Readymade lithium iron phosphate packs

[qdlaty]

MalcolmB
My experience is over 3.5 years in EVs for EV company. I don't know if it's long but I also have education in chemistry (electrochemistry, to be precise) and my PhD research topic is polymer electrolytes for lithium ion batteries.
(and my second name is MODESTY )

But all I'm always telling is to hold the excitement for new factories and technology. I've been in plenty battery factories, I've tested some of new technology (including nano stuff) and I know that best approach is to take everything easy.
You can not reject technology because is not capable of giving 50C continuous. Think first what exactly you need. Do some math and then you will see.
My usual time to get to work is 25-40 minutes, mostly driving. If I use currents over 2C I will have to push car for last 3 km.
And I'm always keeping that in mind.

LFP technology is good but the market is flooded with various "mutations" of ATL or A123 that have nothing to do in comparison to original product. And it's very hard to get large amount from A123 or ATL. And the circle is closed - people want LFP so they will buy it from other companies and then will complain about the performance.
Second thing is the information that you can overcharge/discharge LFP so no BMS is needed. Sure, but you are shortening cells life. And if you do it everytime you will shorten the pack life even in half. So, instead every 3 years getting new batteries you will need it much sooner. And proper BMS will least for 8-10 years so it's cost will be returned with first battery pack.
Second thing is that LFP and new lithium titanate oxide (LTO) technology have lower voltage range so the energy density drops with it.

My point is to use technology available on market for longer time, already verified that is used by many BIG manufacturers. If LFP or LTO will be mass manufactured and widely available old (NCM) technology will be replaced.

That's all for Today. I really need some sleep.

[retepsnikrep]

Someone on the EV discussion list has been testing PHET cells and they haven't been looking that good.

Some original Thundersky cells performed well (100 & 200Ah) whilst others were fairly poor. They rather ruined their reputation in the US with a large batch of cells thay were simply junk. The latest cells in both Cobalt and Iron phosphate chemistries seem to be good.

Cedric reports a 10 fold improvement in internal resistance at 0C on the newer cells.

I concur with Paul, my 2003 30x200ah TS cells are still performing ok. Capacity may now be down and they like being at 25C+ but I don't push my vehicle far enough for it to become a problem.

Shame they (TS) F*()ed up with their forary into the US market as I am sure they would be snowed under with demand if the first batch had been OK.

I would def buy another set when mine finally fail, especially if the newer ones like Cedric reports have a much lower IR.

You pays your money you take your choice. Technology marches on and I am sure the newer cells/nano tech will impact in the near future. I look forward to a 10kw 50kg pack in the not too distant future.

[MalcolmB]

Not readymade packs, but I just came across this: http://zeva.com.au/tech/LiFePO4.php a comparison of the latest lithium iron phosphate cells by Zero Emission Vehicles Australia. Cells from PHET come out as best all-round value, and A123 come out as best performers.

The Tech Info section on the website also has some good basic information for anyone just getting into EVs.

[Tom Thomson]

I long ago gave up being embarassed when flaunting my ignorance so here I go again. What is "C" when referring to battery output?
tommyt

[MalcolmB]

Flaunt away Tom. If I attempt to explain it's bound to lure in someone who really knows what they're talking about

The amount of energy a battery can deliver depends on how fast you discharge it. The higher the current you draw from it, the less energy you can pull out. This applies to all battery chemistries, although some – such as lead acid – are more affected by high discharge rates than others.

The continuous current that a battery can deliver also depends on its size: the bigger the battery, the more current you can draw

"C" is a measure of the rate of discharge (or charge) that takes into account battery capacity (Ah). If you discharge a 20Ah battery at the 1C rate you draw 20 amps from it. If you discharge it at the 2C rate, you draw 40 amps from it, and so on.

[Alan Ward]

I am new to this amazing forum so do not yet know how to use it properly. But I heard that Ian Goodman is the new agent in UK for these Li-iron-phosphate batteries with battery management system. I do not know details but Ian Goodman in Essex is telephone 01268 779159. From Alan Ward

[qdos]

I am new to this amazing forum so do not yet know how to use it properly. But I heard that Ian Goodman is the new agent in UK for these Li-iron-phosphate batteries with battery management system. I do not know details but Ian Goodman in Essex is telephone 01268 779159. From Alan Ward

It's great to see you join us here Alan I'm really glad to see you posting. I've just been out visiting another car builder today and he'll be joining the forum any moment too! There's more and more people finding their way to us now that the site has been updated. I had a phone call from another chap who'd found his way to our do through surfing the net and he's going to join the Society too. I believe Chris and Nikki's hard work is starting to pay dividends So I'd like to say well done once again. Now I just hope that the discussion tomorrow at Goodwood goes the right way in showing the Committee that all this work that's been going on is paying off and that the worst thing that the Society can do is to abandon it !

So far it's been 100% positive votes in favour of it continuing

If anyone hasn't voted yet please do so here Your vote is important