Lithium battery charging

[booster]

This may be nothing more than a non associated thing, but maybe an indicator of more than that.


I have watched the Craigslist used car listings for many years, some out of curiosity about current pricing, and even more about see what things the higher mile vehicles list for already done repairs so I can get a feel for what one would expect to have to address with any of the vehicles if you have one or are thinking of buying one.


One thing that I have started seeing occasionally across the board for the plug in electric vehicles a claim, and I am assuming the seller sees it as a good thing, that the vehicle had not ever been on a "fast charger".


This may relate to what some of the lithium battery makers have recommended in lower max change rates for their batteries. Battleborn for one. It also could be BMS related with Battleborn, though, also so not certain.


I don't follow any electric vehicle forums or such so I don't know if this is a discussion point on them or not, but that would logically be where the Craigslist sellers would have gotten the idea, I think.


Anybody seen anything else like this elsewhere?

[Davydd]

My Valence lithium batteries charge from my Delta 330 second alternator at about 275 amps at high idle. I assume maybe higher cruising down the highway. I haven’t checked it yet but my previous van could take as much charge as the 4.0 wire could deliver. When plugged into shore power my Xantrex Freedom XC Pro 3000 inverter/charger limits it to 150 amps charge rate. It takes longer to recharge the batteries on shore power than from the engine.

My previous Elite Power Solution batteries are 6.5 years old (2015) and were fine under the same scenario. Technomadia people had the same batteries but from an older generation lasted 8.5 years but they abused their batteries storing their bus RV long periods of time in Arizona on asphalt over the years and finally destroyed them when a power outage drew the batteries down to zero for a long period of time. You can learn about their experience from their website Technomadia.com. They were one of the first with lithium batteries in an RV from 2011.

If you are talking about electric engine batteries, then that is another subject I doubt I will ever encounter in an RV.

[Bud]

Originally Posted by booster

This may be nothing more than a non associated thing, but maybe an indicator of more than that.


I have watched the Craigslist used car listings for many years, some out of curiosity about current pricing, and even more about see what things the higher mile vehicles list for already done repairs so I can get a feel for what one would expect to have to address with any of the vehicles if you have one or are thinking of buying one.


One thing that I have started seeing occasionally across the board for the plug in electric vehicles a claim, and I am assuming the seller sees it as a good thing, that the vehicle had not ever been on a "fast charger".


This may relate to what some of the lithium battery makers have recommended in lower max change rates for their batteries. Battleborn for one. It also could be BMS related with Battleborn, though, also so not certain.


I don't follow any electric vehicle forums or such so I don't know if this is a discussion point on them or not, but that would logically be where the Craigslist sellers would have gotten the idea, I think.


Anybody seen anything else like this elsewhere?

Sure booster, and I've posted it. Heck if I know where I read it, but not here or as you mentioned any "electric vehicle forums". Tesla does NOT allow full charging or discharging. They will since they know where all their vehicles are, at least in the US, during a 'catastraphy'? provide the opportunity for an increased SOC and discharge. Battery life matters with Tesla, but I don't know how long that has been happening. Maybe the founders of Tesla started it as Elon did not tell the truth (it happens) about Founding Tesla. That was just "an Elon" per one of the original founders. Interesting human world? But then you already know that booster, and lived in it and still do!

Bud

[booster]

Originally Posted by Bud

Sure booster, and I've posted it. Heck if I know where I read it, but not here or as you mentioned any "electric vehicle forums". Tesla does NOT allow full charging or discharging. They will since they know where all their vehicles are, at least in the US, during a 'catastraphy'? provide the opportunity for an increased SOC and discharge. Battery life matters with Tesla, but I don't know how long that has been happening. Maybe the founders of Tesla started it as Elon did not tell the truth (it happens) about Founding Tesla. That was just "an Elon" per one of the original founders. Interesting human world? But then you already know that booster, and lived in it and still do!

Bud

Are talking about the unused space they leave at the top and bottom of the state of charge as in doing a 10% to 95% usable range? If so, that isn't what I am talking about. I am referring to the charging rate as in how many amps per 100ah of capacity or some other rate spec. I think Tesla has some very high rate chargers around for rapid charging?

[avanti]

Originally Posted by booster

I think Tesla has some very high rate chargers around for rapid charging?

I think that is the point of the "never been rapid-charged" claim. There is a theory that rapid charging abuses the batteries.

[booster]

Originally Posted by avanti

I think that is the point of the "never been rapid-charged" claim. There is a theory that rapid charging abuses the batteries.

Is there anyplace or anybody in particular that is pushing that theory? Would be interesting to see their qualifications to judge before making any judgement on the idea.

[JohnnyFry]

One thing I would point out
is that electric vehicle batteries have a critical difference from batteries used in RV applications: they are liquid cooled to maintain them within design limits. There is no doubt that Li batteries generate heat during a high “C” charge rate and without cooling the heat could well have deleterious effects on the battery.

[avanti]

Originally Posted by booster

Is there anyplace or anybody in particular that is pushing that theory? Would be interesting to see their qualifications to judge before making any judgement on the idea.

Here's a discussion that at least appears to be balanced:

https://www.myev.com/research/intere...r-electric-car

I have no data.

[booster]

Originally Posted by JohnnyFry

One thing I would point out
is that electric vehicle batteries have a critical difference from batteries used in RV applications: they are liquid cooled to maintain them within design limits. There is no doubt that Li batteries generate heat during a high “C” charge rate and without cooling the heat could well have deleterious effects on the battery.

Yep, and that is one of the reasons it is a bit surprising to see that being said about vehicle batteries as they would have very good cooling and controls in most cases, I would think.

[avanti]

Do EVs run their cooling systems during charging or just while driving?

[booster]

Originally Posted by avanti

Do EVs run their cooling systems during charging or just while driving?

Good question. I would assume they would be automatic and come on if the internal temps needed it, but never seen it stated as such,

[Bud]

Originally Posted by booster

Are talking about the unused space they leave at the top and bottom of the state of charge as in doing a 10% to 95% usable range? If so, that isn't what I am talking about. I am referring to the charging rate as in how many amps per 100ah of capacity or some other rate spec. I think Tesla has some very high rate chargers around for rapid charging?

Sorry booster, sometimes I can't read. But now I need to come up with an example: my Samsung A71 5G I re-optioned to not fast charge about 3 days ago.

Bud

[Boxster1971]

Originally Posted by avanti

Do EVs run their cooling systems during charging or just while driving?

My Chevrolet Bolt EV will cool or heat batteries as needed, especially when on a charger.

[Boxster1971]

Just read this from an SAE newsletter. . .

"R&D work to solve an excessive noise problem created by an EV’s battery fast charger has led to advances in thermal management, heat dissipation – and reduced fire risks. D2H Advanced Technologies, a U.K.-based specialist engineering company, found the noise to occur during the vehicle’s fast-charge cycles. It was caused by high pumping-power requirements for the coolant, essential to dissipate battery heat."

https://www.sae.org/news/2021/04/an-...r-ev-batteries

[Winston]

Sorry Booster, we can't add any meaningful data. Our Elite cells say they can be charged at 3C - - for our pack, that would be 1500 amperes! The most we've seen is 250 amps, with 100 amps being more typical. Guess we're stuck slow-charging!

[booster]

Originally Posted by Winston

Sorry Booster, we can't add any meaningful data. Our Elite cells say they can be charged at 3C - - for our pack, that would be 1500 amperes! The most we've seen is 250 amps, with 100 amps being more typical. Guess we're stuck slow-charging!

I think that 3C is pretty typical of what we have historically seen for allowable rates, so not surprising.



I suppose this also brings up the question of defining fast and slow charging as that has quite a range.


With the vehicles you can plug into normal 20 amp 110v, I think, all the way up to the huge output rapid charging stations. A normal outlet would be limited to under 100 amps at 12v, so not very much in a 76K watt hour bank at maybe .015C.


Now we have those like Battleborn at something in the .5C range so pretty differnt.


It will be interesting to see how all this shakes out over time.


It may turn out the lithium gets cheap enough that it won't matter, or the trade offs off doing some things that shorten life are overridden by other needs. I think this is where they are on phone batteries now.

[booster]

Originally Posted by avanti

Here's a discussion that at least appears to be balanced:

https://www.myev.com/research/intere...r-electric-car

I have no data.

Interesting article that at least referenced some actual testing. To bad they were in the extreme heat that probably skewed data one way or the other, but who knows which.


As with all this kind of stuff, how the numbers are presented and calculated can make a bit difference in the how the whole thing gets interpreted.


27% reduction in life vs 24% doesn't sound too bad at 50K miles with only 3% difference.


If you look at the increase in degradation it is 3%/24% or a 12.5% increase in degradation that sounds worse for 50K miles.


If you look at the battery saving or reduction in degradation it is 3%/27% which is 11.5% decrease by not always fast charging.


If they cutoff life at 20% reduction in capacity, both packs were beyond acceptable capacity loss. Probably from the heat.

[israndy]

Fast charging can be mitigated by fast cooling, if you have ever been at a Tesla Supercharger for long you will hear one or another car get loud for a few minutes as the batteries are cooled. Typically when they hit about 135°, on my car that's about 45% of the way thru, I charge to 80% or less at Superchargers so it only comes on once during the cycle.

Some cars DON'T have that capability (I'm looking at you Nissan) and driving fast on the highway followed immediately by charging fast off the highway gives the car no chance to cool down, heat kills lithium batteries. It would certainly be better if you NEVER fast charged that Leaf, thus the comment on the used cars.

I have charged at 50kW using CHAdeMO and the Tesla NEVER turns on the cooling system. The downside of this is the car is heat soaked and stays that way after the charge. Not sure if that's gonna be bad in the long run, most owners either charge at home using AC or Supercharge which has the cooling cycle.

For an RV battery I would consider it like the Leaf. No dedicated cooling system. Perhaps put a thermometer on it to see the highest it gets to and change your config if it is getting too hot during charge. I am looking at getting one of those DC-DC Inverters to slow the progress of charging so my alternator doesn't get too hot as well.