The real dangers of Lithium Ion batteries.......

[Phil Perry]

Because you have only made 9 posts.

Yes that's right Nick,. . . .Robbo and I only joined last week, but we've made a coupla Kiloposts already. . . . .

 

 

[UltraFlash]

I'd suggest using the Australian made LiFePo4 packs from Booma RC boomarc.com

 

These packs have a build in battery balancing circuit, that prevents individual cells going over voltage and balances the pack.

 

I use these in RC Turbine Jets, where the starting current exceeds 30A for over a minute, with no issues in over 500 starts each.

 

 

[UltraFlash]

Also if you ever buy batteries (LiFePo4 or otherwise) from hobbyking always buy them from the international warehouse. I've bought many from the Australian Warehouse and determined the packs from the AU warehouse swell much easier and have a much shorter lifespan than those shipped from HKG.

 

We suspected this was because AU stock has been sitting idle for ~6 months, from packing, shipping in a sea container and then sitting in the AU warehouse for months.

 

 

[NickBond]

Thanks for that advice Ultrafish

 

 

[Keith Page]

I,m thinking of putting the hobby king zippy flight max lifepo4 (see attached pic) as a replacement to my odyssey. At $125 and 1kg. The price and weight and various advantages make it an attractive choice. I would like to hear from members that are using this battery, specifically, in a Jabiru 230D, how they have physically installed this battery and their experience in using this type of battery and any other helpful comments that I should be aware of. Cheers

A safety tribute to Major............ I can remember Major giving some good advice, "Do not use them". No negotiating.

Reason:- They catch fire and can not be extinguished.. He even went as far as trying to get RAAus to disallow the use of these batteries.. Last I heard he was not having much luck with RAAus management regarding this issue.

 

As usual he had all his evidence in order..

 

Regards,

 

KP.

 

 

[Head in the clouds]

A safety tribute to Major............ I can remember Major giving some good advice, "Do not use them". No negotiating.Reason:- They catch fire and can not be extinguished.. He even went as far as trying to get RAAus to disallow the use of these batteries.. Last I heard he was not having much luck with RAAus management regarding this issue.

As usual he had all his evidence in order..

 

Regards,

 

KP.

It doesn't seem to matter how many threads there are on this subject, and how many times people explain it, some people probably won't ever understand the difference between Lipos and LifePO4s.

 

So - just one more time - Lipos (Lithium Ion batteries) catch fire, but LifePO4s (Lithium Ferro-Phosphate batteries - the Ferro is IRON (not Ion) so LifePO4s are sometimes called Lithium Iron batteries - which sounds like Lithium Ion hence the confusion) - they CANNOT catch fire. As far as aviation is concerned Lipos are Dangerous Goods but LifePO4s are not, and provided they're not very large batteries, LifePO4s are usually delivered to you by Airmail because they're totally safe, non-hazardous, can't catch fire, can't sustain fire. The only potential danger from LifePO4s, hence the restriction on size that can be carried by air, is the possibility of something external shorting the contacts of the battery and setting fire to something else on the plane - that's something else, not the battery itself. Lipos can never be delivered by airmail ....

 

In the opinions of many of those who use them LifePO4s are better than sliced bread because they're 1/8 the weight of a similar capacity Lead/Acid or Gel cell. LifePO4s are only about 10% heavier than Lipos for similar power/energy density batteries. LifePO4s offer a huge advantage to some aircraft where their low weight can mean a significant weight saving. Some aircraft can't benefit from the low battery weight because they need the battery weight where the manufacturer installed it, to keep the CoG right.

 

LifePO4s cost about 4x the cost of a similar capacity Lead/Acid or Gel cell battery.

 

 

[Bruce Tuncks]

My LiFePO4 battery was less than half the price of the Odyssey it replaced at about $90 compared with over $200.

 

But I have seen an expensive LiFePO4 battery housed in a casing to look like a motorbike battery, and it didn't say what the amp-hours were. It said some tricky stuff about "lead-acid equivalent", whatever that means, and the battery was too light to have much of anything inside.

 

 

[Bruce Tuncks]

The way we are going, "ultralight" aviation will be the LAST to give up lead-acid batteries.

 

 

[Downunder]

The way we are going, "ultralight" aviation will be the LAST to give up lead-acid batteries.

And carburetors......(at least in man carrying vehicles)

 

 

[jetjr]

Bruce, can you get some pics of your battery,

 

life type for $90 seems cheap

 

The packaged life models include protection and charge circutry. Yes they are rated differently and are very light.

 

 

[Bruce Tuncks]

 

 

[Bruce Tuncks]

I'd like to know more about what they mean about the different ratings.. There is Amp-hours and cranking amps, what else ? The battery in the pic is rated at 252 cranking amps and 8.4 amp-hours.

 

 

[UltraFlash]

Amp hours is the energy storage capacity, current capacity is what current the battery can deliver.

 

So for example, an 8.4Ah battery can (theoretically) deliver 8.4A for one hour, 16.8A for half an hour or 84A for 6 minutes (0.1hr).

 

The current ratings is what current the battery can deliver to a load (such as a starter motor).

 

C discharge ratings show the current rating as a factor of the battery capacity (I.e. How many multiples of the batteries capacity it can deliver in current) for example 30C as above would mean the battery can deliver 30 x 8.4A = 252A.

 

Finally is the C charge rating, this is typically either 1, 2 or 5 C. This means the battery can only be charged at (depending on the battery) 8.4A, 16.8A or 42A. At these figures, the uncontrolled output from an alternator could be damaging to a battery with a low C charge rating.

 

I won't get into peak C ratings or duty cycles as this may confuse the matter.

 

One last point, LiFePO4 batteries (or any lithium) need to be charged using a specially programmed charger, they need to charge on a constant voltage charge, not a constant current charge like all other batteries. You couldn't hook up one of these direct to the output of an alternator and expect it to provide full capacity and be fully charged without a regulation circuit to manage the charge process.

 

 

[Bruce Tuncks]

Good stuff UltraFlash. If you just use the standard Jabiru alternator system the battery will puff up. They have no vent for gases. They also puff up if you let them discharge too much.

 

My system of switching off ( at 14.4 volts) works, but it is a bit primitive. I think Kyle Communications has designed a more professional setup.

 

You need the right voltage cutoff, but you also need to balance the individual cells sometimes.

 

The battery comes with a connector to do this and you need a special charger .

 

 

[Head in the clouds]

Amp hours is the energy storage capacity, current capacity is what current the battery can deliver.So for example, an 8.4Ah battery can (theoretically) deliver 8.4A for one hour, 16.8A for half an hour or 84A for 6 minutes (0.1hr).

The current ratings is what current the battery can deliver to a load (such as a starter motor).

 

C discharge ratings show the current rating as a factor of the battery capacity (I.e. How many multiples of the batteries capacity it can deliver in current) for example 30C as above would mean the battery can deliver 30 x 8.4A = 252A.

 

Finally is the C charge rating, this is typically either 1, 2 or 5 C. This means the battery can only be charged at (depending on the battery) 8.4A, 16.8A or 42A. At these figures, the uncontrolled output from an alternator could be damaging to a battery with a low C charge rating.

 

I won't get into peak C ratings or duty cycles as this may confuse the matter.

 

One last point, LiFePO4 batteries (or any lithium) need to be charged using a specially programmed charger, they need to charge on a constant voltage charge, not a constant current charge like all other batteries. You couldn't hook up one of these direct to the output of an alternator and expect it to provide full capacity and be fully charged without a regulation circuit to manage the charge process.

Good post UF, full of precise and detailed information, thanks.

 

Just one caveat though. I agree that most manufacturers of Life (and Lipo, but we're not talking about them) batteries recommend the use of cell balancing chargers but for the ones I'm familiar with it's a recommendation not an absolute. In post #65 above Horsefeathers describes how he just fitted a Life battery replacing his previous one with no other changes to the system, presumably, and with no problems.

 

In practice that scenario is the norm according to my battery supplier. My Life battery is a Shorai and before buying it (it was $250, so I gave it more than passing consideration before forking out ..., ) I had a lengthy discussion with the importer who was very forthcoming with information and candid advice. The short version was that Shorai recommend that for best performance and greatest longevity of the battery then a cell balancing charger is the best way to go BUT in real life most of their customers just bought the battery and installed it in place of the existing battery which was usually a gel cell, and he had not heard of any problems.

 

The majority of their customers were motorsport users, motorcycles, offroad buggies, karts and the like. Motorcyclists were by far the highest users of them as the light weight contributed to lowering the CG for their bikes. The importer/distributor's main concern was that the Life batteries should not be charged at higher than their specified charge rate, as that would shorten the battery life more than most other factors - but it won't make it catch fire!!

 

Our Rotax 912 charge rate is just a little high for my Shorai battery, and the charge rate from many sport bikes is a bit high too. The distributor's recommendation is that some load be kept on the electrical circuit to keep the charge rate down a little. In motorcycles this happens almost automatically because most of them ride with headlights on at all times, so he suggested we do something similar with the planes. Since we often don't have any specific load on the electric circuit it's probably a good idea to add a bit of electronitrickery to keep the charge rate down, in my case it needs to stay below 20A, and the R912 charge rate is 25A if not loaded. (Perhaps Kylecommunications might consider making up a 'magic box' current limiting device we could install to keep the charge rate below 20A? I'll buy one ...)

 

The distributor went on to say that he would recommend having the cells balanced once a year at a minimum, if we didn't want to buy our own suitable charger they would do it free and with a one day turnaround, we could Express Post satchel the battery each way by airmail so in most cases it would only be away for three days.

 

Below is a picture of my battery, the case is CF re-inforced and built to a milspec and there is nothing in the case material or its content which can catch fire or sustain fire, or is toxic in any way. The disposal instructions are to just chuck it in the garbage ... The whole thing weighs just under 1kg (it's so light you'd really think it's just an empty casing) and it's an 18Ah with 270CCA which cranks the 912 noticeably more energetically than a similar capacity gel cell battery.

 

One of the really great benefits of the Life battery that hasn't been mentioned is that it maintains its charge for long periods. In 'normal' temperatures it will drop only approx 0.1V per month so after sitting idle for 4 months it'll still be at 14V or so (fully charged they're 14.4V), and even after a year they'll still start your engine easily. More astounding is that they're the opposite of a gel or lead/acid cell as far as cold is concerned. Gel and lead/acid will go flat quite quickly in cold temperatures but if you really want to keep your Life battery fully charged for years - keep it in the fridge.

 

For a size comparison, notice the 'Bic' lighter standing next to the battery -

 

 

 

[Bruce Tuncks]

Lovely neat and clean installation there in that picture.

 

 

[jetjr]

thanks to Bruce and HIC

 

I see Earth x now sell ETX 680, 900 and 1200? which specifically for aircraft

 

As part of the circutry it has self checking and alarm output

 

.......and no one seriously selling in AU

 

Sonex now approve them so the aviation world is moving slowly.

 

Re cost, a new PC625 Odyssey is around $300 ($460 full price) so the $400 USD isnt crazy for a 5kg weight saving

 

I believe auto batteries have different discharge test methods, temp and duration, and not sure which one is main claim of CCA. Tests might not be applicable to LiFe.

 

 

[Oscar]

Does anybody have any experience of the Aussie-made Fusion LiFePo4 batteries?: http://www.fusionagmbatteries.com.au/tabid/323/cid/8/Products/LithiumIonPolymer.aspx

 

Allowing for typical advertising hyperbole, they seem to be by specification, pretty competitive with the better-quality o/s batteries.

 

 

[dutchroll]

...... but LifePO4s (Lithium Ferro-Phosphate batteries - the Ferro is IRON (not Ion) so LifePO4s are sometimes called Lithium Iron batteries - which sounds like Lithium Ion hence the confusion) - they CANNOT catch fire.

Well it's true that it didn't catch fire......

 

 

 

[jetjr]

Look OK, internal BMS, but sizes not a drop in fit for PC625.

 

Any idea on prices?

 

The video shows what happens with non BMS types. A an unfused SLA might not be pretty either?

 

BMS works as a load and charge limiter and its why that feature is very important

 

 

[Bruce Tuncks]

They look good Oscar, but there are a few point to note:

 

1. There is no maximum current spec at least on the smaller ones. They don't seem to want you to use them for starting.

 

2. What charging circuitry is there? The best system is to individually charge cells, and this needs a special plug, which I don't see.

 

3. At the risk of showing the sort of cultural cringe I hate in Jab bashers, I wonder where the cells themselves came from, as I didn't think they were made in Australia. I reckon they were just packaged up here.

 

But they are certainly packaged up nicely and look like real batteries. More so than mine.

 

 

[Oscar]

Personally, I found that fairly reassuring.

 

For sue, you wouldn't want that happening inside the occupant container, but if that situation happened on the cowl-side of the firewall, a properly set-up engine installation should be able to survive it. In real life, I'd be more worried about the situation of what had CAUSED the dead short, and whether THAT had started a fire.

 

 

[Bruce Tuncks]

Great video of the short circuit. In post 40 I offered a prize for telling me how to set one of these batteries on fire, and the dead short was one possibility of course. Well there were no takers so I had to drink the bottle of red myself.

 

I would not like to share the cockpit with that battery though with those fumes. At least in the Jabiru it is on the other side of the firewall. Mind you, I reckon an Odyssey given the same treatment would not be nice to share a cockpit with either.

 

Nev reckons we all should have a battery isolater switch, so I bet he likes that video.

 

 

[Oscar]

They look good Oscar, but there are a few point to note:1. There is no maximum current spec at least on the smaller ones. They don't seem to want you to use them for starting.

2. What charging circuitry is there? The best system is to individually charge cells, and this needs a special plug, which I don't see.

 

3. At the risk of showing the sort of cultural cringe I hate in Jab bashers, I wonder where the cells themselves came from, as I didn't think they were made in Australia. I reckon they were just packaged up here.

 

But they are certainly packaged up nicely and look like real batteries. More so than mine.

Bruce: those are all questions to which I do not know the answer - and to be honest, I do not have the background knowledge to even ask the right questions! I did note that they appear to be focussed on deep-cycle applications, and as a boat-owner I understand the differences, but this is an area where a forum such as this - or even perhaps RAA - could provide a set of guidelines for those of us who do not have the knowledge to make an informed decision.

 

I am thinking here, of perhaps a 'cheat sheet' of the essential electrical parameters that would lead a knowledgeable person to a 'go/no go' decision.

 

Perhaps I am untypical, but I am intensely interested in using a LiFePo4 battery in my own aircraft, for a number of reasons:

 

a) I want to trade some changes in my Jab. that will add weight over standard, with the weight advantage of a LiFeP04 battery to still retain the best usable load I can get;

 

b) In general terms, the low-discharge when unused and high-cranking power characteristics are the best match for my likely type of operation;

 

c) I have had less than wonderful experiences of lead-acid and AGM batteries in 'unusual' circumstances, and the LiFePo4 batteries seem to me to be more 'robust' when considered in terms of package size and electrical capability.

 

As an aside, but of interest to me, is the fact that it seems as if LiFeP04 discharge characteristics are almost the perfect match for an EFI installation. If things on the charging side go pear-shaped, the LiFePo4 battery will continue to fire the injectors up to the last gasp, giving the best possible 'emergency landing' choices.

 

If those - and there are obviously quite a few of you out there - with the expertise to sift the wheat from the chaff of advertising blurbs for the rest of us could produce a set of guidelines for choosing a LiFePo4 battery, I for one would be extremely grateful.

 

 

[dutchroll]

The video shows what happens with non BMS types. A an unfused SLA might not be pretty either?BMS works as a load and charge limiter and its why that feature is very important

An unfused short on an SLA would possibly be spectacular, at least along the path of the short circuit.

But what possible scenario in an aircraft would result in it being unfused or having a long length of unprotected "fat" wire which could short it this way? That would violate even the most basic electrical system installation principles.

 

SLA batteries have a long track record in safe aircraft operation. Li batteries (of all types) don't. Maybe one day they will. But at the moment they don't.

 

I recall a discussion once about a very new type of surgery versus an older but very reliable method of the same surgery. I agreed with the sentiment that it would be preferable to let them experiment on someone else, not myself. When it became more mainstream with a proven track record, sure let's consider it!