On 27 Sep 2002 at 18:43, Victor Tikhonov wrote: > "David Roden (Akron OH USA)" wrote: > > > > > > LiIon TS-LP42V > > > Price $1300 in 1001 qty > > > Weight 35Kg > > > 100Ah * 42V = 4200Wh > > > energy density 120Wh/Kg or 154Wh/Litre > > > price per kWh: $309 > > > Cycle life: 500@80%DOD > > > > > > > To add a few data points to TS-LP42V: > > cycle life > 500 at 80 Ah: $0.618/kWh > cycle life > 1200 at 50 Ah: $0.26/kWh > cycle life > 2400 at 20 Ah: $0.13/kWh > > Not quite as good as NiCd, but the pack is twice as light.
I don't agree with the way you calculated this. To make it comparable to my previous nicad figures (which were not really calculated correctly; see below), you should calculate the 1200 cycles at 50 ah, not 80ah; and the 2400 cycles at 20 ah : 50ah * 42v = 2100wh * 1200 cycles = 2520 kWh over lifetime $1300 / 2520 = $0.52 / kWh 20ah * 42v = 840Wh * 2400 cycles = 2016 kWh over lifetime $1300 / 2016 = $0.64 / kWh There is a better way to calculate the cost per kWh for both -- compute it on the ah capacity for the given number of cycles. That is, take 80ah for the first 500 cycles, 50ah for the next 700, and 20ah for the final 1200. > cycle life 1000 at 100% dod is not valid point, you don't get > any performance at about last 5% of capacity (sag) ... Fair enough. So, we'll compute both at 80% DOD. OK? Let's do that for TS-LP42V: 80 ah * 42v * 500 cycles = 1680 kWh 50 ah * 42v * 700 cycles = 1470 kWh 20 ah * 42v * 1200 cycles = 1008 kWh Total delivered kWh over 2400 cycles = 4158 kWh * 0.8 (DOD) = 3326 kWh $1300 / = $0.39 / kWh Now we'll calculate capacity for STM5-100MR, using 120ah * 6v * 1000 cycles = 720 kWh 100ah * 6v * 1000 cycles = 600 kWh 80ah * 6v * 1000 cycles = 480 kWh Total delivered kWh over 3000 cycles = 1800 kWh * 0.8 (DOD) = 1440 kWh $347 / 1 = $0.24 kWh So the nicads still cost about one-third less per kWh delivered. But you are correct that the LiIon has a very large advantage in specific energy. If a turnkey charging system could be developed, and sold at an affordable price, these LiIon would be an excellent choice for advanced EVs. > > Question: > > How come MRE100 are 120 Ah, not 100Ah? The STM5-100MR blocks are conservatively rated. The 100 ah capacity is at the middle, not beginning, of the 3000 cycle life. The specifications state that they deliver 120ah for the first 1000 cycles. The comparison above takes this into account. > > If you only look at life time nothing beats NiCd. > > All to all, PbA everyone uses comes out almost the most expensive > per kWh for its life. Majority is not so rich, nor uneducated, so > my guess lowest initial out of pocket cost is the first priority... For AGMs, this is true. Here's a cost computation for Optimas: Optima D750S (from Uve's page) Price ~$130 in small quantity Mass = 20.5kg Capacity 125 min @ 25a => 52ah Capacity 47ah @ 75 amps (estimated) => 564 Wh Capacity 624 Wh at Specific energy = 27.5 Wh/kg Cycle life 220 @ 80% DOD 47ah * 12v * 220 cycles = 124 kWh total * 0.8 (DOD) = 99 kWh $130 / 99kWh = $1.31 / kWh (!) This is based on Optima's specifications. Even if we allow that they MIGHT achieve 500 cycles, which I emphasize is based on anecdotal reports and should NOT be considered a valid specification, we still get 47ah * 12v * 500 cycles * 0.8 DOD = 226 kWh $130 / 226kWh = $0.58 / kWh BUT, flooded golf car batteries beat all of the above hands down for economy of operation. Look at this: US Battery 2200 (from US Battery's web pages) Price ~$50 each in small quantity Mass 28.6kg Capacity 115min @ 75a => 144ah @ 75a => 864 wh Specific energy = 30 Wh/kg Cycle life 550 @ 80% DOD 144ah * 6v * 550 cycles = 1815 kWh * 0.8 (DOD) = 1452 kWh total $50 / 1452kWh = $0.03 / kWh So, here's the conclusion: Battery (Cost per kWh delivered over battery lifetime) USBMC Golf car lead ($0.03) Saft NiCd ($0.24) TS LiIon ($0.39) Evercell NiZn ($0.61) Optima YT lead ($0.58 - $1.31) Of course there are other issues to consider besides cost per kWh, but anybody who isn't wealthy has to look at this. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Want to unsubscribe, stop the EV list mail while you're on vacation, or switch to digest mode? See http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = David Roden - Akron, Ohio, USA 1991 Solectria Force 144vac 1991 Ford Escort Green/EV 128vdc 1970 GE Elec-trak E15 36vdc 1974 Avco New Idea rider 36vdc = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Thou shalt not send me any thing which says unto thee, "send this to all thou knowest." Neither shalt thou send me any spam, lest I smite thee. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
