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Electric boats - the future???


MJG

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13 hours ago, peterboat said:

Then they were the ones I bought, along with James and the others, the packs were 5 years old and had many replacement batteries of which I purchased 30 of the newest. As to why they were failing who knows? In my boat they are lightly stressed in comparison to the bus they were in.

Of course it could be down to Valence saying charge to 100% rather than the 80% us second user's seem to do?

It could also be down to the fact that these buses were in service in 2015 IIRC which means the design -- including the BMS -- will be almost 10 years old. Not only have batteries improved since then, the knowledge about how to maximise their lifetime has also improved and BMS have got better with the widespread adoption of EVs. If the bus BMS didn't take good care of the batteries (charge/discharge control, balancing etc) then lifetime will be reduced.

 

There's little or no evidence that properly-managed LFP lifetime (total energy throughput in MWh) is reduced even by regular charging up to 100% and discharge down to 0% (the same is not true for chemistries like NMC used in most EV cars, phones, laptops etc.) -- this is why battery suppliers with inbuilt BMS like BYD (which logs charge/discharge, temperature, call balance, total energy usage...) now specify battery lifetime this way, not as a number of cycles.

 

For example the BMS LVL 15.4 lifetime capacity is specified as 48MWh, meaning 3100 cycles at 0-100% SoC, 3900 cycles at 0-80% or 10%-90% or 20%-100%, 5200 cycles at 0-60% or 20%-80% or 40%-100% and so on.

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It could easily be thermal managment problems.

 

Even very well established manufacturers can get things badly wrong like Nissan did with the Leaf.

 

https://cleantechnica.com/2018/09/29/nissans-long-strange-trip-with-leaf-batteries/

 

It is relatively early days in all this electromobility lark so mistakes will be made. It doesn't necessarily mean the batteries are the problem it is the design of the system managing the batteries.

 

Those original Nissan Leaf cars are fine in the UK but had lots of problems in the USA as it is usually hotter there.

 

 

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18 minutes ago, magnetman said:

It could easily be thermal managment problems.

 

Even very well established manufacturers can get things badly wrong like Nissan did with the Leaf.

 

https://cleantechnica.com/2018/09/29/nissans-long-strange-trip-with-leaf-batteries/

 

It is relatively early days in all this electromobility lark so mistakes will be made. It doesn't necessarily mean the batteries are the problem it is the design of the system managing the batteries.

 

Those original Nissan Leaf cars are fine in the UK but had lots of problems in the USA as it is usually hotter there.

 

 

Actually Nissan Leafs even in the UK have much worse battery life than most EVs because they didn't properly cool the batteries during high-current change/discharge and did a poor job with the BMS -- so thermal and design problems, as you said.

 

This is where a lot of the "your EV will need its battery replacing after a few years and it'll cost a fortune" FUD has come from -- for newer EVs with proper battery cooling and management the batteries are likely to last longer than the rest of the car in most cases.

Edited by IanD
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57 minutes ago, IanD said:

It could also be down to the fact that these buses were in service in 2015 IIRC which means the design -- including the BMS -- will be almost 10 years old. Not only have batteries improved since then, the knowledge about how to maximise their lifetime has also improved and BMS have got better with the widespread adoption of EVs. If the bus BMS didn't take good care of the batteries (charge/discharge control, balancing etc) then lifetime will be reduced.

 

There's little or no evidence that properly-managed LFP lifetime (total energy throughput in MWh) is reduced even by regular charging up to 100% and discharge down to 0% (the same is not true for chemistries like NMC used in most EV cars, phones, laptops etc.) -- this is why battery suppliers with inbuilt BMS like BYD (which logs charge/discharge, temperature, call balance, total energy usage...) now specify battery lifetime this way, not as a number of cycles.

 

For example the BMS LVL 15.4 lifetime capacity is specified as 48MWh, meaning 3100 cycles at 0-100% SoC, 3900 cycles at 0-80% or 10%-90% or 20%-100%, 5200 cycles at 0-60% or 20%-80% or 40%-100% and so on.

 

13 minutes ago, magnetman said:

It could easily be thermal managment problems.

 

Even very well established manufacturers can get things badly wrong like Nissan did with the Leaf.

 

https://cleantechnica.com/2018/09/29/nissans-long-strange-trip-with-leaf-batteries/

 

It is relatively early days in all this electromobility lark so mistakes will be made. It doesn't necessarily mean the batteries are the problem it is the design of the system managing the batteries.

 

Those original Nissan Leaf cars are fine in the UK but had lots of problems in the USA as it is usually hotter there.

 

 

The big stainless steel boxes the batteries were in were water tight and had a BMS and full thermal management. I along with James and Paul took enough apart. One had nearly all new batteries which are now mine others had mostly or all original batteries. Now the question is, is it the replacement batteries that are having the problems? And are they the same as the original setup by Valence? Who knows not me

19 minutes ago, magnetman said:

It could easily be thermal managment problems.

 

Even very well established manufacturers can get things badly wrong like Nissan did with the Leaf.

 

https://cleantechnica.com/2018/09/29/nissans-long-strange-trip-with-leaf-batteries/

 

It is relatively early days in all this electromobility lark so mistakes will be made. It doesn't necessarily mean the batteries are the problem it is the design of the system managing the batteries.

 

Those original Nissan Leaf cars are fine in the UK but had lots of problems in the USA as it is usually hotter there.

 

 

They are Nissan recently said that most leads are still on the road and still on their original batteries in the UK 

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Just now, peterboat said:

 

The big stainless steel boxes the batteries were in were water tight and had a BMS and full thermal management. I along with James and Paul took enough apart. One had nearly all new batteries which are now mine others had mostly or all original batteries. Now the question is, is it the replacement batteries that are having the problems? And are they the same as the original setup by Valence? Who knows not me

 

When you say "full thermal management" do you mean liquid cooling (like all modern EVs do to extend battery lifetime)? Or just temperature monitoring (like the Nissan Leaf did...) to avoid the expense of liquid cooling)?

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2 minutes ago, IanD said:

 

When you say "full thermal management" do you mean liquid cooling (like all modern EVs do to extend battery lifetime)? Or just temperature monitoring (like the Nissan Leaf did...) to avoid the expense of liquid cooling)?

Full air conditioned cooling and heating from looking at the system.

Coolant pipes in and air con pipes into the unit.

Edited by peterboat
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Googling suggests the Valence batteries were changed to Forsee LTO batteries in the Boris buses but I don't know how accurate that is.

 

(Something happened in between the Valence story and this one though...

 

 

Wikipedia has this

   
Transmission

Diesel in series
18 kWh[3] Microvast Lithium Titanate battery,Microvast LpTO,[4] Siemens ELFA2[5] electric traction motor[6]

 

Maybe it was the Microvast which replaced the Valence. LTO has a different cell voltage but could be made to work with different series and parallel arrangements.

 

This article says some are now 100% electric with Forsee batteries.

 

https://www.sustainable-bus.com/news/equipmake-new-routemaster-repower-metroline/

 

Looks like the Wrightbus thing but maybe something else.

 

Valence is now called "Lithion battery"

 

https://www.lithionbattery.com/products/modules/

 

 

Edited by magnetman
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6 minutes ago, magnetman said:

Googling suggests the Valence batteries were changed to Forsee LTO batteries in the Boris buses but I don't know how accurate that is.

 

(Something happened in between the Valence story and this one though...

 

https://www.sustainable-bus.com/news/equipmake-new-routemaster-repower-metroline/

 

Looks like the Wrightbus thing but maybe something else.

 

Valence is now called "Lithion battery"

 

https://www.lithionbattery.com/products/modules/

 

 

Interesting Andrew, because the full module was removed, you would have thought that if Valence were doing the job  they would have replaced the batteries only?

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Interestingly I have some unused LTO battery blocks which I think came from the same source originally so perhaps these are overstock items which were not required while replacing the problem batteries in the Wrightbus New Routemaster. It wasn't all of them which were running on diesel but quite a few.

 

Of course it could also be a driver training issue. Some people like putting their foot down which presumably kicks the diesel into action if the battery voltage drops too quickly.

 

3 minutes ago, peterboat said:

Interesting Andrew, because the full module was removed, you would have thought that if Valence were doing the job  they would have replaced the batteries only?

 

I think it was Wrightbus who had to do the fix not the battery manufacturer.

Interesting article in the Guardian

 

https://www.theguardian.com/uk-news/davehillblog/2015/jul/24/boriss-bus-a-political-journey-part-44-the-flat-battery-affair

 

"

Transport for London (TfL) had already set about dealing with the problem, which is being addressed at no extra charge by manufacturer Wrightbus of Ballymena. "

Edited by magnetman
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4 minutes ago, magnetman said:

Interestingly I have some unused LTO battery blocks which I think came from the same source originally so perhaps these are overstock items which were not required while replacing the problem batteries in the Wrightbus New Routemaster. It wasn't all of them which were running on diesel but quite a few.

 

Of course it could also be a driver training issue. Some people like putting their foot down which presumably kicks the diesel into action if the battery voltage drops too quickly.

 

 

I think it was Wrightbus who had to do the fix not the battery manufacturer.

Interesting article in the Guardian

 

https://www.theguardian.com/uk-news/davehillblog/2015/jul/24/boriss-bus-a-political-journey-part-44-the-flat-battery-affair

 

 

Its early on Andrew, so the supplier was Valence for the replacement batteries, I know because I have them. The warranties from Valence was five years so though Wrightbus  did the work no doubt Valence paid.

I installed these batteries a couple of years ago so dates seem right as well for a pack replacement to something else?

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