Lead Acid + UltraCap = Perfection?

[TylerDurden]

3*100=300W

300*3.75=1125Wmin

1125/60=18.75Wh

18.75/3=6.26Ah

10-6.26=3.74

:?

 

[Battboy]

Hang in there. Sandia Laboratories Report will answer your concerns. Lots of nice curves & fancy graphs to support our claims.

Best,

Don Harmon

 

[eP]

Hang in there. Sandia Laboratories Report will answer your concerns. Lots of nice curves & fancy graphs to support our claims.

Support - if you convert them the same way as your minutes to houres ? :wink:

Or we should convert yours claims ?

 

[safe]

10C discharge rates tend to increase the Peukert Effect... at least that would make sense. Lead Acid batteries suffer a real drop off of performance at just 1C. You are better off building any electric bike to use Lead Acid batteries at 1C or less which is part of the reason you need 86lbs of batteries to get any kind of decent performance with them.

What would be more interesting is to know the Peukert Effect for something like 5C because then you can compare it better with other chemistries.

Even the SubC NiMh cells can pull the 10C discharge rates but they map (I've seen the charts) to roughly equal to 2C for Lead Acid. Basically all chemistries have a "chart" and we would love to see it for the LifeBatts. When it comes to design you always want to run your batteries at a discharge rate that protects your capacity otherwise you are wasting the energy you have.

This gets back to the Ultracapacitor Buffering Scheme that could help a lot to make all battery chemistries better performing. If in those times when the throttle is not wide open the battery could be recharging it's internal Ultracapacitor then when you do get on the throttle the energy is there without a Peukert Effect.

Average Discharge might be 30% less than Maximum Discharge in real world riding.

(and so all that 30% represents unnecessary Peukert losses)

 

[7circle]

by safe on Wed Jan 23, 2008 10:36 pm
Also I place more stock in this analysis in Wayne Brown's comment because he lays out verifiable facts rather than subjective opinion & political spin.
Mr. Tahil, your article is in error. Your company does some very nice research & your paper well done but, it is in error, especially on page 12 where it states; “Existing LiIon/LiMP “Energy Batteries” for EVs require about 0.3kg of Lithium metal equivalent per kWh, in the form of Lithium Carbonate.” I show you very clearly above where Saft states that it only takes 76.92g or 0.07692kg of Lithium metal equivalent per kWh.

This "error" is suspiciously deliberate designed to shore up Mr. Tahil's conslusions.
Anyway, there are numerous comments by the author & he seems to sincerely believe his own spin.
So only 20 to 30 years supply of lithium then?
I should live so long, so I'm not particularly worried.

I had a look at Lithium Carbonate chemical structure. http://www.americanelements.com/fuel-cell.html
It is Li2CO3 which has molecular weight of 73.8 = 6.9x2+12+16x3
and Lithium Metal just 6.9 mol'r weight.

So the quote by Mr Tahil of
0.3kg/kWh of lithium carbonate (LiCO4)
compared to 0.0742kg/kWh of Lithium Metal

is not rediculous with 0.300kg * (6.9/73.8 ) = 0.028kg for Lithium Metal

What I want to know is how much energy does it take to refine Li2C03 or some of the other raw mined materials.

 

[Mathurin]

Yeah I've thought about simply adding a TV filter cap or some such in parallel with lead bricks to kill off peukert from the controller's pwm. Sure controllers already have one, but it's likely less then optimal. Never got around to it tho.

 

[mace1934]

Read these, wept.

In search of Lithium: The battle for the 3rd element:
http://www.dailymail.co.uk/home/moslive ... ement.html

The Trouble with Lithium 2:
http://www.meridian-int-res.com/Project ... oscope.pdf

Larry

 

[Kurt]

It is able to deliver the benefits of both technologies

What is the benefits of lead?

kurt.

 

[PaulM]

It is able to deliver the benefits of both technologies

What is the benefits of lead?

kurt.

Anti-wheelspin :lol:

 

[Kurt]

I have been forced to go back to lead while me headway pack is being repaired. I am running 3 X 18ah sla bricks.They would have only about 30 cycles on them and a forgot how bad lead was. I got just over 3ah from them when the lvc Kicked in on my controller. I have to tow them around in my bob trailer because of the weight and size. Having to charge them as soon as you get home is a pain as well.

The real world Ah rating of lead when put under a 2c load is disappointing to say the least.

Kurt.

 

[deronmoped]

All this argument about who controls and running out of readily accessible lithium leaves out a huge fact. Technology does not sit on it's hands. If anything it advances quicker then we can keep up with it. Lithium will be "old hat" before you know it. Either something better then batteries will come along or they will find better materials for batteries.

Deron.

 

[Kaño]

Safe, are you talking about a Capcell like the ones use in audio car?

Link:
http://cgi.ebay.com/NEW-POWER-ACOUSTIK-CAPCELL-600-Amp-DigitaL-Capacitor_W0QQitemZ220365037845QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item220365037845&_trksid=p3286.c0.m14&_trkparms=72%3A1234|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

 

[monster]

it says on http://www.withouthotair.com that there is plenty of lithium to go round. enough to replace all cars currently in existance with lithium battery powered electric cars twice over. lead acid is already a very high C rate cell but has very low energy density. putting ultra caps in to lead acid cells would add weight. lead acid is already 9C so the ultra caps aren't needed. might help with adsorbing regen. so ultra caps are only usefull on hybrid cars. if im gonna invest in an expensive new battery its not going to be lead.