LiFePO4 Batteries - Vehicle/Camping/Homes

[ol' boy]

Thought i'd start a thread, as some of us are interested in this new battery technology for a few applications.
Mainly Camping or Vehicle Deep Cycle etc.

Positives:
Longevity (cycles) if correctly looked after (DoD)
High current In and Out
Weight

Negatives:
Price
Longevity is not proven (in a real world application)
If a cell fails, the battery is a throw away

spook seems to be well versed with these batteries. Perhaps he can add some more info.
From my research, the batteries are too expensive and untested to warrant using just yet.
I have read some stories of LifePO4 batteries dieing in 11 months.

When considering a Deep Cycle 120Ah Battery;
AGM:
1000 cycles at 50%, $675

LifePO4:
1740 cycles at 100% or 8000 cycles to 30%, $1790

Does anyone know if there are concerns of using a LifePO4 battery in a vehicle and leaving the lights on all night?
Can it damage individual cells in the battery? Can it render the Battery a throw away?

How do they preform with only 20% SoC left? A lead acid will be sagging at these levels of discharge, probably can not start a vehicle.
Do the LifePO4 still crank at near capacity when at such a state of discharge?

Issues with LifePO4 cell balancing when charging?

Ambient temperature effects on LifePO4 Battery output?
Percentage of Cell Output at Zero Degrees? Or minus 10 degrees C?
(Ie: 10 second cranking loads)
LifePO4 and High Temp ageing of Battery? (Temps greater than 40 degrees C)

[JasonC]

even though I'm not across all of the tech specs, I can see they will replace lead acid and AGM where weight is an issue
they are so much lighter than the other types of batteries
hopefully the price will start dropping soon

ps. 120Ah AGM batteries can be had for about $300 these days

[ol' boy]

ps. 120Ah AGM batteries can be had for about $300 these days

I know, but not at the specs of the above link
But you are correct, i can buy 100Ah AGM batteries from Ford for $100ea
So its hard to justify the price of a LifePO4 Battery in that economy.

[shred]

I just received a couple of LiFePO4 cells from China. Planning to use them with solar panels salvaged from old garden lights and ESP8266 boards to report in if any of the gates near the house have been left open. The 3.3v terminal voltage is perfect for running the ESP8266 WiFi modules and unlike other lithium cells, these seem fairly tolerant of over charging... well, they don't catch fire anyway.

Silicon Chip magazine had a write-up on them in June 2013, although the availability has improved a bit since then. I think I paid about $12 inc postage for 4 x AA size cell from dx.com. Each has about 700mAh capacity, but at 3.3v. It sounds like a lot of people use these with a "short circuit cell" to replace 2 x regular AA cell with a single LiFePO4. The slightly higher terminal voltage and low internal resistance of the LiFePO4s gives a bit of a boost to torches, camera flashes and other things that draw a fair bit of current. Just need to be very careful that you don't fry the gear by installing all LiFePO4 cells!

[mtv]

I've been using for portable comms.

Very happy with the performance.

Balanced charging monitors each individual cell.

[spook]

There are many benefits in using lifepo4 for energy storage, the most important are, usable capacity, no gases, safe unlike some other lithium chemistries. Sustainable voltages through the discharge cycle are another bonus, they won't explode, are fully recyclable and you will get about 50% of what you paid back when recycling them. You can place cells anywhere as they are light and sit them in any way, upside down flat on their side or side by side in a line. You can put any size current into them and draw what ever you want, as long as you have big enough connections. The biggest bonus is how much energy you get out of them compared to lead acid. The best thing is all your usable energy is within a short voltage range so you can actually use them and yet stop them cycling, which extends the life even more. That's what the military do, they have a set of parameters and a discharge override switch for emergencies

As for negatives, they only occur when they are badly handled and charged. If you are prepared to pay retail for lifepo4 cells, then they are expensive and no matter what they all claim, if they are plastic packed, you may have inferior cells. The claims of some cells being better than others, is true, the best cells to use are military or industrial grade cells, which are designed for heavy constant use in rough conditions. So are normally encased in metal containers unlike retail, which come in plastic and if treated well will do the job.

Depending on how you make your pack up, will depend on whether you have energy if a cell fails. Retailers, sell packs in 100ah and up sizes, so if you are running a 12v nominal system, you would have a 12v cell pack. Which is 4x3.2v cells in series and enclosed so you can't get to them. Lifepo4 always comes in 3.2v cells, it's the capacity that is different. In Ev's, they use small cell sizes as does industry and the military, which are accessible by the user and if one cell collapses, it only reduces your capacity, not your voltage as with large cell packs.

As for longevity, know people who have been using lifepo4 for more than 5 years and their cell packs still provide 100% of their capacity. Longevity depends on your charge/discharge regimes. You can get decades out of them if your charge and discharge parameters are right. I have an electric mountain bike which uses lifepo4 and had that for 4 years, use it nearly ever day and it's capacity is still 100%. Also have a lifepo4 starter pack for the last 3 years and that's still in perfect condition with full capacity. Also have a 700ah and 480ah pack, plus AAA lifepo4 in my camera's. As stated earlier, you hare to be careful with AAA lifepo4 because they have a higher initial voltage compared to other types and give huge amounts of energy. You can get AAA and AA lifepo4 and dummy cells to compensate for the high voltages.

It's important to know a bit about this technology before you start using it, otherwise you will probably end up with a very short lifespan from them. Especially if you use standard chargers and their regimes, or what retailers tell you will work.

I got into this technology because a friend was using Li in his model planes and bragging about how much longer they lasted compared to nic batteries. Did some reading on them and found a number of lithium chemistries around and lifepo4 seemed to be the best for home or mobile energy storage.

Bought a set of second hand industrial cells to play round with and spent the next couple of years learning and experimenting with them, until felt I knew enough to set up a system for my bus then house. That meant getting a dedicated BMS which I got from an EV enthusiast in Canada as none on the market were satisfactory for lifepo4. He re-programmed one he made for his E car and E bike, so it would work on his newly installed solar system, made a few and had a couple spare. Finally decide what worked best was a dedicated charge controller for lifepo4 and as there are none on the market anywhere, had them built to my specifications and they are great, connect and forget. With a couple of proviso's.

Have done a lot of experimenting, testing and using them in all types of weather and read up on the chemistries so understand a bit. So happy to try and answer anyones questions if I can, but not technical ones, just hands on.

[ol' boy]

I have read that LFP's don't exploded under a short circuit.
Just like in this video

[ol' boy]

As for longevity, know people who have been using lifepo4 for more than 5 years and their cell packs still provide 100% of their capacity.

Wow, thats amazing.
So they still provide 100% of their rated Voltage and Rated Ah current, for the same time duration under load as when new?


The construction of these units is more like a Supercapacitor than a Battery at times.




This video might be interesting to some:


Another with a LifePo4 Battery punctured with a 3 inch nail (don't get any idea weirdo)

[spook]

Wow, thats amazing.
So they still provide 100% of their rated Voltage and Rated Ah current, for the same time duration under load as when new?

Treated and used properly, lifepo4 capacity lose is very small compared to lead acid. Lifepo4 is not the best lithium for capacity and there are different densities and packaging which determine capacity. As 90% of energy is stored within the 12-14v range you will notice very little lose and always have full voltages, unlike lead acid.

Other lithium chemistries are better for some installations and use, for home and mobile storage, lifepo4 seems to be the best all round, for safety and longevity. When choosing for home or mobile energy storage, prismatic cells seem to be the best and safest to use, they don't seem to bulge or buckle as much as envelope cells and handle temperature changes much better.

The biggest problem with this technology, is your mind set. Everyone I've come across including me, that has them or researched them have a huge problem in changing their energy thinking from lead acid regimes to lithium regimes. It's really hard, because our minds are programed into lead acid mentality and lithium is not lead acid and nothing like it in any way, other than it stores electrical energy.

[ol' boy]

Yes, i see the inclusion of Iron in LifePo construction really gives a huge leap in longevity, but at the expense of charge times and discharge times.
Sure is an interesting field.
Reminds me of Solar Panels and the rapid development in output once the items become more mainstream.

So what is the difference with LifePo4 regimes compared to Lead Acid?
Seem they both benefit from shallow states of discharge when it comes to life expectancies.

I just see LifePo4 as a much faster storage system, in terms of inrush current as well as output current.
Which could be advantageous when you only have a short window of power generation (Car Deceleration, Car Alternator for short Periods, Short Solar Generation Window)

The great benefit with LifePo4 over LA, seems their ability to be taken well beyond 50% SoC (DoD) without harming the cells, as you do with LA.
AGM 50% DoD
LipePo4 80% DoD
So you get an extra 30% DoD without sacrificing the Battery Longevity by too much with LifePo4.
But not only that, Output remains high with the LifePo, even with high loads, as the Battery falls below 50% DoD.
As well as a much better rate of self discharge.

EDIT: This is a good read


I see what you mean spook, there is so much more to it.
These LifePo4 Batteries have really turned the eBike industry on its head.

Example:

I have electric scooter with pack of 3 -12 volt AGM's 36 volt, I am going to get the LifePo4 because they are much lighter and charge much much faster . Cost here for 12 volt 14AH is 89 euros, so 3 x 89= approx 270 euros. Also the ones I am buying can get 90 percent charge in about an hour compared to 5 hours on the AGM's. Nice for when touring the countryside and there are thousands of charging stations now in the Netherlands.

Some kids with 8000Watt and 10,000Watt pushbikes (eBike) doing over 100k's!
Obviously weight and power output of the LifePo4 has made high speeds and good range possible for the eBike.
5 years ago, it was probably impossible to achieve these results.



Wonder when the Road Laws will catch up with Technology in this arena

[gordon_s1942]

I remember a few years ago that there was a 'dual cell' Battery on the market primarily aimed then at the Off Road market.
One 'section' was a standard Lead Acid and the other was a Sealed Lead Acid or similar I think.
According to the advertising of the day, the standard Lead Acid portion handled the heavy short term current load required to crank over an engine and the SLA portion powered all the lights and other low power uses in a vehicle which it was more suited to handle.
This division of course meant you could leave the lights and other low current users on without that drain affecting the Lead Acid section so it always had power to turn the engine over when required.
Other than seeing it at a Camping Show in Sydney a few years ago, it seems to have 'disappeared' which made me wonder how good the makers claims were.

[hoe]

depending on state you are in, the limit is 200 or 250w, so they are totally illegal......

also you need a motorcycle licence if vehicle is capable of more than 50kmh...

[ol' boy]

Looks like a job for.... A Mode and B Mode

[gordon_s1942]

Apparently there is something about having these fitted with pedals means they are classed as 'Motor Assisted', NOT motor driven !!
I was told some of them are too heavy to pedal, even down hill but when your riding them, you make the pretense of Pedaling away madly so as to appear your doing the work, not the motor.

[mtv]

Please keep the subject on topic.

LiFePO4 Batteries - Vehicle/Camping/Homes

[ol' boy]

As the storage and configuration of LifePo4 Batteries seems endless.
A search on the net will show some companies that have turned a shipping container into one giant battery!
Made for remote deployment in the Mining Industry and Other situations where Mw's of power are needed for temporary situations!

China have built a Mega LifePo4 Battery that takes up a football field, it also has some Wind Turbines and Solar panels to keep it topped up.

This is an interesting read, the first boat to circumnavigate the world using only solar power and storage batteries, happened 5 years ago!


For some of us here, possibly looking at LifePo4 for 4WD or Camping situations, we have one main concern..... Charging!

1. Charging from Vehicle Alternator (DC-DC Charger built for LifePo4)
2. Charging from Solar Panels (Need a good programable Charger)
3. 240V Charging once home (maintaining)

DC-DC charger for LifePo4 Batteries have only just come out here, RedArc confess to having one.


Trouble is, it only does LifePo4 Batteries and it costs $780 AUD

[lsemmens]

Sorry still off topic: but as an adjunct to Hoe's post about power limits.

[spook]

That redarc controller is useless for lifepo4, it's designed for use with an alternator using low voltages. If you use one if these your pack will be lucky to last 2-5 years. You should never take lifepo4 over 14v and never below 12v, the best charge and discharge parameters are upper 14v, lower12v and recharge 13.6v. For solar you need an mppt controller that can handle big voltages and amps and protects your pack, not stresses it as this item would. The price is also horrendous for 25amps low voltage, it's much simpler to make a lifepo4 charger than it is a lead acid. There are no float, equalisation or temp controls, it's just bulk charge until the pack reaches 14v.

I had to have solar charge controllers built and the 40amp cost close over $400 each delivered from china and when my 60amps arrive expect them to cost just over $500. If I bought 10 or more, the price would drop but these were specially made for me. Got my panels and cells as a bulk buy with some friends, but they weren't interested in the controllers and built their own controls using a simple BMS, standard charge controllers, voltage alarms and relay switches. They work really well but you need a bit more technical knowledge than me, so worked out what I thought was needed and searched for a manufacturer who would make then for me.

On my bus had a 60amp dc to dc charger, which was used on my AGM's and as there are no satisfactory lifepo4 charge controllers, may set up a voltage alarm and relay switch to use it on the lifepo4. I'm also looking at getting made up a dc to dc and mains charger for lifepo4 and have asked the manufacture to give me a quote for both. The thing is, lifepo4 charge so fast, doubt I'll need to use the alternator unless camped for a week in a cave.

[Guiseppe]

Depending on how you make your pack up, will depend on whether you have energy if a cell fails. Retailers, sell packs in 100ah and up sizes, so if you are running a 12v nominal system, you would have a 12v cell pack. Which is 4x3.2v cells in series and enclosed so you can't get to them. Lifepo4 always comes in 3.2v cells, it's the capacity that is different. In Ev's, they use small cell sizes as does industry and the military, which are accessible by the user and if one cell collapses, it only reduces your capacity, not your voltage as with large cell packs.

Please explain. I would have thought that losing 3.2V must reduce your voltage.

Bought a set of second hand industrial cells to play round with and spent the next couple of years learning and experimenting with them, until felt I knew enough to set up a system for my bus then house. That meant getting a dedicated BMS which I got from an EV enthusiast in Canada as none on the market were satisfactory for lifepo4. He re-programmed one he made for his E car and E bike, so it would work on his newly installed solar system, made a few and had a couple spare. Finally decide what worked best was a dedicated charge controller for lifepo4 and as there are none on the market anywhere, had them built to my specifications and they are great, connect and forget. With a couple of proviso's.

Have done a lot of experimenting, testing and using them in all types of weather and read up on the chemistries so understand a bit. So happy to try and answer anyones questions if I can, but not technical ones, just hands on.

Some more details on the solar chargers please.

[spook]

Please explain. I would have thought that losing 3.2V must reduce your voltage.

Some more details on the solar chargers please.

Cell packs are made up in series and parallel connections, put 4 x 50amp x 3.2v in series and you get 50amps at 12.8v. Put 4x50amp 3.2v in parallel and you get 3.2v at 200amps. Using 4x100ah cells to get a 100amps 12.8v pack, means is you lose a cell, you lose your 12v energy. But if you use 8x50amp cells in series parallel and one cell goes down, you can still have 12v at 50amps. The cost of replacing a cell is much cheaper at lower capacities and you can carry spare cells with you if traveling. I will carry my 120amp pack in the bus as a back up for the main house pack and for using energy away from the bus. It is light and small compared to lead acid and an excellent portable power supply.

My post above gives the relevant details of the charge controllers.