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Lithium ion batteries


capnthommo

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Just a little incidental here. Has anyone else, as I have, been thinking about L ion batteries as used in electric/hybrid cars? Dry cells, you can part charge, and you can discharge really deeply without damaging. At least that's what it seems to me. Any thoughts?

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There are previous threads here about these batteries. Also there are some boats already useing them. I was chatting to a boat builder at Crick show last year, he had them on his show boat. Very impressive. Problem I would say is the initial cost. If I was having a new boat built I would definitely consider them .         Ian. 

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2 minutes ago, Mike the Boilerman said:

L ion batteries are great. It's the charging that is the problem. How are you going to do it? They will catch fire if you charge them with a conventional alternator, AIUI. 

I think you need to fit a complete new charging system when you use these batteries? Ian.

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7 minutes ago, ianali said:

I think you need to fit a complete new charging system when you use these batteries? Ian.

 

Yes, this. 

ISTR the charging profile is so critical that some L ion batts are now supplied with all the charging electronics built into the battery. This I think, will turn out to be the way to go.

Or maybe I am thinking of NiFe batteries...

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Actually I think not. The Samsung phones catching fire used L ion batteries and the energy in a phone battery is miniscule compared to a boat battery. Probably in the order of 1ah. Imagine the size of the boat battery fire if you get the charging wrong on a 200ah battery. 

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2 hours ago, Mike the Boilerman said:

 

Yes, this. 

ISTR the charging profile is so critical that some L ion batts are now supplied with all the charging electronics built into the battery. This I think, will turn out to be the way to go.

Or maybe I am thinking of NiFe batteries...

Oh no, you're not NiFe batteries are about as solid as you can get, run flat, overcharge, whatever. My set is (I guess) approaching 50 years old.

Li-ions are hugely critical. Anyone remember the 'plane that caught fire at Heathrow a few years back?  'Twas due to some fault I the charging circuit - IIRC

 

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On 11/03/2017 at 10:57, OldGoat said:

Oh no, you're not NiFe batteries are about as solid as you can get, run flat, overcharge, whatever. My set is (I guess) approaching 50 years old.

Li-ions are hugely critical. Anyone remember the 'plane that caught fire at Heathrow a few years back?  'Twas due to some fault I the charging circuit - IIRC

 

 

Ok thanks!!

So why don't we all use NiFe batteries? I know there is a reason but I can't remember it...

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2 hours ago, Murflynn said:

when I took a cheapo cordless drill to pieces I was surprised to find that the 'battery' actually included a circuit board.  

are all lithium-ion batteries like that?

That will be a battery protection circuit. Generally two MOSFETs and a little IC that monitors voltage and/or current.

In normal operation both FETs are on. If the voltage or current go outside set limits, the IC shuts off one or other of the FETs (one for charge, one for discharge).

The features vary, but many will cut off for overvoltage (4.3V or so), undervoltage (2.8V or so), overcurrent for charging (a few C), and overcurrent for discharging (many C).

These circuits aren't sufficient to ensure a proper charge cycle on their own, and in normal use they should never trigger. They're just a failsafe for if something else goes wrong.

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32 minutes ago, OldGoat said:

Oh no, you're not NiFe batteries are about as solid as you can get, run flat, overcharge, whatever. My set is (I guess) approaching 50 years old.

Li-ions are hugely critical. Anyone remember the 'plane that caught fire at Heathrow a few years back?  'Twas due to some fault I the charging circuit - IIRC

I worked at a product/packaging test centre about 10 years ago and we tested Li-ion batteries for F1 cars. They wouldn't even allow them to be transported by air freight until all the testing had been completed. We were doing vibration, impact and other mechanical transit/distribution tests. We didn't see any issues in our tests but different designs behave differently.

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12 hours ago, capnthommo said:

Just a little incidental here. Has anyone else, as I have, been thinking about L ion batteries as used in electric/hybrid cars? Dry cells, you can part charge, and you can discharge really deeply without damaging. At least that's what it seems to me. Any thoughts?

They bring many benefits the main ones for us boaters is mainly the part charging without damage for those of us not on grid power.  However the initial cost of is way out of reach for most for even a modest sized bank.   Depending how you use the boat (mainly in winter) the cost is more likely better to be directed towards solar.   

1 minute ago, blackrose said:

I worked at a product/packaging test centre about 10 years ago and we tested Li-ion batteries for F1 cars. They wouldn't even allow them to be transported by air freight until all the testing had been completed. We were doing vibration, impact and other mechanical transit/distribution tests. We didn't see any issues in our tests but different designs behave differently.

I think any energy dense product will have the same restrictions.

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3 hours ago, Mike the Boilerman said:

Actually I think not. The Samsung phones catching fire used L ion batteries and the energy in a phone battery is miniscule compared to a boat battery. Probably in the order of 1ah. Imagine the size of the boat battery fire if you get the charging wrong on a 200ah battery. 

You can say that with any product that is energy dense and no product either now or in the future will be 100% safe.  Diesel and petrol have had their history of disasters!

Edited by Robbo
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29 minutes ago, Robbo said:

I think any energy dense product will have the same restrictions.

Ok, but I don't remember doing any similar tests specifically looking for any propensity to cause fires for any other products in transit.

The point is that Li-ion batteries have caused fires due to a combination of their chemistry and design. It's an inherent problem that isn't quite the same for other energy dense products.

Edited by blackrose
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1 hour ago, Mike the Boilerman said:

 

Ok thanks!!

So why don't we all use NiFe batteries? I know there is a reason but I can't remember it...

(Rising to the bait - but for the edification of the assembled masses)

  • Points for:-
  • Difficult to destroy
  • Large fluid reservoir
  • can be left in any state of charge
  • Points against:-
  • Expensive
  • Bulky
  • Relatively high internal resistance
  • general market resistance and lack of knowledge
  • most battery management systems don't optimise charging regime

I wouldn't bang on about them, but I notice that Bimble now sell them, so that gives some credibility... Very popular in TrumpLand where folks don't have a public electricity supply.

 

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2 hours ago, blackrose said:

Ok, but I don't remember doing any similar tests specifically looking for any propensity to cause fires for any other products in transit.

The point is that Li-ion batteries have caused fires due to a combination of their chemistry and design. It's an inherent problem that isn't quite the same for other energy dense products.

Are they dangerous even when discharged?

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I was offered a lot of these at £180 each. Very tempting at the time because it stated on the manufacturer's website that they could be charged with a regular lead acid charger. The claim that they're £2000 each when new is quite true. As I needed perhaps 20, I thought it was too much of a risk. They came from Sainsbury's delivery vans that were taken out of use quickly because the payload was too small thanks to all the batteries. Delivery vans tend to be kept below 3.5 tonnes to allow the drivers to suffer overwork and fatigue without any legal impediment.

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Blimey, they do look to be good value.  Local to me as well, but my leccy boat already has four 110AH leisure batteries bought just last year, so I can't really afford to swap them out.  I'd be looking at eight batteries, same weight as my present lead acids, but more than twice the capacity.

Edited by Murflynn
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5 hours ago, Murflynn said:

Blimey, they do look to be good value.  Local to me as well, but my leccy boat already has four 110AH leisure batteries bought just last year, so I can't really afford to swap them out.  I'd be looking at eight batteries, same weight as my present lead acids, but more than twice the capacity.

Also, you can discharge them to pretty much zero so effectively four times the capacity... Unless you've already accounted for that.

5 hours ago, Mike the Boilerman said:

Interesting to note how heavy they are at 20kg for a 138ah battery. I was under the impression L ion batts were feather light. 

I guess the fact that the usable capacity, as stated above, is so much greater makes them effectively much lighter.

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I  believe LiFePO 4 batteries are more suited to boats as they don't catch fire and are almost as light as lion. One problem is they hate 100% charging ie. overcharging kills them, and they hate going below 20% SOC. If your charge controller cuts the charge at 90 odd SOC and cuts them off from the load at 20 odd SOC then that is ok, but will your alternator like its load being cut off by the charger?.  They also do not neatly give a nominal 12 volts, like the NIFe mentioned above they have different cell voltages to LA, so you can get 11 volt or 13 volt batteries but not 12 volt. So sort out the charger and the voltage issues then they are just expensive.  Probably in 10 years or so LA will be obsolete and out of fashion but till then it is best value.

 

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