Lithium batteries, overcharging and fire.

[utopia]

Ok, I know there have been many discussions on the subject of lithium batteries.
I've been tempted by the light weight and small size and so, despite still having some uncertainty, I bit the bullet and have fitted Magneti Marelli Li.Fe PO4 batteries to both the monster (M750) and my 650 Dommie.
I remain somewhat nervous though, mainly about the prospect of them bursting into flames.
And then today, on the "other" forum, someone posted a pic of a burnt out KTM.
I have no details but a lithium battery was in the mix.

The other day I noticed that it says on the case of my batteries that the charge rate should not exceed 15V.
Now, that might not be a problem if your reg/rec is working correctly but we all know that these units are unreliable .. indeed mine has previously malfunctioned, boiled a lead/acid battery and burnt out the multiconnector to the alternator.
My new reg/rec is hard wired, but I'm still not totally confident that the system is failsafe.
And 15V doesn't sound like much of a safety margin.

In my earlier considerations of lithium batteries, it was pointed out that the newer Ducatis such as the Panigale are fitted with Lithium batteries from new.
However, I have no idea whether the charging circuit has been modified to suit, or if it is the same basic design as mine.
And therein lies my question.

In a similar vein, I find myself wondering if it is possible to fit a voltage limiting device which would operate in much the same way as a fuse does to limit current ?
This would not be a second voltage regulator, but a failsafe limiter which would "blow" in the event of exceeding the charge voltage, or have some other mode of operation to ensure 100% that high voltage charging was impossible.

You'll have to excuse my relative ignorance of electrickery here, I'm afraid.

As a secondary issue, I'm wondering if there would be any advantage in wiring the headlamp to be on all the time, to soak up some of the excess.
I have heard suggestions of it being wired directly from the battery in these cases, but that's all I know.
I can't help wondering if this has something to do with the circuitry on the Pani etc.

So, I confess my ignorance and humbly enquire of the forum experts.
I thank you.

[slob]

You need a specialist L-ion charger, to prevent overcharging. My understanding is it's overheating during charging causing an organic electrolyte to overheat that precipitates a fire.
If you're sufficiently worried, remove the battery from the bike and charge it on paving slab or similar.
An electronics engineer friend of mine uses these for mobile batteries although I don't know if you'd get one large enough for a bike battery.

ps. 'charge rate' in volts is misleading, Amps is what you should be looking at. Think of Voltage like water pressure and Amperage as flow. Charge is measured in Coulombs and an Amp is one Coulomb per Second (Charge rate) Although too high a voltage will still cause you problems. I assume the Voltage warning is because the Li battery doesn't have sufficient internal resistance to regulate itself.

[Ron1000]

As per Slobs reply, you need a specialist charger.

I've only recently fitted a LW battery to make the evo (even more) lighter.

Can't remember the make but the instructions specifically say you need a different type of charger and even gives you part numbers of ones that will work.

[utopia]

I already have a dedicated L-ion charger for top-up/maintenance charging (I believe the desulphation mode on regular charger/tenders is the issue here) .... but that's not the problem.
My concern is for normal, in use charging via the alternator and reg/rec (and potential problems with malfunction thereof leading to charging at a higher voltage than 15V).
Basically, does a modern, L-ion battery require a modern charging circuit to go with it, which contains some sort of (failsafe) voltage overload limiter, in case the reg/rec should fail.
And can such a facility be retrofitted somehow to an older system.

And yes, my electrics does stretch as far as understanding charge capacity, ie volts, amps, coulombs and time ... but not a lot further.
The main (only ?) reason that I'm concerned about voltage is that it says "caution - do not charge above 15V" on the battery casing.
With my limited electrical knowledge it seems entirely possible (and experience seems to confirm) that a charge circuit malfunction could lead to charging at over 15V, and this is what I would like to address.

Also ...
Ok, I could fit a mosfet reg/rec, which would probably be more reliable but crucially, I still don't think it would be entirely failsafe, but would merely reduce the odds of failure, ie not entirely guarding against it.
I could also fit a battery monitor, but this would merely be an alert and would rely on my noticing it and taking action to avoid catastrophe .. I want something that operates more like a fuse, ie it shuts the system down by itself as soon as there is a problem, requiring no action from me whatsoever.

[BigOz]

LiFePO4 batteries are considered not to decompose like other Lithium cell types, e.g. Liithium-ion or Lithiumi-ion polymer (LiPo) which can be very impressive when they go.
It will get very hot if abused by overcharging and in extreme situations may emit white smoke but I've not heard of one deflagrating as the other types do. It is certainly possible they get hot enough that other items in the locality will reach their auto ignition temperature if it is close and not a material suited to high temperatures.

Your battery is likely a 4sXp (four cells in series and some number in parallel to give the cold crank rating depending on the output rating of the cells) setup which means the maximum charge voltage is 14.4 or 3.6V per cell and without an in built protection circuit in the battery (which some have) if your reg rec outputs more than 14.4V (it should not) you will overcharge your cells.
At 15V or 3.75V per cell I'd bet that would already be damaging the cells in so far as it would be limiting the life of the cells.

If nervous I'd consider a small voltmeter added to the instruments.

[BigOz]

Plenty of abuse here, lots of smoke but no fire...

https://youtu.be/EMARDvMz62A

[damien666]

Have a look at www.carrotcycles.co.uk
Shorai lithium IRON batteries. Can be charged with standard lead battery charger (not optimate type) or dedicated shorai charger.

[jonzi]

Originally Posted by BigOz

Plenty of abuse here, lots of smoke but no fire...

https://youtu.be/EMARDvMz62A

Much more fun

https://www.youtube.com/watch?v=0rjn5BC3EOQ

[BigOz]

Originally Posted by jonzi

Much more fun

https://www.youtube.com/watch?v=0rjn5BC3EOQ

That is a lithium-ion polymer cell and those you don't want in your motorcycle, but Boing does put them in their 787 Dreamliners.

The chemistry on those would be LiCoO2 (lithium cobalt oxide).

[Mr Gazza]

I had a fair bit of experience with Lithium-Polymer cells with electric model aeroplanes.
First there was Nickel-Cadmium cells, which were heavy. Then came Nickel-Metal Hydride which were heavy too but gave a bit more power for a little longer.
Li-Pos were met with a lot of suspicion when they first appeared. They were much lighter and much more powerful than anything before, but required special chargers and speed controllers... And were very expensive.!
I saw plenty go up in flames. it was always due to mis-use of some sort, either the wrong charger or charging regime, Poor ventilation in the model, crash damage or a direct short.

I remember connecting one into a model wrong and instantly ripped it out, chucking it over my shoulder in one movement. It was smoking by the time it passed my ear and on fire when it landed.

They swell if they are on the way out and become a little more volatile at that stage. If the cells were a write off, the trick would be to drop a scalpel into them and watch the fizz and clouds of toxic smoke. Flames would sometimes issue too.

However that was the first generation of Li-Pos. Later ones were not so volatile and would usually only get as far as the swelling stage with no pyrotechnics and not ignite or smoke when stabbed..

Lithium-ion is of course a completely different thing and we are also well down the line as far as the "White Heat of Technology" is concerned, so I would say that if they are sold for Motorcycle fitment, then the conventional charging system should be okay unless stated by the battery suppliers to the contrary.
However a reg/rec failure or short circuit still carries the risk of a fire. A rather hefty fuse would protect against most shorts, but for protecting against charge surges, perhaps a BEC (battery electronic control) might be the thing.
On a model a BEC is used to prevent the battery from discharging below a threshold voltage (from which it will not recover). By shutting off the current to the motor, allowing the radio and servos to still work to glide to a controlled landing.
I am sure that a BEC with a "High" threshold should be possible to make or even already be commercially available?

StevieL is a bit of a wizard with electronics...He might be your man..

[Nickj]

I've used BECs, most are for relatively low power applications, having said that there are many HV UBECs that can handle 12V and over 5A, that could add additional smoothing to the input. It depends on what the battery needs for charging, I'd think more volts and less current.

Do these batteries use cell balancing charging?? This just balances the cells to equal charge states, I guess it would be inbuilt if it's used.

A possibility might be a charge unit between the regulator output and the battery which would be something else again.

[Mr Gazza]

Glad you mentioned UBECs as I needed to jog my memory.

I discovered that a BEC is also known as a "Battery Elimination Circuit" and a UBEC is a "Universal Battery Elimination Circuit"

I was also reminded that the other function of a BEC as part of a speed controller, is to regulate the current to the servos.

A UBEC is simply a BEC that is independent of a speed controller and will handle higher input voltages and is capable of supplying higher regulated current to servos and ancillaries.

So a UBEC is a regulator of sorts and is kind of what we are looking for, but with ratings tailored to a motorcycle's needs.

It begs the question; are we looking at simply doubling up on the regulator part of the reg/rec as a precaution against the R/R failing... Can you regulate the current twice?

What would a secondary reg' do with any surplus current? Would it's function be to illuminate a warning light? Or shut off the battery, thus killing the engine?

I know what you're after Jeff but I'm running out of know how. Hope I'm on the right track?

[Dukedesmo]

I'm still undecided about lithium batteries.

I have had no problems with my current Motobatts (3 bikes with them), they have plenty of power and will start the bike no problem even after a lengthy layup - even on the Lemans which needs some serious power to turn it over. Sure they are heavy but I can put up with a few kilos of extra weight for no hassle starting.

I would also be a tad concerned about potential fires, especially as bike batteries are often in a place where a fire really wouldn't be welcome whilst riding i.e. under the tank (containing 17L of petrol) on the Monster and under my arse on the Guzzi.

Also because my bikes live all together in a workshop/office/garage where I also have 2 cars, usually a few jerry cans of petrol and a 2000L tank of heating oil (albeit it's not connected to the house) so I'd rather reduce the chances...

[BigOz]

I build and fly multi-rotors at the moment and have 20+ LiPo batteries hanging around, the safe way to make them ready for disposal when they get a bit dicey is to put them in a bucket of salty water until they have fully discharged.
LiPo are not the right choice for an automotive battery, LiFePO4 lithium iron phosphate (aka LiFe and Lithium Iron) are the common choice although there are lithium cells that contain manganese that also do not show the violent decomposition issues of the older technologies.
BECs and UBECs are used in models to save on using a separate battery for the receiver and other electronics, they regulate the propulsion battery voltage down to the required voltage.
The two types of regulator I'm aware of are linear and switching, linear or shunt regulators which I believe is another term for them, turn the excess into heat and switching do exactly what the name implies, the electronics in them turn the output on and off very quickly to regulate the output.
I've had both kinds of regulator give up in the past on models when the input voltage went over their rated specification and the failure sometimes resulted in the unregulated voltage making it past the regulator.
I've also heard of issues with stacking regulators but that is mostly due to electrical noise issues if I remember correctly.
I've been running a Shorai LiFePO4 battery with no issues for a couple of years now, I did have a few early teething issues but that was a loose terminal and once that was sorted I've had no issues I remember.
Regarding cell balancing, some batteries have internal circuitry to ensure the cells stay balanced, some like my Shorai have a balance port for a supplementary charger but no balancing when charged by the running bike and some have no balancing at all.
An unbalanced battery can become the start of more serious battery issues so I use my balance charger regularly to keep mine in good condition.

[Dirty]

Originally Posted by BigOz

the safe way to make them ready for disposal when they get a bit dicey is to put them in a bucket of salty water until they have fully discharged.

What a waste. Get yourself a decent air rifle and a field