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View Full Version : Why Prius batteries last 350K miles but Vectrix batteries only 23K miles, SLA less



NonPolluter
16 September 2010, 0911
Does anybody have a guess as to why batteries on modern electric scooters and motorcycles last as little as ..

The Ego-2 scooter, used daily, lasted about 6 months before the range became less.
.. 2K-3K miles on Sealed Lead Acid China electric scooters
.. Vectrix on Visforvoltage forum: 22K miles per postings, average

Yet, the Prius hybrid has NiMH batteries that last a reported 350K miles.

Yet, fishing boats in the Pacific Northwest have wet-cell (aka flooded) batteries that last up to 20 years, in use.

Yet, one member of the Vancouver Electric Vehicle Association had wet cell batteries on his converted-to-electric Pontiac last 8.5 years.

Yet, most of the Sealed Lead Acid revived batteries on revived battery electric pickup truck are still in use 4 years after these batteries were salvaged from the discards pallet.

Yet, Jay Leno has several antique electric cars that still run on their original batteries.

Why is battery life much shorter for our modern electric moto's, in your opinion, or perhaps, your experience?

jpanichella
16 September 2010, 0917
Interesting thread.

In the case of the Prius, perhaps the fact that the batteries are assisted by an ICE is responsible for their longevity.

I have a friend who worked on a tugboat in Portland, and he said they used flooded NiCAD batteries, which have an absurdly long lifespan. And supposedly the "memory" rumor on them is due to overcharging. Here's a thread I started on flooded NiCADs in the parts section. There is a link there that has some pretty interesting stuff.

http://www.elmoto.net/showthread.php?275-Flooded-NiCad-Batteries-anybody&p=1638#post1638

DaveAK
16 September 2010, 1251
350K of pure electric power, or 350K vehicle miles?

Richard230
16 September 2010, 1350
My Hi Power LiFePO4 batteries seem to not be performing as well as they did when newer. They have 1300 miles on them at what I would guess as an average of about 20 miles per recharge. (That would be roughly about 1/2 to 2/3 of their fully discharged state. I have only run them down to "empty" once.) I still believe that quality control has been a problem for Hi Power.)

electrician
16 September 2010, 1618
Could it be that the batteries that are in a bike are smaller than the batteries that are in a car? Larger batteries can take more abuse (charging and discharging) than smaller ones with thinner and smaller plates. This is just a guess.

Richard230
16 September 2010, 1752
I am pretty sure that the batteries in any of the production cars are much different than the ones applicable (and available for the consumer to buy in small amounts a relatively low price) for motorcycle use. I'll bet they are much higher quality and of a different shape and size.

BaldBruce
16 September 2010, 1909
Battery chemistry, battery construction details, and battery use are the three main drivers of life IMO.

1) The varius chemistries have inherent pros and cons in terms of shelf life and cycle life. Some average kind of numbers to give you a ball park reference:
A) lead acid - 500 cycles down to 80% DOD for deep cycle types (Only a few deep cycles for starter type batterires.), unlimited shelf life if cared for properly.
B) NiCAD - 750 cycles down to 0% DOD, 10 year shelf life
C) NiMH - 1000 Cycles down to 0% DOD, 20 year shelf life
D) Li family - 1500 Cycles down to 20% DOD, 5 year shelf life (significant variation depending on cathode choices made...)
2) Construction details like in a lead acid battery, the plate thickness drives deep cycle life. Quality control in general of materials and construction in particular have a large effect.
3) Battery use probably has the largest effect. Take an automotive starter battery that is not designed to deep cycle down to voltage below 10 volts a few times and it will expire pretty quickly. Draw more than the rated C rate from a battery consistantly and it will give up the ghost quickly. (I think this is where the motorcycle dilema is. Many people are pulling way more amps out of their batteries than it was designed for. Leading to rapid loss of AH and early death:eek:.)

The NiMH in a prius live to be so old because of the way they are used (pampered). They are never disharged below 25% and never charged past 80%. They spend their entire life in the sweet spot of their useage.

markcycle
17 September 2010, 0436
Battery chemistry, battery construction details, and battery use are the three main drivers of life IMO.

1) The varius chemistries have inherent pros and cons in terms of shelf life and cycle life. Some average kind of numbers to give you a ball park reference:
A) lead acid - 500 cycles down to 80% DOD for deep cycle types (Only a few deep cycles for starter type batterires.), unlimited shelf life if cared for properly.
B) NiCAD - 750 cycles down to 0% DOD, 10 year shelf life
C) NiMH - 1000 Cycles down to 0% DOD, 20 year shelf life
D) Li family - 1500 Cycles down to 20% DOD, 5 year shelf life (significant variation depending on cathode choices made...)
2) Construction details like in a lead acid battery, the plate thickness drives deep cycle life. Quality control in general of materials and construction in particular have a large effect.
3) Battery use probably has the largest effect. Take an automotive starter battery that is not designed to deep cycle down to voltage below 10 volts a few times and it will expire pretty quickly. Draw more than the rated C rate from a battery consistantly and it will give up the ghost quickly. (I think this is where the motorcycle dilema is. Many people are pulling way more amps out of their batteries than it was designed for. Leading to rapid loss of AH and early death:eek:.)

The NiMH in a prius live to be so old because of the way they are used (pampered). They are never disharged below 25% and never charged past 80%. They spend their entire life in the sweet spot of their useage.

Couldn't have said it better myself thanks

Draw more than the rated C rate from a battery consistently and it will give up the ghost quickly. (I think this is where the motorcycle dilemma is. Many people are pulling way more amps out of their batteries than it was designed for. Leading to rapid loss of AH and early death.)

This is the main problem with battery life, you just have to buy more battery than you need if you want the batteries to last. You have to pull less than the rated C rate for a long life out of the batteries, depending on the batteries maybe half the rated C rate should be the average current pull

Mark

NonPolluter
20 September 2010, 1353
How can we charge OUR elmoto batteries manually, to stay in the 25% to 80% SOC zone?

Is there a Thundersky-approved or factory-ceritified battery charger?

Do you agree that the Thundersky LIFEPO4 batteries should be stored at a 40% SOC? (Also, what does "stored" mean - 2 days? 2 weeks? 2 years?

BaldBruce
21 September 2010, 1758
How can we charge OUR elmoto batteries manually, to stay in the 25% to 80% SOC zone?

Is there a Thundersky-approved or factory-ceritified battery charger?

Do you agree that the Thundersky LIFEPO4 batteries should be stored at a 40% SOC? (Also, what does "stored" mean - 2 days? 2 weeks? 2 years?

Pretty easy to not abuse your batteries! Don't completely discharge your batteries all the time. Either design your battery pack larger or use less of your capacity. If you are designing for a 10 mile commute, don't put in 10.0001 miles worth of energy storage! When charging don't overcharge any of the lithium or nickel chemestries. (Lead is different and likes to be at 100%)

TS sells their own brand of chargers. It is extremely interesing to note that even though the web page data sheets list the max charge voltage of all their LiFeYPO4 batteries as 4.2V, their own charger has a max voltage limit of 3.65 Volts! Jack R. tore one apart and found that this limit was factory hard set with absolutely no chance of adjustment......

Lithium batteries are stored at 40 to 60% SOC. This is defined as months of long term storage. Keep in mind you must periodically check that the self disharge has not brought the voltage level down to a dangerous level. You absolutely do not want to have the volatge go to zero. (dead battery) Remember that the self disharge rate is about 3 to 5% per month depending on exact chemistry and construction of Li types. I have 18650 cells I manufactured back in 2003 that are still in decent shape. I just take them out of storage once every 6 moths or so and charge them back up. (I only abuse them in the summer in my RC Hummer.:eek:)

electrician
22 September 2010, 0702
18,650 cells? Wow, that must be one large R/C Hummer, lol.

BaldBruce
22 September 2010, 0948
18,650 cells? Wow, that must be one large R/C Hummer, lol.

I wish:D. I could build three Teslas with that many cells. (18650s are what they use in the roadster.)

eronsilva
26 September 2010, 0021
I have 18650 cells I manufactured back in 2003 that are still in decent shape
Wow! That's a huge inventory! I am impressed, mostly by the "I manufactured" part! :)
(Richard, no disrespect intended)

larryrose11
26 September 2010, 1756
Prius (and all HEV's) pamper the batteries. They are maintained between 40-60% for their entire life's. and stay well within the C rating. As for a LI battery, Only charging them up to 80% SOC (as I have harped on in the past) and keeping them cool will help a lot. As mentioned earlier, stay within the C ratting, and don't let them get hot as well

kidsonroll
07 June 2011, 0205
First of all, it's very unusual for the battery to fail that early. I would definately suggest you call Toyota Customer care to report it as they should be interested in such an uncommon event.

Next, did you have the recall work done on the battery for the corrosion issue and did you enquire as to the possibility of that being the cause of the failure....if that's what caused it I would think this would be replace under warranty.

Finally, I also agree that going to a salvage battery (recent salvage so the battery won't have been severely depleted) would be a much less expensive route to go. Even check on Ebay as they often sell for around $500 in good condition and then you'd simply need to pay for the install.
:)

frodus
07 June 2011, 0841
18,650 cells? Wow, that must be one large R/C Hummer, lol.
18650 is the format of the cell, 18mm diameter x 65.0mm long, not the quantity.

podolefsky
07 June 2011, 1031
Battery chemistry, battery construction details, and battery use are the three main drivers of life IMO.

1) The varius chemistries have inherent pros and cons in terms of shelf life and cycle life. Some average kind of numbers to give you a ball park reference:
A) lead acid - 500 cycles down to 80% DOD for deep cycle types (Only a few deep cycles for starter type batterires.), unlimited shelf life if cared for properly.
B) NiCAD - 750 cycles down to 0% DOD, 10 year shelf life
C) NiMH - 1000 Cycles down to 0% DOD, 20 year shelf life
D) Li family - 1500 Cycles down to 20% DOD, 5 year shelf life (significant variation depending on cathode choices made...)
2) Construction details like in a lead acid battery, the plate thickness drives deep cycle life. Quality control in general of materials and construction in particular have a large effect.
3) Battery use probably has the largest effect. Take an automotive starter battery that is not designed to deep cycle down to voltage below 10 volts a few times and it will expire pretty quickly. Draw more than the rated C rate from a battery consistantly and it will give up the ghost quickly. (I think this is where the motorcycle dilema is. Many people are pulling way more amps out of their batteries than it was designed for. Leading to rapid loss of AH and early death:eek:.)

The NiMH in a prius live to be so old because of the way they are used (pampered). They are never disharged below 25% and never charged past 80%. They spend their entire life in the sweet spot of their useage.


Did you mean 20%, or 80% DOD for li? [edit] I think I'm mixing up DOD and SOC. I thought DOD was 0% when fully charged, SOC was 100% when fully charged?

I think it's useful to define what is meant by "lifetime". I think 80% of original capacity is a typical number, for example a 100 Ah cell might be 80 Ah after 1500 cycles.

These numbers vary a lot by discharge rate. Manufacturers usually spec them at 0.5C or 1C discharge. I have data from GBS that shows 80% capacity remaining after 2000 cycles to 100% DOD. But that's at 0.5C. Curves at 3C wouldn't really be that helpful since I don't discharge at 3C constantly. What I'd really like to know is what happens if you are at 0.5-1C 90% of the time, and 3-5C 10% of the time?

The SLA batteries in my R Martin are going after less than 200 cycles, and almost all of those are above 50% DOD. These are B&B EB50-12 - supposedly made for mobility, emergency power...basically large loads. But maybe they're still not really optimized for an EV, even one that's only 3 kW.

DRZ400
07 June 2011, 1141
I kinda been using my batteries in the 80 % range...only because I've been too lasy to install the Mini BMS. I put 3, 10amp diode in series with my 86v charger, the charger typically shuts off with the cells around 3.45 - 3.5 volts. Then I use the CA to be sure and use no more than 33AH when riding. I probably have 30cycles so far. Going to put on the BMS next week...that or go to the shore.

chef
07 June 2011, 1306
In addition to the narrow range of battery SOC that the Prius NiMH pack operates in, I've heard that the Prius expands its pack utilization as the battery deteriorates. Don't quote me on it, it's from someone who works at a high-end battery company.

Using a simple example with round #s, let's assume a 10Ah pack. It could be designed to provide 2Ah of energy operating in the 40-60% SOC range, the very middle of its output curve. In 5 years let's say the pack degrades to 8Ah total capacity if it were drained from full to empty. But to get 2Ah out of it, its operating range could be expanded to 37.5-62.5%. In 10 years if the pack degrades to 6Ah, the range could be expanded to 33.5-66.5%.

The tradeoff is longevity vs utilization. ElMotos have limited space and can't afford to carry around a bunch of dead weight, at least not with current battery technology. To minimize battery degradation in Elmotos, stop charging before the battery is full (say, only to 90% capacity) and discharge as little as possible between charges.


Battery chemistry, battery construction details, and battery use are the three main drivers of life IMO.
...

The NiMH in a prius live to be so old because of the way they are used (pampered). They are never disharged below 25% and never charged past 80%. They spend their entire life in the sweet spot of their useage.

Skeezmour
29 August 2011, 2326
kidsonroll,

Give me a call or email me at work (manzanitamicro.com). We have done this type of stuff before and I can give you a run down of options.

Cheers.

larryrose11
31 August 2011, 0902
Skeez:
What are ya thinking? What are the options you tried? What worked best? Just curious, as we all have talked about a genset in a sidecar.

Skeezmour
31 August 2011, 0922
Given that we have a charger that can move up to 18kw just off of 240v AC and alot more off of DC (near 100amps at 350v+). Not the cheapest option but if done right it can work on anything up to a small pickup with no problems.

larryrose11
01 September 2011, 1939
kidsonroll
ON the topic about the Genset: You could just use Variac, bridge, hooked to the 220 plug on a Genset. This is just like a Bad Boy charger. but what you save in cash outlay you loos in control
I know some variacs are motorized, so the voltage step is controllable, like from the cabin. If ya leave the batteries connected, you have better transient performance and such but, with a Bad Boy style setup, you could damage your pack.

ZoomSmith
01 September 2011, 2219
Gene and Larry, I think "kidsonroll" is a spammer. He's quoted a project from another forum (I think). Feel free to continue the conversation though.

teddillard
02 September 2011, 0349
He's quoted a project from another forum (I think).

...ya think? :cool:

http://www.diyelectriccar.com/forums/showthread.php/generator-direct-power-ev-distance-48794.html

(orig post: 08-24-2010, 02:57 PM m38mike Senior Member)

ZoomSmith
02 September 2011, 1217
Thanks for finding the original post Ted.

@kidsonroll: Adios Muchacho!