What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

LiFePo battery?

RVjim

RVjim

Well Known Member
Anyone tried the light weight motorcycle batteries. They have been around for about six years, so they are not a new item.

Ballistic has a 20 amp hour battery with 410 Cold Cranking Amps (CCA) the weights 2.5 pounds. Lists for $190 at your closest motorcycle shop. It is 3.5" thick by 4.5" wide by 3.5" tall.
I installed one in my RV-6A, and it seems to work fine. However, this is a new installation. Time will tell. Or perhaps someone else that has already done this.

There is a a larger Ballistic battery that is 4.5" thick by 4.5" wide by 3.5" tall. It weighs 3 pounds and has 28 amp hours capacity with 500 CCA. And cost about $250.

Shorai is another LiFePo battery manufacturer. They have a 3.4" thick by 6.6" long by 6.10" tall battery case. One weights 4.2 pounds and has 27 AH with 405 CCA. List price was around $250.
Another model weighs 5 pounds and has 36 AH with 500 CCA.

I'm thinking of installing the 4.2 pound battery to start my IO-540 engine.

So, does anyone have any experience with these?

Jim Ayers
 
For thought: How much weight are you saving? How much more are you paying for that weight savings? A little math will tell you how much each pound saved will cost you.... Is that "per pound" dollar amount worth it to you? (I.e. if you spend an additional $150 to save 5lbs, that's $30/lb.) If you need that weight savings to improve the utility of the aircraft, I say go for it. If not, you may be better off spending the money on fuel or maintenance.
 
FredMagare said:
For thought: How much weight are you saving? How much more are you paying for that weight savings? A little math will tell you how much each pound saved will cost you.... Is that "per pound" dollar amount worth it to you? (I.e. if you spend an additional $150 to save 5lbs, that's $30/lb.) If you need that weight savings to improve the utility of the aircraft, I say go for it. If not, you may be better off spending the money on fuel or maintenance.
Click to expand...

I have a PC680, which weighs a little under 15 pounds and is priced about $130-150. Based on this comparison it appears that the LiFePo battery saves 12 pounds for a cost of only $60. Pretty amazing if it holds up in service.
 
I just became aware of these batteries two days ago as a friend showed me one. If you can imagine picking up a mostly empty battery case with maybe 2-3 cells in it, thats about what they feel like weight-wise. Pretty amazing.

From wikipedia: "lithium iron phosphate cells are virtually incombustible in the event of mishandling during charge or discharge, and can handle high temperatures without decomposing."

Here is the Shorai's FAQ: http://www.shoraipower.com/t-faq.aspx
 
Last edited:
I asked an A&P friend of mine and his comment/question was whether these batteries are still a major fire/explosion hazard. Unfortunately, I don't know enough about them to assess whether this is really an issue with the newer generation Li batteries.

If the safety is not an issue, I'll be thinking about replacing my Odyssey with a Li battery eventually.

Here's a website: http://www.lithiumaviationbattery.com/
Sounds like these are fabricated in the US.

cheers,
greg
 
That's a huge weight savings! I'll wait a while to see how these work out, but if the safety is as advertised, I'll put one in for my backup battery, and replace the PC680 when it fails.

Jim, let us know how this works out, and thank's for your post!

Roger

RV-9a flying
RV8 painted
 
The Odyssey batteries seem to last a really long time, wonder how long these LiFePo will last????

If it is only a one or two year battery, that will get expensive rather quickly.
 
I was told at the Motorcycle shop that a standard alternator will work fine.

I was also told that the LiFePo battery should NEVER be put on a trickle charger. This will quickly distroy the battery.
However, in a no load condition (storage) the LIFePo battery will have 90% of its capacity after one year.

Ballistic and Shorai both have a special charger for their battery.
I bought one for my Ballistic battery for about $80.
The charger is used to balance the cells. This will allow the LiFePo battery to operate twice as long as a lead acid battery. However, I haven't figured out, yet, when the battery needs to be "balanced".

I've already verified one of the LiFePo battery characteristics. When the battery is first used to start the engine, it seems a little light on cranking. However, the second try really comes on strong.
Perhaps the higher CCA battery would have been a better choice.
Balistic battery with 500 CCA and 28 AH for about $250. However, it does weigh 3 pounds, instead of 2.5 pounds. 4.5" wide by 4.5" thick by 3.5" tall.

Jim Ayers
 
To balance one of these batteries it must be equipped with one of those multi pin connectors that lets you check each cells voltage. Automatic balancing chargers do this for you. The model heli and airplane guys have more info on this than you can stand to read about. Check out one of their forums to learn all about it.

LiFePo batteries are very different in how you can charge, discharge and handle them compared to LiPo. I would never put a LiPo battery anywhere near my airplane. Look at some youtube videos on em to see why...
 
Brantel said:
LiFePo batteries are very different in how you can charge, discharge and handle them compared to LiPo. I would never put a LiPo battery anywhere near my airplane. Look at some youtube videos on em to see why...
Click to expand...

Agreed but just to be clear LiFePo batteries and LiPo batteries are two completely different animals. I have LiPo's in various r/c helis I have and I'm very paranoid when charging them.
 
I see that the operating temp range for the LiFePo batts are -20F to 160F. I would think that 160F could be an issue if the battery is located on the engine side of the firewall. Imagine how hot the engine compartment would get after shutting down in Texas on a 100F day and letting it heat soak.:eek:
 
Last edited:
kbehrent said:
I see that the operating temp range for the LiFePo batts are -20F to 160F. I would think that 160F could be an issue if the battery is located on the engine side of the firewall. Imagine how hot the engine compartment would get after shutting down in Texas on a 100F day and letting it heat soak.:eek:
Click to expand...

Only reason why there is a need to put it forward of the firewall is for CG purposes...if the battery is much lighter then it should be inside the airplane where it will not be exposed to temperature extremes.
 
One thing to check...

It seems that Shorai (and perhaps others) are getting a little creative with their capacity ratings: (from http://www.shoraipower.com/t-faq.aspx)

Shorai LFX are based on a completely different chemistry. Not only do they have less than 1/3 the internal resistance per capacity than do lead-acid, they are also the ultimate "deep-cycle" battery. The internal "completely discharged" capacity of a Shorai LFX is 1/3 the rated "PBeq" capacity. For example, the LFX18 12V series have 6Ah cells internally. But the cells are capable of 90% discharge without damage and while retaining more cranking ability. As such, the USABLE capacity(or "reserve capacity") of an LFX18 12V battery is on or very near par with 18AHr-rated lead acid batteries, while providing superior cranking performance and a vast reduction in weight. The Shorai PBeq AHr (lead-acid equivalent) rating system therefore allows users to compare a very different technology from lead-acid, but on a close apples-to-apples basis when making a choice.

If my reading is correct, a Shorai LiFePo battery rated at "12Ah lead-acid equivalent" would have an actual capacity of 4Ah.

-DC
 
ive been using these in my race motorcycles and my street motorcycle. the power is constant right till they die (finally killed one tried to start a bike not realizing the fuel was off). my race bikes get used one weekend a month during the summer and never in the winter.

if you try to run the starter constantly, they will get hot. otherwise they are great batteries. the other thing is you cannot use a trickle charger with them. either use a battery designed for them or a high amp jump starter.

i was actually contemplating making these for the aero industry but havent found a reliable source for cells yet.
 
rocketbob said:
Only reason why there is a need to put it forward of the firewall is for CG purposes...if the battery is much lighter then it should be inside the airplane where it will not be exposed to temperature extremes.
Click to expand...

Way too much rework to move out of the engine compartment. :(
 
You CAN use a trickle charger with these

From the Shorai FAQ:

"Q. Can I use Lead-Acid battery chargers or charger/tenders?
A.Yes. HOWEVER, you may NOT use a charger/tender if it has an automatic "desulfation mode", which cannot be turned off. We have confirmed with Deltran, makers of the "Battery Tender" brand, that their products do NOT have a desulfation mode, and are therefore OK for use with Shorai LFX, for example."


They go on to suggest using their special charger, though it doesn't seem like these batteries really need one - they self discharge very slowly (about 1/6 of the self discharge rate of a lead-acid battery).

Mark Olson RV-7A F1-EVO Rocket
 
kbehrent said:
I see that the operating temp range for the LiFePo batts are -20F to 160F. I would think that 160F could be an issue if the battery is located on the engine side of the firewall. Imagine how hot the engine compartment would get after shutting down in Texas on a 100F day and letting it heat soak.:eek:
Click to expand...

Tracy Saylor (in his RV-6) measured the temperature on the forward side of the firewall next to the firewall from start up until the engine cooled after shut down.

The highest temperature was 35 degrees F over ambient.

So for the 100 degree F day in Texas, it would be about 135 degrees F max.
For the 106 degrees at 6 pm in Dodge City going to Oshkosh, that would be 141 degrees F.
Still under the operating temperature of 160 degrees F.
However, after shut down, the battery would be in a storage condition. Which usually has a wider allowable temperature range.

Jim Ayers
 
RVjim said:
...
I've already verified one of the LiFePo battery characteristics. When the battery is first used to start the engine, it seems a little light on cranking. However, the second try really comes on strong.
...
Jim Ayers
Click to expand...

I'm pretty sure thats the battery warming up. They may not bee so great in really cold weather since the output voltage drops dramatically when they are cold. But as you saw, as current flows, they heat up due to internal resistance and then work better.

What I'd be concerned about is if it's so cold they don't have enough voltage to turn the starter motor. In that case they won't "self-warm" since no current would flow. Would require external heating in that situation. It may not be an issue at all, I'm just supposing...
 
amilder said:
What I'd be concerned about is if it's so cold they don't have enough voltage to turn the starter motor. In that case they won't "self-warm" since no current would flow.
Click to expand...

Incorrect. Current will still definitely flow, even if it's insufficient to turn the starter. I'm not so sure the battery is going to self-warm enough to make that much difference, but in any case current will still flow.
 
battery balance

Hi All,

The Ballistic LiFePo battery has a "battery balance" sequence. I was told that this is used when the battery voltage in a static state (stored with no load) drops below 13.0 volts.

The charger for the Ballistic battery has a plug in connector, in addition to the two terminal clips, to allow the charger to "balance" the cells. Doing this is supposed to give this battery twice the life of a lead-acid battery.

I haven't gotten the charger for my Shorai battery yet. I expect it to be similar, if not identical, to the Ballistic unit.

I took a 24 amp hr Concorde battery out of my RV-3 and installed the 27 amp hr (9 amp hr?) Shorai battery yesterday. This removes 19 pounds from the baggage compartment.
Now I can install the electric flap motor in the baggage comparment so I can remove the flap handle from the cockpit.

Regards,
Jim Ayers
 
Just got a pair of LFX18L1-BS12's. Incredibly light, 2.32 lbs. I'll be doing a torture test soon. :)

I pulled the trigger on buying some after reading this: http://www.advrider.com/forums/showthread.php?t=664944

photo%252520%2525281%252529.JPG
 
I look forward to hearing the results of the "torture test".

BTW - for those interested in one use-case for the LiFePo, they were "revolutionary" when they were chosen for the OLPC (one laptop per child) project. The reason for the battery in that situation was -rugged, voltage tolerant, extreme heat tolerant (run a laptop in desert countries where the ambient is 130+ and you can imaging most laptops are not happy).

As for "sitting on the bench". I had pulled one out of a working laptop back in early 2008 and recently put it back into service. It didn't even seem to know it was 3yrs later.

Yeah - they are incredibly light weight.
 
Last edited:
Tonight I wired one of my Shorai batteries into my Cessna 150. Its a 1966 with a pull start so I'm able to turn it over without turning the mag key. And the starter is a big old honkin thing.

Did ten sequences of cranking the engine for 5 seconds and pausing for 5 seconds, so to not damage the starter.

Voltage prior to the cranking sequence was 13.51 volts. Voltage afterward was 13.22 after a 5 minute pause. The battery did not feel warm at all at any point. Temp in the hangar is about 60 deg.

It turned just as strongly on the first go as it did on the tenth. Didn't seem to slow down at all.

I was quite satisfied that it will work fine to crank an engine over, and my test didn't seem to phase it.

Next test will be a hour-long constant-current draw test to simulate running essential loads on one battery.
 
Last night after I typed this email and before I pulled the battery out of the 150 I did my test sequences 5 more times. Still no sign of slower cranking!

I went with the smaller size 2 battery because I am putting two in my Rocket in a much more forward location. The next size up is about the size of a PC680.

FWIW the battery in the 150 is a Gill 25 (25aH) so even though the battery I'm using is an 18aH and smaller in capacity it didn't seem to care. I guarantee I would have ran down the Gill battery.
 
Hey Bob - I started seriously looking at these a month or so ago, then got busy with other stuff - thanks a bunch for the testing! Keep us informed as you go along - I'd love to save that much weight on the airplanes - just think of how good a backup battery it would make, even if you didn't want to use it as a primary.

How does the Shorei compare dimensionally with the P680? I have read several different dimensions for it - figure if you have one, we can get an honest appraisal.

Paul
 
I have one of the larger case Shorai (LFX27) batteries and have compared it to the PC680 that's in my Rocket.

It's not as wide or as tall as the PC680 but it's thickness (depth?) is tapered and is thicker than the PC680, so it won't fit in a box that can't accommodate a thicker battery. It's considerably lighter than the PC680.

I did cranking tests with the LFX27 and found that, while it was able to start the IO540 in my Rocket, it turned the motor over more slowly than the PC680 when the temperature was about 70F. Also, once the engine started, it drew 50+ amps of recharging current (I have a 60A alternator) for a longer time than I would have thought. I wouldn't be comfortable with this battery in my Rocket, I would use one next larger in size.

The recharging current I saw bothers me a bit as the Shorai spec says a maximum of 24 amps. I am not sure if this rating is in place due to the battery overheating if charged at a high current from completely discharged state, or if there is some other reason. Regardless, expect a high current draw on your alternator after starting an engine with one of these batteries.

My IO540 has a Sky-Tec NL inline starter, so it's not lacking in torque.
 
Since the internal resistance of these batteries is low I suspect they are going to draw much more when discharged, but for a shorter period.
 
We are watching this technology carefully and anxious to include them in our aircraft due to the weight saving and improved starting performance. We haven't pulled the trigger yet though because we aren't yet comfortable that we know all the potential failure modes. In our Carbon Cub the battery is right below the pilot's butt in the seat pedastal. We can't have them exploding or otherwise failing catastrophically for obvious liability reasons in all-electric aircraft. We've had the LFX18A1-BS12 in a couple of our company aircraft for at least six months now and all is well.

If anyone knows of known failure modes I'd LOVE to hear about it!
 
The charging requirements are what I've been wondering about too. They don't have any kind of BMS internally do they? I'd hate to have one between my knees in a 3 and have it let go.
 
Failure Modes

RC pilots probably have more experience of failure modes of this type of battery than most. Have a look at their sophisticated chargers with cell balancing etc. An incredibly light and powerful power source, there is plenty of material on RC sites.

As usual do the research and make your choice.

Happy Flying
Rob
 
rv8or said:
RC pilots probably have more experience of failure modes of this type of battery than most. Have a look at their sophisticated chargers with cell balancing etc. An incredibly light and powerful power source, there is plenty of material on RC sites.

As usual do the research and make your choice.

Happy Flying
Rob
Click to expand...

They use LiPo batteries, not LiFePo. Big difference. I wouldn't want a LiPo battery anywhere close to my airplane. I have a friend that almost burned down his house charging LiPo's.
 
If you really care to have the skinny on charging LiFePo

Go to the this site www.evtv.me/

These guys are LiFePo guru's and argue the correct and safe charging methods for them. They contend it is all about amps/voltage profile of the charger and over charging is the culprit in failures. They contend that BMS's are more trouble and more dangerous than they are worth.

Not sure where that leaves us as I am not sure what the charging curve would look like for a LiFePo in a plane being charged by an alternator.

Think I'll stick with the safe and excellent service of the PC 680 for now.
 
If I power my avionics off the PC680 aux bat for 1 hour then do a quick start up on the PC925 my alt current goes to 60 amps once crossfeed contactor is closed. After 30 min of engine operation both batteries are fully charged. I don't know that I would want my batteries charging any quicker.
 
BMS???

aerhed said:
...They don't have any kind of BMS internally do they?...
Click to expand...

gereed75 said:
Go to the this site www.evtv.me/
...They contend that BMS's are more trouble and more dangerous than they are worth.

...
Click to expand...

BMS? And I thought NASA was the worst user of acronyms without explanation.

A quick search of the acronym dictionary reveals 110 meanings of the acronym "BMS."
The best fit appears to be this one:

BMS Battery Management System (rechargeable battery technology)THIS MUST BE IT!!!
 
Last edited:
torture test #2

Tonight I felt a little adventurous and decided to do a full-on load test. Armed with a 20% off coupon I ran over to Harbor Freight and picked up one of the 500A load testers. It was on sale and only $40 with the coupon.

I thought what the heck, lets really torture this thing.

Connected it to the load tester and cranked it up to 400A draw. Pretty much simulating a short. Left it there for about 15 seconds, and I could hear things getting hot in the battery. The voltage ran down quickly and steadily. The battery was quite warm to the touch.

Disconnected it, let it cool for about a half hour, and charged it up with an old Sears battery charger I have.

It drew 10A initially from the charger and settled down to 8A. About an hour later I checked on it and it was charged, drawing less than an amp.

Disconnected it from the charger and left it. Did a quick check with a voltmeter and it was showing 14.2V. Tomorrow I will check the battery voltage again.

Test passed.
 
Beware

So I've been doing some research on these LiFePO batteries. I talked with a FAA electrical Designated Engineering Representative. He points out that although the LiFePO batteries are safer than other Li chemistries, when they fail they still put out electrolyte that is about as flammable as gasoline; whereas other Li chemistries put out gas that ignites immediately when in contact with oxygen.

Yes, this is completely contrary to what wikipedia says about LiFePO. Check out this guy's experience.


As a mitigation you could put the battery in a stainless steel box in the same way you put a stainless firewall between you and the engine. With this setup you have to make sure that the box is well ventilated with a 1.5 inch DIA tube to the exterior recommended. The failure mode can be explosive so the fire isn't contained it can cause shrapnel on top of the fire hence the large vent recommendation.

The DER also points out that even tiny cell phone batteries have a fire ball 2-3 feet in diameter when they fail, you can imagine the fire ball with a battery like we're talking about here. Also people point out the low failure rate of cell phone and laptop batteries but they are in relatively low charge and discharge situation unlike cranking an engine which makes them more susceptible to failure.

So it may make more sense to use these batteries for backup batteries rather than cranking batteries. I run 2 PC625s, one for cranking and one for emergency backup so I could still save 10 lbs.

I'd like to see someone take a Shorai battery and make it fail to see what the failure mode looks like. How long does it burn, how hot does it get, then a box could be designed to contain the potential fire.

Keep all this in mind as you experiment with these batteries, everybody wants to save 20 lbs and this sounds really promising but I don't want to see anyone get hurt.

Bill
N84WJ, RV-8, 700 hrs
http://rv-8.blogspot.com/
 
Lithium Aviation Battery

I just spoke with Andy Reich of Lithium aviation battery's. Seems to be very knowledgeable about his product and is very willing to get some feedback. He wants to join the vans air force community, I referred him to Dough Reeves.

Soooh! I ordered a new battery from him at cost of $375.00 and $10.00 for shipping. I will post further info after installation and evaluation. I like that I do not have to create a new battery box and the weight savings is substantial. The replacement battery weigh's 3 Lbs.

Bob Wieczorek
RV6a
 
"...he clearly states that he had regulator problems and this was on top of a defective battery from the factory."

I wonder if they could fit all that on my headstone.
 
Lithium batts

I dont see any internal circuitry inside a shorai battery when I took it apart.
I checked warranty on both shorai and Ballistic. Neither warranties their battery if used in aircraft they said.
 
Hi Bob,

how far did you get with your lithium battery installation?

We want to finish our RV7 in autumn and consider a lithium battery as well. However, as a model-aviator I do know that not every lithium-battery is the same.

Thanks,

HotDoc


wings05rv6a said:
I just spoke with Andy Reich of Lithium aviation battery's. Seems to be very knowledgeable about his product and is very willing to get some feedback. He wants to join the vans air force community, I referred him to Dough Reeves.

Soooh! I ordered a new battery from him at cost of $375.00 and $10.00 for shipping. I will post further info after installation and evaluation. I like that I do not have to create a new battery box and the weight savings is substantial. The replacement battery weigh's 3 Lbs.

Bob Wieczorek
RV6a
Click to expand...
 
Bringing this old thread back because I am starting a test with an LiFePO4 battery. I'll post results as I get them.

To start, the test platform is my RV-8 150hp Lycoming O320-E2A with a Catto 2-blade propeller. The power plant has a 12lb inertia ring installed. The panel is day/night VFR with AP, GPS, and electric DG and AI. It is a typical airplane with typical loads for starting and flight operations.

The reason for my test is that the current battery is an Odyssey PC680 and it has been acting weak - initial crank stops at first compression for 1/2 a second or more and then pulls through with starting typically after 5-8 blades. The battery is 5 years old so it seemed a good place to start.

Since the airplane is almost exclusively day-VFR at the moment, I went with the Shorai LFX18L1-BS12 (12v 18Ah 270 CCA). The battery's specifications are slightly better than the Odyssey 680.

When I start a panel upgrade, I can add a second battery with split circuitry for redundancy.

Testing will be delayed a few days (I don't want to make the switch and immediately head out on a long flight) but I wanted to queue this up in case there are specific data points people want me to collect.


First impression is the physical size of the battery - IT IS TINY. 2.6" x 5.8" x 4.1" and is very light at 2.1lbs. It seems like its a toy because it is so small and so light.

Price for a new Odyssey PC680 was $116 vs price for a new Shorai LFX18L1-BS12 was $160.

Weight for a new Odyssey PC680 was 15.4 lbs vs weight for a new Shorai LFX18L1-BS12 was 2.1 lbs.

For those the do the "price of weight savings" game, that is $3.25 per pound.
 
Last edited:
Hi Glen

Forgive me if I didn't see it, but you didn't state what kind of starter you have. You are describing "to a T" an issue that I have with the older Skytech LS- The bump, pause, then crank

I changed my LS for the new style Skytech NL "in-line" and the problem went away. I too suspected my battery and swapped that out before swapping out the starter - Improved, but still did the pause & crank

If you have a Skyteck SL you may want to consider changing it to a NL.

Best of Luck,
Clark
 
Thanks Clark, I'll check the starter when I swap in the new battery.

UPDATE: Just looked at the paperwork (then had a peek under the cowl). The plane has a Magnaflite MZ-6204 starter.
 
Last edited:
You must log in or register to reply here.
Back
Top