Real World Thundersky Discharge Specs

[mattW]

I was a little worried about the current rating Of the thundersky cells I was planning to get, I have heard they over play their specs, but here are some encouraging real world numbers from our Aussie EV forums, I asked about pulling 5C:

as far as doing it healthy, i would say so, rod dilkes pulls 450A out of his 90AH (also 5C) pretty regularly in his conversion. his pack is now a year old and going strong.

Most i have pulled out of my pack is 250A (just over 6C) and it sagged to 2vpc.
The thundersky batteries seem to be pretty consistent as far as volage sag goes, 0.2v per 1C of current.
so at 250A my pack sagged from 3.2v to 2v, at 70A it sags to 2.7v.
rob masons old 200AH packs in his mustang fall to 2.6vpc at 600A (3C).
the new 200AH pack in his triton ute fall to 1.7vpc at 1600A (8C)

Those are the packs i have seen in person.

Id doubt your bike would pull 300A continuous, at 60kmh, mine pulls 40-50A@58v (i also have a yesa booster pack in series with the thunderskys in case you were wondering).

[Manntis]

Originally Posted by mattW

I was a little worried about the current rating Of the thundersky cells I was planning to get, I have heard they over play their specs, but here are some encouraging real world numbers from our Aussie EV forums, I asked about pulling 5C:

Rod is the TS guru. I know he sells TS cells, but he's one of those mates who sells them because he knows they're good - not pushing crap on people for a quick buck. I've had the pleasure of talking with him at length on the phone (haven't been fortunate enough to visit Australia in person yet) and he comes across as a real stand-up bloke.

[mattW]

So that means that the current levels are confirmed, the quality control is confirmed and all that is left to see if the cycle/shelf life lives up to the various 1000, 1500 and 2000 cycle claims I have seen.

By the way I just got a quote for my 72V 60Ah pack delivered for $1.80 per Ah or AU$2484 for the whole pack. The supplier just waits for a big enough group buy and then buys them in bulk, seems like every 3 months or so.

[david85]

This sounds promising.......

[Lexus]

I was reading somewhere about this guys bike .. I think it said he was using TS




I have blog some inform on it

http://blackops3103.multiply.com/jou...htning_Lithium




http://visforvoltage.org/forum/2725-...valley-meeting

Richard Hatfield of Lightning Motors presentation @ EAA Silicon Valley meeting
Submitted by reikiman on Sat, 01/19/2008 - 23:58. EV Events
Just listened to some exciting news and an interesting presentation. The EAA Silicon Valley chapter hosted Richard Hatfield of Lightning Motors. This is the motorcycle built w/ ThunderSKY LiFEPO4 batteries which has recently been shown around a bit.

See here: http://www.eaasv.org/meetings.html

Quote:
Guest speaker Richard Hatfield of Lightning Motors.

Those of you who were at the December meeting saw his Lithium powered Yamaha 1000 electric motorcycle. He will describe the design of this motorcycle which includes ThunderSky 90 Amp-hour Lithium Ferro Phosphate batteries and a Zivan charger. He'll also discuss Lightning Motors' plans to offer these bikes to 'beta testers' and their plans to offer AC drive conversion kits to those who prefer cars. Here is a related LA Times article that was reprinted in TreeHugger.

He has an interesting background for this -- He's been doing business development work in China for 20 yrs, has many contacts, has been doing car racing (SCCA and the like) for a long time, etc. I found this to be rather promising, he's not just a fly by night I'll go to China and get rich guy, he's been developing knowledge of the market for a long time. He has a couple businesses going, one of which is importing solar PV panels. Another is the EV company.

For the EV company he has a rather broad vision, much more than just building an uuber motorcycle. He described a range of motorcycles besides the one they've already built for demo purposes. Actually he had ?3? motorcycles with him (maybe only 2). Additionally he wants to build a commuter bike (250cc equivalent), and a couple larger ones equivalent to 1000cc and 1600cc. He also talked about building four-wheelers .. I think.

Additionally to building vehicles he wants to provide the basic building blocks as well. Motors, controllers, battery systems, kits to convert a car or motorcycle, etc. He even used the phrase "open source" saying that if someone wanted to buy parts from him and build their own vehicles for sale that would be great.

Hmm, seems I've heard a similar business model recently...

He claims he'll be able to start shipping products in Q4.

He is looking at several battery suppliers, not just ThunderSKY. Interestingly one of them is the same batteries that LifeBATT is selling. These are the cylindrical LiFePO4 in the 10AH size, and I asked him directly if these were the same batteries and he answered "Yes, LifeBATT is also an importer of these batteries". usatracy, weren't you claiming to know who LifeBATT's supplier is? This sounds curious given the recent exchanges with Don Harmon.

He had some sample batteries on hand including a full pack made from the 10AH cylindrical cells. BTW to be fair to Don, the pack construction was nowhere near the same as the pictures on the LifeBATT site. The construction was two boards with the cells between those boards, and the battery terminals poking through the boards, and a layer of plastic wrapped around the whole thing. There is a BMS unit. The sample pack was 3 rows of 8 cells each (24 cells) so that would be a 77 volt pack, 10 AH, and the whole pack weighed 15 lbs(??) okay, using the specs on LifeBatt.com I estimate this pack weighed 20 lbs. One guy thought it was heavy but once I pointed out how much kwh's were in there that put it into perspective. Uh, on another tab I have the SiliconeBatteriesUSA chart showing the weight for GreenSaver batteries, the 12v12ah battery weighs 9 lbs per battery, so hows that for perspective. The equivalent kwh's in SLA would be 60+ lbs and a lot bigger.

Another battery he had was a cell the same form factor as the A123 M1 cell, and which he said tested the same as the A123. That company is planning to go into production with larger cells than that.

Something I didn't ask about, and he didn't talk about, was the patent issue which Don Harmon is repeatedly raising. If all these companies are using the PhosTech technology w/o paying patents ...? Earlier this week I saw an exchange in one mailing list where someone discussed the impossibility of using ThunderSKY batteries in a vehicle to sell because ...??... they didn't spell it out but it would certainly raise an interesting liability to be reselling batteries that were under patent trouble.

[DVR]

Originally Posted by mattW

By the way I just got a quote for my 72V 60Ah pack delivered for $1.80 per Ah or AU$2484 for the whole pack. The supplier just waits for a big enough group buy and then buys them in bulk, seems like every 3 months or so.

Matt who quoted you that? Was it Trev at F&F?
Have you had any discussion about BMS?

[mattW]

Yeah it was trev, he said he has an electrical engineer working on a prototype and wondered whether EV power would sell me a BMS without buying the batteries from them. I am hoping I could just get the components from EV power and solder up the 24 units myself to save the labour time/cost but I haven't followed that up yet.
The batteries will still cost close to 5 grand once the BMS and charger are paid for, but I think it will be worth it. Performance estimates look good too.

[JeffPritchard]

Is a BMS for lithium battery charging only critical when charging the cells in series?

If one were to come up with a clever switching "mechanism" to charge the cells in parallel, and use them in series, would that negate the need for a multi-segment BMS?

thanks,
jp

[david85]

I sent an Email to this guy a little while ago: http://www.evalbum.com/1497

He had nothing bad to say about the TS batteries, but he also mentioned that he only had about 50 cycles on the pack at the time.

[alex]

Originally Posted by JeffPritchard

Is a BMS for lithium battery charging only critical when charging the cells in series?

If one were to come up with a clever switching "mechanism" to charge the cells in parallel, and use them in series, would that negate the need for a multi-segment BMS?

thanks,
jp

So what? a 3.2v charger system?

Don't you get the battery balancing problems whether you do it in series or parallel?