Interesting article on Li-Ions
- Thread starter CharlesSwallow
- Start date
maxi77
Well-Known Member
If you mistreat stored energy systems they bite back, not that new really. If they invented the lead today we would probably not be allowed to use them at all.
All batteries do need to be treated properly and the more eneergy they store in a given space the greater their potential for problems.
All batteries do need to be treated properly and the more eneergy they store in a given space the greater their potential for problems.
Evadne
Well-Known Member
When the FAA approved Li-ion batteries in laptops, i.e. allowed passengers to run them in aircraft, it was because their tests showed that when they burst into flames the plane wouldn't crash. Not because they couldn't burst into flames on your lap!
Actually I've found them quite stable, most problems caused by their willingness to discharge their entire contents at a phenomenal rate, if you give them the chance. The other big problem is their flammability in a fire, they provide their own oxygen once they get going.
Actually I've found them quite stable, most problems caused by their willingness to discharge their entire contents at a phenomenal rate, if you give them the chance. The other big problem is their flammability in a fire, they provide their own oxygen once they get going.
Billjratt
Well-Known Member
on the subject of new battery technology, my son bought a Li Fe battery and special charger for his motorbike recently. I was surprised at the light weight of it and the speed at which it recharged.
Assuming it's not too easily destroyed, I think we may see them afloat soon.
Assuming it's not too easily destroyed, I think we may see them afloat soon.
sarabande
Well-Known Member
I dealt with a major lorry fire on the M5 near Taunton about 12 years ago. Lorry load was lithium batteries from Yeovil helicopter factory being taken for disposal. They got wet from the rain, shorted out, and a big fire which dug a 3 ft hole in the tarmac.
Nasty things if not handled properly.
Nasty things if not handled properly.
Evadne
Well-Known Member
It's afloat already!
Li-Fe is a safer version of the Li-ion, and is used in the Torqeedo electric outboards.
Li-Fe is a safer version of the Li-ion, and is used in the Torqeedo electric outboards.
Avocet
Well-Known Member
There are several Li-ion chemistries available and not all of them suffer the "thermal runaway" problems that some of the higher capacity ones do.
greenalien
Well-Known Member
I was recharging a 3-year old camcorder battery a few weeks ago - after about 4 hours on charge, it exploded, like a thunderflash, scattering burning chemicals over a 3m radius. Luckily I was nearby at the time, and was able to quickly extinguish the fires. If I'd been further away, it could have burned my house down.
From now on, I will never leave anything with a lithium battery charging unattended...
From now on, I will never leave anything with a lithium battery charging unattended...
electrosys
Well-Known Member
Apart from the fire risk, the other bad news about Li-ion batteries is that they start to deteriorate from the moment they're manufactured, whether they're used or not - so there's really no point buying a second battery to keep unused 'as a spare', 'cause it's life expectancy will be exactly the same as the one which is actually being used. Life expectancy is about 3 yrs, I believe. NiMH's on the other hand, have a much longer life-span if they're being used infrequently.
That's why I prefer 'em ...
That's why I prefer 'em ...
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agurney
Well-Known Member
+1
.. was diving with SWMBO many years ago, and in trying to turn her torch on she inadvertently unscrewed the cap .. the NiCds were a sight to see as they fizzed and bubbled in the salt water.
Evadne
Well-Known Member
The "standard" figures relate to a battery life of 500 charge/discharge cycles. But you're right, they also deteriorate in time, whether used or not. For this reason the manufacturers quote a much lower capacity for a cell than it has when new. My Torqeedo is 3 years old now and showing no sign of deterioration, but once past 5 years I'd expect noticeably reduced capacity.
They're not all bad, though. About 1/3 the weight of equivalent lead acid, and you can use almost all of the capacity. Capacity is also less limited by current draw, unlike, say primary alkalines or NiCd. You can also charge them as rapidly as you can discharge them, as long as you don't charge them at too high a Voltage. Lots of smoke and flames then: there are lots of pretty videos of overcharging LiPos like this one. Don't try this at home.
mobeydick
Well-Known Member
I believe Sea Minx had Li-Ion batteries?
http://www.sealine.co.za/view_topic.php?id=66578&forum_id=21
MD
http://www.sealine.co.za/view_topic.php?id=66578&forum_id=21
MD
Evadne
Well-Known Member
Apparently so. Also most Hybrid cars, such as the Prius and Tesla, most laptops and all modern mobile phones. My own experience is that lithium fires are rare, there are usually at least three levels of safeties on both charge and discharge. Over Voltage is the best way to get them to go off like that.
Other things catching fire in the necessarily complex, high current capacity circuit are more likely and just as dangerous in the end. A bit like cars I think: petrol is unbelievably dangerous: volatile, flammable and explosive, yet is hardly ever the direct cause of a car catching fire.
Spyro
Well-Known Member
I had a nast experience when trying to solder a new CR2032 battery in my hanheld GPS, I couldn't believe the bang that thing made and the way it scattered bits all over the kitchen ceiling. I was very luck to have turned away at the time it went bang.
2Tizwoz
Well-Known Member
Do Water and Electric Cars Mix? A Look at the Safety Standards & Fire Service Response to Emergencies
An interesting video Click here
On the other hand I recently bought a Li-ion powered led torch.
No size but 1400 lumens and it gives out more light than a 150w security light.
An interesting video Click here
On the other hand I recently bought a Li-ion powered led torch.
No size but 1400 lumens and it gives out more light than a 150w security light.
Bosun Higgs
N/A
Interesting but in the sort of racing we do ( unlike Flaming 
) most competitors dont even empty the water tanks let alone remove the clutter that accumulates. So lightweight batteries? That would be taking the whole thing altogether too seriously,. And thats not British,.
) most competitors dont even empty the water tanks let alone remove the clutter that accumulates. So lightweight batteries? That would be taking the whole thing altogether too seriously,. And thats not British,.