciate the video. Keeping the technical withdrawal DT's away over this festive season :) Hope you had a great Christmas New Year. Love your video's Clive.

The very flat discharge curve makes them good for powering 3.3v boards.

Another point of having two MOSFETs, even if there wasn't the diode issue, is that it allows it to independently block charging vs discharging. When the battery is at its max voltage, you want to be able to prevent further _charging,_ but you don't want to prevent _discharging_ (which would just make the battery useless), and likewise when it's too low, you want to prevent further discharging but don't want to prevent somebody being able to charge it back up to make it useful again...

both of my work vans are entirely LifePo4 including the starter battery. Both have auxillary battery systems of 160AH and 800AH respectively and lifepo4 is the only way to go. I can draw hundreds of amps with little to no voltage drop all the way to 80% discharge.

Since you mentioned practicality of solar Christmas lights.. Yay Clive!! I have played with a standard sized garden "solar bank", panel about 95mmX80mm with lithium Ion, as well as many 50x50 with NiMh. The NiMh units all had 600 or 800mAh and "high" operating current of 35 to 50mA and drained the cell whether or not connected to a string of lights. My load was the magnet wired seed/fairy lights that required only about 15mA but unfortunately could not span even one cloudy summer day. One unit that is NLA had 2mA operating I. I imagine that's either about protection from overcharge or poor design. The lithium bank had 8mA drain, auto-dimming, a cheapo 1200mAh cell, and performed well even during the winter solstice near Toronto, Canada. Not super bright, but indeed super pretty. Partially thanks to you I have custom 12/24" pitch fairy lights... Beware of the wasteoids!!

Excellent video. I like to tinker with things myself and learning about batteries has helped me. I have two solar street lights. Two things I look for is: 1. How much does the solar panel actually output 2. What type of batteries are in it and are they actually rated for the capacity spec Well I found that the panel indeed outputs what the specs stated on the listing. But with the batteries this is where they go cheap to save money. Usually some used grade b cells that are 40-70% rated capacity. Which is why most people find that the solar light stays on for half or less than what stated. Most cases there is more room in the casing to upgrade the battery capacity.

THANK YOU for calling it a "CELL" and not battery. I wish I could make my own giant "CELL" 3.2 volts as big as a trash can.

After watching Rich's pyrotechnic display I think I'd go for these lithium iron phosphate cells for my DIY powerwall. I've got a lead-acid server room UPS and these batteries stack up nicely to 12V.

Thanks for the PO4 because I actually did want to know what that meant. :P

i love your voice - i know nothing of electronics, but i put your videos on just to be soothed

Thanks Clive. I learned something new today.

So, two things, one for Clive, one for the comments. Clive, one thing about the two FETs, you're right about the diode blocking, but that's only part of it. The 'OC' is charge FET, and the 'OD' is discharge. That's how the chip is able to cut current flow when it exceeds a threshold. As for the LiFePo4, they're 'better' for some applications. One nice characteristic is that you can usually charge them pretty aggressively and they'll take it. I've seen some that will allow you to charge as hard as you discharge. That's great for regenerative braking or hybrids. I wish they were more popular so the price would go down.

8:40 "feels like defusing a bomb" I was thinking just this morning that I'd love to see a Big Clive video about collapsing circuits and other Hollywood bomb tropes. With fireworks. And cats.

Love that Clive watches @richrebuilds too

I truly enjoy your videos! keep them coming bud...

I think it's touchingly patriotic of Glaswegian officials to have earnest meetings and a few experiments about the possibility that Glasgow in December might be the perfect place to utilise solar power. Us Sassenachs that have visited Glasgow in December probably wouldn't have wasted our time in the meetings - but love of country is a powerful and mostly admirable thing.

Nice to see the LiFe cells in things now. I had assumed it was a Li-io 26650 cell.

I'm presently using these grey Lifepo4 cells in a self built 10KwH battery bank charging off of 2Kw of solar panels fixed to the roof of my truck. I control the charge/discharge Voltage via my solar charger/inverter & balance them with BMS boards. They work very well: many times more efficient than lead acid & very long life compared to Lithium ion. With the right charge/discharge profile they may well last a lifetime with just a little power loss that can be offset by adding more batteries in the future.

A 4S LiFePo4 battery can also directly replace a 6 cell Lead Acid battery (Like a Car or MC battery).

I do like LiFePo4 cells- not a patch on modern Lipos in terms of capacity and current-output but they certainly have their place. Back in the day they were popular in parts of the r/c model hobby; we'd rip apart Dewalt battery packs to liberate the ( genuine ) A123 branded cells for our 1/8 scale monster trucks. I still have my old packs, and they still work fine- just heavier and chunkier than an equivalent Lipo pack so they fell out of favour after a while.

Very interesting. Thanks Clive.

You just need to come hang out in Southern California for the winter. We've got plenty of sun for your solar Xmass lights. It's just a pain to string them on palm trees ;) IIRC Andreas Spies did a bunch of tests with different battery types including the LiFePO4 cells about a year ago. -Jake

LFP batteries from Battle Born/Dragonfly and a few imports are being used in RVs. The BB10012 is a 100Ah 12V pack in a car battery form factor that replaces the deep cycle coach/house batteries. LFP in a 4-S configuration yields a more compatible (than Li-Ion/LiPo) 12.8V nominal voltage and a range of 14.4-10V (BMS limited) which works well enough with lead acid charging systems. More stable and safer than Li-Ion with a 10 year warranty. LFPs are fussy about temperature and go off-line below freezing (25 degF for charge circuit, lower for discharge) so some owners move them inside the coach since there's no hydrogen or corrosive gasses venting out. The cost is high initially but lower than LA over their lifespan. Charging efficiency, minimal self-discharge, usable capacity, and light weight crush lead acid performance.

Hey BigClive, Pro Tip that I use at my Aerospace job; Score the heatshrink and then hit it with a heat gun and let it split itself.. :P

I use them in the AA form, in pairs with dummy batteries, in high power flashgun units (Sony HVL-F60M, Godox TT685s) . The refresh rate for a 1/1 discharge is about 1", which is much less time than when using NI-MH (or seldom Alkaline). The downsides are the relative low energy density, the (sorta) special charger needed and the inability of the flashguns to cope with overheating... the last I suppose is probably due to the flash designers expecting a longer recycle time from 'common' batteries :-) I was very pleased to find them, albeit a bit pricier, in a big french retailer currently operating in Greece, in the spares section of solar garden lights!

"That's just the peril of solar panels, they don't put out much power when you need it the most." is a very accurate summary of my experience with them too. Although I guess maybe if you're in a hot climate and plan to run your air conditioning on a battery buffer + solar panel its output trends will meet your demands better. Technically solar panels get less efficient with heat, but when allowing for some ventilation around the panels the extra sunlight to convert into electricity is almost guaranteed to compensate generously for that "efficiency problem".

For EV's Tesla is not using LiFePO4 chemistry in its battery cells, but NCA. For model S, the cell type is the 18650 (like the purple one you hold). For model 3, it is also NCA chemistry (LiNiCoAlO2), but in the 2170 (21700) cell model.

The two mosfets used with cell protection chips like that actually operate independently to block in one direction for over-charge and the other direction for over-discharge.

This chemistry is used in cheap solar street lights because the voltage matches that of white leds , often they feed the leds direct with no other circuitry , the flat voltage with discharging keeps light output fairly constant.

watched again in 2021 - wondered if I had missed the further investigation of the pv panel in summertime. I am addicted.

"I'll get down closer here so you can watch me have a terrible accident." 😂

Another advantage is the voltage. 90% of the capacity they stay between 3.2 and 3.4V tange... so you can power 3.3V chips (Arduino projects..) directly. At the same time it’s a disadvantage as it is impossible to guess their charge level by voltage (works somewhat for lunch-ion) as the voltage sits so close to 3.3V between 30% and 95% of capacity. Military likes to use such batteries due to their tolerance in case of improper handling. Some people here say they are expensive. Can’t confirm that. I’d rather say they are cheap. Many types are tested for 5000x and more cycles, taking this into account they are easily 10x cheaper in kW/h

I like the solar lights that come with 18650 cells. The cells they ship with aren't great, but it makes it easy to replace it with one of more capacity. I have some with NiMH cells, and they can't last the night even in summertime. Some have pouch cells, and pulling them apart enough to get to the solder pads on the circuit board is usually the point where I don't consider it worth doing. I don't have spare working pouch cells, I have plenty of 18650's. Lithium-iron should eliminate the need to upgrade at all, provided there's enough capacity from the factory.

Damn bigclive, how do you keep reading my mind? First a few days ago I was thinking of asking how you test battery packs and you post a video, and now 5 minutes ago I was literally just looking at an ad that has a whole bunch of these batteries, but much larger. GET OUT OF MY MIND!

I got a 20Ah 36v LIFEPO4 batttery in my ebike, using it with a GNG electric motor kit. I put it together myself, mid engine with the belt drive, great in hills :) The LIFEPO4 batteries shall be good and i cannot complain yet, i has had it for like 3 years. I put a saddle pack over it so it looks nice under it on the rack. Tesla use the 18650 batteries i has read somewhere.

That other video reminded me of a fire at the local fireworks factory. I was having flashbacks to the great war...and i wasn't even alive at that time. Impressive, very impressive.

The expert Clive quickly make the device safe before continuing with the disassembly...

I started buying only LiFePo, because in Arizona and West Texas, the denser/standard lithium battery packs for jump starting a car or charging a phone will expand. Never had one explode, but it's not worth the risk. I even used a permanent car battery size for a few years, and it had no trouble in freezing 🥶 or burning 🥵 temps.

Went and looked at the video. That was quite the spark show.

Great video , thanks, it will be interesting to see how this technology develops. It seems to have a lot of potential.

Strange how words bring back memories of our youth, for example you said slit, and the old tongue twister "I slit a sheet; a sheet I slit; and on the slitted sheet I sit!" rushes through my mind. Don't know if that one made it to your side of the pond or not.

A few years ago people would disassemble DeWalt battery packs to get their hands on the A123 cells, which AFAIK use this technology. Major advantage: you can charge and discharge them at ridiculous rates.

This streetlight will work fine closer to equator. Because of the lack of distinct winter season with many dark hours. Else you may add low voltage from mains via a "winterswitch".

YES at last a video about Lifepo ! Do you know the LITO batteries ? Lithium Titanate. It's a very cool battery and i think it would be fun to test and open. And you could do a series on batteries, because there are so many different kind, maybe just the interesting ones.

Thank you for sharing this information.

So in the first video you measured the battery is that how they sell them by size and capacity. Last night I did a quick search on lifepo4 on amazon they seemed 18850 was popular. It was late I didn't watch your quality video til this morning. Cheers from coldass, kansas.

I use 3x26650 LiFePO4 in a power pack for my instrument effects pedals. The pedals handle the 10.8v immediately after charging fine and at the pack stays at around 9.0-9.9v for a long time. Much safer for charging/handling, and less stressful on the 9v pedals' circuitry compared to the alternative higher voltage Li-ion alternatives.

lifepo is genius for some applications .. The 26650 from a123 system is the best vape cell on the market 140amp burst

Ya know it's gonna be good when Clive breaks out the explosion containment pie dish

4 of these make great replacement for 12 batteries in kids toys and UPS. UPS batteries often kill them selves when used. These cost a fortune but well worth it you have multiple power failures and let them run to zero.

FOR THE RECORD: I AM VERY INTERESTED IN 18650 AND LARGER TYPE BATTERIES. THX FOR THE GOOD CONTENT.

Hello Clive, you should have a look at Lithium titanate aka LTO batteries. They are even more long lasting and more inert.

we use LiFePo4 cells as a 12v starter battery in aircraft. partly for low temp performance, but mostly because they are bulletproof. we shot a nail through one and it just sat there and took it. still it has to be in an aluminium bunker because boeing cocked it up by using LiPo's without adequate protection and without armour in the dreamliner.

@bigclivedotcom Clive, stop it! Enough! I'm trying to get work done but you keep posting excellent videos that I have to watch. You're killing my productivity. ... Oh, to hell with it. Keep 'em coming.

A123 systems made a nice 26650 cell, 2500mah and could do 60c discharge which is great for RC cars and even planes where you don't need long run times, they allowed extremely fast charge too for the time, I used them for years and still have the packs I made and are still working perfectly. Lipo cells are much preferred for power density though but they don't last very many cycles in comparison.

I have those same purple battery's for my vape, i have had them for two years and no noticeable loss

That is some quality stuff. Great lessons learned. So is this circuit diagram a smaller version of BMS ? I mean, can I use many of these small circuits in a battery pack instead of a BMS ? I am a Ralfy subscriber for years and I learned about you through him :) keep up bros

I've been playing around with some solar charging of batteries, mostly using lead/acid batteries that I already have. One of the reasons is faking more daylight in my greenhouse (which is why I started making my own version of your RGB LED controller!) Another thing is a solar light for my front gate, walkway and front porch.

It is amazing how much energy these modern batteries can hold, I assembled a 3S-3P 18650 pack this morning and just held it in my hands marvelling at the fact it has about the same, if not more, energy in it than one of my 12v SLA batteries, but also the fact that if the SHTF and the things went boom, they'd be a lot more lethal than said SLAs... :S

thankyou Clive.

Tesla uses NCA Li-Ion batteries, not LiFePO4. They aren't used much for plug in EVs as the specific energy density is lower resulting is massive packs.

I swear I learn something new every damn day! Too bad I forget 10 things every half hour thanks to alcohol

I had a funny Big Clive moment today (Jan 4) I wanted to share... The blower motor resistor pack died on my car this morning, and I was stuck with only the Hurricane setting for my heater. To add insult to injury, the servo motor that opens the various air doors has been bad for a while, leaving me with only the dash vents, but that wasn't an issue until I was stuck with the Hurricane-or-Off option. Down to the auto parts box store, plug the new resistor pack into the wiring harness and leave it dangling until I get home and install it properly (I've done it with the old coiled resistor type, so I figured this would be OK)... I had all fan speeds for about 45 seconds, when the new resistor pack failed. I look down at it and realized there is a thermal disconnect, a copper-ish tab soldered to another terminal so it fails open when overheated. My Big Clive Moment? I look down, and say (with a very poor accent) "Not to worry, I'll just reflow the sahl-der when I get home." And I did just that, with my 1970s unfused Weller iron. And my fan works as it should, now that I installed the resistor pack deep within the bowels of the modern car dashboard where it can be cooled by the airflow as it was designed. :-)

hi a tp5000 module can be used to charge a lifepo4 cell 2A switching charger can also be used for lipo/li-ion

You might like to get a ceramic knife or any other non conductive blade material you like. Sometimes you can get Soviet scalpels on ebay which are equipped with sapphire blades.

Interesting. Thank you.

Whenever handling Efest cell, you should have the explosion containment pie dish ready! Even looking at it may be dangerous...

given how solar isn't going to keep ya warm in the winter anyway, can you look into thermo-electric generators? You'll get to talk about Seebeck effect & how your stove can keep the batteries charged

Great info!

You didn't cover the operating temperature.. think it works at a lower temp then most batteries. But can't remember. 🤔

The problem with solar is it doesn't work in the dark. However if you use thin film solar panels you can get probably close to full power in un-idealistic situations. ie. bad angle to the sun, overcast, partial shading etc. Problem is they cost a little more and are larger in size, they have a shorter lifespan and are less friendly to the environment but they should work in Isle of Man or any other overcast area. After that obviously you just size for the application depending on how many daylight hours you have.

Clive, I was wondering if you could get hold of the advent calendar helicopter that Stuart Ashen and Nerdcubed(Dan) Built over Christmas as it's not working? It would be interesting if you could take a look at it =)

Wow thx! So charge Li-Ion baterie about 55 % for storage? I have several cellphones Im not using and I always charge them to about 95 % for storage. So not anymore I guess;)

Dude... we need to get you some sort of ceramic, or space age plastic blade to cut these things open with! My heart can't take much more of this!!

Teslas don't use LiFePO4 cells. They use an Aluminum-Manganese-Cobalt chemistry that is even different from a typical laptop battery. I believe LiFePO4 cells are used in Priuses. They are also quite popular in e-bikes. LiFePO4 cells main disadvantage is about half the energy density by volume. Properly cared for with thermal management and cell balancing during charging, traditional Li-ion batteries are safe. Rich's buddy was charging the battery with a standard Lead-acid charger.

Im using double lifepo4 cells in series for devices that have a 5v linear regulator, needs to drop much less when using those.

One of your videos on USB power packs showed you shorting the center two wires in the cable going to the cell phone made the phone negotiate a higher charge rate. Could I make a male & female USB plug & receptacle with a short going toward the phone that would tell the phone to try to get a higher charge rate from chargers?

Besides the unwillingness to burst into flames, Their higher number of charge cycles is only on paper better than Li-ion. If you charge a Li-ion cell with a voltage range comparable to LiFePo4, it gets the same number of cycles, so energy density, and cycle life is very similar in all but the most demanding applications, Cost Wise LiFePo4 have an advantage.

Thank you.

You are amazing, where do you find the time for all this fun? Glad you do though....

I also think that electric cars, especially Teslas, are using Lithium-Polymer based cells for their battery packs, because that's the only way how they can get something like 100kWh into one car. Maybe car manufacturers like VW, which used to build only internal combustion engines, playing it safe on electric vehicles until it's almost too late, and now offer electric cars with ridiculously low ranges per battery charge, use LiFePO4-batteries for their cars.

Also a Rich Rebuilds fan.

In the words of my favourite comedian Billy Connolly! “Hey guys I found a even rainier place” good old Scotland

Hi Clive, What's the temperature stability like? Li-Ion are terrible when they get cold, is the LiFePO any better (with this being an external device)? BTW, is that 18650 you're waving about really 3100mAh? I tend to look at anything over 2600mAh with suspicion unless it's come direct from a manufacturer.

These things last ... forever. I've put a LiFePO4 pack of 48Volts (52 actually) with an external BMS on my electric scooter... back in 2007. Still charges today like a champ ! Somebody show me a normal Li-Ion battery of a phone that lasts reliably more than 5 years...

using em for my boat - got a few vids on the big ones

Iirc the cutoff conditions should be settable for some protection ics via external resistors