The end of lead acid batteries

[Chalky]

What you've bought is a single lion cell and s simple power converter. The electronics can provide 5v at 2A max - I use these a lot to power small robots in the lab.

Scaling the battery up is expensive. Using more than 1 cell will require a battery management system that can monitor cell temperature, voltage and manage the SOC of each cell - get it wrong and you've got a small bomb on your hands.

To make a multi cell lithium battery safe and reliable needs high reliability electronics which isn't cheap...

[Loafer]

I think the voltage profile thing is an important point. LiFePo4 batteries keep a pretty steady voltage until nearly flat. By comparison a lead acid battery varies from perhaps 12.8v down to 10.5v. Taking my Trojans for example, they will happily run the inverter on a high demand (electric kettle) when well charged. They can be used down to 20% SoC without major life impact, however once getting below say 50% SoC they start to struggle to deliver high currents at a reasonable voltage.

 

The inverter is a constant power device (for a given load) and so as the voltage from the batteries reduces the current taken has to increase and you get a bit of a vicious circle where a reducing voltage causes an increasing current which causes a reducing voltage. At some point well before the miminim SoC the inverter gives up due to under-voltage.

 

By comparison a LiFePo4 with its flat voltage profile will be able to service big loads right down to nearly flat. It is worth bearing in mind that an AH rating is pretty meaningless in terms of useful energy, since the voltage is also a factor in determining power and energy. So a 100AH 12v battery will be able to deliver much less energy than a 100AH LiFePo4 battery since the former only briefly has a voltage of 12.8v, and towards the end is well below 12v, whilst the latter can deliver 12.8v over most of its discharge profile.

 

 

Some good stuff in there.

 

Does anyone know how LiPo batteries will react to solar input all day in the summer? It seems that their 'best voltage' is at 50% SOC, from what I've read, but with a good solar array they're going to be kept at a much higher SOC all day.

 

Does this mean that special solar chargers will have to be developed for LiPo banks then?

[Chalky]

It all depends on how the charge circuit / power converter that's built into the battery and how the battery management system is configured.

[peterboat]

I have a renault twizy with lithium batteries, It is 57 volts so the forum tells me although 60 volts is bandied around as well forums dont jou just love them? Anyway it takes 3.5 hours to fully charge it I regularly charge it at sub zero temperatures and we have forum members in Norway Sweden etc. If I am to leave it any length of time it is recommended to leave it at 60% charge. It also has a 12 volt lead acid battery which charges from the lithium battery both during charging and whilst moving [so they tell me]. If I run it right down it goes into limp home mode to protect the lithium battery. They reckon that the battery should have a 10 year life at which point it should be down to 70% of its range . Very few have had new batteries so maybe this is true? All I know is that I have great fun with Le Twiz and as yet have nor paid to charge it, so long may it be fun to use it

[Chalky]

The voltage on the Renault is below 60v so it's classified as low voltage. Above 60v you need voltage sensing, leakage sensing and lots of other kit which adds cost.

[peterboat]

The voltage on the Renault is below 60v so it's classified as low voltage. Above 60v you need voltage sensing, leakage sensing and lots of other kit which adds cost.

£3500 for a battery pack though one of the members is going to be building battery packs soon a lot cheaper its what he does for a living

[smileypete]

£3500 for a battery pack though one of the members is going to be building battery packs soon a lot cheaper its what he does for a living

 

For some buyers reduced BIK taxation for business and no London congestion charge helps.

 

For that reason the Mitsi Outlander PHEV is quite popular, can do a bit of towing too.

[Arthur Brown]

Li batteries need to be charged to full (or nearly) then they NEED the charging to stop. http://www.bbc.co.uk/news/business-20942484 is an example of how LiPoly batteries can go expensively wrong when ill-treated.

 

 

New chargers will need to correctly monitor the SOC of the battery and cut the charging as 99% SOC approaches. Float charge will be very detrimental to the battery. Then we need alternator chargers "programmed" to the right charge profile for LiPoly, and mains chargers too, Use the wrong charger and your life may disappear in a cloud of smoke.

 

Probably LiPoly batteries are the wrong battery for the house battery in a NB simply because the current charge profiles of automotive alternators, mains chargers and solar controllers are unsuitable.

 

ALSO although they are good for giving high currents they only contain their rated capacity of energy. If the battery is flat it has no more to give so people will need similar capacity of battery to that lead acid which is installed just it's (now) 10x the price of a lead acid battery to replace a LiPoly battery.

 

Also when a generator can put 100a into a 100AH battery for one hour to fill it to 100%soc the generator needs to be thermally managed to ensure that it doesn't overheat, because the usual engine alternator charging a lead acid battery delivers only a reducing current so the alternator's internal losses will be different and the internal temperatures will be different.

[Dave_P]

 

 

So how do you charge them then? Just connect them up to any old conventional 12v battery charger and the battery electronics sucks what it wants/needs?

 

(Dave P is being very coy about what he uses to charge his 5v Li Ion. Why would that be?)

 

Edit to add, having checked his link to what he purchased I see it comes with a mains charger that does all the managing. it can't just be connected to his engine alternator!

Sorry. Been away. Not being coy. Odd question though. I just plug it into the mains and it charges.

[nicknorman]

All this talk about needing to stop charging comes, I suggest, from people who didn't read the spec I posted. Yes of course a raw cell is like that but when the cells are packaged into a lead-acid-replacement battery, the electronics takes care of all of that. That is why the Mastervolt spec talks about float charge voltage as well as bulk charge voltage, both of which are similar to lead acid figures. And that is part of the reason why such batteries are very expensive.

Edited March 28, 2016 by nicknorman

[charlie - uk]

The Alternator, is just a device that outputs continous voltage at 12v or 24v. There is nothing wrong with using LiPo batteries for house batteries. Plenty of RV's use them now very effectively. They do however need a 12v or 24v LiPo charger, connected after the alternator to adequately charge them.

 

We will all be using them given time, its just evolution of technology simple as that....

[Arthur Brown]

Lithium batteries are great, without them mobile phones would be almost impossibly big and the mobile tablet/iPad simply wouldn't exist. But these applications have had to manage the charge and discharge requirements of the LiPo battery. Failure to adapt to the required charging profile will be the cause of incidents. http://www.telegraph.co.uk/news/1526424/Exploding-laptops-prompt-Dell-battery-recall.htmlis another example of an incident where failure cope with the needs of the battery lead to incidents.

 

Use LiPo batteries right and they will work, bodge an unprotected battery into service on a system designed for lead acid and expect flames.

[MtB]

The Alternator, is just a device that outputs continous voltage at 12v or 24v. There is nothing wrong with using LiPo batteries for house batteries. Plenty of RV's use them now very effectively. They do however need a 12v or 24v LiPo charger, connected after the alternator to adequately charge them.

 

We will all be using them given time, its just evolution of technology simple as that....

 

It's their resiliance to abuse that concerns me. Boaters manage to find all manner of methods of destroying their lead acid cells and all that happens is the lights go dim. With LiPo it seems they catch fire as a first response to misuse, so the management electronics have to be 100% bulletproof or serious consequences arise. 100% reliable electronics are a myth, as any fule kno.

[nicknorman]

It's their resiliance to abuse that concerns me. Boaters manage to find all manner of methods of destroying their lead acid cells and all that happens is the lights go dim. With LiPo it seems they catch fire as a first response to misuse, so the management electronics have to be 100% bulletproof or serious consequences arise. 100% reliable electronics are a myth, as any fule kno.

But the point is that a packaged lithium battery cannot be abused. It simply shuts off before over-discharging or over -charging. It doesn't mind being left flat.

 

As to the reliability of the control and protection electronics well yes, electronics can fail but a competent manufacturer will have reliable electronics plus redundancy / back-up systems. An incompetent manufacturer will go bust pretty quickly.

 

So yes, electronics can fail but when the probability approaches that of being beamed into space and experimented on by aliens, the only solution is to don the tin foil hat.

 

I seem to recall that the same doom-mongering occurred when trains were invented that could do an outrageous 20mph. Human beings simply could not cope with such a speed, allegedly.

[MtB]

But the point is that a packaged lithium battery cannot be abused. It simply shuts off before over-discharging or over -charging. It doesn't mind being left flat.

 

 

Yeah right. You're not using your imagination Nick.

 

Lets imagine Midland chandeliers start flogging these for £100 each. How long before we get a post here saying, for example, "I've levered to top off my Lithium battery pack and connected some wires directly to the cell terminals. A bloke in the pub said this is how to get the last 20% out of them so I don't have to recharge so often. Is this ok?" I'm sure you can think of other stupid and dangerous things that can be done with them too.

 

As someone once said, "When engineers claim they've made something idiot-proof, the universe responds by building a better idiot" (or something like that).

 

This is what I meant, rather than intelligent users who abide by the instructions.

Edited March 28, 2016 by Mike the Boilerman

[dmr]

A mate of mine who worked in the automotive industry said that if all cars used lithium batteries then there would not be enough Lithium in the world to go round. Maybe this was just wishful thinking as his company made bits for internal combustion engine.

I 'spose we could always go to other worlds and harvest the diLithium crystals but that would send the price thru the roof.

 

...............Dave

[peterboat]

All this talk about needing to stop charging comes, I suggest, from people who didn't read the spec I posted. Yes of course a raw cell is like that but when the cells are packaged into a lead-acid-replacement battery, the electronics takes care of all of that. That is why the Mastervolt spec talks about float charge voltage as well as bulk charge voltage, both of which are similar to lead acid figures. And that is part of the reason why such batteries are very expensive.

The twiz just stops charging when its full I can see the screen on the car when its charging it registers 100% does a cell balance for about 5 mins then shuts down. The charger is very input voltage sensitive so that can be an issue.

[smileypete]

Yeah right. You're not using your imagination Nick.

 

Lets imagine Midland chandeliers start flogging these for £100 each. How long before we get a post here saying, for example, "I've levered to top off my Lithium battery pack and connected some wires directly to the cell terminals. A bloke in the pub said this is how to get the last 20% out of them so I don't have to recharge so often. Is this ok?" I'm sure you can think of other stupid and dangerous things that can be done with them too.

 

Yer havin a larf!

 

When people knacker their cheapo lead acid batts, it's seems extremely difficult to get them to do anything other than simply get out their chequbook to pay for a new set.

 

The small minority that don't would probably be concientious enough not to open and abuse a packaged lithium batt in that way.

 

How many on here have opened up a laptop bat or drill bat? Very few if any I expect.

[CaneyJ]

Ok seriously people need to stop mentioning LiPos.

 

They are great for maximum power to weight ratio in small electronics but they will blow up when abused.

 

The Lithium battery that should be talked about here is LITHIUM IRON PHOSPHATE [LiFePO4]

 

It has a slightly lower power to weight but will not violently explode.

 

Here's an example video on a LiFe cell and what happens when you abuse one:

 

Plenty of videos showing a comparison of LiPo cells exploding as a comparison.

 

Bare in mind lead-acid batteries can also explode.

 

As for the Twizy argument, that again uses a third lithium technology called Lithium-Ion which can be charged at sub-zero temperatures.

 

LiFePO4 is the battery to use in our situation but it can't be charged at sub-zero.

[Loafer]

Ok seriously people need to stop mentioning LiPos.

 

They are great for maximum power to weight ratio in small electronics but they will blow up when abused.

 

The Lithium battery that should be talked about here is LITHIUM IRON PHOSPHATE [LiFePO4]

 

It has a slightly lower power to weight but will not violently explode.

 

Here's an example video on a LiFe cell and what happens when you abuse one:

 

Plenty of videos showing a comparison of LiPo cells exploding as a comparison.

 

Bare in mind lead-acid batteries can also explode.

 

As for the Twizy argument, that again uses a third lithium technology called Lithium-Ion which can be charged at sub-zero temperatures.

 

LiFePO4 is the battery to use in our situation but it can't be charged at sub-zero.

 

Sounds worthy of research, and as a LiPo user for my drone, I'm interested in all manifestations of the Lithium battery.

 

Aren't ALL lithium-based batteries a bit risky though, if not in a 'safe, controlled environment'?

 

Caney, don't go into a huge technical spread to enlighten me - I plan to look it all up for myself!

 

Good post though - I am alerted.

[smileypete]

Seems that when lithium batts go up, excessive temps plays a part (before they go pop thatis )

 

Earlier laptops used to get quite hot, I seem to recall the Boeing problems were partly due to heat, Tesla cars have gone to great lengths to provide cooling for their lithium pack.

[PaulG]

Lithium batteries are great, without them mobile phones would be almost impossibly big and the mobile tablet/iPad simply wouldn't exist. But these applications have had to manage the charge and discharge requirements of the LiPo battery. Failure to adapt to the required charging profile will be the cause of incidents. http://www.telegraph.co.uk/news/1526424/Exploding-laptops-prompt-Dell-battery-recall.htmlis another example of an incident where failure cope with the needs of the battery lead to incidents.

 

Use LiPo batteries right and they will work, bodge an unprotected battery into service on a system designed for lead acid and expect flames.

Indeed.

 

The LIPO battery in a mobile phone is normally a single-cell battery. Under most circumstances it is either charged within the phone or with a dedicated charger, and so it is pretty safe.

 

High capacity LIPO batteries are a very differerent animal, as they are usually multi-cell.

 

The charging regime is totally different from lead-acid batteries, NiMH and NiCad. Chargers for these types of battery should never be used to charge a LIPO.

 

LIPOs require a balance charger to detect the level of charge in the individual cells, and then to adjust the charge rate accordingly so that all the cells are charged to the same level.

 

Current models of high capacity LIPO batteries are not safe for use on a boat.

 

They should not be charged in an enclosed space, and ideally should be placed in a fireproof contaner while charging.

 

Even if it doesn't actually catch fire, fumes emitted by a failed battery can be poisonous.

 

Further information on LIPO charging and failure incidents here:

 

http://www.rcgroups.com/forums/showthread.php?t=209187

[peterboat]

Indeed.

 

The LIPO battery in a mobile phone is normally a single-cell battery. Under most circumstances it is either charged within the phone or with a dedicated charger, and so it is pretty safe.

 

High capacity LIPO batteries are a very differerent animal, as they are usually multi-cell.

 

The charging regime is totally different from lead-acid batteries, NiMH and NiCad. Chargers for these types of battery should never be used to charge a LIPO.

 

LIPOs require a balance charger to detect the level of charge in the individual cells, and then to adjust the charge rate accordingly so that all the cells are charged to the same level.

 

Current models of high capacity LIPO batteries are not safe for use on a boat.

 

They should not be charged in an enclosed space, and ideally should be placed in a fireproof contaner while charging.

 

Even if it doesn't actually catch fire, fumes emitted by a failed battery can be poisonous.

 

Further information on LIPO charging and failure incidents here:

 

http://www.rcgroups.com/forums/showthread.php?t=209187

But they are safe enough on my Twiz

I think a lot of this is scare tactics there are thousands of cars out there running on these batteries and they are fine. Also petrol cars catch fire all the time, and so do diesels everything we use and do carries a risk

[Top cat]

I think we are going to have to wait for the automotive industry to come up with a charging and battery management system that will be tailored to the batteries used. ( much like the current situation which is for lead acid).

My Yaris hybrid uses NiMh batteries rather than lithium , I presume Toyota went that route for a reason. I also notice the Toyota dont think battery cars are the way to go, they favour fuel cells. Could they be the successor to lead acid?

 

Top Cat

[RubyTuesday]

Lithium battery management systems do already exist, however due to the different applications that lithium batteries are used in, there is normally a high degree of customisation to the systems. There is a huge DIY EV world out there and they are all over lithium batteries.

 

This chap Dacian (http://electrodacus.com) has made a very interesting box that works as a BMS but at the voltatages more commonly found in domestic power rather than EV applications. He talks about Lithium and how lead acid is outdated.

 

Lithium batteries are far easier to charge, they only require one chance stage of constant current. The only difference is the precise under and over voltage control that is required to protect the cells. In fact it is so important that if the battery bank hits it's lower voltage it will disconnect it from the load.

Every cell that makes up the bank is monitored for its individual voltage and the balanced while charging to make sure they are all even. This is why there is an additional connection to each cell.

 

Going on the fact that the marine world needs electrical items that can't be messed with... Dacians box is not really that but for those with a fair grasp of electronics. However something may be on its way soon.... Wink wink... What Dacian also shows us is that this equipment does not need to be expencive at all. The biggest problem is always going to be boaters requirement to charge from alternators, which are unfriendly to batteries at the best of times.

 

Ps. Lithium batteries (LiFePO4 are the types used in these applications, not the super high energy dencity RC plane and car types) are perfectly safe. Check out YouTube for videos

http://youtu.be/p21iZVFHEZk

http://youtu.be/EMARDvMz62A

It's a shame that like hydrogen (because of the Hindenburg) or Switch mode power supplies in audio (because of early attempts) this technology now has a stigma and fear attached to it.

Edited April 16, 2016 by RubyTuesday